,,the ,,economic ,,aspects ,,of ,,geology ,c4 ,k4 ,,leith ,,university ,,of ,,wisconsin ,illustration ,,new ,,york ,,henry ,,holt ,,and ,,company ,,copyright1 #aiba ,,by ,,henry ,,holt ,,and ,,company ,august1 #aibc ,,printed ,,in ,,the ,u4 ,s4 ,a4 ,,contents ,,page ,,chapter ,i4 ,,introduction #a ,,survey ,,of ,,field #a ,,economic ,,applications ,,of ,,the ,,several ,,branches ,,of ,,geology ,,and ,,of ,,other ,,sciences #c ,mineralogy and petrology #c ,stratigraphy and paleontology #d ,structural geology #e ,physiography #f ,rock alterations or metamorphism #aj ,application of other sciences #aj ,,treatment ,,of ,,the ,,subject ,,in ,,this ,,volume #aa ,,chapter ,,ii4 ,,the ,,common ,,elements1 ,,minerals1 ,,and ,,rocks ,,of ,,the ,,earth ,,and ,,their ,,origins #ac ,,relative ,,abundance ,,of ,,the ,,principal ,,elements ,,of ,,the ,,lithosphere #ac ,,relative ,,abundance ,,of ,,the ,,principal ,,minerals ,,of ,,the ,,lithosphere #ad ,,relative ,,abundance ,,of ,,the ,,principal ,,rocks ,,of ,,the ,,lithosphere #af ,,water 7,,hydrosphere7 #ah ,,soils ,,and ,,clays #ah ,,comparison ,,of ,,lists ,,of ,,most ,,abundant ,,rocks ,,and ,,minerals ,,with ,,commercial ,,rocks ,,and ,,minerals #ah ,,the ,,origin ,,of ,,common ,,rocks ,,and ,,minerals #ah ,igneous processes #ai ,igneous after-effects #ai ,weathering of igneous rocks and veins #bj ,sedimentary processes #bb ,weathering of sedimentary rocks #bc ,consolidation1 cementation1 and other sub-surface alterations of rocks #bd ,cementation #bd ,dynamic and contact metamorphism #be ,,the ,,metamorphic ,,cycle ,,as ,,an ,,aid ,,in ,,studying ,,mineral ,,deposits #bg ,,chapter ,,iii4 ,,some ,,salient ,,features ,,of ,,the ,,geology ,,and ,,classification ,,of ,,mineral ,,deposits #bi ,,various ,,methods ,,of ,,classification #bi ,,names #ca ,,mineral ,,deposits ,,as ,,magmatic ,,segregations ,,in ,,igneous ,,rocks #cd ,,mineral ,,deposits ,,within ,,and ,,adjacent ,,to ,,igneous ,,rocks1 ,,which ,,were ,,formed ,,immediately ,,after ,,the ,,cooling ,,and ,,crystallization ,,of ,,the ,,magmas ,,through ,,the ,,agency ,,of ,,hot ,,magmatic ,,solutions #cf ,evidence of igneous source #cg ,possible influence of meteoric waters in deposition of ores of this class #da ,zonal arrangement of minerals related to igneous rocks #db ,the relation of contact metamorphism to ore bodies of the foregoing class #de ,,secondary ,,concentration ,,in ,,place ,,of ,,the ,,foregoing ,,classes ,,of ,,mineral ,,deposits ,,through ,,the ,,agency ,,of ,,surface ,,solutions #df ,,residual ,,mineral ,,deposits ,,formed ,,by ,,the ,,weathering ,,of ,,igneous ,,rocks ,,in ,,place #ej ,,mineral ,,deposits ,,formed ,,directly ,,as ,,placers ,,and ,,sediments #ea ,mechanically deposited minerals #ea ,chemically and organically deposited minerals #eb ,,sedimentary ,,mineral ,,deposits ,,which ,,have ,,required ,,further ,,concentration ,,to ,,make ,,them ,,commercially ,,available #ed ,,anamorphism ,,of ,,mineral ,,deposits #eg ,,conclusion #eh ,,chapter ,,iv4 ,,mineral ,,resources--,,some ,,general ,,quantitative ,,considerations #fj ,,world ,,annual ,,production ,,of ,,minerals ,,in ,,short ,,tons #fj ,,world ,,annual ,,production ,,of ,,minerals ,,in ,,terms ,,of ,,value #fb ,,significance ,,of ,,geographic ,,distribution ,,of ,,mineral ,,production #fc ,,the ,,increasing ,,rate ,,of ,,production #fc ,,capital ,,value ,,of ,,world ,,mineral ,,reserves #fd ,,political ,,and ,,commercial ,,control ,,of ,,mineral ,,resources #fe ,,reserves ,,of ,,mineral ,,resources #fe ,,chapter ,v4 ,,water ,,as ,a ,,mineral ,,resource #fg ,,general ,,geologic ,,relations #fg ,,distribution ,,of ,,underground ,,water #fh ,,movement ,,of ,,underground ,,water #ga ,,wells ,,and ,,springs #gb ,,composition ,,of ,,underground ,,waters #gc ,,relation ,,of ,,geology ,,to ,,underground ,,water ,,supply #ge ,,surface ,,water ,,supplies #gf ,,underground ,,and ,,surface ,,waters ,,in ,,relation ,,to ,,excavation ,,and ,,construction #gh ,,chapter ,,vi4 ,,the ,,common ,,rocks ,,and ,,soils ,,as ,,mineral ,,resources #hj ,,economic ,,features ,,of ,,the ,,common ,,rocks #hj ,granite #hb ,basalt and related types #hb ,limestone1 marl1 chalk #hb ,marble #hc ,sand1 sandstone1 quartzite 7and quartz7 #hd ,sand and gravel #hd ,clay1 shale1 slate #he ,the feldspars #hf ,hydraulic cement 7including ,portland1 natural1 and ,puzzolan cements7 #hf ,,geologic ,,features ,,of ,,the ,,common ,,rocks #hh ,building stone #hh ,crushed stone #ij ,stone for metallurgical purposes #ia ,clay #ia ,limitations of geologic field in commercial investigation of common rocks #ib ,,soils ,,as ,a ,,mineral ,,resource #id ,origin of soils #id ,composition of soils and plant growth #if ,use of geology in soil study #ig ,,chapter ,,vii4 ,,the ,,fertilizer ,,group ,,of ,,minerals #ii ,,general ,,comments #ii ,,nitrates #aja ,economic features #aja ,geologic features #ajb ,,phosphates #ajd ,economic features #ajd ,geologic features #aje ,,pyrite #ajg ,economic features #ajg ,geologic features #ajh ,,sulphur #aji ,economic features #aji ,geologic features #aaj ,,potash #aaa ,economic features #aaa ,geologic features #aab ,,chapter ,,viii4 ,,the ,,energy ,,resources--,,coal1 ,,oil1 ,,gas 7,,and ,,asphalt7 #aae ,,coal #aae ,,economic ,,features #aae ,world production and trade #aae ,production in the ,united ,states #aag ,coke #aah ,classification of coals #aai ,,geologic ,,features #abc ,,petroleum #abg ,,economic ,,features #abg ,production and reserves #abh ,methods of estimating reserves #acd ,classes of oils #acf ,conservation of oil #acg ,,geologic ,,features #adj ,organic theory of origin #adj ,effect of differential pressures and folding on oil genesis and migration #adb ,inorganic theory of origin #adc ,oil exploration #add ,,oil ,,shales #aej ,,natural ,,gas #aea ,economic features #aea ,geologic features #aea ,,asphalt ,,and ,,bitumen #aea ,economic features #aea ,geologic features #aec ,,chapter ,,ix4 ,,minerals ,,used ,,in ,,the ,,production ,,of ,,iron ,,and ,,steel 7,,the ,,ferro-,,alloy ,,group7 #aed ,,general ,,features #aed ,,iron ,,ores #aeh ,,economic ,,features #aeh ,technical and commercial factors determining use of iron ore materials #aeh ,geographic distribution of iron ore production #afj ,world reserves and future production of iron ore #afb ,,geologic ,,features #aff ,sedimentary iron ores #aff ,iron ores associated with igneous rocks #aga ,iron ores due to weathering of igneous rocks #aga ,iron ores due to weathering of sulphide ores #agc ,,manganese ,,ores #agc ,economic features #agc ,geologic features #agf ,,chrome 7,,or ,,chromite7 ,,ores #agh ,economic features #agh ,geologic features #agi ,,nickel ,,ores #ahj ,economic features #ahj ,geologic features #aha ,,tungsten 7,,wolfram7 ,,ores #ahb ,economic features #ahb ,geologic features #ahd ,,molybdenum ,,ores #ahe ,economic features #ahe ,geologic features #ahf ,,vanadium ,,ores #ahg ,economic features #ahg ,geologic features #ahh ,,zirconium ,,ores #ahi ,economic features #ahi ,geologic features #ahi ,,titanium ,,ores #aij ,economic features #aij ,geologic features #aij ,,magnesite #aia ,economic features #aia ,geologic features #aib ,,fluorspar #aic ,economic features #aic ,geologic features #aid ,,silica #aie ,economic features #aie ,geologic features #aif ,,chapter ,x4 ,,copper1 ,,lead ,,and ,,zinc ,,minerals #aig ,,copper ,,ores #aig ,economic features #aig ,geologic features #aii ,copper deposits associated with igneous flows #bjj ,copper veins in igneous rocks #bja ,porphyry coppers #bjc ,copper in limestone near igneous contacts #bjd ,copper deposits in schists #bjd ,sedimentary copper deposits #bje ,general comments #bjf ,,lead ,,ores #bji ,economic features #bji ,geologic features #baa ,,zinc ,,ores #bac ,economic features #bac ,geologic features #baf ,,chapter ,,xi4 ,,gold1 ,,silver1 ,,and ,,platinum ,,minerals #bba ,,gold ,,ores #bba ,economic features #bba ,geologic features #bbf ,,silver ,,ores #bca ,economic features #bca ,geologic features #bcd ,,platinum ,,ores #bcg ,economic features #bcg ,geologic features #bci ,,chapter ,,xii4 ,,miscellaneous ,,metallic ,,minerals #bda ,,aluminum ,,ores #bda ,economic features #bda ,geologic features #bdc ,,antimony ,,ores #bdf ,economic features #bdf ,geologic features #bdh ,,arsenic ,,ores #bdi ,economic features #bdi ,geologic features #bea ,,bismuth ,,ores #beb ,economic features #beb ,geologic features #beb ,,cadmium ,,ores #bec ,economic features #bec ,geologic features #bed ,,cobalt ,,ores #bed ,economic features #bed ,geologic features #bee ,,mercury 7,,quicksilver7 ,,ores #bee ,economic features #bee ,geologic features #beh ,,tin ,,ores #bfj ,economic features #bfj ,geologic features #bfa ,,uranium ,,and ,,radium ,,ores #bfc ,economic features #bfc ,geologic features #bfd ,,chapter ,,xiii4 ,,miscellaneous ,,non-,,metallic ,,minerals #bfg ,,natural ,,abrasives #bfg ,economic features #bfg ,geologic features #bfi ,,asbestos #bgj ,economic features #bgj ,geologic features #bga ,,barite 7,,barytes7 #bgb ,economic features #bgb ,geologic features #bgc ,,borax #bgd ,economic features #bgd ,geologic features #bge ,,bromine #bgg ,economic features #bgg ,geologic features #bgh ,,fuller',s ,,earth #bgh ,economic features #bgh ,geologic features #bgi ,,graphite 7,,plumbago7 #bgi ,economic features #bgi ,geologic features #bhb ,,gypsum #bhc ,economic features #bhc ,geologic features #bhd ,,mica #bhe ,economic features #bhe ,geologic features #bhg ,,monazite 7,,thorium ,,and ,,cerium ,,ores7 #bhh ,economic features #bhh ,geologic features #bhi ,,precious ,,stones #bhi ,economic features #bhi ,geologic features #bia ,,salt #bid ,economic features #bid ,geologic features #bie ,,talc ,,and ,,soapstone #bii ,economic features #bii ,geologic features #bii ,,chapter ,,xiv4 ,,exploration ,,and ,,development #cja ,,the ,,general ,,relations ,,of ,,the ,,geologist ,,to ,,exploration ,,and ,,development #cja ,,partly ,,explored ,,versus ,,virgin ,,territories #cjc ,,the ,,use ,,of ,,all ,,available ,,information #cjd ,,cooperation ,,in ,,exploration #cje ,,economic ,,factors ,,in ,,exploration #cjf ,,geologic ,,factors ,,in ,,exploration #cjg ,,mineral ,,provinces ,,and ,,epochs #cjh ,,classification ,,of ,,mineral ,,lands #cji ,,outcrops ,,of ,,mineral ,,deposits #caa ,some illustrative cases #cab ,topography and climate as aids in searching for mineral outcrops #cad ,size and depth of ore bodies as determined from outcrops #cae ,the use of placers in tracing mineral outcrops #caf ,the use of magnetic surveys in tracing mineral ledges #cag ,,the ,,use ,,of ,,electrical ,,conductivity ,,and ,,other ,,qualities ,,of ,,rocks ,,in ,,exploration #cai ,,the ,,use ,,of ,,structure ,,and ,,metamorphism ,,in ,,exploration #cai ,,drilling ,,in ,,exploration #cbj ,,quantitative ,,aspects ,,of ,,geologic ,,exploration #cba ,,origin ,,of ,,mineral ,,deposits ,,as ,a ,,factor ,,in ,,exploration #cbb ,,lake ,,superior ,,iron ,,ore ,,exploration ,,as ,,an ,,illustration #cbc ,,development ,,and ,,exploitation ,,of ,,mineral ,,deposits #cbf ,,chapter ,,xv4 ,,valuation ,,and ,,taxation ,,of ,,mineral ,,resources #cbh ,,popular ,,conception ,,of ,,mineral ,,valuation #cbh ,,valuation ,,and ,,taxation ,,of ,,mines #cbi ,intrinsic and extrinsic factors in valuation #cbi ,values of mineral deposits not often established by market transfers #cca ,the ad valorem method of valuation #cca ,other methods of mineral valuation and taxation #cce ,,general ,,comments ,,on ,,taxation ,,of ,,mineral ,,resources #cch ,,chapter ,,xvi4 ,,laws ,,relating ,,to ,,mineral ,,resources #cdb ,i4 ,,laws ,,relating ,,to ,,ownership ,,and ,,control ,,of ,,mineral ,,resources #cdb ,on alienated lands #cdc ,on the public domain #cdd ,nationalization of mineral resources #cde ,effect of ownership laws on exploration #cdg ,use of geology in relation to ownership laws #cdi ,,ii4 ,,laws ,,relating ,,to ,,extraction ,,of ,,mineral ,,resources #cee ,,iii4 ,,laws ,,relating ,,to ,,distribution ,,and ,,transportation ,,of ,,mineral ,,resources #cee ,,iv4 ,,other ,,relations ,,of ,,geology ,,to ,,law #cef ,,chapter ,,xvii4 ,,conservation ,,of ,,mineral ,,resources #cei ,,the ,,problem #cei ,,differences ,,between ,,private ,,and ,,public ,,efforts ,,in ,,conservation #cfc ,,the ,,interest ,,rate ,,as ,a ,,guide ,,in ,,conservation #cfd ,,anti-,,conservational ,,effects ,,of ,,war #cfe ,,conservation ,,of ,,coal #cff ,,measures ,,introduced ,,or ,,proposed ,,to ,,conserve ,,coal #cfg 7,a7 ,mining and preparation of coal #cfh ,progress in above methods #cgj 7,b7 ,improvement of labor and living conditions at the mines #cgb 7,c7 ,introduction or modification of laws to regulate or to remove certain restrictions on the coal industry #cgc 7,d7 ,distribution and transportation of coal #cgf 7,e7 ,utilization of coal #cgg 7,f7 ,substitutes for coal as a source of power #cgh ,,division ,,of ,,responsibility ,,between ,,government ,,and ,,private ,,interests ,,in ,,the ,,conservation ,,of ,,coal #cgi ,,conservation ,,of ,,minerals ,,other ,,than ,,coal #chb ,,chapter ,,xviii4 ,,international ,,aspects ,,of ,,mineral ,,resources #chc ,,world ,,movement ,,of ,,minerals #chc ,movement of minerals under pre-war conditions of international trade #che ,changes during the war #che ,post-war condition of the mineral trade #chg ,,tendencies ,,toward ,,international ,,cooperation ,,and ,,possibility ,,of ,,international ,,control ,,of ,,minerals #chi ,methods of international cooperation #cia ,,conservation ,,in ,,its ,,international ,,relations #cic ,,exploration ,,in ,,its ,,international ,,relations #cie ,,valuation ,,in ,,its ,,international ,,relations #cif ,,relative ,,position ,,of ,,the ,,united ,,states ,,in ,,regard ,,to ,,supplies ,,of ,,minerals #cif ,,the ,,coal ,,and ,,iron ,,situation ,,of ,,western ,,europe ,,under ,,the ,,terms ,,of ,,the ,,peace #djj ,,conclusion #djc ,,literature #djc ,,chapter ,,xix4 ,,geology ,,and ,,war #dje ,,geology ,,behind ,,the ,,front #dje ,,geology ,,at ,,the ,,front #djh ,,effect ,,of ,,the ,,war ,,on ,,the ,,science ,,of ,,economic ,,geology #dab ,,chapter ,,xx4 ,,geology ,,and ,,engineering ,,construction #dac ,,foundations #dac ,,surface ,,waters #dad ,,tunnels #dad ,,slides #dae ,,subsidence #dag ,,railway ,,building #dag ,,road ,,building #dah ,,geology ,,in ,,engineering ,,courses #dai ,,chapter ,,xxi4 ,,the ,,training1 ,,opportunities ,,and ,,ethics ,,of ,,the ,,economic ,,geologist #dbj ,,pure ,,versus ,,applied ,,science #dbj ,,course ,,of ,,study ,,suggested #dbb ,field work #dbe ,specialization in studies #dbf ,a degree of ,economic ,geology #dbg ,,the ,,opportunities ,,of ,,the ,,economic ,,geologist #dbh ,,ethics ,,of ,,the ,,economic ,,geologist #dcj ,,illustrations ,,figure ,,page #a4 ,graphic representation of volume change in weathering of a ,georgia granite #ba #b4 ,commercial 7financial7 control of the mineral resources of the world #fd #c4 ,political 7territorial7 control of the mineral resources of the world #fd #d4 ,the fertilizer situation in the ,united ,states #ajj #e4 ,diagram showing the chemical composition and heat efficiency of the several ranks of coal #abb #f4 ,origin and development of coal #abc #g4 ,chart showing the present tendency of the ,united ,states in respect to its unmined reserve of petroleum #acd #h4 ,the annual output of the principal oil fields of the ,united ,states for the last twenty years #ace #i4 ,curve showing the usual decline in oil field production after the period of maximum output is reached #acf #aj4 ,chart showing the relative values of the principal petroleum products manufactured in the ,united ,states from #ahii to #aiad #ach #aa4 ,alteration of ,lake ,superior iron formation to iron ore by the leaching of silica #afh #ab4 ,representing in terms of weight the mineralogical changes in the katamorphism of serpentine rocks to iron ore1 eastern ,cuba #agb #ac4 ,diagram showing gradation from syenite to bauxite in terms of volume #bde ,,chapter ,i ,,introduction ,,survey ,,of ,,field ,in adapting ourselves to physical environment it has been necessary to learn something about the earth4 ,mainly within the last century has this knowledge been organized into the science of geology1 and only within the last few decades have the complex and increasing demands of modern civilization required the applications of geology to practical uses1 resulting in the development of the science generally known as economic geology4 ,this science is not sharply marked off from the science of geology proper2 almost any phase of geology may at some time or some place take on its economic aspect4 ,the usefulness of economic geology was first recognized in relation to mineral resources1--and particularly in relation to metallic resources1 their discovery and development1--but the science has been found to have much wider practical application4 ,the practice of the economic geologist in recent years has taken on many new phases4 ,the geologist is called upon to study the geologic features of mineral deposits1 their occurrence1 structure1 and origin4 ,the basic information thus acquired is useful in estimating reserves and life of mineral deposits4 ,this leads naturally to considerations of valuation4 ,because valuation plays such a large part in any tax program1 the geologist is being used by tax boards of the federal and state governments4 ,both in the formulation of laws relating to mineral resources1 and in the litigation growing out of the infraction of these laws1 the economic geologist plays a part4 ,one cannot go very far with the study of mineral resources without consideration of the question of conservation4 ,geologists are called on not only for broad surveys of the mineral reserves1 but for the formulation of general principles of conservation and their application to specific mines and minerals4 ,the geologist's familiarity with the distribution and nature of mineral resources has given him a part in coping with broad questions of international use of natural resources4 ,war conditions made it necessary to use new sources of supply1 new channels of distribution1 and new methods of utilization4 ,the economic geologist came into touch with questions of international trade1 tariffs1 and shipping4 ,but economic geology is not solely confined to mineral resources4 ,in relation to engineering enterprises of the greatest variety--canals1 aqueducts1 tunnels1 dams1 building excavations1 foundations1 etc4--geology now figures largely1 both in war and in peace4 ,the nature1 amount1 and distribution of underground water supplies are so involved with geologic considerations that a considerable number of geologists give up their time wholly to this phase of the subject4 ,it might seem from this list of activities that geology is spreading too far into the fields of engineering and commerce1 but there are equally rapid extensions of other fields of knowledge toward geology4 ,the organization of these intermediate fields is required both in the interest of science and in the interest of better adaptation of the race to its environment4 ,the geologist is required to do his part in these new fields1 but not to abandon his traditional field4 ,it is proposed in this volume to discuss the economic aspects of geology without exhaustive discussion of the principles of geology which are involved4 ,practically the whole range of geologic science has some sort of economic application1 and it would be futile to attempt in one volume even a survey of the science of geology as a whole4 ,our purpose is rather to indicate and illustrate1 in some perspective1 the general nature of the application of geology to practical affairs4 ,in professional preparation for the practice of economic geology there is no easy short-cut4 ,students sometimes think that a smattering of geological principles1 combined with a little business and economic information1 may be sufficient4 ,analysis of professional successes should make it clear that economic geologists are most effective and in most demand1 not primarily because of business aptitude1 though this helps1 but because of their proficiency in the science of geology itself4 ,in short1 to enter successfully the field of economic geology one should first become a scientist1 if only in a limited field4 ,the traditional conception of the geologist as a musty and stooped individual1 with a bag1 hammer1 and magnifying glass1 collecting specimens to deposit in a dusty museum1 will doubtless survive as a caricature1 but will hardly serve to identify the economic geologist in his present-day work4 ,in writing this book1 it is hoped in some measure to convey an impression of the breadth and variety in this field4 ,few other sciences offer so wide a range of opportunity1 from the purely scientific to the practical and commercial1 coupled with travel1 exploration1 and even adventure4 ,,economic ,,applications ,,of ,,the ,,several ,,branches ,,of ,,geology ,,and ,,of ,,other ,,sciences ,there is no phase of geology which at some time or place does not have its economic application4 ,many references to these applications are made in other chapters4 ,it is proposed here to indicate briefly some of the phases of geologic science which are most necessary to the practice of economic geology4 ,the student in his preparation cannot afford to eliminate any of them on the ground that they are merely scientific or academic or theoretical4 ,,mineralogy ,,and ,,petrology ,mineralogy1 the study of minerals1 and petrology1 the study of rocks 7aggregations of minerals71 are of course elementary requisites in preparation4 ,there must be familiarity with the principal minerals and rocks1 and especially with the methods and processes of their identification1 with their nature1 and with their origin4 ,this involves a study of their crystallography1 chemical composition1 physical qualities1 and optical properties as studied with the microscope4 ,in recent years the microscopical study of polished and etched surfaces of ores has proved a valuable tool4 ,,stratigraphy ,,and ,,paleontology ,stratigraphy and paleontology are concerned with the sedimentary and life history of the earth4 ,the determination of the ages of the earth's strata and of the conditions of their deposition is required in the practice of economic geology4 ,for example1 a detailed knowledge of the succession of rocks and their ages1 as determined by fossils and other stratigraphic evidence1 is vital to the interpretation of conditions in an oil or coal field1 and to the successful exploration and development of its deposits4 ,the success of certain paleontologists and stratigraphic specialists in oil exploration is an evidence of this situation4 ,certain iron ores1 phosphates1 salts1 potash1 and other minerals1 as well as many of the common rocks used for economic purposes1 are found in sedimentary deposits1 and require for their successful exploration and development the application of stratigraphic and paleontologic knowledge4 ,closely related to stratigraphy 7as well as to physiography1 see pp4 #f-aj7 is the study of sedimentation1--i4 e41 the study of the physical1 chemical1 climatic1 and topographic conditions of the deposition of sediments4 ,this is coming to play an increasingly large part in geologic work1 and is essential to the interpretation of many mineral deposits1 particularly those in which stratigraphic and physiographic questions are involved4 ,still another aspect of the problem of stratigraphy and sedimentation is covered by the study of paleogeography1 or the areal distribution of the faunas and sediments of geologic periods caused by the alternating submergence and emergence of land areas4 ,in the search for the treasures of sedimentary deposits1 a knowledge of ancient geographies and of ancient faunas makes it possible to eliminate certain regions from consideration4 ,from a study of the faunas of eastern ,kansas and ,missouri1 and of those along the eastern part of the ,rocky ,mountains1 it has been inferred that a ridge must have extended across eastern ,kansas during early ,pennsylvanian time1--a conclusion which is of considerable economic importance in relation to oil exploration4 ,,structural ,,geology ,structural geology is the study of the physical forms and relations of rocks which result mainly from deformation by earth forces4 ,if rocks remained in their original forms the structural problem would be a comparatively easy one1 but usually they do not4 ,often they are faulted and folded and mashed to such an extent that it is difficult to go behind the superposed structural features to the original conditions in order to work out the geologic history4 ,not only is structural study necessary for the interpretation of geologic history1 but it is often more directly applicable to economic problems1--as when1 for instance1 ore deposits have been formed in the cracks and joints of rocks1 and the ore deposits themselves have been faulted and folded4 ,water resources are often located in the cracks and other openings of rocks1 and are limited in their distribution and flow because of the complex attitude of deformed rocks4 ,oil and gas deposits often bear a well-defined relation to structural features1 the working out of which is almost essential to their discovery4 ,it is not desirable to stop with the merely descriptive aspects of structural geology1 as is so often done2 for much light can be thrown on the economic applications of this subject by consideration of the underlying principles of mechanics1--involving the relations of earth stresses to rock structures4 ,the mere field mapping and description of faults and joints is useful1 but in some cases it is necessary to go a step further and to ascertain the mechanical conditions of their origin in order to interpret them clearly4 ,if1 for illustration1 there are successive groups of mineralized veins in a mining camp1 the later ones cutting the earlier ones1 these might be treated as separate structural units4 ,but if it can be shown that the several sets of veins have formed from a single movement1 that there is no sharp genetic separation between the different sets and that they are a part of a single system1 this interpretation throws new light on exploration and development1 and even on questions of ownership and extralateral rights 7,chapter ,,xvi74 ,,physiography ,physiography is a phase of geology which investigates the surface features of the earth4 ,it has to do not only with the description and classification of surface forms1 present and past 7physical geography or geomorphology71 but with the processes and history of their development4 ,the subject is closely related to geography1 climatology1 sedimentation1 and hydrology4 ,as one of the latest phases of geology to be organized and taught1 its economic applications have been comparatively recent and are not yet widely recognized4 ,because of this fact its economic applications may be summarized at somewhat greater length than those of the other branches of geology above mentioned1 which are to be more or less taken for granted4 ,the central feature of physiography is the so-called erosion cycle or topographic cycle4 ,erosion1 acting through the agencies of wind1 water1 and ice1 is constantly at work on the earth's surface2 the eroded materials are in large part carried off by streams1 ultimately to be deposited in the ocean near the continental margins4 ,the final result is the reduction of the land surface to an approximate plain1 called a peneplain1 somewhere near sea level4 ,geological history shows that such peneplains are often elevated again with reference to sea level1 by earth forces or by subsidence of the sea1 when erosion again begins its work1--first cutting narrow1 steep gulches and valleys1 and leaving broad intervening uplands1 in which condition the erosion surface is described as that of topographic youth2 then forming wider and more extensive valleys1 leaving only points and ridges of the original peneplains1 in which stage the surface is said to represent topographic maturity2 then rounding off and reducing the elevations1 leaving few or none of the original points on the peneplain1 widening the valleys still further and tending to reduce the whole country to a nearly flat surface1 resulting in the condition of topographic old age4 ,the final stage is again the peneplain4 ,this cycle of events is called the erosion cycle or topographic cycle4 ,uplift may begin again before the surface is reduced to base level2 in fact1 there is a constant oscillation and contest between erosion and relative uplift of the land surface4 ,the action of the erosion cycle on rocks of differing resistance to erosion and of diverse structure gives rise to the great variety of surface forms4 ,the physiographer sees these forms1 not as heterogeneous units1 but as parts of a definite system and as stages in an orderly series of events4 ,he is able to see into the topographic conditions beyond the range of immediate and direct observation4 ,he is able to determine what these forms were in the past and to predict their condition in the future4 ,he is able to read from the topography the underground structure which has determined that topography4 ,a given structure may in different stages of topographic development give quite diverse topographic forms4 ,in such a case it is important to realize that the diversity is only superficial4 ,on the other hand1 a slight local divergence from the usual topographic forms in a given region may reflect a similar local divergence in the underground structure4 ,thus it is that an appreciation of the physiographic details may suggest important variations in the underground structure which would otherwise pass undiscovered4 ,many mineral deposits owe their origin or enrichment to weathering and other related processes which are preliminary to erosion4 ,these processes vary in intensity1 distribution1 and depth1 with the stage of erosion1 or in relation to the phase of the erosion cycle4 ,they vary with the climatic conditions which obtain on the erosion surface4 ,mineral deposits are therefore often closely related to the topographic features1 present and past1 in kind1 shape1 and distribution4 ,a few illustrative cases follow4 ,many of the great copper deposits of the western ,united ,states owe their values to a secondary enrichment through the agency of waters working down from the surface4 ,when this fact of secondary enrichment was discovered1 it was naturally assumed that the process was related to the present erosion surface and to present climatic and hydrologic conditions4 ,certain inferences were drawn1 therefore1 as to depth and distribution of the enriched ores4 ,this conception1 however1 proved to be too narrow2 for evidences were found in many cases that the copper deposits had been concentrated in previous erosion cycles1 and therefore in relation to erosion surfaces1 now partly buried1 different from the present surface4 ,the importance of this knowledge from an exploring and development standpoint is clear4 ,it has made it possible to find and follow rich ores1 far from the present erosion surface1 which would otherwise have been disclosed solely by chance4 ,studies of this kind in the copper camps are yet so recent that much remains to be learned4 ,the economic geologist advising exploration and development in copper ores who does not in the future take physiographic factors into account is likely to go wrong in essential ways1 as he has done in some cases in the past4 ,not only is it necessary to relate the secondary enrichment of copper deposits to the erosion surface1 present or past1 but by a study of the conditions it must be ascertained how closely erosion has followed after the processes of enrichment4 ,in some cases erosion has followed so slowly as to leave large zones of secondary enrichment4 ,in other cases erosion has followed up so closely after the processes of secondary enrichment as to remove from the surface important parts of the secondarily enriched deposits4 ,the iron ores of the ,lake ,superior region are the result of the action of waters from the surface on so-called iron formations or jaspers4 ,here again it was at first supposed that the enrichment was related to the present erosion surface2 but upon further studies the fact was disclosed that the concentration of the ores took place in the period between the deposition of ,keweenawan and ,cambrian rocks1 and thus a new light was thrown on the possibilities as to depth and distribution of the ores4 ,the old pre-,cambrian surface1 with reference to which the concentration took place1 can be followed with some precision beneath the present surface4 ,this makes it possible to forecast a quite different depth and distribution of the ores from that which might be inferred from present surface conditions4 ,present surface conditions1 of low relief1 considerable humidity1 and with the water table usually not more than #ajj feet from the surface1 do not promise ore deposits at great depth4 ,the erosion which formed the old pre-,cambrian surface1 however1 started on a country of great relief and semi-arid climate1 conditions which favored deep penetration of the surface waters which concentrated the ores4 ,the iron ores of eastern ,cuba are formed by the weathering of a serpentine rock on an elevated plateau of low relief1 where the sluggish streams are unable rapidly to carry off the products of weathering4 ,where streams have cut into this plateau and where the plateau breaks down with sharp slopes to the ocean1 erosion has removed the products of weathering1 and therefore the iron ore4 ,an important element1 then1 in iron ore exploration in this country is the location of regions of slight erosion in the serpentine area4 ,one of the largest discoveries was made purely on a topographic basis4 ,it was inferred merely from a study of topography that a certain large unexplored area ought to carry iron ore4 ,subsequent work in the thick and almost impenetrable jungle disclosed it4 ,bauxite deposits in several parts of the world require somewhat similar conditions of concentration1 and a study of the physiographic features is an important factor in their location and interpretation4 ,a physiographic problem of another sort is the determination of the conditions surrounding the origin of sedimentary ores4 ,certain mineral deposits1 like the ,clinton iron ores1 the copper ores in the ,red ,beds of southwestern ,united ,states and in the ,mansfield slates of ,germany1 many salt deposits1 and almost the entire group of placer deposits of gold1 tin1 and other metals1 are the result of sedimentation1 from waters which derived their materials from the erosion of the land surface4 ,it is sometimes possible from the study of these deposits to discover the position and configuration of the shore line1 the depth of water1 and the probable continuity and extent of the deposits4 ,similar questions are met in the study of coal and oil4 ,this general problem is one of the phases of geology which is now receiving a large amount of attention1 not only from the standpoint of ore deposition1 but from a broader geologic standpoint4 ,in spite of the fact that sedimentary processes of great variety can be observed in operation today1 it is yet extremely difficult to infer from a given sedimentary deposit the precise conditions which determined its deposition and limited its distribution4 ,for instance1 sedimentary iron formations furnish a large part of the world's iron ore4 ,the surface distribution1 the structure1 the features of secondary enrichment1 are all pretty well understood2 likewise the general conditions of sedimentation are reasonably clear1--but the close interpretation of these conditions1 to enable us to predict the extent of one of these deposits1 or to explain its presence in one place and absence in another1 is in an early and sketchy stage4 ,an understanding of the principles and methods of physiography is also vital to an intelligent application of geology to water resources1 to soils1 to dam and reservoir construction1 and to a great variety of engineering undertakings1 but as these subjects involve the application of many other phases of geology1 they are considered in separate chapters4 7,chapters ,v1 ,,vi1 and ,,xx47 ,,rock ,,alterations ,,or ,,metamorphism ,this is one of the newer special phases of geology which for a long time was regarded as the plaything of the petrographer or student of rocks4 ,with the systematic development of the subject1 however1 it was found that the extremely numerous and complex alterations of rocks and minerals may be definitely grouped1 and that they are controlled by broad principles4 ,it became apparent also that these principles apply both to the economic and non-economic minerals and rocks1--in other words1 that the segregation of economic minerals is a mere incident in pervasive cycles of the alterations which affect all rocks4 ,metamorphic geology1 therefore1 for some geologists becomes a convenient approach to the subject of economic geology4 ,it has the great advantage that it tends to keep all minerals and all processes of ore deposition in proper perspective with relation to rocks and rock processes in general4 ,it is not argued that this is the only approach or that it is the best for all purposes4 ,a brief account of this phase of geology is given in ,chapter ,,ii4 ,,application ,,of ,,other ,,sciences ,geology is sometimes defined as the application of other sciences to the earth4 ,considered broadly1 there is no phase of science which is not involved in economic geology4 ,in other chapters in this book many references are made to applications of engineering1 mathematics1 physics1 chemistry1 metallurgy1 biology1 and economics4 ,at different times and places the requirements for earth materials are quite different4 ,in the ,stone ,age there was little use for metals2 in later ages the use of metals broadened4 ,the multiplicity of demands of modern civilization1 the increasing knowledge of processes of metallurgy1 chemistry and physics1 better transportation1 better organization of commercial life1 and many other factors1 tend to bring new earth materials into use1--and1 therefore1 into the field of economic geology4 ,a comparatively few years ago alumina1 one of the most common and abundant substances of the earth's crust1 was in no general demand except for very limited use as an ornament4 ,little attention was paid to it by economic geologists as a commercial product2 now1 however1 aluminum is in great demand1 and the raw materials which produce it have become the subjects of intensive study by economic geologists4 ,in short1 economic geology includes the consideration of man in reaction to his physical environment4 ,there are some earth materials and some conditions of the earth environment which do not yet come within the field of economic geology4 ,but so large a proportion of them do1 that the complete economic geologist should indeed be almost omniscient4 ,when one considers what an insignificantly small portion of this field can be covered by any individual1 it is apparent that the title of economic geologist implies no mastery of the entire field4 ,there is yet no crowding4 ,,treatment ,,of ,,the ,,subject ,,in ,,this ,,volume ,in scope and manner of treatment this volume follows somewhat the writer's presentation of the subject in university teaching4 ,the purpose is to explain the nature of the economic demands for the science of geology1 and to discuss something of the philosophy of the finding and use of raw materials4 ,somewhat generalized statistics are used as a means of gaining perspective4 ,no effort has been made for detailed accuracy or for completeness4 ,so far as possible the quantitative features are expressed in general proportions1 and where specific figures are given they are meant to indicate only such general proportions4 ,the thought has been not to be so specific that the figures would soon be out of date4 ,all standard statistical sources have been drawn on1 but the principal sources have been the results of the various special investigations called out by the war1 in which the writer had a part4 ,on the geologic side many sources have been drawn on outside of the writer's own experience4 ,for the most part1 no specific references or acknowledgments are made1 on the ground that the book aims to present the general features which are now the more or less common knowledge of economic geologists4 ,to make the references really adequate for exhaustive study would not only burden the text1 but would require a specificity of treatment which it has been hoped to avoid4 ,the illustrative cases chosen for discussion are often taken from the writer's field of experience4 ,this field has been principally the ,lake ,superior region1 but has included also the principal mineral deposits of ,north ,america1 ,cuba1 and limited areas in ,south ,america and ,europe4 ,thus the ,lake ,superior iron and copper region might seem to be brought forward more than is warranted by its scientific or economic importance4 ,for this1 the writer offers no apology4 ,an author's perspective is largely determined by his background of training and experience1 and a frank recognition of this fact may aid in determining the weight to be given to his conclusions4 ,it might even add to scientific efficiency if each writer were to confine his discussion almost solely to matters within his own range of observation and study4 ,the writer's indebtedness for information derived from the printed page and for personal discussion and advice is of wide range4 ,he would express his warm appreciation of the friendly spirit of cooperation and advice with which this effort has been aided--a spirit which he likes to think is particularly characteristic of the profession of economic geology4 ,in particular he would acknowledge the efficient aid of ,mr4 ,julian ,d4 ,conover in preparation and revision of the manuscript4 ,,chapter ,,ii ,,the ,,common ,,elements1 ,,minerals1 ,,and ,,rocks ,,of ,,the ,,earth ,,and ,,their ,,origins ,a list of the solid substances of the earth making up the so-called lithosphere 7or rock sphere7 in order of their abundance1 does not at all correspond to a list made in order of commercial importance4 ,some of the most valuable substances constitute such a small proportion of the total mass of the lithosphere that they hardly figure at all in a table of the common substances4 ,,relative ,,abundance ,,of ,,the ,,principal ,,elements ,,of ,,the ,,lithosphere ,when reduced to the simplest terms of elements the outer ten miles of the lithosphere consists of3#a ,,percentage ,,of ,,principal ,,elements ,,in ,,the ,,lithosphere ,oxygen #dg4cc ,silicon #bg4gd ,aluminum #g4he ,iron #d4ej ,calcium #c4dg ,magnesium #b4bd ,sodium #b4df ,potassium #b4df ----- #ih4je ,the remainder of the elements exist in quantities of less than #a per cent4 ,none of these principal elements occur separately in nature and none of them are mined as elements for economic purposes4 ,,relative ,,abundance ,,of ,,the ,,principal ,,minerals ,,of ,,the ,,lithosphere ,minerals exceptionally consist of single elements1 but ordinarily are combinations of two or more elements2 for instance1 quartz consists of a chemical combination of silicon and oxygen4 ,the proportions of the common minerals in the outer ten miles of the lithosphere are in round numbers as follows3 ,,percentage ,,of ,,common ,,minerals ,,in ,,lithosphere ,feldspar #di ,quartz #ba ,augite1 hornblende1 and olivine #ae ,mica #h ,magnetite #c ,titanite and ilmenite #a ,kaolin1 limonite1 hematite1 dolomite1 calcite1 chlorite1 etc4 #c --- #ajj ,in making up this table it is assumed that the rocks to a depth of ten miles are about #ie per cent of igneous type1 that is1 crystallized from molten magma1 and about #e per cent of sedimentary type1 that is1 formed from the weathering and erosion of igneous rocks or preexisting sediments1 and deposited in beds or layers1 either by water or by air 7see pp4 #af-ag74 ,more reliable figures for the relative abundance of the minerals are available for each of the two classes of rocks1 igneous and sedimentary4 ,the igneous rocks contain minerals in about the following proportions3 ,,percentage ,,of ,,common ,,minerals ,,in ,,igneous ,,rocks ,feldspar #ej ,quartz #ba ,augite1 hornblende1 olivine1 etc4 #ag ,mica #h ,magnetite #c ,titanite and ilmenite #a --- #ajj ,the sedimentary rocks contain minerals in about the following proportions3 ,,percentage ,,of ,,common ,,minerals ,,in ,,sedimentary ,,rocks ,quartz #ce ,feldspar #af ,white mica #ae ,kaolin 7clay7 #i ,dolomite #i ,chlorite #e ,calcite #d ,limonite #d ,gypsum1 carbon1 rutile1 apatite1 magnetite1 etc4 #c --- #ajj ,the sedimentary rocks comprise three main divisions3 7#a7 ,the muds and clays1 with their altered equivalents1 shale1 slate1 etc42 7#b7 the sands1 with their altered equivalents1 sandstone1 quartzite1 quartz-schist1 etc42 7#c7 the marls1 limestones1 and dolomites1 with their altered equivalents1 marble1 talc-schist1 etc4 ,for brevity these groups are referred to respectively as shale1 sandstone1 and limestone4 ,the proportions of minerals in each of these groups of rocks are as follows3 ,,percentage ,,of ,,common ,,minerals ,,in ,,shale1 ,,sandstone1 ,,and ,,limestone ---------------------------------------- --- ,average ,average ,average shale sandstone limestone ---------------------------------------- --- ,quartz #ca4ia #fi4gf #c4ga ,kaolin #aj4jj #g4ih #a4jc ,white mica #ah4dj ,chlorite #f4dj #a4ae ,limonite #d4ge 4#hj ,dolomite #g4ij #c4dd #cf4bea ,calcite #g4ba #ef4ef ,gypsum #a4ag 4#ab 4#aj ,feldspar #ag4fj #h4da #b4bj ,magnetite 4#eh ,rutile 4#ff 4#ab 4#jf ,ilmenite 4#be ,apatite 4#dj 4#ah 4#ji ,carbon 4#ha ---------------------------------------- --- ,total #ajj4jj #ajj4jj #ajj4jj ---------------------------------------- --- #a3 ,includes small amount of ,fe,c,o#c4 ,in comparing the mineral composition of igneous and sedimentary rocks1 it will be noted that the most abundant single mineral of the igneous rocks1 and the most abundant mineral of the lithosphere as a whole1 is feldspar2 that next in order is quartz2 and that third comes a group of dark green minerals typified by augite and hornblende1 commonly called ferro-magnesian silicates because they consist of iron and magnesia1 with other bases1 in combination with silica4 ,the sedimentary rocks1 which are ultimately derived from the destruction of the igneous rocks1 contrast with the igneous rocks mainly in their smaller proportions of feldspars and ferro-magnesian minerals1 their higher proportions of quartz and white mica 7sericite or muscovite71 and their content of kaolin1 dolomite1 calcite1 chlorite1 limonite1 etc41 which are nearly absent from the unaltered igneous rocks4 ,evidently the development of sediments from igneous rocks has involved the destruction of much of the feldspars and ferro-magnesian silicates1 and the building from the elements of these destroyed minerals of more quartz1 white mica1 clay1 dolomite1 calcite1 chlorite and limonite4 ,the composition of the minerals of the sedimentary rocks is such as to indicate that the constituents of the air and water have been added in important amounts to accomplish this change of mineral character4 ,for instance1 carbon dioxide of the atmosphere has been added to lime and magnesia of the igneous rocks to make calcite and dolomite1 water has been added to some of the alumina and silica of the igneous rocks to make kaolin or clay1 and both oxygen and water have been added to the iron of the igneous rocks to make limonite4 ,,relative ,,abundance ,,of ,,the ,,principal ,,rocks ,,of ,,the ,,lithosphere ,just as elements combine chemically to form minerals1 so do minerals combine mechanically1 either loosely or compactly1 to form rocks4 ,for instance1 quartz is a mineral4 ,an aggregation of quartz particles forms sand or sandstone or quartzite4 ,most rocks contain more than one kind of mineral4 ,sedimentary rocks occupy considerable areas of the earth's surface1 but they are relatively superficial4 ,it has been estimated that if spread evenly and continuously over the earth1 which they are not1 they would constitute a shell scarcely a half mile thick4#b ,igneous rocks are relatively more abundant deep below the surface4 ,if the sediments be assumed to be limited to a volume equivalent to a half-mile shell1 and the remainder of the rocks be assumed to be igneous1 it is evident that to a depth of ten miles #ie per cent of the rocks are igneous4 ,our actual observation is confined to a shallow superficial zone in which sediments make up at least half of all the rocks4 ,igneous rocks can be divided for convenience into two main types3 7#a7 granite and allied rocks1 containing a good deal of silica and therefore acid in a chemical sense1 and 7#b7 basalt and allied types1 containing less silica and more lime1 magnesia1 iron1 soda and potassa1 and therefore basic in a chemical sense4 ,the former are light-colored gray and pink rocks while the latter are dark-colored green and gray rocks4 ,granite and basalt as technically defined are very common igneous rocks1--so common that the names are sometimes used to classify igneous rocks in general into two great groups1 the granitic and the basaltic4 ,it has been estimated that about #fe per cent of the igneous rocks are of the granitic group and #ce per cent of the basaltic group4 ,sedimentary rocks1 as already indicated1 consist principally of three groups1 which for convenience are named shale1 sandstone1 and limestone4 ,if we approximate the average composition of each group and the average composition of the igneous rocks from which they are ultimately derived1 it can be calculated that sedimentary rocks must form in the proportions of #hb per cent shale1 #ab per cent sandstone1 and #f per cent limestone4 ,only this combination of the three sediments will yield an average composition comparable with that of the parent igneous rocks4 ,as actually observed in the field the sandstones and limestones are in relatively higher percentage than is here indicated1 suggesting that part of the shales may have been deposited in deep seas where they cannot be observed1 and that part may have been so changed or metamorphosed that they are no longer recognized as shales4 ,,soils ,,and ,,clays ,weathered and disintegrated rocks at the surface form soils and clays4 ,no estimate is made of abundance1 but obviously the total volume of these products is small as compared with the major classes of earth materials above noted1 and in large part they may be included with these major classes4 ,,water 7,,hydrosphere7 ,it has been estimated that all the water of the earth1 including the ocean1 surface waters1 and underground waters1 constitutes about #g per cent of the volume of the earth to a depth of #aj miles4#c ,,comparison ,,of ,,lists ,,of ,,most ,,abundant ,,rocks ,,and ,,minerals ,,with ,,commercial ,,rocks ,,and ,,minerals ,of the common rocks and minerals figuring as the more abundant materials of the earth's crust1 only a few are prominently represented in the tables of mineral resources4 ,of these water and soils stand first4 ,others are the common igneous and sedimentary rocks used for building and road materials4 ,missing from the lists of the most abundant minerals and rocks1 are the greater part of the commercially important mineral resources--including such as coal1 oil1 gas1 iron ore1 copper1 gold1 and silver1--implying that these mineral products1 notwithstanding their great absolute bulk and commercial importance1 occur in relatively insignificant amounts as compared with the common rock minerals of the earth4 ,,the ,,origin ,,of ,,common ,,rocks ,,and ,,minerals ,the common rocks and minerals develop in a general sequence1 starting with igneous processes1 and passing through stages of weathering1 erosion1 sedimentary processes1 and alterations beneath the surface4 ,the commercial minerals are incidental developments under the same processes4 ,,igneous ,,processes ,the earliest known rocks are largely igneous4 ,sedimentary rocks are formed from the breaking down of igneous rocks1 and the origin of rocks therefore starts with the formation of igneous rocks4 ,igneous rocks are formed by the cooling of molten rock material4 ,the ultimate source of this molten material does not here concern us4 ,it may come from deep within the earth or from comparatively few miles down4 ,it may include preexisting rock of any kind which has been locally fused within the earth4 ,wherever and however formed1 its tendency is to travel upward toward the surface4 ,it may stop far below the surface and cool slowly1 forming coarsely crystallized rocks of the granite and gabbro types4 ,igneous rocks so formed are called plutonic intrusive rocks4 ,or the molten mass may come well toward the surface and crystallize more rapidly into rocks of less coarse1 and often porphyritic1 textures4 ,such intrusive rocks are porphyries1 diabases1 etc4 ,or the molten mass may actually overflow at the surface or be thrown out from volcanoes with explosive force4 ,it then cools quickly and forms finely crystalline rocks of the rhyolite and basalt types4 ,these are called effusives or extrusives1 or lavas or volcanics1 to distinguish them from intrusives formed below the surface4 ,the intrusive masses may take various forms1 called stocks1 batholiths1 laccoliths1 sills1 sheets and dikes1 definitions and illustrations of which are given in any geological textbook4 ,the effusives or volcanics at the surface take the form of sheets1 flows1 tuffs1 agglomerates1 etc4 ,some of the igneous rocks are themselves mineral products1 as for instance building stones and road materials4 ,certain basic intrusive igneous rocks contain titaniferous magnetites or iron ores as original constituents4 ,others carry diamonds as original constituents4 ,certain special varieties of igneous rocks1 known as pegmatites1 carry coarsely crystallized mica and feldspar of commercial value1 as well as a considerable variety of precious gems and other commercial minerals4 ,pegmatites are closely related to igneous after-effects1 discussed under the next heading4 ,as a whole1 the mineral products formed directly in igneous rocks constitute a much less important class than mineral products formed in other ways1 as described below4 ,igneous after-effects4 ,the later stages in the formation of igneous rocks are frequently accompanied by the expulsion of hot waters and gases which carry with them mineral substances4 ,these become deposited in openings in adjacent rocks1 or replace them1 or are deposited in previously hardened portions of the parent igneous mass itself4 ,they form contact-metamorphic and certain vein deposits4 ,pegmatites1 referred to above1 are in a broad sense in this class of igneous after-effects1 in that they are late developments in igneous intrusions and often grade into veins clearly formed by aqueous or gaseous solutions4 ,among the valuable minerals of the igneous after-effect class are ores of gold1 silver1 copper1 iron1 antimony1 mercury1 zinc1 lead1 and others4 ,while mineral products of much value have this origin1 most of them have needed enrichment by weathering to give them the value they now have4 ,,weathering ,,of ,,igneous ,,rocks ,,and ,,veins ,no sooner do igneous rocks appear at or near the earth's surface1 either by extrusion or as a result of removal by erosion of the overlying cover1 than they are attacked vigorously by the gases and waters of the atmosphere and hydrosphere as well as by various organisms1--with maximum effect at the surface1 but with notable effects extending as far down as these agents penetrate4 ,the effectiveness of these agents is also governed by the climatic and topographic conditions4 ,under conditions of extreme cold or extreme aridity1 weathering takes the form mainly of mechanical disintegration1 and chemical change is less conspicuous4 ,under ordinary conditions1 however1 processes of chemical decomposition are very apparent4 ,the result is definitely known4 ,the rocks become softened1 loose1 and incoherent4 ,voids and openings appear4 ,the volume tends to increase1 if all end products are taken into account4 ,the original minerals1 largely feldspar1 ferro-magnesian minerals1 and quartz1 become changed to clay1 mixed with quartz or sand1 calcite or dolomite1 and iron oxide1 together with residual particles of the original feldspars and ferro-magnesian minerals which have only partly decomposed4 ,in terms of elements or chemical composition1 water1 oxygen1 and carbon dioxide1 all common constituents of the atmosphere and hydrosphere1 have been added2 and certain substances such as soda1 potassa1 lime1 magnesia1 and silica have in part been carried away by circulating waters1 to be redeposited elsewhere as sediments1 vein fillings1 and cements4 ,figure #a illustrates the actual mineral and volume changes in the weathering of a granite--one of the most common rocks4 ,the minerals anorthite1 albite1 and orthoclase named in this figure are all feldspars2 sylvite and halite are chlorides of potash and soda4 ,the weathering processes tend to destroy the original minerals1 textures1 and chemical composition4 ,they are collectively known as katamorphic alterations1 meaning destructive changes4 ,the zone in which these changes are at a maximum is called the zone of weathering4 ,this general zone is principally above the surface or level of the ground-waters1 but for some rocks it extends well below this level4 ,in some regions the ground-water level may be nearly at the surface1 and in others1 especially where arid1 it may be two thousand or more feet down4 ,disintegrated weathered rocks form a blanket of variable thickness1 which is sometimes spoken of as the residual mantle1 or mantle rock4 ,illustration3 ,,fig4 #a4 ,graphic representation of volume change in weathering of a ,georgia granite4 ,mineral products formed by weathering from common igneous rocks include soils1 clay1 bauxite1 and certain iron1 chromite1 and nickel ores4 ,again the commercial importance of this group is not large1 as compared with products formed in other ways described below4 ,the same weathering processes described above for igneous rocks cause considerable changes of economic significance in deposits formed as igneous after-effects4 ,in some cases they result in removing the less valuable minerals1 thus concentrating the more valuable ones1 as well as in softening the rock and making it easier to work2 and in other cases they tend to remove the valuable constituents1 which may then be redeposited directly below or may be carried completely out of the vicinity4 ,the oxide zones of many ore bodies are formed by these processes4 ,,sedimentary ,,processes ,sedimentary rocks are formed by the removal and deposition of the weathered products of a land surface4 ,air1 water1 and ice1 moving under the influence of gravity and other forces1 all aid in this transfer4 ,the broken or altered rock materials may be merely moved down slopes a little way and redeposited on the surface1 forming one type of terrestrial or subaerial deposits1 or they may be transferred and sorted by streams4 ,when deposited in streams or near their mouths1 they are known as river1 alluvial1 or delta deposits4 ,when carried to lakes and deposited they form lake deposits4 ,ultimately the greater part of them are likely to be carried to the ocean and deposited as marine sediments4 ,part of the weathered substances are carried mechanically as clay and sand1 which go to make up the shale and sandstone sediments4 ,part are carried in solution1 as for example lime carbonate and magnesium carbonate1 which go to make up limestone and dolomite4 ,some of the dissolved substances are never redeposited1 but remain in solution as salts in the sea1 the most abundant of which is sodium chloride4 ,some of the dissolved substances of weathering1 such as calcite1 quartz1 and iron oxide1 are carried down and deposited in openings of the rocks1 where they act as cements4 ,the sediments as a whole consist of three main types1--shales 7kaolin1 quartz1 etc471 sandstones 7quartz1 feldspar1 etc471 and limestones or dolomites 7carbonates of lime and magnesia74 ,of these1 the shale group is by far the most abundant4 ,there are of course many sediments with composition intermediate between these types4 ,there are also sediments made up of large undecomposed fragments of the original rocks1 cemented to form conglomerates1 or made up of small fragments of the original rocks cemented to form arkoses and graywackes4 ,these1 however1 may be regarded as simply stages in the alteration1 which in repeated cycles of weathering must ultimately result in producing the three main groups1--shales1 sandstones1 and limestones4 ,mineral products formed by sedimentary processes include sandstones1 limestones1 and shales1 used as building stone and road materials2 certain sedimentary deposits of iron1 like the ,clinton ores of the southeastern ,united ,states and the ,brazilian ores2 important phosphate deposits2 most deposits of salt1 gypsum1 potash1 nitrates1 etc42 comparatively few and unimportant copper deposits2 and important placer deposits of gold1 tin1 and other metals1 and precious stones4 ,with the aid of organic agencies1 sedimentary processes also account for the primary deposition of coal and oil4 ,,weathering ,,of ,,sedimentary ,,rocks ,after sedimentary rocks are formed1 and in many cases covered by later sediments1 they may be brought again by earth movements and erosion to the surface1 where they in turn are weathered4 ,the weathering of sedimentary rocks proceeds along lines already indicated for the igneous rocks4 ,residual mantles of impure clay and sand are commonly formed4 ,the mineral composition of sedimentary rocks being different from that of igneous rocks to start with1 the resulting products are in slightly different proportions2 but the changes are the same in kind and tend merely to carry the general process of alteration farther in the same direction1--that is1 toward the production of a few substances like clay1 quartz1 iron oxide1 and calcite1 which are transported and redeposited to form clay1 sand1 and limestone4 ,cycles of this kind may be repeated indefinitely4 ,by weathering of sedimentary rocks are produced some soils1 certain commercial clays1 iron ores1 lead and zinc ores1 and other valuable mineral products4 ,,consolidation1 ,,cementation1 ,,and ,,other ,,subsurface ,,alterations ,,of ,,rocks4 ,cementation4 ,no sooner are residual weathered mantles formed or sedimentary rocks deposited1 whether under air or water1 than processes of consolidation begin4 ,settling1 infiltration of cementing materials1 and new growths1 or recrystallization1 of the original minerals of the rock all play a part in the process4 ,the mud or clay becomes a shale1 the sand becomes sandstone or quartzite1 the marl becomes limestone or marble4 ,all the minute openings between the grains1 as well as larger openings such as fissures and joints1 may thus be filled4 ,at the same time the cementing materials may replace some of the original minerals of the rock1 the new minerals either preserving or destroying the original textures4 ,this process is sometimes called metasomatic replacement4 ,igneous rocks as a rule are compact1 and hence are not so much subject to the processes of cementation as sedimentary rocks2 but certain of the more porous phases of the surface lavas1 as well as any joints in igneous rocks1 may become cemented4 ,all of these changes may be grouped under the general term cementation4 ,a special phase of consolidation and cementation is produced near intrusive igneous rocks through the action of the heat and pressure and the expelled substances of the igneous rock4 ,this is called contact metamorphism or thermal metamorphism4 ,the processes are even more effective when acting in connection with the more intense metamorphism described under the next heading4 ,by cementation some of the common rocks1 especially the sediments1 become sufficiently compact and strong to be useful as commercial products1 such as building stones and road materials4 ,more important as mineral products are the cementing materials themselves4 ,these are commonly quartz1 calcite1 or iron oxide1 of no especial value1 but locally they include commercially valuable minerals containing gold1 copper1 silver1 lead1 zinc1 and many other mineral products4 ,it is a matter of simple and direct observation1 about which there is no controversy1 that many minerals are deposited as cements in the openings in rocks or replacing rocks4 ,as to the source of the solutions bringing in these minerals1 on the other hand1 there has been much disagreement4 ,in general1 the common cementing materials such as quartz and calcite1 as well as some of the commercial minerals1 are clearly formed as by-products of weathering1 and are transported and redeposited by the waters penetrating downward from the surface4 ,the so-called secondary enrichment of many valuable veins is merely one of the special phases of cementation from a superficial source4 ,in other cases it is believed that deep circulation of ordinary ground-waters may pick up dispersed mineral substances through a considerable zone1 and redeposit them in concentrated form in veins and other trunk channels4 ,for still other cementing materials1 it is suspected that the ultimate source is in igneous intrusions2 in fact1 deposits of this general character show all gradations from those clearly formed by surface waters1 independently of igneous activity1 to those of a contact-metamorphic nature and others belonging under the head of igneous after-effects4 ,hypothesis and inference play a considerable part in arriving at any conclusion as to the source of cementing materials1--with the result that there is often wide latitude for difference of opinion and of emphasis on the relative importance of the different sources of ore minerals4 ,dynamic and contact metamorphism4 ,beneath the surface rocks are not only cemented1 but may be deformed or mashed by dynamic movements caused by great earth stresses2 the rocks may undergo rock flowage4 ,the result is often a remarkable transformation of the character of the rocks1 making it difficult to recognize their original nature4 ,also1 igneous intrusions may crowd and mash the adjacent rocks1 at the same time changing them by heat and contributions of new materials4 ,this process may be called contact metamorphism1 but in so far as it results in mashing of the rocks it is closely allied to dynamic metamorphism4 ,the former term is also applied to less profound changes in connection with igneous intrusions1 which result merely in cementation without mashing4 ,dynamic and contact metamorphism may in some cases produce rocks identical in appearance with those produced by ordinary processes of cementation and recrystallization without movement4 ,for instance1 it is difficult to tell how much movement there has been in the production of a marble1 because both kinds of processes seem to produce much the same result4 ,commonly1 however1 the effect of dynamic metamorphism is to produce a parallel arrangement of mineral particles and to segregate the mineral particles of like kind into bands1 giving a foliated or schistose or gneissic structure1 and the rocks then become known as slates1 schists1 or gneisses4 ,commonly they possess a capacity to part along parallel surfaces1 called cleavage4 ,the development of the schistose or gneissic structure is accompanied by the recrystallization of the rock materials1 producing new minerals of a platy or columnar type adapted to this parallel arrangement4 ,even the composition of the rock may be substantially changed1 though this is perhaps not the most common case4 ,whereas by weathering the rock is loosened up and disintegrated1 substances like carbon dioxide1 oxygen1 and water are abundantly added1 and light minerals of simple composition tend to develop1--by dynamic metamorphism on the other hand1 carbon dioxide1 oxygen1 and water are usually expelled1 the minerals are combined to make heavier and more complex minerals1 pore space is eliminated1 and altogether the rock becomes much more dense and crystalline4 ,while segregation of materials is characteristic of the surficial products of weathering1 the opposite tendency1 of mixing and aggregation1 is the rule under dynamic metamorphism1 notwithstanding the minor segregation above noted4 ,dynamic metamorphism is for the most part unfavorable to the development of mineral products4 ,ore bodies brought into a zone where these processes are active may be profoundly modified1 but not ordinarily enriched4 ,one of the exceptions to this general rule is the development of the cleavage of a slate1 which enables it to be readily split and thereby gives it value4 ,contact metamorphism1 on the other hand1 may develop valuable mineral deposits 7see pp4 #bj1 #de-df74 ,,the ,,metamorphic ,,cycle ,,as ,,an ,,aid ,,in ,,studying ,,mineral ,,deposits ,all of the chemical1 mineralogical1 and textural changes in rocks above described may be collectively referred to as metamorphism4 ,the phase of metamorphism dealing with surficial weathering1 similar changes below the surface1 and the formation of sediments1 is called katamorphism or destructive change4 ,the phase of metamorphism dealing with the constructive changes in rocks1 due to cementation1 dynamic movements1 and igneous influences1 is called anamorphism4 ,some geologists confine the term metamorphism to the changes involved in contact and dynamic metamorphism1 and call the resulting products metamorphic rocks4 ,the zone in which katamorphism is most active1 usually near the surface1 is called the zone of katamorphism4 ,the deeper zone in which anamorphism is preponderant is called the zone of anamorphism4 ,there are no definite limits of depth to these zones4 ,a given rock may be undergoing katamorphism while rocks on either side at the same depth are suffering anamorphism4 ,by katamorphism rocks break down to produce the surficial rocks1 and by anamorphism the surficial rocks are again consolidated and altered to produce highly crystalline rocks1 which are not dissimilar in many of their characteristics to the igneous rocks from which all rocks trace their ultimate origin4 ,in other words1 anamorphism tends toward the reproduction of igneous rocks1 though it seldom fully accomplishes this result4 ,these two main groups of changes together constitute the metamorphic cycle4 ,some rocks go through all phases of the cycle1 but others may pass directly from one phase to an advanced phase without going through the intermediate stages4 ,for instance1 an igneous rock may become a schist without going through the intermediate stage of sedimentation4 ,rocks are not permanent in their condition1 but at practically all times and places are undergoing some kind of metamorphism which tends to adapt them to their environment4 ,the conception of rocks as representing phases or stages in a progressive series of changes called the metamorphic cycle aids greatly in correlating and holding in mind many details of rock nature and origin1 and brings into some sort of perspective the conditions which have produced rocks4 ,a schistose sediment comes to be regarded as an end product of a long series of alterations1 beginning with igneous rocks and passing through the stages of weathering1 sedimentation1 cementation1 etc41 each of which stages has been responsible for certain mineralogical1 chemical1 and textural features now characterizing the rock4 ,the alternation of constructive and destructive changes of the metamorphic cycle1 and the repetitions of the cycle itself1 periodically work over the earth materials into new forms4 ,usually the cycles are not complete1 in the sense that they seldom bring the rock back to exactly the same condition from which it started4 ,more sediments are formed than are changed to schists and gneisses1 and more schists and gneisses are formed than are changed back to igneous rocks4 ,salts in the ocean continuously accumulate4 ,the net result of the metamorphic cycle1 is1 therefore1 the accumulation of materials of the same kinds4 ,incidental to these accumulations is the segregation of commercial mineral products4 ,the metamorphic cycle becomes a logical and convenient geologic basis for correlating1 interpreting1 and classifying mineral products4 ,because of the great variety of materials and conditions represented in mineral deposits1 prodigious efforts are required to remember them as independent entities2 but as incidents or stages in the well-known progress of the metamorphic cycle1 their essential characteristics may be easily remembered and kept in some perspective4 ,ores of certain metals1 such as iron1 occur in almost every phase of the metamorphic cycle1--as igneous after-effects1 as weathered products1 as sediments1 and as schists4 ,the ores of each of these several phases have group characteristics which serve to distinguish them in important particulars from ores belonging to other phases of the cycle4 ,having established the position of any particular ore in the metamorphic cycle1 a number of safe inferences are possible as to mineralogical composition1 shape1 extent1 and other conditions1 knowledge of which is necessary for an estimate of commercial possibilities4 ,,footnotes3 #a ,clarke1 ,f4 ,w41 ,data of geochemistry3 ,bull4 #fie1 ,u4 ,s4 ,geol4 ,survey1 #aibj1 p4 #ce4 #b ,clarke1 ,f4 ,w41 ,data of geochemistry3 ,bull4 #fie1 ,u4 ,s4 ,geol4 ,survey1 #aibj1 p4 #cc4 #c ,clarke1 ,f4 ,w41 ,data of geochemistry3 ,bull4 #fie1 ,u4 ,s4 ,geol4 ,survey1 #aibj1 pp4 #bb-bc4 ,,chapter ,,iii ,,some ,,salient ,,features ,,of ,,the ,,geology ,,and ,,classification ,,of ,,mineral ,,deposits ,,various ,,methods ,,of ,,classification ,mineral products may be classified according to use1 commercial importance1 geographic distribution1 form and structure1 mineralogical and chemical composition1 or origin4 ,each of these classifications is useful for some purposes4 ,the geologist usually prefers a classification based on origin or genesis4 ,in the following chapters on mineral resources1 however1 such a classification is not the primary one1 because of the desire to emphasize economic features4 ,the mineral commodities are treated as units and by group uses4 ,some mineral commodities have so many different kinds of origin in different regions that to distribute them among several genetic groups in description would make it impossible to preserve the unity necessary for consideration of the economic features4 ,while in the descriptive chapters many references are made to origin1 it may be difficult for the reader to assemble them in perspective2 for this reason we summarize at the outset some of the salient features of origin of mineral deposits and of their geologic classification4 ,to the layman the reason for emphasis on origin is often not clear4 ,the practical man frequently regards this phase of the subject as merely incidental to the immediate economic questions--a playground for harmless theorists4 ,the answer of the economic geologist is that in no other way than by a knowledge of origin is it possible to arrive at an understanding of conditions which so well enables one to answer many practical questions4 ,in the exploration for mineral deposits1 it is obvious that an understanding of the kinds of geologic conditions and processes under which a given type of deposit is known to develop results in the elimination of much unpromising territory1 and the concentration of work on favorable localities4 ,in forming any estimate of mineral deposits beyond the ground immediately opened up1--for instance1 in estimating depth1 form1 change in values1 mineralogical character1 or interruptions due to faulting1--it is difficult to form any intelligent conception of the probabilities unless the history of the deposit is understood4 ,if1 for instance1 the ore is known to be formed by hot waters1 associated with the cooling of igneous rocks1 different conditions are to be expected below the zone of observation than if the ore is formed by surface waters4 ,if the ore body is formed as a single episode under simple geologic conditions1 the interpretation of the possibilities in the situation may be quite different from the interpretation applied where the history has been more complex4 ,if the surface conditions suggest possibilities of secondary enrichment of the ores1 the interpretation of the conditions underground will be different from those applied where there is no evidence of such enrichment4 ,where a mineral deposit is completely opened up in three dimensions1 it is often possible to work out economic questions of tonnage1 grade1 shape1 and values1 without the aid of geology4 ,also1 where conditions are comparatively simple and uniform throughout a district1 the local knowledge of other mines may be a sufficient basis for answering these questions for any new property developed4 ,empirical methods may suffice4 ,however1 it is seldom that the conditions are so simple that some geological inference is not necessary4 ,even where problems are settled without calling in the geologist1 geological inferences are required in the interpretation of1 and projection from1 the known facts4 ,it is often the case that the practical man has in his mind a rather elaborate assortment of geologic hypotheses1 based on his individual experience1 which make the so-called theories of the geologist seem conservative in comparison4 ,the geologist comes to the particular problem with a background of established geologic principles and observations1 and his first thought is to ascertain all the local conditions which will aid in deciphering the complete history of the mineral deposit4 ,there is no fact bearing on the history1 however remote from practical questions1 which may not be potentially valuable4 ,with this digression to explain the geologist's emphasis on origin of mineral products1 we may return to a consideration of a few of the principles of rock and mineral genesis which have been found to be significant in the study of mineral products4 ,in the preceding chapters it has been indicated that mineral deposits are mere incidents in the mass of common rocks2 that they are made by the same processes which make common rocks1 that none of the processes affecting mineral deposits are unique for these minerals1 and that most common rocks are on occasion themselves used as mineral resources4 ,these facts are emphasized in order to make it clear that the study of mineral deposits cannot be dissociated from the study of rocks1 and that the study of the latter is essential to bring mineral deposits into their proper perspective4 ,absorption in the details of a mineral deposit makes it easy for the investigator to forget or minimize these relations4 ,nevertheless1 in the study of mineral deposits1 and especially deposits of the metallic minerals1 certain geologic features stand out conspicuously against the common background indicated above4 ,our discussion of these features will follow the order of rock genesis indicated in the description of the metamorphic cycle4 ,,names ,any classification of mineral deposits on the basis of origin is more or less arbitrary4 ,the sharp lines implied by the use of class names do not exist in nature4 ,mineral deposits are so complex and so interrelated in origin1 that a classification according to genesis indicates only the essential and central class features2 it does not sharply define the limits of the classes4 ,it is practically impossible for any geologist to present a classification which will be accepted without qualification by other geologists1 although there may be agreement on essential features4 ,difficulties in reaching agreement are increased by the inheritance from the past of names1 definitions1 and classifications which do not exactly fit present conceptions based on fuller information1--but which1 nevertheless1 have become so firmly established in the literature that it is difficult to avoid their use4 ,in the progress of investigation many new names are coined to fit more precisely the particular situation in hand1 but only in fortunate cases do these new names stand up against the traditional currency and authority of old names4 ,the geologist is often in despair in his attempt to express his ideas clearly and precisely1 and at the same time to use terms which will be understandable by his readers and will not arouse needless controversy4 ,as illustrative of the above remarks reference may be made to a few terms commonly used in economic geology1 such as primary1 secondary1 syngenetic1 epigenetic1 supergene1 hypogene1 protore1 etc4 ,the most commonly used of these terms are primary and secondary4 ,it is almost impossible to define them in a way which will cover all the conceptions for which they have been used1 and yet in their context they have been very useful in conveying essential ideas4 ,an ore formed by direct processes of sedimentation has sometimes been called primary1 whereas an ore formed by later enrichment of these sediments has been called secondary4 ,an ore formed directly by igneous processes has been called primary1 while an ore formed by enrichment of such primary ore by later processes has been called secondary4 ,it is clear1 however1 that these terms are merely relative1 with application to a specific sequence1 and that they do not fix the absolute position of the ore in a sequence applying to all ores4 ,for instance1 ores deposited directly as sediments or placers may be derived from the erosion of preexisting ore bodies1--in which case it may sometimes be convenient to refer to the sedimentary ores or placers as secondary and the earlier ores as primary4 ,or a sulphide deposit originating through igneous agencies may undergo two or three successive enrichments1 each successive one secondary to the preceding1 but primary to the one following4 ,in spite of these obvious difficulties1 the terms primary and secondary may be entirely intelligible as indicating relative order of development under a given set of conditions4 ,the term syngenetic has been used for mineral deposits formed by processes similar to those which have formed the enclosing rocks and in general simultaneously with them1 and epigenetic for those introduced into preexisting rocks4 ,in certain cases syngenetic may be roughly synonymous with primary1 and epigenetic with secondary1 and yet a primary ore may be epigenetic4 ,for instance1 zinc sulphides in the ,mississippi valley limestones 7pp4 #ed-ee7 are epigenetic1 and yet are primary with reference to a later enrichment4 ,the two sets of terms are meant to convey somewhat different ideas and are not interchangeable4 ,ransome#d has suggested1 especially for vein and contact deposits1 a series of names which has the considerable advantage of definiteness3--hypogene ores1 formed in general by ascending non-oxidizing solutions1 perhaps hot2 supergene ores1 formed in general by oxidizing and surface solutions1 initially cold and downward moving2 and protores1 or metallized rock or vein substances which are too low in tenor to be classed as ores1 but which would have been converted into ores had the enriching process been carried far enough4 ,in this connection ,ransome defines primary ore as unenriched material that can be profitably mined4 ,in view of the general use of the terms primary and secondary as expressing a sequential relation of ore development1 it is doubtful whether this more precise definition will supersede the older usage4 ,also it may be noted that commercial conditions might require1 under these definitions1 the designation of an ore as a protore at one time or place and as a primary ore at another4 ,hypogene ores are dominantly primary1 and supergene ores are dominantly secondary1 but either may include both primary and secondary ores4 ,the terms of these several classifications overlap1 and seek to express different aspects of the same situation4 ,while almost synonymous in certain applications they are not in others4 ,in this text the writer has certainly not escaped the difficulties in regard to names above referred to1 nor in fact has he made any exceptional effort to do so4 ,his chief purpose is to convey1 in somewhat elementary terms1 an understandable idea of the central features of economic geology4 ,in the main1 the most widely accepted terms are used4 ,almost at every turn it would be possible1 in the interests of precision1 to introduce qualifying discussions of names1--but at the expense of continuity and perspective in the presentation of the principal subject-matter4 ,the writer does not wish to minimize the necessity for careful and precise nomenclature2 but he regards it important that the student focus his attention on the central objective facts of the subject1 and that he do not become misled by the sometimes over-strenuous advocacy of certain names or classifications in preference to others4 ,if the facts are understood1 he will ordinarily have no difficulty in judging the significance of the variety of names proposed to express these facts4 ,if1 on the other hand1 the student approaches the subject with a ready-made set of names and definitions learned by rote1 he is in danger of perceiving his facts from one angle only and through a distorted perspective4 ,,mineral ,,deposits ,,as ,,magmatic ,,segregations ,,in ,,igneous ,,rocks ,in this class are included deposits which crystallize within the body of igneous rock1 almost1 if not quite1 simultaneously with the adjacent rock4 ,these deposits form one of the main types of syngenetic deposits4 ,the titaniferous magnetites constitute a widely distributed but at present commercially unavailable class of iron ores4 ,the magnetite crystals of these deposits interpenetrate with the other constituents of an igneous rock1 commonly of a gabbro type1 and the deposits themselves are essentially igneous rocks4 ,their shapes are for the most part irregular1 their boundaries ill-defined1 and their concentration varying4 ,while their magmatic origin is clear1 there is little agreement as to the precise conditions which determined their segregation in the molten rock4 ,there is often a tendency for the ores to follow certain primary sheeted structures in the igneous mass1 a fact for which the reason is not obvious4 ,the ,sudbury nickel ores1 of ,ontario1 ,canada1 the principal source of the world's nickel1 lie mainly within and along the lower margin of a great intrusive igneous mass of a basic type called norite1 and locally the ores project beyond the margin into adjacent rocks4 ,their textures and their intercrystallization with the primary minerals of the igneous rock have suggested that they are essentially a part of the norite mass1 and that they crystallized during some segregative processes which were effective before the magma had solidified4 ,near the ores there are likely to be granitic rocks1 which1 like the ores1 seem to be segregations from the norite magma4 ,locally both the ores and the associated granitic rocks replace the main norite body in such a fashion as to indicate their slightly later crystallization4 ,however1 the intimate association of the ores with the primary minerals in the magma1 together with their absence from higher parts of the norite and from the extraneous rocks far from the contact1 indicate to other investigators that they were not brought in from outside in vagrant solutions which followed the intrusion of the main magma1 but that they were segregated within the magma essentially in place4 ,the occurrence of these heavy ores near the base of the norite naturally suggests that they were segregated by sinking to the bottom of the molten magma1 but this conclusion implies certain physical conditions of the magma which have not yet been proved4 ,again the precise nature of the process and the part played in it by aqueous and gaseous solutions are subject to some doubt and controversy4 ,the settlement of this problem awaits the solution of the more general problem of the origin and crystallization of magmas4 ,in this general class of igneous deposits may be mentioned also diamonds1 platinum1 chromite1 corundum1 and other mineral products1 although for the formation of commercial ores of many of these substances further concentration by weathering and sedimentation has been required4 ,pegmatites are coarsely crystalline acid dike rocks which often accompany a large igneous intrusion and which have obviously crystallized somewhat later than the main igneous mass4 ,they may constitute either sharply delimited dikes or more irregular bodies which grade into the surrounding igneous mass4 ,they have a composition roughly similar to the associated igneous rock1 but usually a different proportion of minerals4 ,they are probably the result of the differentiation of the parent magma4 ,the pegmatites are of especial interest to the economic geologist because of the frequency with which they carry commercial minerals1 such as the precious stones1 mica1 feldspar1 cassiterite 7tin ore71 and others4 ,they show a complete gradation from dikes of definitely igneous characteristics to veins consisting largely of quartz in which evidence of igneous origin is not so clear4 ,the pegmatites thus afford a connecting link between ores of direct igneous sources and ores formed as igneous after-effects1 which are discussed in the next paragraph4 ,aplites are fine-grained acid igneous rocks of somewhat the same composition as the pegmatites and often show the same general relations to ores4 ,,mineral ,,deposits ,,within ,,and ,,adjacent ,,to ,,igneous ,,rocks ,,which ,,were ,,formed ,,immediately ,,after ,,the ,,cooling ,,and ,,crystallization ,,of ,,the ,,magmas ,,through ,,the ,,agency ,,of ,,hot ,,magmatic ,,solutions4 ,these deposits are closely associated in place and age with igneous rocks1 either intrusive or extrusive1 and are usually considered to have come from approximately the same source2 and yet they afford distinct evidence of having been deposited after the adjacent igneous rocks were completely crystallized and fractured4 ,they are thus epigenetic deposits4 ,they are not themselves igneous rocks and they do not constitute pegmatites1 but they often grade into pegmatites and belong to the same general stage in the sequence of events4 ,they include deposits formed by contact metamorphism4 ,they are sometimes designated by the general term igneous after-effects--a term also applied in some cases to pegmatites4 ,some geologists discriminate between deep vein deposits 7p4 #dc7 and contact-metamorphic deposits1 but the two are so closely related in place and origin that for our purposes they will be considered together4 ,the ores of this class are clearly deposited from vagrant solutions which wander through openings of all kinds in the igneous rock and outward into the adjacent country rocks4 ,they also replace the wall rocks2 limestone is especially susceptible4 ,this is a phase of contact metamorphism4 ,some of the most important metalliferous deposits belong in this class1 including most of the gold1 silver1 copper1 iron1 lead and zinc ores of the western ,united ,states and the copper deposits of ,lake ,superior4 ,in general1 ores of this class are more abundant about intrusive igneous rocks1 that is about igneous rocks which have stopped and cooled before reaching the surface1--than in association with extrusive igneous rocks which have poured over the surface as lava flows--but the latter are by no means insignificant1 including as they do such deposits as the ,lake ,superior copper ores1 the ,kennecott copper ores of ,alaska1 some of the gold-silver deposits of ,goldfield and other ,nevada camps1 and many others4 ,there is general similarity in the succession of events shown by study of ore bodies related to intrusives4 ,first1 the invasion of the magma1 resulting in contact metamorphism of the adjacent rocks1 sometimes with1 and often without conspicuous crowding effects on the invaded rocks2 second1 the cooling1 crystallization1 and cracking of both the igneous rock and the adjacent rock2 third1 the introduction of ore-bearing solutions into these cracks1--sometimes as a single episode1 sometimes as a long continued and complex process forming various types of minerals at successive stages4 ,this order may in some cases be repeated in cycles1 and overlapping of the successive events is a common feature4 ,one of the interesting facts is the way in which the igneous mass has invaded and extensively altered the country rocks in some mineral districts1--in some cases by crowding and crumpling them1 and in others without greatly disturbing their structural attitudes4 ,the latter is illustrated in the ,bingham district of ,utah and the ,philipsburg district of ,montana4 ,in such cases there is so little evidence of crowding of the country rocks as to raise the question how such large masses of intrusives could be introduced without greater disturbing structural effect4 ,this leads naturally to consideration of the general problem of the manner of progress of magmas through adjacent rocks1--a subject which is still largely in the realm of speculation1 but which is not thereby eliminated from the field of controversy4 ,facts of this kind seem to favor the position of certain geologists that magmas may assimilate the rocks they invade4 ,,evidence ,,of ,,igneous ,,source ,no one ever saw one of these deposits in the process of formation2 the conclusion1 therefore1 that they originated from hot solutions1 either aqueous or gaseous1 or both1 which were essentially after-effects of igneous activity and came from the same primary source as the associated igneous rocks1 is an inference based on circumstantial evidence of the kind below summarized3 7#a7 ,the close association both in place and age with igneous rocks4 ,this applies not only to individual deposits1 but to certain groups of deposits which have common characteristics1 and which constitute a metallogenic province2 also to groups of the same geologic age1 which indicate a metallogenic epoch 7pp4 #cjh-cji74 ,the association with igneous rocks in one place might be a coincidence but its frequent repetition can hardly be so explained4 ,a zonal arrangement of minerals about intrusives is often noted4 ,geologic evidence often shows the processes of ore deposition to have been complete before the next succeeding geologic event1--as for instance in the ,tonopah district of ,nevada 7p4 #bcf71 where the ores have been formed in relation to certain volcanic flows and have been covered by later flows not carrying ore1 without any considerable erosion interval between the two events4 7#b7 ,the general contrast in mineralogical and chemical composition1 texture1 and mineral associations1 between these ore minerals and the minerals known to be formed by ordinary surficial agencies under ordinary temperatures4 ,the latter carry distinctive evidences of their origin4 ,when1 therefore1 a mineral group is found which shows contrasting evidences1 it is clear that some other agencies have been at work2 and the natural assumption is that the solutions were hot rather than cold2 that they came from below rather than above4 7#c7 ,the contrast between the character and composition of these ores 7and their associated gangue7 and the character and composition of the wall rocks1 together with the absence of leaching of the wall rocks1 favor the conclusion that the ore minerals are foreign substances introduced from extraneous sources4 ,the source not being apparent above and the processes there observed not being of a kind to produce these results1 it is concluded that the depositing solutions were hot and came from below4 7#d7 ,the fact that many of the ore minerals are never known to develop under ordinary temperatures at the surface4 ,for some of them1 experimental work has also indicated high temperature as a requisite to their formation4 ,quartz1 which is a common associate of the ores and often constitutes the principal gangue1 serves as a geologic thermometer in that it possesses an inversion point or temperature above which it crystallizes in a certain form1 below which in another4 ,in deposits of this class it has often been found to crystallize at the higher temperatures4 ,the quartz sometimes shows bubbles containing liquid1 gas1 and small heavy crystals1 probably of ferric oxide1 as in the ,clifton-,morenci district of ,arizona4 ,it is clear that the ore-bearing solutions in these cavities1 before the crystallization of the heavy mineral inclusions1 held dissolved not only much larger quantities of mineral substances than can be taken up by water at ordinary temperatures1 but also a substance like ferric oxide which is entirely insoluble under ordinary cool conditions4 7#e7 ,the association of the ores with minerals carrying fluorine and boron1 with many silicate minerals1 such as garnet1 amphiboles1 pyroxenes1 mica 7sericite7 and others1 and with other minerals which are known to be characteristic developments within or near igneous masses and which are not known to form under weathering agencies at the surface4 ,various characteristic groupings of these associated minerals are noted4 ,in limestone much of the mass may be replaced by garnet and other silicates in a matrix of quartz4 ,in igneous rock the ore-bearing solutions may have altered the wall rock to a dense mixture of quartz1 sericite1 and chlorite4 ,where sericite is dominant1 the alteration is called sericitic alteration4 ,where chlorite is important1 it is sometimes called chloritic or propylitic alteration4 ,the chloritic phases are usually farther from the ore deposit than the sericitic phases1 indicating less intense and probably cooler conditions of deposition4 ,locally other minerals are associated with the ores1 as1 for instance1 in the ,goldfield district of ,nevada 7p4 #bcj71 where alunite replaces the igneous rock4 ,alunite is a potassium-aluminum sulphate1 which differs from sericite in that sulphur takes the place of silicon4 ,in the quartzites of the lead-silver mines of the ,coeur d',alene district of ,idaho 7p4 #bab71 siderite or iron carbonate is a characteristic gangue material replacing the wall rock4 ,quartz in some cases1 as noted above1 gives evidence of high temperature origin and therefore of igneous association4 ,jasperoid quartz1 as well illustrated in the ,tintic district of ,utah 7p4 #bce71 may show texture and crystallization suggestive of deposition from colloidal solution1--a process which can occur under both cold and hot conditions1 but which is believed to be accelerated by heat4 ,certain minerals1 such as magnetite1 ilmenite1 spinel1 corundum1 etc41 are often found as primary segregations within the mass of igneous rock4 ,these and other minerals1 including minerals of tin and tungsten1 monazite1 tourmaline1 rutile1 and various precious stones1 are characteristically developed in pegmatites1 which are known to be igneous rocks1 crystallized in the later stages of igneous intrusion4 ,when1 therefore1 such minerals are found in other ore deposits an igneous source is a plausible inference4 ,for instance1 in the copper veins of ,butte1 ,montana 7p4 #bja71 are found cassiterite 7tin oxide7 and tungsten minerals4 ,their presence1 therefore1 adds another item to the evidence of a hot-water source from below4 7#f7 ,the occasional existence of hot springs in the vicinity of these ore deposits4 ,where hot springs are of recent age they may suggest by their heat1 steady flow1 and mineral content1 that they are originating from emanations from the still cooling magmas4 ,in the ,tonopah camp 7p4 #bcf71 cold and hot springs exist side by side1 exhibiting such contrasts as to suggest that some are due to ordinary circulation from the surface and that others may have a deep source below in the cooling igneous rocks4 ,this evidence is not conclusive4 ,hot springs in general fail to show evidence of ore deposition on any scale approximating that which must have been involved in the formation of this class of ore bodies4 ,much has been made of the slight amounts of metallic minerals found in a few hot springs1 but the mineral content is small and the conclusion by no means certain that the waters are primary waters from the cooling of igneous rocks below4 ,in this connection the mercury deposits of ,california 7p4 #bei71 contribute a unique line of evidence4 ,in areas of recent lavas1 mercuric sulphide 7cinnabar7 is actually being deposited from hot springs of supposed magmatic origin1 the waters of which carry sodium carbonate1 sodium sulphide1 and hydrogen sulphide1--a chemical combination known experimentally to dissolve mercury sulphide4 ,the oxidation and neutralization of these hot-spring solutions near the surface throws out the mercury sulphide4 ,at the same time the sulphuric acid thus formed extensively leaches and bleaches the surrounding rocks4 ,such bleaching is common about mercury deposits4 ,when it is remembered that the mercury deposits contain minor amounts of gold and silver and sulphides of other metals2 that they are closely associated with gold and silver deposits2 and further that such gold1 silver1 and other sulphide deposits often contain minor amounts of mercury1--it is easy to assume the possibility that these minerals may likewise have had their origin in hot solutions from below4 ,the presence of mercury in a deposit then becomes suggestive of hot-water conditions4 7#g7 ,ores sometimes occur in inverted troughs indicating lodgment by solutions from below1 as1 for instance1 in the saddle-reef gold ores of ,nova ,scotia and ,australia1 and in certain copper ores of the ,jerome camp of ,arizona 7p4 #bjd47 ,this occurrence does not indicate whether the solutions were hot or cold1 magmatic or meteoric1 but in connection with other evidences has sometimes been regarded as significant of a magmatic source beneath4 ,perhaps no one of these lines of evidence is conclusive2 but together they make a strong case for the conclusion that the solutions which deposited the ores of this class were hot1 came from deep sources1 and were probably primary solutions given off by cooling magmas4 ,the conclusion that some ores are derived from igneous sources1 based on evidence of the kind above outlined1 does not mean necessarily that the ore is derived from the immediately adjacent part of the cooling magma4 ,in fact the evidence is decisive1 in perhaps the majority of cases1 that the source of the mineral solutions was somewhat below2 that these solutions may have originated in the same melting-pot with the magma1 but that they came up independently and a little later1--perhaps along the same channels1 perhaps along others4 ,,possible ,,influence ,,of ,,meteoric ,,waters ,,in ,,deposition ,,of ,,ores ,,of ,,this ,,class ,it is hardly safe1 with existing knowledge1 to apply the above conclusion to all ore deposits with igneous associations1 or in any case to eliminate entirely another agency1--namely1 ground-waters of surface or meteoric origin1 which are now present and may be presumed often to have been present in the rocks into which the ores were introduced4 ,such waters may have been heated and started in vigorous circulation by the introduction of igneous masses1 and thereby may have been enabled to effectively search out and segregate minutely disseminated ore particles from wide areas4 ,this has been suggested as a probability for the ,kennecott copper ores of ,alaska 7p4 #bjj7 and for the copper ores of ,ely1 ,nevada4 ,in the ,goldfield camp 7p4 #bcj7 the ores are closely associated with alunite in such a manner as to suggest a common origin4 ,it has been found difficult to explain the presence of the alunite except through the agency of surface oxidizing waters acting on hydrogen sulphide coming from below4 ,in the early days of economic geology there was relatively more emphasis on the possible effectiveness of ground-waters in concentrating ores of this type4 ,with the recognition of evidence of a deeper source related to magmas1 the emphasis has swung rapidly to the other extreme4 ,while the evidence is sound that the magmatic process has been an important one1 it is difficult to see how and to just what extent this process may have been related to the action of ground-waters1--which were probably present in a heated condition near the contact4 ,it may never be possible to discriminate closely between these two agencies4 ,it seems likely that at some stages the two were so intimately associated that the net result of deposition cannot be specifically assigned either to one or to the other4 ,,zonal ,,arrangement ,,of ,,minerals ,,related ,,to ,,igneous ,,rocks ,evidence is accumulating in many mining districts that ore deposits of these igneous associations were deposited with a rough zonal arrangement about the igneous rock4 ,at ,bingham1 ,tintic1 and ,butte 7pp4 #bjd1 #bjh1 #bce71 copper ores are on the whole closest to the igneous rock1 and the lead1 zinc1 and silver ores are farther away4 ,furthermore1 the quartz gangue near the igneous rock is likely to contain minerals characteristic of hot solutions1 while farther away such minerals as dolomite and calcite appear in the gangue1 suggestive of cooler conditions4 ,in ,cornwall 7p4 #bfb71 tin ores occur close to the intrusives1 and lead-silver ores farther away4 ,the gradations are by no means uniform2 shoots of one class of ore may locally cut abruptly across or through those of another class4 ,the existence of zones horizontally or areally arranged about intrusives suggests also the possibility of a vertical zonal arrangement with reference to the deep sources of the solutions4 ,of course when secondary concentration from the surface1 described later1 is taken into account1 there may be a marked zonal distribution in a vertical direction1 but this is not primary zoning4 ,a few veins and districts show evidence of vertical zoning apparently related to primary deposition2 for the most part1 however1 in any one mine or camp there is yet little evidence of primary vertical zoning4 ,on the other hand1 certain groups of minerals are characteristic of intense conditions of heat and pressure1 as indicated by the coarse recrystallization and high degree of metamorphism of the rocks with which they are associated2 and other groups have such associations as to indicate much less intense conditions of temperature and pressure4 ,depth is only one factor determining intensity of conditions1 but it affords a convenient way to indicate them2 so mineral deposits associated with igneous rocks are sometimes classified by economic geologists on the basis of deep1 intermediate1 and shallow depths of formation4 ,there are a considerable number of minerals which are formed in all three of these zones1 although in differing proportions4 ,there are comparatively few which are uniformly characteristic of a single zone4 ,on the whole1 it is possible to contrast satisfactorily mineral deposits representing very intense metamorphic conditions1 usually associated with formation at great depth1 with those formed at or near the surface2 but there are many deposits with intermediate characteristics which it is difficult to place satisfactorily4 ,the accessible deposits of the deep zone are associated with plutonic igneous rocks which have been deeply eroded1 and not with surface lavas4 ,they are characterized by minerals of gold1 tin1 iron1 titanium1 zinc1 and copper1 and sometimes of tungsten and molybdenum1 in a gangue of quartz1 which contains also minerals such as garnet1 corundum1 amphibole1 pyroxene1 tourmaline1 spinel1 and mica4 ,the deep-zone minerals are not unlike the pegmatite minerals in their grouping and associations4 ,deposits formed at shallow depths are related to extrusive rocks and to intrusives near the surface4 ,erosion has not been deep4 ,mercury1 silver and gold 7tellurides1 native metals1 and silver sulphides71 antimony1 lead1 and zinc minerals are characteristic1 together with alunite1 adularia1 and barite4 ,metallic copper also is not infrequent4 ,very often the gangue material is more largely calcite than quartz1 whereas calcite is not present in the deep zone4#e ,the trend of evidence in recent years has favored the conclusion that the principal ores associated with igneous rocks have not developed at very great depths4 ,even within our narrow range of observation there is a difference in favor of the shallower depths1 and the greatest depths we can observe are after all but trivial on the scale of the earth4 ,a survey of the ore deposits of ,utah has suggested the generalization that ores are more commonly related to intrusive stocks than to the forms known as laccoliths1 and that within and about intrusive stocks the ores are much more abundant near the top or apex of a stock than lower down4#f ,in parts of the region where erosion has removed all but the deeper portions of the stocks1 ore bodies are less abundant4 ,it will be of interest to follow the testing of this generalization in other parts of the world4 ,the scientist is constantly groping for underlying simple truth4 ,such glimpses of order and symmetry in the distribution of ore around igneous rocks as are afforded by the facts above stated1 tempt the imagination to a conception of a simple type or pattern of ore distribution around intrusions4 ,for this reason we should not lose sight of the fact that1 in the present state of knowledge1 the common and obvious case is one of irregular and heterogeneous distribution1 and that there are many variations and contradictions even to the simplest generalization that can be made4 ,the observer is repeatedly struck by the freakish distribution of ores about igneous masses1 as compared with their regularity of arrangement under sedimentary processes to be discussed later4 ,it is yet unexplained how an intrusive like the ,butte granite can produce so many different types of ores at different places along its periphery or within its mass1 and yet all apparently under much the same general conditions and range of time4 ,it is difficult also to discern the laws under which successive migrations of magma1 from what seems to be a single deep-seated source or melting-pot1 may carry widely contrasting mineral solutions4 ,far below the surface1 beyond our range of observation1 it is clear that there is a wonderful laboratory for the compounding and refinement of ores1 but as to its precise location and the nature of its processes we can only guess4 ,other features of distribution of minerals associated with igneous rocks are indicated by their grouping in metallogenic provinces and epochs 7see pp4 #cjh-cji74 ,,the ,,relation ,,of ,,contact ,,metamorphism ,,to ,,ore ,,bodies ,,of ,,the ,,foregoing ,,class4 ,the deposition of ores of igneous source in the country rock into which the igneous rocks are intruded is a phase of contact metamorphism4 ,ordinarily where this deposition occurs there are further extensive replacements and alterations of the country rock1 resulting in the development of great masses of quartz1 garnet1 pyroxene1 amphibole1 and other silicates1 and in some cases of calcite1 dolomite1 siderite1 barite1 alunite1 and other minerals4 ,looked at broadly1 the deposition of ores at igneous contacts under contact metamorphism is a mere incident in the much more widespread and extensive alterations of this kind4 ,hence it is that the subject of contact metamorphism is of interest to economic geologists4 ,the minerals here formed which do not constitute ores throw much light on the nature of the ore-bearing solutions1 the conditions of temperature and pressure1 and the processes which locally and incidentally develop the ore bodies4 ,the subject1 however1 is a complex one1 the full discussion of which belongs in treatises on metamorphism4#g ,we may note only a few salient features4 ,for many hundreds of yards the rocks adjacent to the intrusions may be metamorphosed almost beyond recognition4 ,this is especially true of the limestone1 which may be changed completely to solid masses of quartz and silicates4 ,the shales and sandstones are ordinarily less vitally affected4 ,the shales become dense1 highly crystalline rocks of a hornstone type1 with porphyritic developments of silicate minerals4 ,the sands and sandstones become highly crystalline quartzites1 spotted with porphyritic developments of silicates4 ,occasionally even these rocks may be extensively replaced by other minerals1 as in the ,coeur d',alene district1 where quartzites adjacent to the ore veins may be completely replaced by iron carbonate4 ,a question of special interest to economic geologists is the source of the materials for the new minerals in these extensively altered zones4 ,in some cases the minerals are known to be the result of recrystallization of materials already in the rock1 after the elimination of certain substances such as carbon dioxide and lime1 under the pressures and temperatures of the contact conditions4 ,in such cases there has obviously been large reduction in volume to close the voids created by the elimination of substances4 ,in the majority of cases1 the new substances or minerals are clearly introduced from the igneous source1 replacing the wall rock volume for volume so precisely that such original textures and structures as bedding are not destroyed4 ,in many cases the result is clearly due to a combination of recrystallization of materials already present and introduction of minerals by magmatic solutions from without4 ,so obvious is the evidence of the introduction of materials from without1 that there has been a tendency in some quarters to overlook the extensive recrystallization of substances already present2 and the varying emphasis placed on these two processes by different observers has led to some controversy4 ,,secondary ,,concentration ,,in ,,place ,,of ,,the ,,foregoing ,,classes ,,of ,,mineral ,,deposits ,,through ,,the ,,agency ,,of ,,surface ,,solutions ,mineral deposits of direct magmatic segregation are seldom much affected by surficial alteration1 perhaps because of their coarse crystallization and their intermingling with resistant crystalline rocks4 ,mineral deposits of the igneous after-effect type may be profoundly altered through surficial agencies4 ,the more soluble constituents are taken away1 leaving the less soluble4 ,the parts that remain are likely to be converted into oxides1 carbonates1 and hydrates1 through reaction with oxygen1 carbon dioxide1 and water1 which are always present at the surface and at shallow depths4 ,these processes are most effective at the surface and down to the level of permanent ground-water1 though locally they may extend deeper4 ,this altered upper part of the ore bodies is usually called the oxide zone4 ,it may represent either an enrichment or a depletion of ore values1 depending on whether the ore minerals are taken into solution less rapidly or more rapidly than the associated minerals and rocks2 all are removed to some extent4 ,in certain deposits1 there is evidence that both zinc and copper have been taken out of the upper zone in great quantity2 but they happen to be associated with limestone1 which has dissolved still more rapidly1 with the result that there is a residual accumulation of copper and zinc values4 ,manganese1 iron1 and quartz are usually more resistant than the other minerals and tend to remain concentrated above4 ,the same is true to some extent of gold and silver4 ,the abundance of iron oxide thus left explains the name iron cap or gossan so often applied to the upper part of the oxide zone4 ,not infrequently1 and especially in copper ores1 the upper part of the oxide zone is nearly or entirely barren of values and is called the capping4 ,the depth or thickness of the oxide zone depends on topography1 depth of water table1 climatic conditions1 and speed of erosion4 ,a fortunate combination of conditions may result in a deep oxide zone with important accumulations of values4 ,in other cases erosion may follow oxidation so rapidly as to prevent the growth of a thick oxide zone4 ,it is clear from the study of many ore deposits that the process of oxidation has not proceeded uniformly to the present1 but has depended upon a fortunate combination of factors which has not been often repeated during geologic time4 ,as illustrative of this1 the principal oxidation of the ,bisbee copper ores of ,arizona 7p4 #bjd7 occurred before ,tertiary time1 with reference to a place that has since been covered by later sediments4 ,the conditions in the ,ray1 ,miami1 and ,jerome copper camps of ,arizona 7pp4 #bjc-bje7 likewise indicate maximum oxidation at an early period4 ,the ,lake ,superior iron ore deposits 7pp4 #afg-agj7 were mainly concentrated before ,cambrian time1 during the base-leveling of a mountainous country in an arid or semi-arid climate4 ,the oxide zone of these deposits has no close relation to the present topography or to the present ground-water level4 ,in the ,kennecott 7,alaska7 copper deposits all oxidation has been stopped since glacial time by the freezing of the aqueous solutions4 ,at ,butte and at ,bingham the main concentration of the ores is believed to have occurred in an earlier physiographic cycle than the present one4 ,the cyclic nature of the formation of oxide zones is of comparatively recent recognition1 and much more will doubtless be found out about it in the comparatively near future4 ,its practical bearing on exploration is obvious 7see p4 #cbe74 ,it should be clearly recognized that oxidizing processes are not limited to the zone above the ground-water level4 ,locally oxidizing solutions may penetrate and do effective work to much greater depths1 especially where the rocks traversed at higher elevations are of such composition or in such a stage of alteration as not to extract most of the oxygen4 ,consequently the presence of oxide ores below the water table is not necessarily proof that the water table has risen since their formation4 ,on the other hand1 the facts of observation do indicate generally a marked difference1 in circulation and chemical effect1 between waters above and below this horizon1 and show that oxidation is dominantly accomplished above rather than below this datum surface4 ,during the formation of the oxide zone1 erosion removes some of the ore materials entirely from the area1 both mechanically and in solution4 ,part of the material in solution1 however1 is known to penetrate downward and to be redeposited in parts of the ore body below the oxide zone1--that is1 usually below the water table4 ,evidence of this process is decisive in regard to several minerals4 ,copper is known to be taken into solution as copper sulphate at the surface1 and to be redeposited as chalcocite where these sulphate solutions come in contact with chalcopyrite or pyrite below4 ,not only has the process been duplicated in the laboratory1 but the common coating of chalcocite around grains of pyrite and chalcopyrite below the water level indicates that this process has been really effective4 ,sulphides of zinc1 lead1 silver1 and other metals are similarly concentrated1 in varying degrees4 ,the zone of deposition of secondary sulphides thus formed is called the zone of secondary sulphide enrichment4 ,ores consisting mainly of secondary sulphides are also called supergene ores 7p4 #cc74 ,in some deposits1 as in the copper deposits of ,ray and ,miami1 there is found1 below the secondary sulphide zone1 a lean sulphide zone which is evidently of primary nature4 ,the mineralized material of this zone1 where too lean to mine1 has been called a protore4 ,with the discovery of undoubted evidence of secondary sulphide enrichment1 there was a natural tendency to magnify its importance as a cause of values4 ,continued study of sulphide deposits1 while not disproving its existence and local importance1 has in some districts shown clearly that the process has its limitations as a factor in ore concentration1 and that it is not safe to assume its effectiveness in all camps or under all conditions4 ,at ,butte for instance1 secondary chalcocite is clearly to be recognized4 ,the natural inference was that as the veins were followed deeper the proportion of chalcocite would rapidly diminish1 and that a leaner primary zone of chalcopyrite1 enargite and other primary minerals would be met4 ,however1 the great abundance of chalcocite in solid masses which have now been proved to a depth of #cejj feet1 far below the probable range of waters from the surface in any geologic period1 seems to indicate that much of the chalcocite is primary4 ,the present tendency at ,butte is to consider as secondary chalcocite only certain sooty phases to be found in upper levels4 ,the solid masses of chalcocite in the ,kennecott copper mines seem hardly explainable as the result of secondary sulphide enrichment4 ,no traces of other primary minerals are present and the chalcocite here is regarded as probably primary4 ,the possible magnification of the process of secondary enrichment above referred to has had for its logical consequence a tendency to over-emphasize the persistence of primary ores in depth4 ,the very use of the terms secondary and primary has suggested antithesis between surficial and deep ores4 ,progress in investigation1 as indicated on previous pages1 seems to indicate that the primary ores are not uniformly deep and that in many cases they are distinctly limited to a given set of formations or conditions comparatively near the surface4 ,in general the processes of oxidation and secondary sulphide enrichment have been studied mainly by qualitative methods with the aid of the microscope and by considerations of possible chemical processes4 ,these methods have disclosed the nature but not the quantitative range and relations of the different processes4 ,much remains to be done in the way of large scale quantitative analysis of ores at different depths1 as a check to inferences drawn by other methods4 ,one may know1 for instance1 that a mineral is soluble and is actually removed from the oxide zone and redeposited below4 ,the natural inference1 therefore1 is that the mineral will be found to be depleted above and enriched below4 ,in many cases its actual distribution is the reverse1--indicating that this process has been only one of the factors in the net result1 the more rapid solution and deposition of other materials being another factor4 ,if one were to approach the study of the concentration of iron ores with the fixed idea of insolubility of quartz from a chemical standpoint1 and were to draw conclusions accordingly1 he would fail to present a true picture of the situation4 ,while quartz is insoluble as compared with most minerals1 it is nevertheless more soluble than iron oxide1 and therefore the net result of concentration at the surface is to accumulate the iron rather than the silica4 ,descriptions of enrichment processes as published in many reports are often misleading in this regard4 ,they may be correct in indicating the actual existence of a process1 but may lead the reader to assumptions as to net results which are incorrect4 ,,residual ,,mineral ,,deposits ,,formed ,,by ,,the ,,weathering ,,of ,,igneous ,,rocks ,,in ,,place ,igneous rocks not containing mineral deposits may on weathering change to mineral deposits4 ,the lateritic iron ores such as those of ,cuba 7p4 #agb71 many bauxite deposits1 many residual clays1 and certain chromite and nickel deposits are conspicuous representatives of this class4 ,the chemical and mineralogical changes involved in the formation of these deposits are pretty well understood4 ,certain constituents of the original rock are leached out and carried away1 leaving other constituents1 as oxides and hydrates1 in sufficiently large percentage in the mass to be commercially available4 ,the accumulation of large deposits depends on the existence of climatic and erosional conditions which determine that the residual deposit shall remain in place rather than be carried off by erosion as fast as made4 ,in the glaciated parts of the world1 deposits of this nature have usually been removed and dispersed in the glacial drift4 ,when the minerals of these deposits are eroded1 transported1 and redeposited in concentrated form1 they come under the class of placer or sedimentary deposits described under the following heading4 ,there are of course many intermediate stages1 where the residual deposit is only locally moved and where the distinction between this class of deposits and that next described is an arbitrary one4 ,,mineral ,,deposits ,,formed ,,directly ,,as ,,placers ,,and ,,sediments ,mineral deposits of this class are of large value1 including as they do salt1 gypsum1 potash1 sulphur1 phosphates1 nitrates1 and important fractions of the ores of iron1 manganese1 gold1 tin1 tungsten1 platinum1 and precious stones2 also many common rocks of commercial importance4 ,the minerals of these deposits are derived from the weathering and erosion of land surfaces1 either igneous or sedimentary4 ,they are deposited both under air and under water1 both mechanically and chemically 7in part by the aid of organisms74 ,these deposits form the principal type of syngenetic deposits 7p4 #cb72 the term sedigenetic deposits has also been applied to them4 ,,mechanically ,,deposited ,,minerals ,mechanical erosion of preexisting mineral deposits or rocks and their transportation1 sorting1 and deposition are responsible for the placers of gold1 tin1 tungsten1 platinum1 and various precious stones1 and for certain iron sands and conglomerates4 ,sands1 sandstones1 shales1 and certain clays and bauxites also belong in this group4 ,these deposits may be formed under air or under water1 and under various climatic and topographic conditions4 ,during the process of formation the minerals of differing density are more or less sorted out and tend to become segregated in layers4 ,the process is not unlike the artificial process of mechanical concentration where ores are crushed1 shaken up1 and treated with running water4 ,the process is most effective for minerals which are resistant to abrasion and to solution1 and of such density as to differentiate them from the other minerals of the parent rock4 ,the origin of deposits of this kind is fairly obvious where they are of recent age and have not been subsequently altered or buried4 ,a considerable amount of experimental work has brought out clearly the main elements of the processes4 ,physiographic and climatic conditions play an important part1 and cannot be safely overlooked by anyone studying such deposits4 ,extensive copper deposits exist as sediments 7pp4 #bje-bjf74 ,it is not clear to what extent they are mechanically or to what extent chemically deposited4 ,for the most part the concentration of copper in this manner has not been sufficient to yield deposits of large commercial value2 the mineral is too much dispersed4 ,relatively small amounts are mined in the ,mansfield shales of ,germany and the ,nonesuch shales and sandstones of the ,lake ,superior country4 ,the ,clinton and similar iron ores of the ,united ,states and ,newfoundland1 the pre-,cambrian iron ores of ,brazil1 and the ,jurassic iron ores of ,england and western ,europe 7pp4 #aff-afg7 are now commonly agreed to be direct sedimentary deposits in which mechanical agencies of sorting and deposition played a considerable part4 ,how far chemical and bacterial agencies have also been effective is not clear4 ,the climatic1 topographic1 and other physiographic and sedimentary conditions which cause the deposition of this great group of ores present one of the great unsolved problems of economic geology4 ,the study of present-day conditions of deposition affords little clue as to the peculiar combination of conditions which was necessary to accomplish such remarkable results in the past4 ,on the whole1 minerals of this mechanically deposited group are not greatly affected by later surficial alteration and concentration1 because1 having already been subjected to weathering1 they are in a condition to resist such influences4 ,,chemically ,,and ,,organically ,,deposited ,,minerals ,the products of surface weathering and erosion are in part carried away in chemical solution and redeposited as sediments4 ,sediments thus formed include limestone and dolomite1 siderite1 salt1 gypsum1 potash1 sulphur1 phosphates1 nitrates1 and other minerals4 ,precipitation may be caused by chemical reactions1 by organic secretion1 or by evaporation of the solutions4 ,the processes are qualitatively understood and it is usually possible to ascertain with reasonable accuracy the conditions of depth of water1 relation to shore line1 climate1 nature of erosion1 and other similar factors2 yet the vast scale of some of these deposits1 and their erratic areal and stratigraphic distribution1 present unsolved problems as to the precise combinations of factors which have made such results possible4 ,chemically and organically deposited minerals of this class are usually susceptible to further alteration by surface weathering1 and some of them1 for instance the phosphates and siderites1 are thus secondarily concentrated4 ,these processes are discussed under the next heading4 ,in general the great unsolved problem of the origin of the entire group of mineral deposits in placers and sediments relates to the scale of the results4 ,observation of present-day processes and conditions of deposition of these minerals affords satisfactory evidence of their nature1 but fails to give us a clear idea of the precise combinations of agencies and conditions necessary to produce such vast results as are represented by the mineral deposits4 ,for example1 solution of iron on a land surface and redeposition in bogs and lagoons 7as actually observed to be taking place today7 show how some iron-ore sediments may be formed2 but these processes are entirely inadequate to explain the deposition of iron ores in thick masses over broad areas without intermingling of other sediments--as represented by the ,clinton iron ores of ,north ,america1 the ,jurassic ores of ,europe and ,england1 and the ancient iron ores of ,brazil4 ,the ,paleozoic seas in northern and eastern ,united ,states encroached over land areas to the north and east and deposited ordinary sediments such as sandstone1 shale1 and limestone4 ,suddenly1 without1 so far as known1 tapping any new sources of supply on the ancient land areas1 and without any yet ascertainable change in topographic or climatic conditions1 they deposited enormous masses of iron ore4 ,there is clearly some cyclic factor in the situation which we do not yet understand4 ,the various deposits of salt1 gypsum1 potash1 sulphur1 and other minerals are known to be the result of evaporation1 and the deposition of each of these minerals is known to be related to the degree of evaporation as well as to temperature1 pressure1 and factors such as mass action and crystallization of double salts4 ,the nature of the processes is fairly well understood2 but again1 observation of the present-day operation of these processes fails to give us much clue to the enormous accumulations at certain times and places in the past4 ,it is difficult to say just what conditions of climate1 in combination with particular physiographic factors1 could have preserved uniformity of conditions for the long periods necessary to account for some of the enormously thick salt deposits4 ,again some cyclic factor in the situation remains to be worked out4 ,,sedimentary ,,mineral ,,deposits ,,which ,,have ,,required ,,further ,,concentration ,,to ,,make ,,them ,,commercially ,,available ,the conditions for the direct deposition of sedimentary mineral deposits of the foregoing class are also responsible for the deposition of minerals in more dispersed or disseminated form1 requiring further concentration through surface agencies to render them commercially available4 ,some of these deposits are discussed below4 ,the lead and zinc ores of the ,mississippi ,valley1 ,virginia1 ,tennessee1 ,silesia1 ,belgium1 and ,germany 7pp4 #baa-bab1 #baf-bai7 are in sedimentary rocks far removed from igneous sources4 ,lead and zinc were deposited in more or less dispersed form with the enclosing sediments4 ,it is supposed that deposition was originally chemical and was favored by the presence of organic material1 which is a rather common accompaniment of the sediments4 ,it is supposed further that these organic participants were originally localized during sedimentation in so-called estuarine channels and shore-line embayments4 ,when subsequently exposed to weathering1 the lead and zinc minerals were dissolved and redeposited in more concentrated form in fissures and as replacements of limestone4 ,agreement as to origin of these deposits1 so far as it exists1 does not go beyond these broad generalizations4 ,there is controversy as to whether the original sources of the ore minerals were the sediments directly above1 from which the mineral solutions have been transferred downward during weathering and erosion1 or whether the original minerals were below and have been transferred upward by artesian circulation1 or whether they were situated laterally and have been brought to their present position by movement along the beds1 or whether there has been some combination of these processes4 ,it is the writer's view that the evidence thus far gathered favors on the whole the conclusion of direct downward concentration from overlying sources which have been removed by erosion1 although this conclusion fails to explain why certain sulphide deposits give so little evidence of important downward transfer from their present position4 ,this matter is further discussed on pages #baf-bai4 ,the choice of the various alternatives has some practical bearing on exploration4 ,since these ores were brought into approximately their present position1 they have undergone considerable oxidation near the surface and secondary sulphide enrichment below4 ,the chemical and mineralogical changes are pretty well understood1 but the quantitative range of these changes and their relative importance in determining the net result are far from known4 ,undoubted evidence of secondary sulphide enrichment has led in some quarters to an assumption of effectiveness in producing values which is apparently not borne out by quantitative tests4 ,a group of mineral deposits in sandstones in ,utah is regarded as due to chemical concentration of material originally disseminated in the rock4 ,they include silver1 copper1 manganese1 uranium1 and radium deposits4 ,the ,silver ,reef deposits1 including silver1 copper1 uranium1 and vanadium1 are commercially the most important of this type4#h ,the ore minerals are commonly associated with carbonized material representing plant remains1 and have replaced the calcareous and cementing material of the rock1 and also some of the quartz grains4 ,the deposits are regarded as having been formed by circulating waters which collected the minerals disseminated through the sedimentary rocks1 and deposited them on contact with carbonaceous matter1 earlier sulphides1 or other precipitating agents4 ,the circulation in some places is believed to have been of artesian character and to have been controlled to a large extent by structural features4 ,the ,silver ,reef deposits are near the crest of a prominent anticline4 ,most of the minerals have been later altered by surface solutions4 ,another great group of ores to be considered under this head are the iron ores of ,lake ,superior1--which were originally deposited as sediments1 called jaspers or iron formations1 with too low a percentage of iron to be of use1 and which have required a secondary concentration by surficial agencies to render them valuable4 ,the process of concentration has been a simple one4 ,the iron minerals have been oxidized in place and the non-ferrous minerals have been leached out1 leaving iron ores4 ,this process contrasts with the concentration described above1 in that there is little evidence of collection of iron minerals from disseminated sources4 ,the ,lake ,superior iron ores are essentially residual concentrations in place4 ,the outstanding problems of secondary concentration relate to the structural features which determined the channels through which the oxidizing and leaching waters worked1 and to the topographic and climatic conditions which existed at the time the work was done4 ,as with many other classes of ores1 it was first assumed that these processes were related to the present erosion surface2 but it is now known that concentration happened long ago under conditions far different from those now existing4 ,these deposits contribute to the rapidly accumulating evidence of the cyclic nature of ore concentration4 ,our least satisfactory knowledge of the ,lake ,superior ores relates to the peculiar conditions which determined the initial stage of sedimentation of the so-called iron formation4 ,as in the case of the ,clinton iron ores1 no present-day sedimentation gives an adequate clue4 ,students of the problem have fallen back on the association of the iron formation with contemporaneous volcanic rocks1 as affording a possible explanation of the wide departure from ordinary conditions of sedimentation evidenced by these formations4#i ,coal deposits are direct results of sedimentation of organic material4 ,they are mainly accumulations of vegetable matter in place4 ,to make them available for use1 however1 they undergo a long period of condensation and distillation4 ,conditions of primary deposition may be inferred from modern swamps and bogs2 but1 as in the case of sediments described under the preceding heading1 we are sometimes at a loss to explain the magnitude of the process1 and especially to explain the maintenance of proper surface conditions of plant growth and accumulation for the long periods during which subsidence of land areas and encroachment of seas are believed to have been taking place4 ,the processes of secondary concentration are also understood qualitatively1 but much remains to be learned about the influences of pressure and heat1 the effect of impervious capping rocks1 and other factors4 ,various oil shales and asphaltic deposits are essentially original sediments which have subsequently undergone more or less decay and distillation4 ,the migration of the distillates to suitable underground reservoirs is responsible for the accumulation of oil and gas pools4 ,oil and gas are distillates from these oil shales and asphaltic deposits1 and also from other organic sediments such as carbonaceous limestones4 ,the distillates have migrated to their present positions under pressure of ground-waters4 ,the stratigraphic horizons favorable to their accumulation are generally recognized4 ,the geologist is concerned in identifying these horizons and in ascertaining where they exist underground4 ,he is further concerned in analysis of the various structural conditions which will give a clue to the existence of local reservoirs in which the oil or gas may have been accumulated4 ,so capricious are the oil migrations that the most intensive study of these conditions still leaves vast undiscovered possibilities4 ,,anamorphism ,,of ,,mineral ,,deposits ,mineral deposits formed in any one of the ways indicated above may undergo repeated vicissitudes1 both at the surface and deep below the surface1 with consequent modifications of character4 ,they may be cemented or replaced by introduction of mineral solutions from without4 ,they may be deformed by great earth pressures1 undergoing what is called dynamic metamorphism 7pp4 #be-bg71 which tends to distort them and give them schistose and crystalline characters4 ,they may be intruded by igneous rocks1 causing considerable chemical1 mineralogical1 and structural changes4 ,all these changes may take place near the surface1 but on the whole they are more abundant and have more marked effects deep below the surface4 ,in general all these changes of the deeper zone tend to make the rocks more crystalline and dense and to make the minerals more complex4 ,cavities are closed4 ,the process is in the main an integrating and constructive one which has been called anamorphism1 to contrast it with the disintegrating and destructive processes near the surface1 which have been called katamorphism 7see also pp4 #bg-bh74 ,there is little in the process of anamorphism in the way of sorting and segregation which tends to enrich and concentrate the metallic ore bodies4 ,on the contrary the process tends to lock up the valuable minerals in resistant combinations with other substances1 making them more difficult to recover in mining4 ,later igneous intrusions or the ordinary ground-waters may bring in minerals which locally enrich ores under anamorphic conditions1 but these are relatively minor effects4 ,an illustration of the general effect is afforded by a comparison of the ,cuban iron ores1 which are soft and can be easily taken out1 with the ,cle ,elum iron ores of ,washington1 which seem to be of much the same origin1 but which have subsequently been buried by other rocks and rendered hard and crystalline4 ,in the first case the ores can be mined easily and cheaply with steam shovels at the surface4 ,in the second1 underground methods of mining are required1 which cost too much for the grade of ore recovered4 ,on the other hand1 the same general kind of anamorphic processes1 when applied to coal1 result in concentration and improvement of grade4 ,the same is true up to a certain point in the concentration of oil2 but where the process goes too far1 the oil may be lost 7pp4 #adj-ada74 ,,conclusion ,mineral deposits are formed and modified by practically all known geologic processes1 but looked at broadly the main values are produced in three principal ways3 7#a7 ,as after effects of igneous intrusion1 through the agency of aqueous and gaseous solutions given off from the cooling magma4 7#b7 ,through the sorting processes of sedimentation1--the same processes which form sandstone1 shale1 and limestone4 ,organic agencies are important factors in these processes4 7#c7 ,through weathering of the rock surface in place1 which may develop values either by dissolving out the valuable minerals and redepositing them in concentrated form1 or by dissolving out the non-valuable minerals and leaving the valuable minerals concentrated in place4 ,the latter process is by far the more important4 ,the overwhelming preponderance of values of mineral deposits as a whole is found in the second of the classes named4 ,under all these conditions it appears that the maximum results are obtained at and near the surface4 ,on the scale of the earth even the so-called deep veins may be regarded as deposits from solutions reaching the more open and cooler outer portions of the earth4 ,however1 valuable mineral deposits are found in the deepest rocks which have been exposed by erosion1 and the question of what would be found at still greater depths1 closer to the center of the earth1 is a matter of pure speculation4 ,ultimately all minerals are derived from igneous sources within the earth4 ,the direct contributions from these sources are only in small part of sufficient concentration to be of value2 for the most part they need sorting and segregation under surface conditions4 ,we can only speculate as to causes of the occurrence of valuable minerals in certain igneous rocks and not in others4 ,many granites are intruded into the outer shell of the earth1 but only a few carry minerals2 also1 of a series of intrusions in the same locality1 only one may carry valuable minerals4 ,it is clear that in some fashion these minerals are primarily segregated within the earth4 ,causes of this segregation are so involved with the problem of the origin of the earth as a whole that no adequate explanation can yet be offered4 ,our inductive reasoning from known facts is as yet limited to the segregation within a given mass of magma1 and even here the conditions are only dimly perceived4 ,a discussion of these ultimate problems is beyond the scope of this book4 ,,footnotes3 #d ,ransome1 ,frederick ,leslie1 ,copper deposits near ,superior1 ,arizona3 ,bull4 #edj1 ,u4 ,s4 ,geol4 ,survey1 #aiad1 pp4 #aeb-aec2 ,the copper deposits of ,ray and ,miami1 ,arizona3 ,prof4 ,paper #aae1 ,u4 ,s4 ,geol4 ,survey1 #aiai1 p4 #aef2 ,discussion3 ,econ4 ,geol41 vol4 #h1 #aiac1 p4 #gba4 #e ,for more specific definitions of vertical zones of ore deposition in association with igneous rocks see ,spurr1 ,j4 ,e41 ,theory of ore deposition3 ,econ4 ,geol41 vol4 #g1 #aiab1 pp4 #dhi-dij2 ,lindgren1 ,w41 ,mineral deposits1 ,mc,graw-,hill ,book ,co41 #b;d ed41 #aiai1 ,chapters ,,xxiv-,,xxvi2 and ,emmons1 ,w4 ,h41 ,the principles of economic geology1 ,mc,graw-,hill ,book ,co41 #aiah1 ,chapters ,,vi-,,viii4 ,an excellent discussion of a case of vertical and areal zoning of minerals is contained in ,ore deposits of the ,boulder batholith of ,montana1 by ,paul ,billingsley and ,j4 ,a4 ,grimes1 ,bull4 ,am4 ,inst4 ,min4 ,engrs41 vol4 #eh1 #aiah1 pp4 #bhd-cfh4 #f ,butler1 ,b4 ,s41 ,loughlin1 ,g4 ,f41 ,heikes1 ,v4 ,c41 and others1 ,the ore deposits of ,utah3 ,prof4 ,paper #aaa1 ,u4 ,s4 ,geol4 ,survey1 #aibj1 p4 #bja4 #g ,leith1 ,c4 ,k41 and ,mead1 ,w4 ,j41 ,metamorphic ,geology1 ,pt4 #b1 ,henry ,holt and ,company1 ,new ,york1 #aiae4 #h ,butler1 ,b4 ,s41 ,loughlin1 ,g4 ,f41 ,heikes1 ,v4 ,c41 and others1 ,the ore deposits of ,utah3 ,prof4 ,paper #aaa1 ,u4 ,s4 ,geol4 ,survey1 #aibj1 pp4 #aeb-aeh4 #i ,van ,hise1 ,c4 ,r41 and ,leith1 ,c4 ,k41 ,geology of the ,lake ,superior region4 ,mon4 #eb1 ,u4 ,s4 ,geol4 ,survey1 #aiaa1 pp4 #ejf-eah2 and references there given4 ,,chapter ,,iv ,,mineral ,,resources--,,some ,,general ,,quantitative ,,considerations ,of the #a1ejj known mineral species1 perhaps #bjj figure in commerce as mineral resources4 ,for the mineral substances used commercially1 the term mineral is used in this chapter with a broad significance to cover any or all of the materials from which the needed elements are extracted1--whether these materials be single minerals or groups of minerals2 whether they be rocks or ores2 whether they be liquid or solid4 ,the following figures are generalizations based on the miscellaneous information available4 ,the purpose is to indicate the general perspective rather than the detail which would be necessary for precise statement4 ,,world ,,annual ,,production ,,of ,,minerals ,,in ,,short ,,tons ,exclusive of water1 but inclusive of petroleum1 the world's annual output of mineral resources amounts to two billions of tons4 ,this figure refers to the crude mineral as it comes from the ground and not to the mineral in its concentrated form4 ,of this total extraction1 coal amounts to nearly #gj per cent1 stone and clay #aj per cent1 iron ore about #i per cent1 petroleum #d per cent1 copper ore #c per cent1 and all the remaining minerals constitute less than #f per cent4 ,if spread out on the surface in a uniform mass with an estimated average density based on relative proportions of the crude minerals1 this annual production would cover a square mile to a depth of #b1cjj feet4 ,of the total annual production #he per cent comes from countries bordering the ,north ,atlantic basin2 #ge per cent is accounted for by the ,united ,states1 ,england1 and ,germany2 the ,united ,states has #ci per cent of the total1 ,england #ah per cent1 and ,germany #ah per cent4 ,by continents1 ,europe accounts for nearly #ea per cent1 ,north ,america for nearly #db per cent1 ,asia for nearly #d per cent1 and the remaining continents for nearly #d per cent4 ,the ,united ,states mineral production in recent years has been about #ijj1jjj1jjj tons4 ,according to the ,united ,states census of #aibj1 nearly half of all the establishments or businesses engaged in quarrying or mining operations in this country are operating in oil and gas4 ,of the crude materials extracted from the ground perhaps #aj per cent1 including gold1 silver1 copper1 lead1 zinc1 nickel1 and other ores1 are concentrated mainly at the mine1 with the result that this fraction of the tonnage in large part does not travel beyond the mine4 ,about #ij per cent of the total production1 therefore1 figures largely in the transportation of mineral resources4 ,it is estimated that roughly two-thirds of the annual world production is used or smelted within the countries of origin1 the remaining one-third being exported4 ,of the minerals moving internationally1 coal and iron constitute #ij per cent of the tonnage4 ,the metal smelting capacity of the world in terms of yearly production of crude metal is estimated at nearly #ajj1jjj1jjj short tons4 ,of this amount about #hj per cent is located in the ,united ,states1 ,england1 and ,germany4 ,the ,united ,states alone has over half of the total4 ,of the oil-refining capacity the ,united ,states controls nearly #gj per cent4 ,one of the significant features of the situation above summarized is the concentration of production and smelting in a comparatively few places in the world4 ,this statement applies with even more force to the individual mineral commodities4 ,water may be regarded as a mineral resource in so far as it is utilized as a commodity for drinking1 washing1 power1 irrigation1 and other industrial uses4 ,for purposes of navigation and drainage1 or as a deterrent in excavation1 it would probably not be so classed4 ,while it is not easy to define the limits of water's use as a mineral resource1 it is clear that even with a narrow interpretation the total tonnage extracted from the earth as a mineral resource exceeds in amount all other mineral resources combined4 ,,world ,,annual ,,production ,,of ,,minerals ,,in ,,terms ,,of ,,value ,in terms of value1 mineral resources appear in different perspective4 ,the annual world value of mineral production1 exclusive of water1 is approximately #i1jjj1jjj1jjj4 ,this figure is obtained by dividing the annual value of the ,united ,states output of each of the principal minerals by the percentage which the ,united ,states output constitutes in the world output1 and adding the figures thus obtained4 ,the values here used are mainly selling prices at the mines4 ,it is impossible to reduce the figures absolutely to the value of the mineral as it comes from the ground2 there are always some items of transportation included4 ,this method of figuring is of course only the roughest approximation2 the values as obtained in the ,united ,states cannot be accurately exterpolated for the rest of the world because of locally varying conditions4 ,however1 the figures will serve for rough comparative purposes4 ,of this total value coal represents roughly #fa per cent1 petroleum #ab per cent1 iron #f per cent1 copper #e per cent1 and gold #c per cent4 ,in terms of value1 about #be per cent of the world's mineral production is available for export beyond the countries of origin4 ,of this exportable surplus the ,united ,states has about #dj per cent1 consisting principally of coal1 copper1 and formerly petroleum4 ,the value of the ,united ,states annual mineral production in recent years has been from about #c1ejj1jjj1jjj to #e1ejj1jjj1jjj4 ,annual imports of mineral products into the ,united ,states have averaged recently in the general vicinity of #dej1jjj1jjj1 the larger items being copper1 tin1 fertilizers1 petroleum1 gems and precious stones1 manganese1 nickel1 and tungsten4 ,again the perspective is changed when the value of water resources is considered4 ,as a physiologically indispensable resource1 the value of water in one sense is infinite4 ,there is no way of putting an accurate value on the total annual output used for drinking and domestic purposes1--although even here some notion of the magnitude of the figures involved may be obtained by considering the average per capita cost of water in cities where figures are kept1 and multiplying this into the world population4 ,this calculation would not imply that any such amount is actually paid for water1 because the local use of springs1 wells1 and streams can hardly be figured on a cash basis2 but1 if human effort the world over in securing the necessary water is about as efficient as in the average ,american city1 the figures would indicate the total money equivalent of this effort4 ,,significance ,,of ,,geographic ,,distribution ,,of ,,mineral ,,production ,the remarkable concentration of the world's mining and smelting around the ,north ,atlantic basin1 indicated by the foregoing figures1 does not mean that nature has concentrated the mineral deposits here to this extent4 ,it is an expression rather of the localized application of energy to mineral resources by the people of this part of the world4 ,the application of the same amount of energy in other parts of the world would essentially change the distribution of current mineral production4 ,the controlling factor is not the amount of minerals present in the ground2 this is known to be large in other parts of the world and more will be found when necessary4 ,controlling factors must be looked for in historical1 ethnological1 and environmental conditions4 ,this subject is further discussed in the chapters on the several resources1 and particularly in relation to iron and steel4 ,,the ,,increasing ,,rate ,,of ,,production ,the extraction of mineral resources on the huge scale above indicated is of comparatively recent date4 ,from #ahhj to the end of #aiah the value of the annual mineral production of the ,united ,states has increased from #cfg1jjj1jjj to more than #e1ejj1jjj1jjj1 or nearly fifteen times2 measured in another way1 it has increased from a little over #g per capita to more than #eb4aj ,more coal has been mined in the ,united ,states since #aije than in all the preceding history of the country4 ,more iron ore has been mined since #aijf than in all the preceding history4 ,the gold production of the ,united ,states practically started with the ,california gold rush in #ahdi4 ,the great ,south ,african gold production began in #ahhh4 ,production of diamonds in ,south ,africa began about #ahfi4 ,the large use of all fertilizer minerals is of comparatively recent date4 ,the world's oil production is greater now each year than it was for any ten years preceding #ahia1 and more oil has come out of the ground since #aijh than in all the preceding history of the world4 ,the use of bauxite on a large scale as aluminum ore dated practically from the introduction of patented electrolytic methods of reduction in #ahhi4 ,in one sense the world has just entered on a gigantic experiment in the use of earth materials4 ,the most striking feature of this experiment relates to the vast acquisition of power indicated by the accelerating rate of production and consumption of the energy resources--coal1 oil1 and gas 7and water power74 ,since #ahij the per capita consumption of coal in the ,united ,states has trebled and the per capita consumption of oil has become five times as great as it was4 ,if the power from these sources used annually in recent years be translated roughly into man power1 it appears that every man1 woman1 and child in the ,united ,states has potential control of the equivalent of thirty laborers1--as against seven in #ahij4 ,energy is being released on a scale never before approximated1 with consequences which we can yet hardly ascertain and appraise4 ,this consideration cannot but raise the question as to the ability of modern civilization to control and coodinate the dynamic factors in the situation4 ,,capital ,,value ,,of ,,world ,,mineral ,,reserves ,it is impossible to deduce accurately the capital value of mineral resources from values of annual output1 but again some approximation may be made4 ,the profit on the extraction of mineral resources on the whole1 considering the cost of exploration1 is probably no greater than in other industries 7p4 #ccj74 ,if we assume a #f per cent return1 which perhaps is somewhere near the world-wide standard of interest rate for money1 and capitalize the value of the world's annual output at this rate1 we obtain a world capital value for mineral resources1 exclusive of water1 of #aej billions of dollars4 ,this assumes an indefinitely long life for reserves4 ,this assumption may need some qualifications1 but it is the writer's view 7,chapter ,,xvii7 that it is justified for a sufficiently long period to substantiate the above method of calculation4 ,illustration3 ,,fig4 #b4 ,commercial 7financial7 control of the mineral resources of the world4 ,illustration3 ,,fig4 #c4 ,political 7territorial7 control of the mineral resources of the world4 ,,political ,,and ,,commercial ,,control ,,of ,,mineral ,,resources ,the occurrence of a mineral resource within a country does not necessarily mean control by that particular political unit4 ,a citizen of the ,united ,states may own a mineral resource in ,south ,america4 ,commercial control of this sort was demonstrated during the war to be of more far-reaching significance than had been supposed1 and it became necessary to ascertain1 not only the output of the different countries1 but the commercial control of this output4 ,investigation of this subject for twenty-three leading commodities shows that the political and commercial control are by no means the same4 ,these are partly summarized in the accompanying graphs from ,spurr4#aa ,it is to be noted that the graphs show the control of many commodities as it existed in #aiac1 the last normal year before the war4 ,changes during and since the war have of course largely altered the situation for certain commodities1 notably for iron1 coal1 and potash4 ,these developments are summarized in the discussion of the individual resources4 ,it is also to be noted that the commercial or financial control of the world's minerals1 under the influence of the fostering and protective policies of certain governments discussed in ,chapter ,,xviii1 is at present in a state of flux4 ,considerable changes are taking place today and are to be looked for in the future4 ,,reserves ,,of ,,mineral ,,resources ,annual production figures are only to a very partial extent an indication of the distribution of the great reserves of mineral resources4 ,for instance1 there are enormous reserves of coal in ,china which are not yet utilized to any large extent4 ,the minerals of ,south ,america and ,africa are in a very early stage of development4 ,the total world reserves will of course not be known until exploration and development of the world's resources are complete--a time which will probably never come4 ,figures of reserves represent only our present partial state of knowledge and are likely to be considerably modified in the future4 ,furthermore1 the quantitative accuracy of knowledge of reserves is so variable in different parts of the world that it is almost impossible to make up world figures which have any great validity4 ,there are1 however1 certain broad facts ascertainable4 ,every country in the globe is deficient in supplies of some minerals4 ,the ,united ,states is better off than any other country1 but still lacks many mineral commodities 7see pp4 #cif-cii47 ,no single continent has sufficient reserves of all mineral commodities4 ,for the world1 however1 it may be stated with reasonable certainty that the reserves of the principal minerals are now known to be ample with the exception of those of oil1 tin1 and perhaps gold and silver4 ,by ample we mean sufficient to give no cause for worry for the next few decades4 ,for many mineral commodities the amounts now actually in sight will not last long1 but the possibilities of extension and discovery are so great that a long future availability of these commodities can be counted upon with reasonable safety4 ,the present shortages in oil1 tin1 and other minerals mentioned may be only temporary4 ,there is a large part of the world still to be explored1 and the present reserves merely mark a stage in this exploration4 ,nevertheless1 the ratio of reserves and discovery on the one hand to accelerated use on the other gives cause for much concern4 ,looking forward to the future1 the problem of mineral reserves in general is not one of the possible ultimate amount which the earth may contain--presumably in no case is this deficient--but of the success with which the resource may be found and developed to keep up with the rapid acceleration of demand4 ,in the chapter on conservation the suggestion is made that future difficulties are more likely to arise from failure to coodinate the dynamic factors of supply and demand1 than from absolute shortage of material in the earth4 ,,footnotes3 #aj ,bastin1 ,edson ,s41 and ,mc,caskey1 ,h4 ,d41 ,the work on mineral resources done by the ,u4 ,s4 ,geological ,survey3 ,min4 ,res4 of the ,united ,states for #aiah1 ,u4 ,s4 ,geol4 ,survey1 pt4 #a1 #aibj1 p4 #c;a4 #aa ,spurr1 ,j4 ,e41 ,who owns the earth83 ,eng4 and ,min4 ,jour41 vol4 #aji1 #aibj1 pp4 #chi-cij4 ,,chapter ,v ,,water ,,as ,a ,,mineral ,,resource ,,general ,,geologic ,,relations ,with the solid earth as the special care of geology1 it may seem presumptuous for the geologist to claim the waters thereof1 but he does not disclaim this inheritance4 ,water is so all-pervasive that it is more or less taken for granted2 and so many and so intricate are its relations that it is not easy to make an objective survey of the water problem in its relation to geology4 ,the original source of water1 as well as of air1 is in molten magmas coming from below4 ,these carry water and gases1--some of which are released and some of which are locked up in the rocks on cooling1 to be later released during the alterations of the rocks4 ,it is supposed1 whatever theory of the origin of the earth we favor1 that in its early stages the earth lacked both hydrosphere and atmosphere1 and that during the growth of the earth these gradually accumulated on and near the surface in the manner stated4 ,during alterations at the surface water is added to the mineral constitution of the rocks1 and by alterations deep below the surface it may be subtracted4 ,water is the agent through which most mineral and chemical changes of rocks are accomplished4 ,it is the agent also which is mainly responsible for the segregation of mineral deposits4 ,water1 both as running water and in the solid form of ice1 plays an important part in determining the configuration of the earth's surface4 ,water is the medium in which most sedimentary rocks are formed4 ,it is an important agent in the development of soil and in organic growth4 ,these various influences of water on geological processes touch the economic field at many points1 especially in relation to the concentration of ores and to the development of soils and surface forms4 ,water comes even more directly into the field of economic geology as a mineral resource4 ,water supplies1 for the greatest variety of purposes1 involve geologic considerations at almost every turn4 ,finally1 water may be an aid or a hindrance to excavation and to a great variety of structural operations1 both in war and in peace2 and in this relation it again affords geologic problems4 ,the part played by water in geologic processes1 such as that of mineral segregation1 is more or less incidentally discussed in other chapters4 ,we may consider more fully in this chapter the application of geology to the general subject of water supplies4 ,from the geological point of view1 water is a mineral1--one of the most important of minerals1--as well as a constituent of other minerals4 ,it becomes a mineral resource when directly used by man4 ,it is ordinarily listed as a mineral resource when shipped and sold as mineral water1 but there is obviously no satisfactory line between waters so named and water supplies in general1 for most of them are used for the same purposes and none of them are free from mineral matter4 ,water which is pumped and piped for municipal water supply is as much a mineral resource as water which is bottled and sold under a trade name4 ,likewise water which is used for irrigation1 water power1 and a wide variety of other purposes may logically be considered a mineral resource4 ,notwithstanding the immense economic importance of water as a mineral resource its value is more or less taken for granted1 and considerations of valuation and taxation are much less in evidence than in the case of other mineral resources4 ,water must be had1 regardless of value1 and market considerations are to a much less extent a limiting factor4 ,economic applications of geology to this resource are rather more confined to matters of exploration1 development1 total supply1 and conservation1 than to attempts to fix money value4 ,,distribution ,,of ,,underground ,,water ,free water exists in the openings in rocks where it is sometimes called hygroscopic water4 ,there is also a large amount of water combined molecularly with many of the minerals of rocks1 in which form it is called water of constitution4 ,this water is fixed in the rock so that it is not available for use1 though some of the processes of rock alteration liberate it and contribute it to the free water4 ,the immediate source of underground water1 both free and combined1 is mainly the surface or rain waters4 ,a subordinate amount may come directly from igneous emanations or from destruction of certain hydrous minerals4 ,ultimately1 as already indicated1 even the surface water originates from such sources4 ,the openings in rocks consist of joints and many other fractures1 small spaces between the grains of rocks 7pore space71 and amygdaloidal and other openings characteristic of surface volcanic rocks4 ,many of these openings are capillary and sub-capillary in size4 ,most rocks1 even dense igneous rocks1 are porous in some degree1 and certain rocks are porous in a very high degree4 ,the voids in some surface materials may amount to #hd per cent of the total volume4 ,in general the largest and most continuous openings are near the surface1--where rocks on the whole are more largely of the sedimentary type and are more fractured1 disintegrated1 and decomposed1 than they are deep within the earth4 ,the largest supplies of water are in the unconsolidated sediments4 ,the water in igneous and other dense rocks is ordinarily in more limited quantity4 ,,approximate ,,quantity ,,of ,,water ,,which ,,will ,,be ,,absorbed ,,by ,,soils ,,and ,,rocks#a ---------------------------------------- -------------- ,volume of water asborbed ,material per #ajj of material ---------------------------------------- -------------- ,sandy soil#b #de4d ,chalk soil#b #di4e ,clay#b #ej-eb4g ,loam#b #de4a-fj4a ,garden earth #b #fi4j ,coarse sand #b #ci4d ,peat subsoil#b #hd4j ,sand #cj-dj ,sandstone #e-bj ,limestone and dolomite #a-h ,chalk #f-bg ,granite #jc4-4h ---------------------------------------- -------------- #a3 ,mead1 ,daniel ,w41 ,hydrology3 ,mc,graw-,hill ,book ,co41 ,new ,york1 #aiai1 p4 #cic4 #b3 ,woodward1 ,h4 ,b41 ,geology of soils and substrata3 ,edward ,arnold1 ,london1 #aiab4 ,immediately at the surface1 the openings of rocks may not be filled with water2 but below the surface1 at distances varying with climatic and topographic conditions1 the water saturates the openings of the rocks and forms what is sometimes called the zone of saturation or the sea of underground water4 ,the top surface of this zone is called the water table1 or the ground-water level4 ,the space between the water table and the earth's surface is sometimes referred to as the vadose zone or the zone of weathering1 since it is the belt in which weathering processes are most active4 ,the zone of weathering is not necessarily dry4 ,water from the surface enters and sinks through it and water also rises through it from below2 it may contain suspended pockets of water surrounded by dry rocks2 it is not continuously and fully saturated4 ,the water table or ground-water level may be near or at the surface in low and humid areas1 and it may be two thousand feet or more below the surface in arid regions of high topographic relief4 ,because of the influence of capillarity1 the water table is not a horizontal surface4 ,it shows irregularities more or less following the surface contours1 though not nearly so sharply accentuated4 ,the lower limit of the ground-water is more irregular than the upper surface and is less definitely known4 ,in general1 openings in rocks tend to diminish with depth1 due to cementation and to closing of cavities by pressures which are too great for the rock to withstand4 ,but rocks differ so widely in their original character1 and in their response to physical and chemical environment1 that it is not unusual to find dense and impervious rocks above1 and open and porous rocks below4 ,the lower limit of the zone of abundant underground water varies accordingly4 ,a well may encounter nearly dry rock at a comparatively shallow depth1 or it may reach a porous water-bearing stratum at considerable depth4 ,at the greater depths pockets of water are sometimes found which have a composition different from that of the surface water1 and which evidently are isolated from the surface water by zones of non-pervious rock4 ,attempts have been made to calculate the total volume of underground water by measuring the openings of rocks and making assumptions as to the depth to which such openings may extend4 ,in this manner it has been estimated that1 if all the ground-water were assembled in a single body1 it would make a shell between eighty and two hundred feet thick 7depending on the assumptions7 over all the continental areas4 ,,movement ,,of ,,underground ,,water ,availability of water supplies is determined by the movement or flow of water as well as by its distribution and amount4 ,the natural flow of water underground is caused by gravity in the larger openings1 but in the smaller openings adhesion and capillarity are also important forces4 ,of all the water falling on the surface1 some may not go below the surface at all but may immediately evaporate or join the runoff--that is1 the surface streams4 ,another part may penetrate a little distance into the zone of weathering and then join the runoff4 ,of the water which reaches the zone of saturation1 a part may soon come to the surface in low areas and join the runoff1 and a part may penetrate deeply4 ,above the zone of saturation gravity carries the water downward in devious courses until it reaches the water table4 ,thereafter its course is determined largely by the lowest point of escape from the water table4 ,in other words1 the water table is an irregular surface2 and under the influence of gravity the water tends to move from the high to the low points of this surface4 ,between the point of entrance and the point of escape from the water table1 the water follows various courses1 depending upon the porosity and the openings in the rocks4 ,in general it fills all of the available openings1 and uses the entire available cross section in making its progress from one point to another4 ,the difference in height or the head between the point of entrance and the point of escape1 together with the porosity of the rock and other factors1 determine the general speed of its movement 7see p4 #gc74 ,with equal porosity the flow is at a maximum along a line directly connecting the two points1 and on more devious courses the flow is less4 ,the surface water first enters the ground through innumerable small openings4 ,soon1 however1 it tends to be concentrated into channels of easiest flow1 with the result that in the later part of its underground course it may be much concentrated in large trunk channels4 ,these channels may consist of joints1 or frequently of very coarse and pervious beds4 ,the sedimentary rocks as a whole contain the most voids1 and therefore the largest flow and largest supply of water is often localized in them4 ,of the sedimentary rocks1 sandstones and limestones usually contain the largest and most continuous openings1 and thus afford the freest circulation for water4 ,the voids in fine-grained shales may equal in volume those in sandstones and limestones1 but the openings are so small and discontinuous that the water does not flow freely4 ,regardless of total amount of water1 unless there are continuous openings of some size the flow may be small4 ,the relations of more porous rocks to containing impervious strata also profoundly affect the flow of underground water4 ,between impervious strata the circulation may be concentrated and vigorous within the porous bed4 ,where the porous bed is not so contained1 the movement may be more dispersed and less vigorous locally4 ,the inclination of the beds1 of course1 also affects the direction and amount of the flow4 ,the influence of gravity upon underground water may locally tend toward a state of equilibrium in which there is little movement4 ,in such a case the water is substantially ponded1 and moves only when tapped by artificial openings4 ,,wells ,,and ,,springs ,underground water becomes available for use by means of springs and through wells or bore holes4 ,water rises to the surface in natural springs at points where the pressure or head1 due to its entrance into the ground at a higher level1 is sufficient to force it to the surface after a longer or shorter underground course4 ,the movement may be all downward and lateral to the point of escape1 or it may be downward1 lateral1 and upward4 ,ordinarily1 the course of spring waters does not carry them far below the surface4 ,heat and gases may be added beneath the surface by contact with or contributions from cooling igneous rocks4 ,these may accelerate the upward movement of spring waters1 and yield thermal and gas-charged waters1 as in the springs and geysers of ,yellowstone ,park4 ,when a well is sunk to tap the underground water supply1 the water may not rise in the artificial opening but may have to be lifted to the surface4 ,if1 however1 the water is confined beneath an impervious stratum and is under pressure from the water of higher areas1 a well opening may simply allow it to move upward under its own pressure or head4 ,this pressure may carry it upward only a few feet or quite to the surface or beyond1 in which latter case the well is called an artesian well4 ,the essential condition for an artesian circulation is a porous zone1 inclining downward from the surface beneath an impervious stratum which tends to confine and pond the water4 ,the water at any point in the water-bearing rock is under pressure which is more or less equivalent to the weight of the column of water determined by the difference in height between this point and the point of entrance or feeding area of the water4 ,if the feeding area is higher than the collar of the well1 the water will rise quite to the surface2 if not1 it will rise only part way4 ,capillary resistance1 however1 may and usually does lessen the theoretical pressure so figured4 ,the flow in deep artesian circulations is ordinarily a slow one4 ,for the artesian wells of southern ,wisconsin1 it has been calculated that waters entering the outcrop of the southward dipping sandstone and limestone layers in the northern part of the state have required two or three hundred years to reach a point in the southern part of the state where they are tapped4 ,because of this slow movement1 a large number of wells in any one spot may exhaust the local supply faster than it is replenished from the remainder of the formation4 ,the drilling of additional wells near at hand in such cases does not increase the total yield1 but merely divides it among a larger number of wells4 ,the porosity of the rocks1 and therefore the flow of an artesian circulation1 may in some cases be artificially increased by blasting and shattering4 ,,composition ,,of ,,underground ,,waters ,underground waters are never entirely free from dissolved mineral substances1 and seldom are they free from suspended particles4 ,some waters are desired because they contain very small quantities of dissolved mineral matter4 ,others are prized because they have an unusually high content of certain mineral substances4 ,in determining the deleterious or beneficial effect of dissolved substances1 much depends on the purpose for which the water is to be used1--whether for drinking1 washing1 steam boilers1 or irrigation4 ,near the surface underground waters may carry bacteria1 as well as animal and vegetable refuse1 which from a sanitary standpoint are usually objectionable4 ,deeper waters are more likely to lack this contamination because of filtration through rocks and soils4 ,the dissolved mineral substances of underground water are derived for the most part from the solution of rocks with which the waters come in contact1 particularly at or near the surface4 ,through the agency of underground water most of the mineral and chemical changes of rocks are produced4 ,the dissolved substances in solution at any time and place may therefore be regarded as by-products of rock alterations4 ,locally they may to some extent be derived from direct emanations from cooling igneous masses4 ,the most common mineral substances contained in waters are lime and magnesia4 ,less common1 but abundant locally1 are soda1 potash1 iron1 and silica4 ,waters contain also certain acid and gaseous substances1 the most common of which is carbon dioxide2 and less widespread1 but locally abundant1 are chlorine and sulphur dioxide4 ,where lime and magnesia are abundant the water is ordinarily classed as a hard water4 ,where absent1 or subordinate to soda and potash1 the water is ordinarily classed as a soft water4 ,large amounts of the acid substances like chlorine and sulphur are detrimental for most purposes4 ,where there are unusual amounts of carbon dioxide or other gases present1 they may by expansion cause the water to bubble4 ,if we were to attempt to describe and define the characteristics1 with reference to dissolved mineral content and temperature1 which make a given water more desirable than another1 we should enter a field of the most amazing complexity and one with many surprising contradictions4 ,for the most widespread use1 the most desirable water is a cold water as free from mineral content as possible1 and especially one lacking an excess of lime and magnesia which make it hard2 also lacking an excess of acid constituents like sulphur dioxide1 carbon dioxide1 or chlorine1 which give the water a taste1 or which make impossible its use in boilers4 ,locally and for special reasons1 waters of other qualities are in demand4 ,waters so excessively carbonated as to bubble1 sulphureted waters1 chlorine waters1 waters high in iron1 high in silica1 high in potash1 high in soda1 or high in magnesia1 or waters of high temperature1 may come to be regarded as desirable4 ,it is an interesting fact that any water with unusual taste1 or unusual mineral content1 or unusual temperature1 is likely to be regarded as having medicinal value4 ,sometimes this view is based on scientific knowledge2 sometimes it is an empirical conclusion based on experience2 and again it may be merely superstition4 ,in one case the desirable feature may be the presence of a large amount of carbon dioxide2 in another case it may be its absence4 ,in one case the desirable feature may be high temperature2 in another case low temperature4 ,the same combination of qualities which in a certain locality may be regarded as highly desirable1 may be regarded as highly detrimental somewhere else where certain other types of waters are in vogue4 ,proprietary rights and advertising have brought certain waters into use for drinking purposes which are not essentially different from more widely available waters which are not regarded as having special value4 ,two springs located side by side1 or a spring and a deep well1 whose waters have exactly the same chemical characteristics1 may be used and valued on entirely different scales4 ,any attempt to classify mineral waters sold to the public in any scientific way discloses a most intricate and confused situation4 ,one can only conclude that the popularity of certain waters is not based alone on objective qualities of composition1 but rather on causes which lie in the fields of psychology and commerce4 ,the part played by sentiment in putting value on water is well illustrated by the general preference for spring waters as compared with well waters4 ,in the public mind1 spring water denotes water of unusual purity and of more desirable mineral content than well water4 ,illustrations could be cited of districts in which the surface or spring waters have a composition not different from that of the deeper well waters1 and are much more likely to be contaminated because of proximity to the surface2 and yet people will pay considerable sums for the spring water in preference to the cheaply available well water4 ,,relation ,,of ,,geology ,,to ,,underground ,,water ,,supply ,it is obvious that a knowledge of geology is helpful in locating an underground water supply4 ,locally the facts may become so well known empirically that the well driller is able to get satisfactory results without using anything but the crudest geologic knowledge2 but in general1 attention to geologic considerations tends to eliminate failures in well drilling and to insure a more certain and satisfactory water supply4 ,in drilling for water1 it is essential to know the nature1 succession1 and structure of the rocks beneath the surface in order to be able to identify and correlate them from drill samples4 ,the mere identification of samples is often sufficient to determine whether a well has been drilled far enough or too far to secure the maximum results4 ,in order to arrive at any advance approximation of results for a given locality1 a knowledge of the general geology of the entire region may be necessary4 ,especially for expensive deep artesian wells it is necessary to work out the geologic possibilities well in advance4 ,it is useless1 for instance1 to look for artesian water in a granite2 but in an area of gently inclined strata1 with alternations of porous and impervious layers1 the expert may often figure with a considerable degree of certainty the depth at which a given porous stratum will be found1 and the pressure under which the water will be in this particular stratum at a given point4 ,even the mineral content of the water may in some cases be predicted from geologic study4 ,one of the most obvious and immediately useful services of the geologist in most localities is the collection and preservation of well samples for purposes of identification and correlation of rock formations1 and as a guide to further drilling4 ,failure to preserve samples has often led to useless and expensive duplication of work4 ,the problem of water supply in some localities is comparatively simple and easy4 ,in other areas there is an infinite variety of geologic conditions which affect the problem1 and the geologist finds it necessary to bring to bear all the scientific knowledge of any sort which can be used1--particularly knowledge in relation to the type of rock1 the stratigraphy and the structure4 ,,surface ,,water ,,supplies ,where underground water is not abundant or not cheaply available1 or where larger amounts of water are needed1 as in large cities or for irrigation purposes1 surface water is used4 ,in general1 surface waters are more likely to be contaminated by vegetable and animal matter and to require purification for drinking purposes4 ,surface waters are also used for irrigation1 water power1 drainage1 the carrying of sewage1 etc4 ,this great variety of uses brings the consideration of surface waters into many fields other than geology1 but an understanding and interpretation of the geological conditions is none the less fundamental4 ,this is evidenced by the inclusion of geologic discussions in most textbooks of hydrology1 and in the reports of the ,hydrographic ,branch of the ,u4 ,s4 ,geological ,survey4 ,the very fact that this important branch of governmental investigation is in a charge of the ,u4 ,s4 ,geological ,survey indicates its close relation to geology4 ,the principles of geology used in the study of surface waters relate chiefly to physiography 7see ,chapter ,i74 ,it is usually necessary to know the total quantity of flow1 its annual and seasonal variation1 and the possible methods of equalization or concentration2 the maximum quantity of flow1 the variation during periods of flood1 and the possibilities of reduction or control2 the minimum flow and its possible modification by storage or an auxiliary supply4 ,these questions are obviously related to the size and shape of the catchment area1 the topography1 the rock structure1 the relation between underground flow or absorption and the runoff1 and other physiographic factors4 ,quoting from ,d4 ,w4 ,mead3#ab ,geological conditions are frequently of great importance in their influence on the quantity and regularity of runoff4 ,if the geological deposits of the drainage area are highly impervious1 the surface flow will receive and transmit the water into the mass only through the cracks and fissures in the rock4 ,pervious materials1 such as sandstones1 sands1 gravels1 and cracked or fissured rocks1 induce seepage1 retard runoff1 and1 if such deposits are underlaid with an impervious bed1 provide underground storage which impounds water away from the conditions which permit evaporation1 and hence tends to increase runoff and equalize flow4 ,on the other hand1 if such pervious deposits possess other outlets outside of the stream channel and drainage area1 they may result in the withdrawal of more or less of the seepage waters entirely from the ultimate flow of the stream4 ,coarse sands and gravels will rapidly imbibe the rainfall into their structure4 ,fine and loose beds of sand also rapidly receive and transmit the rainfall unless the precipitation is exceedingly heavy under which conditions some of it may flow away on the surface4 ,many of the highly pervious indurated formations receive water slowly and require a considerable time of contact in order to receive and remove the maximum amount4 ,in flat1 pervious areas1 rainfalls of a certain intensity are frequently essential to the production of any resulting stream flow4 ,in a certain ,colorado drainage area1 the drainage channel is normally dry except after a rainfall of one-half inch or more4 ,a less rainfall1 except under the condition of a previously saturated area1 evaporates and sinks through the soil and into the deep lying pervious sand rock under the surface which transmits it beyond the drainage area4 ,such results are frequently greatly obscured by the interference of other factors1 such as temperature1 vegetation1 etc4 99 99 99 99 99 ,the natural storage of any drainage area and the possibilities of artificial storage depend principally upon its topography and geology4 ,storage equalizes flow1 although the withdrawal of precipitation by snow or ice storage in northern areas often reduces winter flow to the minimum for the year4 ,both surface and sub-surface storage sometimes hold the water from the streams at times when it might be advantageously used4 ,storage1 while essential to regulation1 is not always an advantage to immediate flow conditions4 ,,underground ,,and ,,surface ,,waters ,,in ,,relation ,,to ,,excavation ,,and ,,construction ,scarcely more than a mention of this subject is necessary4 ,in mining1 the pumping charge is one of the great factors of cost4 ,a forecast of the amount and flow of water to be encountered in mining is based on the geologic conditions4 ,the same is true in excavating tunnels1 canals1 and deep foundations4 ,detailed study of the amount and nature of water in the rock and soil of the ,panama ,canal has been vital to a knowledge of the cause and possibilities of prevention of slides4 ,rock slides in general are closely related to the amount and distribution of the water content4 ,the importance of ground-water as a detriment in military operations was shown during the recent war in trenching and other field works4 ,at the outset1 with the possible exception of the ,german army1 a lack of scientific study of ground-water conditions led to much unnecessary difficulty4 ,it soon became necessary to study and map the water conditions in great detail in advance of operations4 ,much of this work was done by geologists 7see ,chapter ,,xix74 ,geological considerations are involved in a great variety of engineering undertakings related to river and harbor improvements1 dam sites1 etc41 mentioned in ,chapter ,,xx4 ,,footnotes3 #ab ,mead1 ,daniel ,w41 ,hydrology3 ,mc,graw-,hill ,book ,co41 ,new ,york1 #aiai1 pp4 #ddg-ddh1 #def4 ,,chapter ,,vi ,,the ,,common ,,rocks ,,and ,,soils ,,as ,,mineral ,,resources ,,economic ,,features ,,of ,,the ,,common ,,rocks ,under the general heading of common rocks are included the ordinary igneous1 sedimentary1 and metamorphic rocks1 and the unconsolidated clays1 sands1 and gravels characteristic of surface conditions1 which are mined and quarried for commercial use4 ,soils are closely related to this group2 but since they present special problems of their own1 they are discussed under a separate heading at the end of the chapter4 ,names of the common rocks will be used with the general commercial significance given them by the ,united ,states ,geological ,survey in its mineral resource reports4 ,because of their inexhaustible quantity and ready availability1 the value of the common rock products is not large per unit of weight2 but in the aggregate it ranks high among mineral products4 ,in respect to tonnage1 common rocks constitute perhaps #aj per cent of the world annual output of all mineral commodities 7exclusive of water74 ,the greater tonnage of the common rocks is used commercially in crushed or comminuted forms for road material1 for railroad ballast1 and for cement1 brick1 concrete1 and flux4 ,in blocks and structural shapes1 of less aggregate tonnage1 they are used as building stone1 monumental stone1 paving blocks1 curbing1 flagging1 roofing1 refractory stone1 and for many other building and manufacturing purposes4 ,the common rocks are commodities in which most countries of the globe are self-sufficing4 ,international trade in these commodities is insignificant1 being confined to small quantities of materials for special purposes1 or to local movements of short distances1 allowed by good transportation facilities4 ,the common rocks are so abundant and widespread that the conservation of raw materials is not ordinarily a vital problem4 ,conservational principles do apply1 however1 to the human energy factor required for their efficient use4 ,in the valuation of common rocks1 also1 the more important factors are not the intrinsic qualities of the stones1 but rather the conditions of their availability for use4 ,because of bulk and comparatively low intrinsic value1 the principal commercial factors in the availability of the common rocks are transportation and ease of quarrying1 but these are by no means the only factors determining availability4 ,their mineral and chemical composition1 their texture and structure1 their durability1 their behavior under pressure and temperature changes1 and other factors enter in to important degrees4 ,the weighting and integration of these factors1 for the purpose of reaching conclusions as to the availability of particular rock materials1 depend also on the purposes for which these materials are to be used4 ,the problem is anything but simple4 ,the search for a particular rock to meet a certain demand within certain limits of cost is often a long and arduous one4 ,on account of the abundance and widespread distribution of common rocks and their variety of uses1 there is a good deal of popular misapprehension as to their availability4 ,many building and manufacturing enterprises have met disastrous checks1 because of a tendency to assume availability of stone without making the fullest technical investigation4 ,many quarrying ventures have come to grief for the same reason4 ,it is easy to assume that1 because a granite in a certain locality is profitably quarried and used1 some other granite in the same locality has equal chances4 ,however1 minor differences in structure1 texture1 and composition1 or in costs of quarrying and transportation1 may make all the difference between profit and loss4 ,even though all these conditions are satisfactorily met1 builders and users are often so conservative that a new product finds difficulty in breaking into the market4 ,a well-established building or ornamental stone1 or a limestone used for flux1 may hold the market for years in the face of competition from equally good and cheaper supplies4 ,the very size of a quarry undertaking may determine its success or failure4 ,,granite ,the term granite1 as used commercially1 includes true granite and such allied rocks as syenite and gneiss4 ,in fact even quartzite is sometimes called granite in commerce1 as in the case of the ,baraboo quartzites of ,wisconsin1 but this is going too far4 ,for statistical purposes1 the ,united ,states ,geological ,survey has also included small quantities of diorite and gabbro4 ,the principal uses of granite are1 roughly in order of importance1 for monumental stone1 building stone1 crushed stone1 paving1 curbing1 riprap and rubble4 ,thirty states in the ,united ,states produce granite1 the leaders being ,vermont1 ,massachusetts1 ,north ,carolina1 ,maine1 ,wisconsin1 ,minnesota1 and ,california4 ,,basalt ,,and ,,related ,,types ,basalt and related rocks are sometimes included under the name trap rock1 which comprises1--besides typical basalt and diabase1--fine-grained diorite1 gabbro1 and other basic rocks1 which are less common in occurrence and are similar in chemical and physical properties4 ,the principal use of these rocks is as crushed stone for road and ballast purposes and for concrete4 ,they are produced in some fifteen states1 the leaders being ,new ,jersey1 ,pennsylvania1 ,california1 and ,connecticut4 ,,limestone1 ,,marl1 ,,chalk ,in the ,united ,states limestone is used principally as crushed stone for road material1 railroad ballast1 concrete1 and cement1 as fluxing stone for metallurgical purposes1 and in the manufacture of lime4 ,minor uses are as building stones1 paving blocks1 curbing1 flagging1 rubble1 and riprap2 in alkali works1 sugar factories1 paper mills1 and glass works2 and for agricultural purposes4 ,for the making of cement1 in metallurgical fluxes1 and in most of the manufacturing and agricultural uses1 both limestone and lime 7limestone with the ,,co#b driven out by heating7 are used4 ,lime is also extensively used in the making of mortar for building operations1 in tanning leather1 and in a great variety of chemical industries4 ,the total quantity of limestone used for all purposes in the ,united ,states nearly equals that of iron ore4 ,nearly every state in the union produces limestone1 but the more important producers are ,pennsylvania 7where a large amount is used for fluxing71 ,ohio1 ,indiana1 ,new ,york1 ,michigan1 and ,illinois4 ,closely associated with limestone in commercial uses1 as well as in chemical composition1 is calcareous marl1 which is used extensively in the manufacture of ,portland cement4 ,chalk is a soft amorphous substance of the same composition as limestone4 ,the main uses of chalk are as a filler in rubber1 and as a component of paint and putty4 ,it is also used for polishing4 ,the principal producers of this commodity are ,england1 ,denmark1 and ,france1 and the chief consumer is the ,united ,states4 ,the ,united ,states depends upon imports for its supply of chalk for the manufacture of whiting4 ,before the war two-thirds came from ,england and a third from ,france4 ,during the war importation was confined to ,england1 with a small tonnage from ,denmark4 ,no deposits of domestic chalk have been exploited commercially4 ,a somewhat inferior whiting1 but one capable of being substituted for chalk in most cases1 is manufactured from the waste fine material of limestone and marble quarries4 ,,marble ,marble is limestone which has been coarsely recrystallized by metamorphism4 ,the marble of commerce includes a small quantity of serpentine as quarried and sold in ,massachusetts1 ,california1 ,maryland1 ,pennsylvania1 and ,vermont1 and also a small amount of so-called onyx marble or travertine obtained from caves and other deposits in ,kentucky and other states4 ,the principal uses of marble are for building and monumental stones4 ,of the twenty-two states producing marble1 the leaders are ,vermont1 ,georgia1 and ,tennessee4 ,a small amount of marble of special beauty1 adapted to ornamental purposes1 is imported from ,european countries1 especially from ,italy4 ,marble imports from ,italy constitute about two-thirds1 both in tonnage and value1 of all stone imported into the ,united ,states4 ,,sand1 ,,sandstone1 ,,quartzite 7,,and ,,quartz7 ,sand is composed mainly of particles of quartz or silica1 though sometimes feldspar and other minerals are present4 ,sandstones are partially cemented sands4 ,quartzites are completely cemented sands4 ,to some extent these substances are used interchangeably for the same purposes4 ,the principal uses of sand in order of commercial totals are for building purposes--for mortar1 concrete1 sand-lime brick1 etc41--as molding sand in foundries1 as a constituent of glass1 in grinding and polishing1 in paving1 as engine sand1 as fire or furnace sand1 in the manufacture of ferrosilicon 7a steel alloy71 and in filters4 ,reference is made to sand as an abrasive and in the manufacture of steel in ,chapters ,,xiii and ,,ix4 ,almost every state produces some sand1 but for some of the more specialized uses1 such as glass sand1 molding sand1 and fire or furnace sand1 the distribution is more or less limited4 ,the ,united ,states ,geological ,survey has collected information concerning the distribution of various kinds of sand and gravel1 and serves a very useful function in furnishing data as to supplies of material for particular purposes4 ,fine molding sands have been imported from ,france1 but during the war domestic sources in ,new ,york and ,ohio were developed sufficiently to meet any requirements4 ,the sandstone of commerce includes the quartzites of ,minnesota1 ,south ,dakota1 and ,wisconsin1 and the fine-grained sandstones of ,new ,york1 ,pennsylvania1 and elsewhere1 known to the trade as bluestone4 ,in ,kentucky most of the sandstone quarried is known locally as freestone4 ,the principal uses of sandstone are for building stone1 crushed stone1 and ganister 7for silica brick and furnace-linings74 ,other uses are for paving blocks1 curbing1 flagging1 riprap1 rubble1 grindstones1 whetstones1 and pulpstones 7see also ,chapter ,,xiii74 ,sandstone is sometimes crushed into sand and is used in the manufacture of glass and as molding-sand4 ,most of the states of the union produce sandstone1 the principal producers being ,pennsylvania1 ,ohio1 and ,new ,york4 ,,sand ,,and ,,gravel ,where sand is coarse and impure and mixed with pebbles1 it is ,ordinarily referred to as sand and gravel4 ,for sand and gravel the principal uses are for railroad ballast1 for road building1 and for concrete4 ,sand and gravel are produced in almost every state in the union1 the largest producers being ,pennsylvania1 ,ohio1 ,illinois1 ,new ,jersey1 and ,north ,carolina4 ,,clay1 ,,shale1 ,,slate ,shale is consolidated clay1 usually with a fine lamination due to bedding4 ,slate is a more dense and crystalline rock1 produced usually by the anamorphism of clay or shale under pressure1 and characterized by a fine cleavage which is usually inclined to the sedimentary bedding4 ,clays are used principally for building and paving brick and tile1 sewer-pipe1 railroad ballast1 road material1 puddle1 ,portland cement1 and pottery4 ,clay is mined in almost every state4 ,ohio1 ,pennsylvania1 ,new ,jersey1 and ,illinois have the largest production4 ,there has been a considerable importation of high-grade clays1 principally from ,england1 for special purposes--such as the filling and coating of paper2 the manufacture of china1 of porcelain for electrical purposes1 and of crucibles2 and for use in ultramarine pigments1 in sanitary ware1 in oilcloth1 and as fillers in cotton bleacheries4 ,war experience showed the possibility of substitution of domestic clays for most of these uses2 but results were not in all cases satisfactory1 and the ,united ,states will doubtless continue to use imported clays for some of these special purposes4 ,shales1 because of their thinly bedded character and softness1 are of no value as building stones1 but are used in the manufacture of brick1 tile1 pottery1 and ,portland cement4 ,slates owe their commercial value primarily to their cleavage1 which gives well-defined planes of splitting4 ,the principal uses are for roofing and1 in the form of so-called mill stock for sanitary1 structural1 and electrical purposes4 ,small amounts are used for tombstones1 roads1 slate granules for patent roofing1 school slates1 blackboard material1 billiard table material1 etc4 ,the color1 fineness of the cleavage1 and size of the flakes are the principal features determining the use of any particular slate4 ,ten states produce slate1 the principal production coming from ,pennsylvania and ,vermont4 ,,the ,,feldspars ,feldspars are minerals1 not rocks1 but mention of them is made here because1 with quartz1 they make up such an overwhelming percentage of earth materials4 ,it is estimated that the feldspars make up #ej per cent of all the igneous rocks and #af per cent of the sedimentary rocks4 ,as the igneous rocks are so much more abundant than the sedimentary rocks1 the percentage of feldspars in the earth approaches the former rather than the latter figure4 ,in most rocks feldspar is in too small grains and is too intimately associated with other minerals to be of commercial importance2 in only one type of rock1 pegmatite1 which is an igneous rock of extremely coarse and irregular texture1 are the feldspar crystals sufficiently large and concentrated to be commercially available4 ,feldspar is used principally in the manufacture of pottery1 china ware1 porcelain1 enamel ware1 and enamel brick and tile4 ,in the body of these products it is used to lower the fusing point of the other ingredients and to form a firm bond between their particles4 ,its use in forming the glaze of ceramic products is also due to its low melting point4 ,a less widespread use of feldspar is as an abrasive 7,chapter ,,xiii74 ,one of the varieties of feldspar carries about #ae per cent of potash1 and because of the abundance of the mineral there has been much experimental work to ascertain the possibility of separating potash for fertilizer purposes2 but1 because of cost1 this source of potash is not likely for a long time to compete with the potash salts already concentrated by nature4 ,feldspar is mined in eleven states1 but the important production comes from ,north ,carolina and ,maine4 ,the ,united ,states also imports some feldspar from ,canada4 ,,hydraulic ,,cement 7including ,portland1 natural1 and ,puzzolan cements7 ,cement is a manufactured product made from limestone 7or marl7 and clay 7or shale74 ,sometimes these two kinds of substances are so combined in nature 7as in certain clayey limestones7 that they are available for cement manufacture without artificial mixing4 ,it is not our purpose in this volume to discuss manufactured products2 but the cement industry involves such a simple transformation of raw materials1 and is so closely localized by the distribution of the raw materials1 that a mention of some of its outstanding features seems desirable4 ,hydraulic cement is used almost exclusively as a structural material4 ,it is an essential ingredient of concrete4 ,originally used chiefly for the bonding of brick and stone masonry and for foundation work1 its uses have grown rapidly1 especially with the introduction of reinforced concrete4 ,it is being used in the construction of roads1 and its latest use is in ship construction4 ,with the exception of satisfactory fuels1 the raw materials required for the manufacture of cement are found quite generally throughout the world4 ,while practically all countries produce some cement1 much of it of natural grade1 only the largest producers make enough for their own requirements and as a result there is a large world movement of this commodity4 ,the world trade is chiefly in ,portland cement4 ,next to the ,united ,states1 the producing countries having the largest exportable surplus of cement in normal times are ,germany and ,great ,britain4 ,france and ,belgium were both large producers and exporters before the war1 but the war greatly reduced their capacity to produce for the time being4 ,sweden1 ,denmark1 ,austria1 ,japan1 and ,switzerland all produce less extensively but have considerable surplus available for export4 ,italy and ,spain have large productions1 which are about sufficient for their own requirements4 ,holland and ,russia import large amounts from the other ,european countries4 ,the far eastern trade absorbs the excess production of ,japan4 ,in ,south ,africa and ,australasia1 production nearly equals demand4 ,in ,canada1 although the industry has been growing very rapidly1 the demand still exceeds production4 ,in ,south and ,central ,america1 ,mexico and the ,west ,indies1 the demand is considerable and will probably increase2 production has thus far been insufficient4 ,several modern mills are either recently completed or under construction in these countries1 and concessions have been granted for several others4 ,these new mills are largely financed by ,american capital4 ,the ,united ,states is the largest single producer of cement in the world1 its annual production being about #de per cent of the world's total4 ,domestic consumption has always been nearly as great as the production1 and exports have usually not exceeded #d per cent of the total shipments from the mills4 ,south and ,central ,america offer fields for exportation of cement from the ,united ,states4 ,,geologic ,,features ,,of ,,the ,,common ,,rocks ,to describe the geologic features of the common rocks used in commerce would require a full treatise on the subject of geology4 ,these are the bulk materials of the earth and in them we read the geologic history of the earth4 ,in preceding chapters a brief outline has been given of the relative abundance of the common earth materials and of the processes producing them4 ,in comparison1 the metalliferous deposits are the merest incidents in the development of this great group of mineral resources4 ,in this section reference will be made only to a few of the rock qualities and other geologic features which require first attention in determining the availability of a common rock for commercial use4 ,the list is very fragmentary1 for the reason that the uses are so many and so varied that to describe all the geologic features which are important from the standpoint of all uses would very soon bring the discussion far beyond the confines of a book of this scope4#ac ,,building ,,stone ,for building stones1 the principal geologic features requiring attention are structure1 durability1 beauty1 and coloring4 ,the structures of a rock include jointing1 sedimentary stratification1 and secondary cleavage4 ,nearly all rocks are jointed4 ,the joints may be open and conspicuous1 or closed and almost imperceptible4 ,the closed joints or incipient joints cause planes of weakness1 known variously as rift1 grain1 etc41 which largely determine the shapes of the blocks which may be extracted from a quarry4 ,where properly distributed1 they may facilitate the quarrying of the stone4 ,in other cases they may be injurious1 in that they limit the size of the blocks which can be extracted and afford channels for weathering agents4 ,some rocks of otherwise good qualities are so cut by joints that they are useless for anything but crushed stone4 ,the bedding planes or stratification of sedimentary rocks exercise influences similar to joints1 and like joints may be useful or disadvantageous1 depending on their spacing4 ,the secondary cleavage of some rocks1 notably slates1 enables them to be split into flat slabs and thus makes them useful for certain purposes4 ,proper methods of extraction and use of a rock may minimize the disadvantageous effects of its structural features4 ,the use of channelling machines instead of explosives means less shattering of the rock4 ,by proper dressing of the surface the opening of small crevices may be avoided4 ,stratified rocks set on bed1 so that the bedding planes are horizontal1 last longer than if set on edge4 ,the durability of a rock may depend on its perviousness to water which may enter along planes of bedding or incipient fracture planes1 or along the minute pore spaces between the mineral particles4 ,the water may cause disastrous chemical changes in the minerals and by its freezing and thawing may cause splitting4 ,for this reason1 the less pervious rocks have in general greater durability than the more pervious4 ,highly pervious rocks used in a dry position or in a dry climate will last longer than elsewhere4 ,durability is determined also by the different coefficients of expansion of the constituent minerals of the rock4 ,where the minerals are heterogeneous in this regard1 differential stresses are more likely to be set up than where the minerals are homogeneous4 ,likewise a coarse-textured rock is in general less durable than a fine-textured one4 ,expansion and contraction of a stone under ordinary temperature changes1 and also under fire and freezing1 must necessarily be known for many kinds of construction4 ,minerals resist weathering to different degrees1 therefore the mineral composition of a rock is another considerable factor in determining its durability4 ,where pyrite is present in abundance it easily weathers out1 leaving iron-stained pits and releasing sulphuric acid which decomposes the rock4 ,abundance of mica1 especially where segregated along the stratification planes1 permits easy splitting of the rock under weathering4 ,likewise the mica often weathers more quickly than the surrounding minerals1 giving a pitted appearance2 in marbles and limestones its irregular occurrence may spoil the appearance4 ,flint or chert in abundance is deleterious to limestones and marbles1 because1 being more resistant1 it stands out in relief on the weathered surface1 interferes with smooth cutting and polishing1 and often causes the rock to split along the lines of the flint concretions4 ,abundance of tremolite may also be disadvantageous to limestones and marbles1 because it weathers to a greenish-yellow clay and leaves a pitted surface4 ,the crushing strength of a rock has an obvious relation to its structural uses4 ,the rock must be strong enough for the specified load4 ,most hard rocks ordinarily considered for building purposes are strong enough for the loads to which subjected1 and this factor is perhaps ordinarily less important than the structural and mineral features already mentioned4 ,it is often necessary to know the modulus of elasticity and other mechanical constants of a rock1 as in cases where it is to be combined with metal or other masonry or to be subjected to exceptional shock4 ,the beauty and coloring of a rock are its esthetic rather than its utilitarian features4 ,they are particularly important in the construction of buildings and monuments for public or ornamental purposes4 ,,crushed ,,stone ,the largest use of rock or stone is in the crushed form for road building1 railway embankments1 and concrete1 and the prospect is for largely increased demands for such uses in the future4 ,for the purpose of road building1 it is necessary to consider a stone's resistance to abrasion1 hardness1 toughness1 cementing value1 absorption1 and specific gravity4 ,limestone cements well1 but in other qualities it is not desirable for heavy traffic4 ,shales are soft and clayey1 and grind down to a mass which is dry and powdery1 and muddy in wet weather4 ,basalt and related rocks resist abrasion1 and cement well4 ,granites and other coarse-grained igneous rocks do not cement well and are not resistant to abrasion4 ,many sandstones are very hard and brittle and resist abrasion1 but do not cement4 ,the application of geology on a large scale to the study of sources and qualities of crushed stone is now being required in connection with the great state and national projects of highway building4 ,this work is by no means confined to a mere testing of the physical qualities of road-building materials found along the proposed route1 but includes a careful study of their geologic occurrence1 distribution1 and probable amounts4 ,in certain of the northern states specialists in glacial geology are preferred for this purpose4 ,,stone ,,for ,,metallurgical ,,purposes ,the use of limestone and other rock for metallurgical fluxes is dependent very largely on chemical composition4 ,comparatively few limestones are sufficiently pure for this purpose4 ,for furnace linings1 the quartzite or ganister must be exceptionally pure4 ,the field search for rocks of the necessary composition has required geologic service4 ,,clay ,for a variety of uses to which clay is put1 it is necessary to know its degree of plasticity1 tensile strength1 shrinkage 7both under air and fire71 fusibility1 color1 specific gravity1 and chemical properties4 ,the testing of clay for its various possible uses is a highly specialized job1 usually beyond the range of a geologist1 although certain geologists have been leaders in this type of investigation4 ,more commonly within the range of a geologist are questions concerning origin1 field classification1 distribution1 quantities1 and other geologic conditions affecting quality and production4 ,clay originates from the weathering of common rocks containing silicates1 by pretty well understood weathering processes 7see ,chapter ,,ii74 ,it may remain in place above the parent rock1 or may be transported and redeposited1 either on land or under water1 by the agencies of air1 water1 and ice4 ,the kind of parent rock1 the climatic conditions and nature of the weathering1 and the degree of sorting during transportation1 all determine the composition and texture of the resulting clay1--with the result that a classification on the basis of origin may indicate the broad group characteristics which it is desirable to know for commercial purposes4 ,for instance1 residual clays from the weathering of granite may be broadly contrasted with residual clays formed by the weathering of limestone1 and both differ in group characteristics from clays in glacial deposits4 ,classification according to origin also may be useful in indicating general features of depth1 quantity1 and distribution4 ,however1 a genetic classification of clays is often not sufficient to indicate the precise characteristics which it is necessary to know in determining their availability for narrow and special technical requirements4 ,furthermore1 clays suitable for certain commercial requirements may be formed in several different ways1 and classification based on specific qualities may therefore not correspond at all to geologic classification based on origin4 ,geologists have been especially interested in the causes of plasticity of clay and in its manner of hardening when dried4 ,in general these phenomena have been found to be due to content of colloidal substances of a clayey nature1 which serve not only to hold the substance together during plastic flow but to bind it during drying4 ,the part played by colloids in the formation of clays1 as well as of many other mineral products1 is now a question which is receiving intensive study4 ,the same processes which produce clay also produce1 under special conditions1 iron ores1 bauxites1 the oxide zones of many sulphide ore bodies1 and soils1 all of which are referred to on other pages4 ,,limitations ,,of ,,geologic ,,field ,,in ,,commercial ,,investigation ,,of ,,common ,,rocks ,in general the qualities of the earth materials which determine their availability for use are only to a minor extent the qualities which the geologist ordinarily considers for mapping and descriptive purposes4 ,the usual geological map and report on a district indicate the distribution and general nature of the common rocks1 and also the extent to which they are being used as mineral resources4 ,seldom1 however1 is there added a sufficiently precise description1 for instance of a clay1 to enable the reader to determine which1 if any1 of the many different uses the material might be put to4 ,the variety of uses is so great1 and the technical requirements for different purposes are so varied and so variable1 that it is almost impossible to make a description which is sufficiently comprehensive1 and at the same time sufficiently exact1 to give all the information desired for economic purposes4 ,if the geologist is interested in disclosing the commercial possibilities in the raw materials of an area1 he may select some of the more promising features and subject them to the technical analysis necessary to determine their availability for special uses4 ,in this phase of his work he may find it necessary to enlist the cooperation of skilled technicians and laboratories in the various special fields4 ,the problem is simplified if the geologist is hunting for a particular material for a specific purpose1 for then he fortifies himself with a knowledge of the particular qualities needed and directs his field and laboratory study accordingly4 ,too often the geologist fails to recognize the complexity and definiteness of the qualities required1 and makes statements and recommendations on the use of raw materials based on somewhat general geologic observations4 ,on the other hand1 the engineer1 or the manufacturer1 or the builder often goes wrong and spends money needlessly1 by failing to take into consideration general geologic features which may be very helpful in determining the distribution1 amount1 and general characters of the raw materials needed4 ,it is difficult to draw the line between the proper fields of the geologist and those of the engineer1 the metallurgist1 and other technicians4 ,it is highly desirable that the specialist in any one of these fields know at least of the existence of the other fields and something of their general nature4 ,too often his actions indicate he is not acutely conscious even of the existence of these related branches of knowledge4 ,the extent and detail to which the geologist will familiarize himself with these other fields will of course vary with his training and the circumstances of his work4 ,whatever his limit is1 it should be definitely recognized2 his work should be thorough up to this limit and his efforts should not be wasted in fields which he is not best qualified to investigate4 ,these remarks apply rather generally to mineral resources1 but they are particularly pertinent in relation to the common rock materials which the geologist is daily handling1--for he is likely to assume that he knows all about them and that he is qualified to give professional advice to industries using them4 ,in connection with metallic resources1 the metallurgical and other technical requirements are likely to be more definitely recognized and the lines more sharply drawn1 with the result that the geologist is perhaps not so likely to venture into problems which he is not qualified to handle4 ,the limits to geologic work here discussed are not necessarily limits separating scientific from non-scientific work4 ,the study and determination of the qualities of rocks necessary for commercial purposes is fully as scientific as a study of the qualities commonly considered in purely geologic work1 and the results of technical commercial investigations may be highly illuminating from a purely geological standpoint4 ,when a field of scientific endeavor has been established by custom1 any excursion beyond traditional limits is almost sure to be regarded by conservatives in the field as non-scientific1 and to be lightly regarded4 ,the writer is fully conscious of the existence of limits and the necessity for their recognition2 but he would explain his caution in exceeding these limits on the ground of training and effectiveness1 rather than on fear that he is becoming tainted with non-scientific matters the moment he steps beyond the boundaries of his traditional field4 ,,soils ,,as ,a ,,mineral ,,resource ,soils are not ordinarily listed as mineral resources2 but as weathered and altered rock of great economic value1 they belong nearly at the head of the list of mineral products4 ,,origin ,,of ,,soils ,soil originate from rocks1 igneous1 sedimentary1 and metamorphic by processes of weathering1 and by the mixing of the altered mineral products with decayed plant remains or humus4 ,the humus averages perhaps #c or #d per cent of the soil mass and sometimes constitutes as much as #ge per cent4 ,not all weathered rock is soil in the agricultural sense4 ,for this purpose the term is mainly restricted to the upper few inches or feet penetrated by plant roots4 ,the general process of soil formation constitutes one of the most important phases of katamorphism--the destructive side of the metamorphic cycle1 described in ,chapter ,,ii4 ,processes of katamorphism or weathering1 usually accompanied by the formation of soils1 affect the surface rocks over practically all the continental areas4 ,the weathering of a highly acid igneous rock with much quartz produces a residual soil with much quartz4 ,the weathering of a basic igneous rock without quartz produces a clay soil without quartz1 which may be high in iron4 ,where disintegration has been important the soil contains an abundance of the original silicates of the rock1 and less of the altered minerals4 ,the production of soil from sedimentary rocks involves the same processes as alter igneous rocks2 but1 starting from rocks of different composition1 the result is of course different in some respects4 ,sandstones by weathering yield only a sandy soil4 ,limestones lose their calcium carbonate by solution1 leaving only clay with fragments of quartz or chert as impurities4 ,a foot of soil may represent the weathering of a hundred feet of limestone4 ,shales may weather into products more nearly like those of the weathering of igneous rocks4 ,silicates in the shales are broken down to form clay1 which is mixed with the iron oxide and quartz4 ,in some localities the soil may accumulate to a considerable depth1 allowing the processes of weathering to go to an extreme2 in others the processes may be interrupted by erosion1 which sweeps off the weathered products at intermediate stages of decomposition and may leave a very thin and little decomposed soil4 ,soils formed by weathering may remain in place as residual soils1 or they may be transported1 sorted1 and redeposited1 either on land or under water4 ,it is estimated by the ,united ,states ,bureau of ,soils#ad that upward of #ij per cent of the soils of the ,united ,states which have been thus far mapped owe their occurrence and distribution to transportation by moving water1 air1 and ice 7glaciers71 and that less than #aj per cent have remained in place above their parent rock4 ,glaciers may move the weathered rock products1 or they may grind the fresh rocks into a powder called rock flour1 and thus form soils having more nearly the chemical composition of the unaltered rocks4 ,glacial soils are ordinarily rather poorly sorted1 while wind and water-borne soils are more likely to show a high degree of sorting4 ,the character of a transported soil is less closely related to the parent rock than is that of a residual soil1 because the processes of sorting and mixture of materials from different sources intervene to develop deposits of a nature quite different from residual soils2 but even transported soil may sometimes be traced to a known rock parentage4 ,where deposited under water1 soil materials may be brought above the water by physiographic changes1 and exposed at the surface in condition for immediate use4 ,or1 they may become buried by other sediments and not be exposed again until after they have been pretty well hardened and cemented1--in which case they must again undergo the softening processes of weathering before they become available for use4 ,where soils become buried under other rocks and become hardened1 they are classed as sedimentary rocks and form a part of the geologic record4 ,many residual and transported soils are to be recognized in the geologic column2 in fact a large number of the sedimentary rocks ordinarily dealt with in stratigraphic geology are really transported soils4 ,the development of soils by weathering should not be regarded as a special process of rock alteration1 unrelated to processes producing other mineral products4 ,exactly the same processes that produce soils may yield important deposits of iron ore1 bauxite1 and clay1 and they cause also secondary enrichment of many metallic mineral deposits4 ,for instance the weathering of a syenite rock containing no quartz1 under certain conditions1 as in ,arkansas1 results in great bauxite deposits which are truly soils and are useful as such1--but which happen to be more valuable because of their content of bauxite4 ,the weathering of a basic igneous rock1 as in ,cuba1 may produce important residual iron ore deposits1 which are also used as soils4 ,weathering of ferruginous limestone may produce residual iron and manganese ores in clay soils4 ,,composition ,,of ,,soils ,,and ,,plant ,,growth ,the mineral ingredients in soils which are essential for plant growth include water1 potash1 lime1 magnesia1 nitrates1 sulphur1 and phosphoric acid--all of which are subordinate in amount to the common products of weathering 7pp4 #bj-bb1 #bc-bd74 ,of these constituents magnesia is almost invariably present in sufficient quantity2 while potash1 nitrates1 lime1 sulphur1 and phosphoric acid1 although often sufficiently abundant in virgin soil1 when extracted from the soils by plant growth are liable to exhaustion under ordinary methods of cultivation1 and may need to be replenished by fertilizers 7,chapter ,,vii74 ,some soils may be so excessively high in silica1 iron1 or other constituents1 that the remaining constituents are in too small amounts for successful plant growth4 ,even where soils originally have enough of all the necessary chemical elements1 one soil may support plant growth and another may not1 for the reason that the necessary constituents are soluble and hence available to the plant roots in one case and are not soluble in the other4 ,plainly the mineral combinations in which the various elements occur are important factors in making them available for plant use4 ,similarly a soil of a certain chemical and mineralogical composition may be fruitful under one set of climatic conditions and a soil of like composition may be barren at another locality--indicating that availability of constituents is also determined by climatic and other conditions of weathering4 ,even with the same chemical composition and the same climatic conditions1 there may be such differences in texture between various soils as to make them widely different in yield4 ,the unit of soil classification is the soil type1 which is a soil having agricultural unity1 as determined by texture1 chemical character1 topography1 and climate4 ,the types commonly named are clay1 clay loam1 silt loam1 loam1 fine sandy loam1 sandy loam1 fine sand1 and sand4 ,in general the soil materials are so heterogeneous and so remote from specific rock origin1 that in such classification the geologic factor of origin is not taken into account4 ,more broadly1 soils may be classified into provinces on the basis of geography1 similar physiographic conditions1 and similarity of parent rocks2 for instance1 the soils of the ,piedmont plateau province1 of the arid southwest region1 of the glacial and loessal province1 etc4 ,in such classification the geologic factors are more important4 ,soils within a province may be subdivided into soil series on the basis of common types of sub-soils1 relief1 drainage1 and origin4 ,,use ,,of ,,geology ,,in ,,soil ,,study ,while the desirability of particular soils is related in a broad way to the character of the parent rocks1 and while by geologic knowledge certain territories can be predicated in advance as being more favorable than others to the development of good soils1 so many other factors enter into the question that the geologic factor may be a subordinate one4 ,a soil expert finds a knowledge of geology useful as a basis for a broad study of his subject2 but in following up its intricacies he gives attention mainly to other factors1 such as the availability of common constituents for plant use1 the existence and availability of minute quantities of materials not ordinarily regarded as important by the geologist1 the climatic conditions1 and the texture4 ,as the geologic factors are many of them comparatively simple1 much of the expert work on soils requires only elementary and empirical knowledge of geology4 ,the geologist1 although he may understand fully the origin of soils and may indicate certain broad features1 must acquire a vast technique not closely related to geology before he becomes effective in soil survey work and diagnosis4 ,for these reasons the mapping and classification of soils1 while often started by geologists of state or federal surveys1 have in their technical development and application now passed largely into the hands of soil experts in the special soil surveys affiliated with the ,u4 ,s4 ,department of ,agriculture and with agricultural colleges4 ,,footnotes3 #ac ,a good summary of this subject may be found in ,engineering ,geology1 by ,h4 ,ries and ,t4 ,l4 ,watson1 ,wiley and ,sons1 #b;d ed41 #aiae4 #ad ,marbut1 ,curtis ,f41 ,soils of the ,united ,states3 ,bull4 #if1 ,bureau of ,soils1 #aiac1 p4 #aj4 ,,chapter ,,vii ,,the ,,fertilizer ,,group ,,of ,,minerals ,,general ,,comments ,soils are weathered rock more or less mixed with organic material4 ,the weathering processes forming soils are in the field of geologic investigation1 but the study of soils in relation to agriculture requires attention to texture and to several of their very minor constituents which have little geologic significance4 ,soil study has therefore become a highly specialized and technicalized subject1--for which a geological background is essential1 but which is usually beyond the range of the geologist4 ,to supply substances which are deficient in soils1 however1 requires the mining1 quarrying1 or extraction of important mineral resources1 and in this part of the soil problem the geologist is especially interested4 ,soils may be originally deficient in nitrates1 phosphates1 or potash2 or the continued cropping of soils may take out these materials faster than the natural processes of nature supply them4 ,in some soils there are sufficient phosphates and potash to supply all plant needs indefinitely2 but the weathering and alteration processes1 through which these materials are rendered soluble and available for plant life1 in most cases are unable to keep up with the depletion caused by cropping4 ,a ton of wheat takes out of the soil on an average #dg pounds of nitrogen1 #ah pounds of phosphoric acid1 #ab pounds of potash4 ,on older soils in ,europe it has been found necessary to use on an average #bjj pounds of mixed mineral fertilizers annually per acre4 ,on the newer soils of the ,united ,states the average thus far used has been less than one-seventh of this amount4 ,the ,united ,states has thus far been using up the original materials stored in the soil by nature1 but these have not been sufficient to yield anything like the crop output per acre of the more highly fertilized soils of ,europe4 ,in addition to the nitrates1 phosphates1 and potassium salts1 important amounts of lime and sulphuric acid1 and some gypsum1 are used in connection with soils4 ,lime is derived from crushed limestone 7pp4 #hb-hc71 and is used primarily to counteract acidity or sourness of the soil2 it is1 therefore1 only indirectly related to fertilizers4 ,sulphuric acid is used to treat rock phosphates to make them more soluble and available to plant life4 ,it requires the mining of pyrite and sulphur4 ,gypsum1 under the name of land-plaster1 is applied to soils which are deficient in the sulphur required for plant life2 increase in its use in the future seems probable4 ,there are also considerable amounts of inert mineral substances which are used as fillers in fertilizers to give bulk to the product1 but which have no agricultural value4 ,the proportions of the fertilizer substances used in the ,united ,states are roughly summarized in ,figure #d4 ,the ,united ,states possesses abundant supplies of two of the chief mineral substances entering into commercial fertilizers1--phosphate rock and the sulphur-bearing materials necessary to treat it4 ,for potash the ,united ,states is dependent on ,europe1 unless the domestic industry is very greatly fostered under protective tariff4 ,for the mineral nitrates the ,united ,states has been dependent on ,chile1 and because of the cheapness of the supply will doubtless continue to draw heavily from this source4 ,however1 because of the domestic development of plants for the fixation of nitrogen from the air1 the recovery of nitrogen from coal in the by-product processes1 and the use of nitrogenous plants1 the ,united ,states is likely to require progressively less of the mineral nitrates from ,chile4 ,the fertilizer industry of the ,united ,states is yet in its infancy and is likely to have a large growth4 ,furthermore much remains to be learned about the mixing of fertilizers and the amounts and kinds of materials to be used4 ,the importance of sulphur as a plant food has been realized comparatively recently4 ,the use of fertilizers in the ,united ,states has come partly through education and the activity of agricultural schools and partly through advertising by fertilizer companies4 ,the increased use of potash has been due largely to the propaganda of the ,german sales agents4 ,an examination of a map showing distribution of the use of fertilizers over the country indicates very clearly the erratic distribution of the effects of these various activities4 ,one locality may use large amounts1 while adjacent territory of similar physical conditions uses little4 ,the sudden withdrawal of fertilizers for a period of three or four years during the war had very deleterious effects in some localities1 but was not so disastrous as expected in others1--emphasizing the fact that the use of fertilizers has been partly fortuitous and not nicely adjusted to specific needs4 ,illustration3 ,,fig4 #d4 ,,fertilizer ,,situation ,,in ,,the ,,united ,,states4 ,,smithsonian ,,institution--,,united ,,states ,,national ,,museum ,,nitrates ,,economic ,,features ,there are several sources of nitrogen for fertilizer purposes3 mineral nitrates1 nitrogen taken from the air by certain plants with the aid of bacteria and plowed into the soil1 nitrogen taken directly from the air by combining nitrogen and oxygen atoms in an electric arc1 or by combining nitrogen and hydrogen to form ammonia1 nitrogen taken from the air to make a compound of calcium1 carbon1 and nitrogen 7cyanamid71 nitrogen saved from coal in the form of ammonia as a by-product of coke-manufacture1 and nitrogen from various organic wastes4 ,nitrogen in the form of ammonia is also one of the potential products of oil-shales 7p4 #aej74 ,while the principal use of nitrogenous materials is as fertilizers1 additional important quantities are used in ammonia for refrigerating plants1 and in the form of nitric acid in a large number of chemical industries4 ,during the war the use of nitrates was largely diverted to explosives manufacture4 ,the geologist is interested principally in the mineral nitrates as a mineral resource1 but the other sources of nitrogen1 particularly its recovery from coal1 also touch his field4 ,almost the single source of mineral nitrates for the world at present is ,chile1 where there are deposits of sodium nitrate or ,chile saltpeter1 containing minor amounts of potassium nitrate4 ,about two-thirds of the ,chilean material normally goes to ,europe and about one-fourth to the ,united ,states4 ,the supply has been commercially controlled chiefly by ,great ,britain and by ,chilean companies backed by ,british and ,german capital4 ,the dependence of the world on ,chile became painfully apparent during the war4 ,germany was the only nation which had developed other sources of nitrogenous material to any great extent4 ,the other nations were dependent in a very large degree on the mineral nitrates1 both for fertilizer and munition purposes4 ,total demands far exceeded the total output from ,chile1 requiring international agreement as to the division of the output among the nations4 ,the stream of several hundred ships carrying nitrates from ,chile was one of the vital war arteries4 ,this situation led to strenuous efforts in the belligerent countries toward the development of other sources of nitrogen4 ,the ,united ,states1 under governmental appropriation1 began the building of extensive plants for the fixation of nitrogen from the air1 and the building of by-product coke ovens in the place of the old wasteful beehive ovens was accelerated4 ,germany before the war had already gone far in both of these directions1 not only within her own boundaries1 but in the building of fixation plants in ,scandinavia and ,switzerland4 ,war conditions required further development of these processes in ,germany1 with the result that this country was soon entirely self-supporting in this regard4 ,one of the effects was the almost complete elimination in ,germany of anything but the by-product process of coking coal4 ,war-time development of the nitrogen industry in the ,united ,states for munition purposes brought the domestic production almost up to the pre-war requirements for fertilizers alone4 ,with the increasing demand for fertilizers and with the cheapness of the ,chilean supply of natural nitrates1 it is likely that the ,united ,states will continue for a good many years to import considerable amounts of ,chilean nitrates4 ,it may be noted that1 although this country normally consumes about one-fourth of the ,chilean product1 ,american interests commercially control less than one-twentieth of the output4 ,presumably1 if for no other purpose than future protection1 effort will be made to develop the domestic industry to a point where in a crisis the ,united ,states could be independent of ,chile4 ,particularly may an increase in the output of by-product ammonia from coke manufacture be looked for 7see also pp4 #aah-aai71 since nitrogenous material thus produced need bear no fixed part of the cost of production1 and requires no protective tariff4 ,the reserves of ,chilean nitrate are known to be sufficient for world requirements for an indefinitely long future4 ,,geologic ,,features ,mineral nitrates in general1 and particularly those of soda and potash1 are readily soluble at ordinary temperatures4 ,mineral nitrate deposits are therefore very rare1 and are found only in arid regions or other places where they are protected from rain and ground-water4 ,the only large deposits known are those of northern ,chile and some extensions in adjacent parts of ,peru and ,bolivia4 ,these are located on high desert plateaus1 where there is almost a total absence of rain1 and form blankets of one to six feet in thickness near the surface4 ,the most important mineral1 the sodium nitrate or ,chile saltpeter1 is mingled with various other soluble salts1 including common salt1 borax minerals1 and potassium nitrate1 and with loose clay1 sand1 and gravel4 ,the nitrate deposits occur largely around and just above slight basin-like depressions in the desert which contain an abundance of common salt4 ,the highest grade material contains #dj to #ej per cent of sodium nitrate1 and material to be of shipping grade must run at least #ab to #ae per cent4 ,the origin of the nitrate beds is commonly believed to be similar to that of beds of rock salt 7pp4 #bie-bih71 borax1 and other saline residues4 ,the source of the nitrogen was probably organic matter in the soil1 such as former deposits of bird guano1 bones 7which are actually found in the same desert basin71 and ancient vegetable matter4 ,by the action of nitrifying bacteria on this organic matter1 nitrate salts are believed to have formed which were leached out by surface and ground waters1 and probably carried in solution to enclosed bodies of water4 ,here they became mingled with various other salts1 and all were precipitated out as the waters of the basins evaporated4 ,deliquescence and later migration of the more soluble nitrates resulted in their accumulation around the edges of the basins4 ,the nitrate beds are thus essentially a product of desiccation4 ,while the origin just set forth is rather generally accepted1 several other theories have been advanced4 ,it has been suggested that the deposits were not formed in water basins1 but that ground water carrying nitrates in solution has been and is rising to the surface1--where1 under the extremely arid conditions1 it evaporates rapidly1 leaving the nitrates mixed with the surface clays4 ,one group of writers accounts for the deposits by the fixation of atmospheric nitrogen through electrical phenomena4 ,still others note the frequent presence of nitrogen in volcanic exhalations and the association of the ,chilean nitrate beds with surface volcanic rocks2 they suggest that these rocks were the source of the nitrogen1 which under unusual climatic conditions was leached out and then deposited by evaporation4 ,,phosphates ,,economic ,,features ,the principal use of natural phosphates is in the manufacture of fertilizers4 ,they are also used in the manufacture of phosphorus1 phosphoric acid1 and other phosphorus compounds1 for matches1 for certain metallurgical operations1 and for gases used in military operations4 ,the material mined is mainly a phosphate of lime 7tricalcium phosphate74 ,to make it available for plant use1 it is treated with sulphuric acid to form a soluble superphosphate2 hence the importance of sulphuric acid1 and its mineral sources pyrite and sulphur1 in the fertilizer industry4 ,a small percentage of the phosphate is also ground up and applied directly to the soil in the raw form4 ,other phosphatic materials are the basic slag from phosphatic iron ores made into ,thomas-process steel1 guano from the ,pacific islands1 and bone and refuse 7tankage7 from the cattle raising and packing countries4 ,these materials are used for the same purposes as the natural phosphates4 ,the ,united ,states is the largest factor in the world's phosphate industry1 with reference both to production and reserves4 ,the largest and most available of the ,european sources are in ,tunis and ,algeria1 under ,french control1 and in ,egypt1 under ,english control4 ,belgium and northern ,france have been considerable producers of phosphates1 but1 with the development of higher grade deposits in other countries1 their production has fallen to a very small fraction of the world's total4 ,there also has been very small and insignificant production in ,spain and ,great ,britain4 ,russia has large reserves which are practically unmined4 ,while there is comparatively little phosphate rock in western ,europe1 a considerable amount of the phosphate supply is obtained as a by-product from ,thomas slag1 derived from phosphatic iron ores4 ,these ores are chiefly from ,lorraine and ,sweden1 but ,english and ,russian ores can be similarly used4 ,outside of ,europe and the ,united ,states1 there are smaller phosphate supplies in ,canada1 the ,dutch ,west ,indies1 ,venezuela1 ,chile1 ,south ,australia1 ,new ,zealand1 and several islands of the ,indian and ,south ,pacific ,oceans4 ,none of these has yet contributed largely to world production1 and their distance from the principal consuming countries bordering the ,north ,atlantic basin is so great that there is not likely to be any great movement to this part of the world4 ,on the other hand1 some of the ,south ,sea islands have large reserves of exceptionally high grade guano and bone phosphates1 which will doubtless be used in increasing amounts for export to ,japan1 ,new ,zealand1 and other nearby countries4 ,the most important of these islands are now controlled by ,great ,britain1 ,japan1 and ,france4 ,a striking feature of the situation is that the central ,european countries1 which have been large consumers of phosphate material1 have lost not only the ,pacific island phosphates but the ,lorraine phosphatic iron ores1 and are now almost completely dependent on ,british1 ,french1 and ,united ,states phosphate4 ,in the ,united ,states1 reserves of phosphate are very large4 ,they are mined principally in ,florida1 ,tennessee1 and ,south ,carolina2 but great reserves1 though of lower grade1 are known in ,arkansas1 ,montana1 ,idaho1 ,wyoming1 and ,utah4 ,there are possibilities for the development of local phosphate industries in the west1 in connection with the manufacture of sulphuric acid from waste smelting gases at nearby mining centers4 ,the ,anaconda ,copper ,mining ,company has taken up the manufacture of superphosphate as a means of using sulphuric acid made in relation to its smelting operations4 ,the ,united ,states is independent in phosphate supplies and has a surplus for export4 ,this country1 ,england1 and ,france exercise control of the greater part of the world's supply of phosphatic material4 ,in competition for world trade1 the ,florida and ,carolina phosphates are favorably situated for export1 but there is strong competition in ,europe from the immense fields in ,french ,north ,africa1 which are about equally well situated4 ,,geologic ,,features ,small amounts of phosphorus are common in igneous rocks1 in the form of the mineral apatite 7calcium phosphate with calcium chloride or fluoride74 ,apatite is especially abundant in some pegmatites4 ,in a few places1 as in the ,adirondacks where magnetic concentration of iron ores leaves a residue containing much apatite1 and in ,canada and ,spain where veins of apatite have been mined1 this material is used as a source of phosphate fertilizer4 ,the great bulk of the world's phosphate1 however1 is obtained from other sources--sedimentary and residual beds described below4 ,phosphorus in the rocks is dissolved in one form or another by the ground-waters2 a part of it is taken up by land plants and animals for the building of their tissues1 and another part goes in solution to the sea to be taken up by sea plants and animals4 ,in places where the bones and excrements of land animals or the shells and droppings of sea animals accumulate1 deposits of phosphatic material may be built up4 ,in certain places where great numbers of sea birds congregate1 as on desert coasts and oceanic islands1 guano deposits have been formed4 ,some of them1 like the worked-out deposits of ,peru and ,chile1 are in arid climates and have been well preserved4 ,others1 like those of the ,west ,indies and ,oceania1 are subjected to the action of occasional rains2 and to a large extent the phosphates have been leached out1 carried down1 and reprecipitated1 permeating and partially replacing the underlying limestones4 ,in this way deposits have been formed containing as high as #he per cent calcium phosphate4 ,even more important bodies of phosphates have been produced by the accumulation of marine animal remains1 probably with the aid of joint chemical1 bacterial1 and mechanical precipitation4 ,these processes have formed the chief productive deposits of the world1 including those of the ,united ,states1 northern ,africa1 and ,russia1 and also the phosphatic iron ores of ,england and central ,europe4 ,the sedimentary features of many phosphate rocks1 particularly their oolitic textures1 show a marked similarity to the features of the ,clinton type of iron ores 7pp4 #aff-afg74 ,the marine phosphate beds originally consist principally of calcium phosphate and calcium carbonate in varying proportions4 ,depending on the amount of secondary enrichment1 they form two main types of deposits4 ,the extensive beds of the western ,united ,states 7in the upper ,carboniferous7 are hard1 and very little enrichment by weathering has taken place2 they carry in their richer portions #gj to #hj per cent calcium phosphate1 and large sections range only from about #cj to #ej per cent4 ,in the southeastern deposits 7,silurian and ,devonian in ,tennessee and ,tertiary in the ,carolinas and ,florida71 there has been considerable enrichment1 the rock is softer1 and the general grade ranges from #fe to #hj per cent4 ,both calcium carbonate and calcium phosphate are soluble in ordinary ground waters1 but the carbonate is the more soluble of the two4 ,thus the carbonate has been dissolved out more rapidly1 and in addition descending waters carrying the phosphate have frequently deposited it to pick up the carbonate4 ,these enriching processes1 sometimes aided by mechanical concentration1 have formed high-grade deposits both in the originally phosphatic beds and in various underlying strata4 ,concretionary and nodular textures are common4 ,the pebble deposits of ,florida consist of the phosphatic materials broken up and worked over by river waters and advancing shallow seas4 ,,pyrite ,,economic ,,features ,the principal use of pyrite is in the manufacture of sulphuric acid4 ,large quantities of acid are used in the manufacture of fertilizers from phosphate rock1 and during war times in the manufacture of munitions4 ,sulphuric acid converts the phosphate rock into superphosphate1 which is soluble and available for plant use4 ,other uses of the acid are referred to in connection with sulphur4 ,pyrite is also used in ,europe for the manufacture of paper from wood-pulp1 but in the ,united ,states native sulphur has thus far been exclusively used for this purpose4 ,the residue from the roasting of pyrite is a high-grade iron ore material frequently very low in phosphorus1 which is desirable in making up mixtures for iron blast furnaces4 ,most of the countries of ,europe are producers of pyrite1 and important amounts are also produced in the ,united ,states and ,canada4 ,the ,european production is marketed mainly on that continent1 but considerable amounts come to the ,united ,states from ,spain4 ,before the war domestic sources supplied a fourth to a third of the domestic demand for pyrite4 ,imports came mainly from ,spain and ,portugal to consuming centers on the ,atlantic seaboard4 ,the curtailment of overseas imports of pyrite during the war increased domestic production by about a third and resulted also in drawing more heavily on ,canadian supplies1 but the total was not sufficient to meet the demand4 ,the demand was met by the increased use of sulphur from domestic deposits 7p4 #aji74 ,at the close of the war supplies of pyrite had been accumulated to such an extent that1 with the prospect of reopening of ,spanish importation1 pyrite production in the ,united ,states practically ceased4 ,war experience has demonstrated the possibility of substitution of sulphur1 which the ,united ,states has in large and cheaply mined quantities4 ,the future of the pyrite industry in the ,united ,states therefore looks cloudy1 except for supplies used locally1 as in the territory tributary to the ,great ,lakes1 and except for small amounts locally recovered as by-products in the mining of coal or from ores of zinc1 lead1 and copper4 ,pyrite production in the past has been chiefly in the ,appalachian region1 particularly in ,virginia and ,new ,york1 and in ,california4 ,,geologic ,,features ,pyrite1 the yellow iron sulphide1 is the commonest and most abundant of the metallic sulphides4 ,it is formed under a large variety of conditions and associations4 ,marcasite and pyrrhotite1 other iron sulphide minerals1 are frequently found with pyrite and are used for the same purposes4 ,the great deposits of ,rio ,tinto1 ,spain1 which produce about half of the world's pyrite1 were formed by replacement of slates by heated solutions from nearby igneous rocks4 ,the ores are in lenticular bodies1 and consist of almost massive pyrite with a small amount of quartz and scattered grains and threads of chalcopyrite 7copper-iron sulphide74 ,they carry about #ej per cent of sulphur1 and the larger part carries about #b per cent of copper which is also recovered4 ,similar occurrences of pyrite on a smaller scale are known in many places4 ,pyrite is very commonly found in vein and replacement deposits of gold1 silver1 copper1 lead1 and zinc4 ,in the ,mississippi valley it is extracted as a by-product from the lead and zinc ores1 and in the ,cordilleran region large quantities of by-product pyrite could easily be produced if there were a local demand4 ,the pyrite deposits of the ,appalachian region are chiefly lenses in schists2 they are of uncertain origin though some are believed to have been formed by replacement of metamorphosed limestones and schists4 ,under weathering conditions pyrite oxidizes1 the sulphur forming sulphuric acid1--an important agent in the secondary enrichment of copper and other sulphides1--and the iron forming the minerals hematite and limonite in the shape of a gossan or iron-cap4 ,pyrite is likewise frequently found in sediments1 apparently being formed mainly by the reducing action of organic matter on iron salts in solution4 ,in ,illinois and adjacent states it is obtained as a by-product of coal mining4 ,,sulphur ,,economic ,,features ,sulphur is used for many of the same purposes as pyrite4 ,under pre-war conditions1 the largest use in the ,united ,states was in the manufacture of paper pulp by the sulphite process4 ,minor uses were in agriculture as a fungicide and insecticide1 in vulcanizing rubber1 and in the manufacture of gunpowder4 ,about #e per cent of the sulphur of the ,united ,states was used in the manufacture of sulphuric acid4 ,during the war this use was greatly increased because of the shortage of pyrite and the large quantities of sulphuric acid necessary for the manufacture of explosives4 ,the replacement of pyrite by sulphur in the manufacture of sulphuric acid has continued since the war1 and in the future is likely to continue to play an important part4 ,sulphuric acid is an essential material for a great range of manufacturing processes4 ,some of its more important applications are3 in the manufacture of superphosphate fertilizer from phosphate rock2 in the refining of petroleum products2 in the iron1 steel1 and coke industries2 in the manufacture of nitroglycerin and other explosives2 and in general metallurgical and chemical practice4 ,the ,united ,states is the world's largest sulphur producer4 ,the principal foreign countries producing important amounts of sulphur are ,italy1 ,japan1 ,spain1 and ,chile4 ,europe is the chief market for the ,italian sulphur4 ,in spite of increased demands in ,europe the ,italian production has decreased as the result of unfavorable labor1 mining1 and transportation conditions1 and the deficit has had to be met from the ,united ,states4 ,japan's sulphur production has been increasing4 ,normally about half of the material exported comes to the ,united ,states to supply the needs of the paper industry in the ,pacific states1 and half goes to ,australia and other ,british colonies4 ,spain's production is relatively small and has been increasing slowly2 most of it is consumed locally4 ,chile's small production is mainly consumed at home and large additional amounts are imported4 ,the sulphur output of the ,united ,states1 which in #aiac-ad was second to ,italy1 now amounts to three-fourths of the entire output of the world1 and the ,united ,states has become a large exporter of sulphur4 ,supplies are ample and production increasing1 with the result that the ,united ,states can not only meet its own demands1 but can use this commodity extensively in world trade4 ,small amounts of sulphur are mined in some of the western states1 but over #ih per cent of the production comes from ,louisiana and ,texas4 ,,geologic ,,features ,native sulphur is found principally in sedimentary beds1 where it is associated with gypsum and usually with organic matter4 ,deposits of this type are known in many places1 the most important being those of ,sicily and of the ,gulf ,coast in the ,united ,states4 ,in the latter region beds of limestone carry lenses of sulphur and gypsum which are apparently localized in dome-like upbowings of the strata4 ,the deposits are overlain by several hundred feet of loose1 water-bearing sands1 through which it is difficult to sink a shaft4 ,an ingenious and efficient process of mining is used whereby superheated water is pumped down to melt the sulphur1 which is then forced to the surface by compressed air and allowed to consolidate in large bins4 ,the ,sicilian deposits are similar lenses in clayey limestones containing #bj to #be per cent of sulphur1 associated with gypsum and bituminous marl2 they are mined by shafts4 ,concerning the origin of these deposits several theories have been advanced4 ,it has been thought that the materials for the deposits were precipitated at the same time as the enclosing sediments2 and that the sulphur may have been formed by the oxidation of hydrogen sulphide in the precipitating waters through the agency of air or of sulphur-secreting bacteria1 or that it may have been produced by the reduction of gypsum by organic matter or bacteria4 ,others have suggested that hot waters rising from igneous rocks may have brought in both the sulphur and the gypsum1 which in crystallizing caused the upbowing of the strata which is seen in the ,gulf fields 7see also p4 #bih74 ,native sulphur is also found in mineral springs from which hydrogen sulphide issues1 where it is produced by the oxidation of the hydrogen sulphide4 ,it likewise occurs in fissures of lava and around volcanic vents1 where it has probably been formed by reactions between the volcanic gases and the air4 ,the ,japanese and ,chilean deposits are of the volcanic type4 ,,potash ,,economic ,,features ,potash is used principally as a component of fertilizers in agriculture4 ,it is also used in the manufacture of soap1 certain kinds of glass1 matches1 certain explosives1 and chemical reagents4 ,for a long time potash production was essentially a ,german monopoly4 ,the principal deposits are in the vicinity of ,stassfurt in north central ,germany 7about the ,harz ,mountains74 ,stassfurt salts are undoubtedly ample to supply the world's needs of potash for an indefinite future4 ,however1 other deposits1 discovered in the ,rhine ,valley in ,alsace in #aijd1 have been proved to be of great extent2 and though the production has hitherto been limited by restrictions imposed by the ,german ,government1 it has nevertheless become considerable4#ae ,the grade 7#ah per cent ,k#b,o7 is superior to the general run of material taken from the main ,german deposits1 and the deposits have a regularity of structure and uniformity of material favorable to cheaper mining and refining than obtains in the ,stassfurt deposits4 ,other countries have also developed supplies of potash1 some of which will probably continue to produce even in competition with the deposits of recognized importance referred to above4 ,noteworthy among the newer developments are those in ,spain4#af ,these have not yet produced on any large scale1 but their future production may be considerable4 ,less important deposits are known in ,galicia1 ,tunis1 ,russia1 and eastern ,abyssinia1 and the nitrate deposits of ,chile contain a small percentage of potash which is being recovered in some of the operations4 ,prior to the war the ,united ,states obtained its potash from ,germany4 ,the ,german potash industry was well organized and protected by the ,german ,government1 which made every effort to maintain a world monopoly4 ,during the war the potash exports from ,germany were cut off1 excepting exports to the neutrals immediately adjoining ,german territory4 ,the result in the ,united ,states was that the price of potash rose so far as to greatly diminish its use as fertilizer4 ,the consequent efforts to increase potash production in the ,united ,states met with considerable success1 but the maximum production attained was only about one-fourth of the ordinary pre-war requirements4 ,the principal ,american sources are alkaline beds and brines in ,nebraska1 ,utah1 and ,california1 and especially at ,searles ,lake1 ,california4 ,these furnished #ge per cent of the total output4 ,minor amounts have been extracted in ,utah from the mineral alunite 7a sulphate of potassium and aluminum71 in ,wyoming from leucite 7a potassium-aluminum silicate71 in ,california from kelp or seaweed1 and in various localities from cement-mill and blast-furnace dusts1 from wood ashes1 from wool washings1 from the waste residues of distilleries and beet-sugar refineries1 and from miscellaneous industrial wastes4 ,at the close of the war1 sufficient progress had been made in the potash industry to indicate that the ,united ,states might become self-supporting in the future1 though at high cost4 ,the renewal of importation of cheap potash from ,germany1 with probable further offerings from ,alsace and ,spain1 makes it impossible for the ,united ,states potash production to continue2 except1 perhaps1 for the recovery of by-products which will go on in connection with other industries4 ,demand for a protective tariff has been the inevitable result 7see ,chapters ,,xvii and ,,xviii74 ,,geologic ,,features ,potassium is one of the eight most abundant elements in the earth4 ,it occurs as a primary constituent of most igneous rocks1 some of which carry percentages as high as those in commercial potash salts used for fertilizers4 ,it is present in some sediments and likewise occurs in many schists and gneisses4 ,various potassium silicates--leucite1 feldspar1 sericite1 and glauconite--and the potassium sulphate1 alunite1 have received attention and certain of them have been utilized to a small extent1 but none of them are normally able to compete on the market4 ,potential supplies are thus practically unlimited in amount and distribution4 ,deposits from which the potash can be extracted at a reasonable cost1 however1 are known in only a few places1 where they have been formed as saline sediments4 ,in the decomposition of rocks the potash1 like the soda1 is readily soluble1 but in large part it is absorbed and held by clayey materials and is not carried off4 ,potash is therefore more sparingly present in river and ocean waters than is soda1 and deposits of potash salts are much rarer than those of rock salt and other sodium compounds4 ,the large deposits in the ,permian beds of ,stassfurt1 as well as those in the ,tertiary of ,alsace and ,spain1 have been formed by the evaporation of very large quantities of salt water1 presumably sea water4 ,they consist of potassium salts1 principally the chloride1 mixed and intercrystallized with chlorides and sulphates of magnesium1 sodium1 and calcium4 ,in the ,stassfurt deposits the potassium-magnesium salts occupy a relatively thin horizon at the top of about #ejj feet of rock salt beds1 the whole underlying an area about #bjj miles long and #adj miles wide4 ,the principal minerals in the potash horizon are carnallite 7hydrous potassium-magnesium chloride71 kieserite 7hydrous magnesium sulphate71 sylvite 7potassium chloride71 kainite 7a hydrous double salt of potassium chloride and magnesium sulphate71 and common salt 7sodium chloride74 ,the potash beds represent the last stage in the evaporation of the waters of a great closed basin1 and the peculiar climatic and topographic conditions which caused their formation have been the subject of much speculation4 ,this subject is further treated in the discussion of common salt beds 7pp4 #bie-bih74 ,in the ,united ,states the deposits at ,searles ,lake1 ,california1 have been produced by the same processes on a smaller scale4 ,in this case evaporation has not been carried to completion1 but the crystallization and separation out of other salts has concentrated the potassium 7with the magnesium7 in the residual brine or mother liquor4 ,the deposits of this lake or marsh also contain borax 7see p4 #bgf71 and differ in proportions of salts from the ,stassfurt deposits4 ,this is due to the fact that they were probably derived1 not from ocean waters1 but from the leaching of materials from the rocks of surrounding uplands1 transportation of these materials in solution by rivers and ground waters1 and concentration in the desert basin by evaporation4 ,the alkali lakes of ,nebraska are believed to be of very recent geologic origin4 ,they lie in depressions in a former sand dune area1 and contain large quantities of potash supposedly accumulated by leaching of the ashes resulting from repeated burnings of the grass in the adjacent country4 ,of other natural mineral sources1 alunite is the most important4 ,the principal deposits worked are at ,marysville1 ,utah1 but the mineral is a rather common one in the western part of the ,united ,states1 associated with gold deposits1 as at ,goldfield1 ,nevada4 ,alunite occurs as veins and replacement deposits1 often in igneous associations1 and is supposed to be of igneous source4 ,its origin is referred to in connection with the ,goldfield ores 7p4 #bcj74 ,,footnotes3 #ae ,gale1 ,hoyt ,s41 ,the potash deposits of ,alsace3 ,bull4 #gae-;,b1 ,u4 ,s4 ,geol4 ,survey1 #aibj1 pp4 #ag-ee4 #af ,gale1 ,hoyt ,s41 ,potash deposits in ,spain3 ,bull4 #gae-;,a1 ,u4 ,s4 ,geol4 ,survey1 #aibj1 pp4 #a-af4 ,,chapter ,,viii ,,the ,,energy ,,resources--,,coal1 ,,oil1 ,,gas 7,,and ,,asphalt7 ,,coal ,,economic ,,features ,coal overshadows all other mineral resources1 except water1 in production1 value1 and demand4 ,it is the greatest of the energy sources--coal1 petroleum1 gas1 and water power4 ,roughly two-thirds of the world's coal is used for power1 one-sixth for smelting and metallurgical industries1 and one-sixth for heating purposes4 ,coal constitutes over one-third of the railroad tonnage of the ,united ,states and is the largest single tonnage factor in international trade2 #gj per cent of the pre-war tonnage of outgoing cargoes from ,england was coal4 ,world production and trade4 ,the great coal-producing countries of the world border the ,north ,atlantic basin4 ,the ,united ,states produces about #dj per cent of the world's total1 ,great ,britain about #bj per cent1 and ,germany about #bj per cent4 ,other countries producing coal stand in about the following order3 ,austria-,hungary1 ,france1 ,russia1 ,belgium1 ,japan1 ,china1 ,india1 ,canada1 and ,new ,south ,wales4 ,there is similarity in the major features of the distribution of coal production and of iron ore production4 ,the great centers of coal production--the ,pennsylvania and ,illinois fields of the ,united ,states1 the ,midlands district of ,england1 and the lower ,rhine or ,westphalian fields of ,germany--are also the great centers of the iron and steel industries of these countries4 ,as in the case of iron ore1 there is rather a striking absence of important coal production in the southern hemisphere and in ,asia4 ,a significant item in the world's distribution of coal supplies is ,england's world-wide system of coaling stations for shipping4 ,the principal coal-producing countries all have large reserves of coal4 ,outside of these countries the world's most important reserves are in ,china1 which may be looked to for great future development4 ,for the most part1 except for the probable ,chinese development1 it is likely that countries now producing most of the coal will continue to do so in the future1 and that outlying parts of the world will continue to be supplied mainly from these countries4 ,the quantity and distribution of the coal reserves of the world have been estimated with perhaps a greater degree of accuracy than those of any other mineral resource4 ,from these estimates it appears that the ,north ,american continent contains about half of the world reserves 7principally in the ,united ,states1 with lesser amounts in ,canada7 and ,asia about one-fourth 7principally in ,china1 with some in ,india74 ,europe contains only one-sixth of the world total1 chiefly in the area of the former ,german ,empire and in ,great ,britain1 with smaller quantities in ,russia1 ,austria-,hungary1 ,france1 and ,belgium4 ,australasia 7,new ,south ,wales71 ,africa 7,british ,south ,africa71 and ,south ,america 7,chile1 ,brazil1 ,peru1 and ,colombia71 together contain less than a tenth of the total reserves4 ,coal being one of the great bases for modern industrialism1 the large reserves of high grade-coals in ,china have led to the belief that ,china may some day develop into a great manufacturing nation4 ,similarly1 the deficiency in coal of most of the ,south ,american and ,african countries seems to preclude their developing any very large manufacturing industries1 except where water power is available4 ,coal reserves and the conservation of coal are further discussed in ,chapter ,,xvii4 ,the war resulted in considerable disturbances in coal production and distribution4 ,there has not yet been a return to normal conditions1 and some of the changes are probably permanent4 ,the great overseas movement of coal from ,germany was stopped and that from ,england curtailed4 ,to some extent the deficiency was supplied by coal exports from the ,united ,states1 particularly to ,south ,america4 ,the shutting off of the normal ,german export to ,france and ,mediterranean countries1 the occupation of the ,french and ,belgian coal fields by the ,germans1 and the partial restriction of ,german exports to ,scandinavian countries1 resulted in ,europe's absorbing most of the ,british coal available for export1 and in addition requiring coal from the ,united ,states4 ,the stress in the world's coal industry to meet the energy requirements of war is too recent and vivid to require more than mention4 ,the world was made to realize almost for the first time the utterly vital and essential nature of this industry4 ,since the war1 there has been a gradual resumption of ,england's export of coal along old lines of international trade4 ,the ,german overseas export trade has not been reestablished1 and cannot be for a long time to come if ,germany fulfills the terms of the ,peace ,treaty4 ,indeed1 because of slow recovery in output of ,german coal1 there is yet considerable lag in the supply available for ,european countries4 ,the terms of the ,peace ,treaty lessened the territory of ,german coal reserves and required considerable additional contributions of coal to be delivered to ,france1 ,belgium1 ,luxemburg1 and ,italy4 ,the increased export of coal from the ,united ,states during the war is likely to be in part continued in the future1 although the great bulk of the ,united ,states production will in the future1 as in the past1 be absorbed locally4 ,most of the coal in the ,united ,states available for export is higher in volatile matter than the ,british and ,german export coal4 ,this quality will in some degree be a limiting factor in exportation4 ,on the other hand1 it may result in wider introduction of briquetting1 coking1 and other processes1 which will tend to improve the local industry and be conservational in their effect4 ,japan will doubtless hold some of the ,asiatic coal market gained during the war4 ,international coal relations are further discussed in ,chapter ,,xviii4#ag ,production in the ,united ,states4 ,the main features of the distribution of coal supplies in the ,united ,states are3 7#a7 ,localization of the anthracite production and reserves in a limited area in the ,lawton region of ,pennsylvania4 ,low-grade anthracite coal also occurs in ,rhode ,island1 ,north ,carolina1 ,colorado1 and ,idaho4 7#b7 ,localization of the bituminous production in the eastern and interior states of ,pennsylvania1 ,west ,virginia1 ,ohio1 ,indiana1 ,illinois1 and ,kentucky4 ,the principal reserves of bituminous coal occur in the same provinces1 but important additional reserves are known in ,texas1 in ,north and ,south ,carolina1 and in the ,rocky ,mountain and ,pacific ,coast provinces4 7#c7 ,the existence of large tonnages of subbituminous coal in the west1 which have not been mined to any extent4 7#d7 ,the existence of large fields of lignite in the ,gulf ,coast region1 and in the ,northern ,plains region1 which have not been mined4 ,coke4 ,about one-sixth of the bituminous coal mined in the ,united ,states is made into coke1 that is1 it is subjected to heat in ovens from which oxygen is excluded in order to drive off the volatile gases 7chiefly hydrocarbons and water7 which constitute about #dj per cent of the weight of the coal4 ,the residual product1 the coke1 is a light1 porous mass with a considerably higher percentage of fixed carbon than bituminous coal4 ,in regard to composition1 coking accomplishes artificially somewhat the same result reached by nature in its slow development of high-grade coals1 but the texture of coke is far different from that of coal4 ,not all bituminous coals are suitable for coke manufacture2 and such coals are frequently divided into two classes1 known as coking and non-coking coals4 ,coke is used principally for smelting purposes4 ,because of its spongy1 porous texture1 it burns more rapidly and intensely than coal4 ,the gases eliminated in coking are wasted in the old-fashioned beehive ovens1 but in modern by-product coke ovens these gases by proper treatment yield valuable coal tar products and ammonia4 ,it is estimated that the sum of the value of the products thus recovered from a ton of coal multiplies the value of the ton of coal at the mine by at least thirteen times4 ,the importance of this fact from the conservational standpoint cannot be too much emphasized4 ,at present over half of the total coke produced in the ,united ,states comes from by-product ovens1 and this proportion will doubtless increase in the future4 ,,balance ,,sheet ,,showing ,,contrast ,,between ,,value ,,of #a ,,ton ,,of ,,bituminous ,,coal ,,at ,,mine ,,and ,,value ,,of ,,products ,,which ,,it ,,contains1 ,,based ,,on ,,conditions ,,prevailing ,,in #aiae4a ,value at ,value at point of mine #aiae ,quantity production1 #aiae ---------------------------------------- --------------------------------- #a ton 7#b1jjj pounds7 7#a1ejj pounds smokeless fuel #e4jjb bituminous coal 7#aj1jjj cubic feet gas1 at contains #a4ac #ij;c4 per #a1jjj #i4jjc 7#bb pounds ammonium sulphate at #b4h;c4 4#fa 7#b-a_/b gallons benzol1 at #cj;c4 4#ged 7#i gallons tar1 at #b4f;c4 4#bcd ,total #a4ace #ae4ei ---------------------------------------- --------------------------------- #a3 ,gilbert1 ,chester ,g41 and ,pogue1 ,joseph ,e41 ,the energy resources of the ,united ,states--,a field for reconstruction3 ,bull4 #ajb1 ,u4 ,s4 ,national ,museum1 vol4 #a1 #aiai1 p4 #aa4 #b3 ,figure based upon approximate selling price of anthracite4 #c3 ,figure based upon average price of city gas4 #d3 ,these figures would be much higher if an adequate coal products industry were in existence4 #e3 ,this figure shows clearly that lowering the cost of production cannot be expected to lower the price of coal4 ,even if the cost of production were eliminated1 the price of coal would merely be a dollar less4 ,classification of coals4 ,the accurate naming and classification of different varieties of coal is not an easy matter4 ,the three main classes1--anthracite1 bituminous1 and lignite1--have group characteristics determined by their composition1 color1 texture1 origin1 and uses1 and for general purposes these names have reasonably definite significance4 ,however1 there is complete gradation in coal materials from peat through lignite to bituminous and anthracite coals2 many varieties fall near the border lines of the main groups1 and their specific naming then becomes difficult4 ,in addition1 coal is made up of several substances which vary unequally in their proportions4 ,it is difficult to arrange all of these variables in a graded series in such a fashion as to permit of precise naming of the coal4 ,furthermore1 the scientific naming of a coal may not serve the purpose of discriminating coals used for different commercial purposes4 ,even the commercial names vary among themselves1 depending on the use for which the coal is being considered4 ,thus it is that the naming and classification of coals is a perennial source of difficulty and controversy4 ,the earliest and most widely used classification is based on the ratio between fixed 7or non-volatile7 carbon and volatile constituents1 called the fuel ratio4 ,for this purpose proximate analyses of coal are made1 in terms of fixed carbon1 volatile matter1 moisture1 ash1 and sulphur4 ,anthracite has a higher fuel ratio than bituminous coal2 that is1 it has more fixed carbon in relation to volatile matter4 ,similarly bituminous coal has a higher fuel ratio than lignite4 ,the fuel ratio measures roughly the heat or calorific power of the coal1 in other words1 its fuel value4 ,however1 some bituminous coals have a higher calorific power than some anthracites1 because a large part of their volatile matter is combustible and yields more heat than the corresponding weight of fixed carbon in the anthracite4 ,the fuel ratio pretty well discriminates coals of the higher ranks1 and gives a classification corresponding roughly with their commercial uses4 ,for the lower ranks of coal it is not so satisfactory1 because the volatile constituents of such coals contain large and varying percentages of non-combustible hydrogen1 oxygen1 and nitrogen4 ,also such coals contain larger and more variable amounts of moisture1 which is inert to combustion and requires heat for its evaporation4 ,two coals of the lower ranks with the same fuel ratio may have very different fuel qualities and different commercial uses1 because of their different amounts of inert volatile matter and of water4 ,for these coals it is sometimes desirable to supplement the chemical classification by physical criteria4 ,for instance1 subbituminous coal may be distinguished from lignite1 not by its fuel ratio alone1 but by its shiny1 black appearance as contrasted with the dull1 woody appearance of lignite4 ,bituminous may be distinguished from subbituminous by the manner of weathering4 ,other classifications have attempted to recognize these difficulties and still maintain a purely chemical basis by considering separately the combustible and non-combustible volatile constituents4 ,for this purpose1 it is necessary to have not merely approximate analyses1 but the ultimate analyses in terms of elements4 ,definitions of the principal kinds of coal by ,campbell1#ah of the ,united ,states ,geological ,survey1 are as follows3 ,anthracite4 ,anthracite is generally well known and may be defined as a hard coal having a fuel ratio 7fixed carbon divided by the volatile matter7 of not more than #ej or #fj and not less than #aj4 ,semianthracite4 ,semianthracite is also a hard coal1 but it is not so hard as true anthracite4 ,it is high in fixed carbon1 but not so high as anthracite4 ,it may be defined as a hard coal having a fuel ratio ranging from #f to #aj4 ,the lower limit is uncertain1 as it is difficult to say where the line should be drawn to separate hard from soft coal and at the same time to divide the two ranks according to their fuel ratio4 ,semibituminous4 ,the name semibituminous is exceedingly unfortunate1 as literally it implies that this coal is half the rank of bituminous1 whereas it is applied to a kind of coal that is of higher rank than bituminous--really superbituminous4 ,semibituminous coal may be defined as coal having a fuel ratio ranging from #c to #g4 ,its relatively high percentage of fixed carbon makes it nearly smokeless when it is burned properly1 and consequently most of these coals go into the market as smokeless coals4 ,bituminous4 ,the term bituminous1 as generally understood1 is applied to a group of coals having a maximum fuel ratio of about #c1 and hence it is a kind of coal in which the volatile matter and the fixed carbon are nearly equal2 but this criterion cannot be used without qualification1 for the same statement might be made of subbituminous coal and lignite4 ,as noted before1 the distinguishing feature which serves to separate bituminous coal from coals of lower rank is the manner in which it is affected by weathering4 ,subbituminous4 ,the term subbituminous is adopted by the ,geological ,survey for what has generally been called black lignite1 a term that is objectionable because the coal is not lignitic in the sense of being distinctly woody1 and because the use of the term seems to imply that this coal is little better than the brown1 woody lignite of ,north ,dakota1 whereas many coals of this rank approach in excellence the lowest grade of bituminous coal4 ,subbituminous coal is generally distinguishable from lignite by its black color and its apparent freedom from distinctly woody texture and structure1 and from bituminous coal by its loss of moisture and the consequent breaking down of slacking that it undergoes when subjected to alternate wetting and drying4 ,lignite4 ,the term lignite1 as used by the ,geological ,survey1 is restricted to those coals which are distinctly brown and either markedly woody or claylike in their appearance4 ,they are intermediate in quality and in development between peat and subbituminous coal4 ,illustration3 ,,fig4 #e4 ,diagrams showing the chemical composition and heat efficiency of the several ranks of coal4 ,upper diagram3 ,comparative heat value of the samples of coal represented in the lower diagram1 computed on the ash-free basis4 ,lower diagram3 ,variation in the fixed carbon1 volatile matter1 and moisture of coals of different ranks1 from lignite to anthracite1 computed on samples as received1 on the ash-free basis4 ,after ,campbell4 ,,geologic ,,features ,geologic features of coal may be conveniently described in terms of origin or genesis4 ,coal has essential features in common with asphalt1 oil1 and gas4 ,they are all composed of carbon1 hydrogen1 and oxygen1 with minor quantities of other materials1 combined in various proportions4 ,they are all organic products which owe their origin to the decay of the tissues of plants and perhaps animals4 ,they have all been buried with other rocks beneath the surface4 ,the common geologic processes affecting all rocks have in the main determined the evolution of these organic products and the forms in which we now find them4 ,originating at the surface1 they have participated in the constructive or anamorphic changes of the metamorphic cycle1 which occur beneath the surface1 and under these influences have undergone various stages of condensation1 refinement1 distillation1 and hardening4 ,all stages in the development of coal have been traced4 ,in brief1 the story is this3 ,illustration3 ,,fig4 #f4 ,origin and development of coal4 ,after ,gilbert4 ,this exhibit shows the successive chemical stages in the evolution of coal4 ,the striking qualities of the original are lost in the reproduction through the use of designs in the place of realistic coloring1 but the effect is retained sufficiently to indicate the nature of the sequence and the directness with which it leads back to an origin in vegetal accumulations4 ,the evolutionary process is seen to take the form of increasing density through the progressive expulsion of volatilizable matters in the course of geologic time4 ,this inference is substantiated beyond reasonable question by the actual presence of organic remains in coal beds4 ,grasses1 trees1 and other plants growing in swamps and bogs decay and form a vegetable mold in the nature of peat4 ,a peat bog from the top downward consists of 7#a7 living plants1 7#b7 dead plants1 and 7#c7 a dense brownish-black mass1 of decayed and condensed vegetable material1 in which the vegetable structure is more or less indistinct4 ,peat consists chiefly of fixed carbon and volatile matter1 also of sulphur1 moisture1 and ash4 ,the volatile matter consists mainly of various combinations of hydrogen and carbon1 called hydrocarbons2 it goes off in gas or smoke when the peat is heated to a red heat4 ,the fixed carbon is the carbon left after the volatile matter has been driven off4 ,the ash represents the more incombustible mineral matter1 usually of the nature of clay or slate4 ,the moisture in peat may be as high as #ij per cent4 ,the essential condition for thick accumulation of peat seems to be abundance of moisture1 which favors luxuriant growth and protects the plant remains from complete oxidation or decay4 ,without moisture the vegetable material would completely oxidize1 leaving practically no residue1 as it does in dry climates4 ,for the formation of thick peat beds1 there seems to be implied some sort of a balance between the slow building up of organic accumulations and the settling of the area to keep it near the elevation of the water table4 ,present day bog deposits are known in some cases to have a thickness of forty feet4 ,this thickness is not enough to account for some of the great coal seams within the earth2 but there seems to be no escape from the conclusion that the same sort of deposits1 formed on a larger scale in the past1 were the first step in the formation of the coal seams4 ,flat1 swampy coastal plains are believed to furnish the best conditions for thick accumulation of peat4 ,there is good evidence that most of the deposits accumulate essentially in place1 without appreciable transportation4 ,in time these surface accumulations of vegetable material may subside and be buried under clay1 sand1 or other rock materials4 ,the processes of condensation begun in the peat bog are then carried further4 ,they result in the second stage of coal formation1 that of lignite or brown coal4 ,this is brown1 woody in texture1 and has a brown streak4 ,it has a higher percentage of fixed carbon1 and less volatile matter and water1 than peat4 ,continuation of the processes of induration produces subbituminous coal1 or black lignite1 which is usually black and sometimes has a fairly bright luster4 ,it is sometimes distinguished from bituminous coal1 where weathered or dried1 by the manner in which it checks irregularly or splits parallel to the bedding1--the characteristic feature of bituminous coal being columnar fracture4 ,the next stage in coal formation is bituminous coal4 ,it has greater density than the lignites or subbituminous coals1 is black1 more brittle1 and breaks with a cubical or conchoidal fracture4 ,it is higher in fixed carbon1 lower in volatile matter and water4 ,a variety of bituminous coal1 called cannel coal1 is characterized by an unusually high percentage of volatile matter1 which causes it to ignite easily4 ,this material has a dull luster and a conchoidal fracture4 ,it is composed almost entirely of the spores and spore cases1 which are resinous or waxy products1 of such plants as lived in the parent coal swamp4 ,there are gradations from bituminous coal into anthracite coal4 ,semibituminous and semianthracite are names used to some extent for these intermediate varieties4 ,the final stage of coal formation is anthracite1--hard1 brittle1 black1 with high luster and conchoidal fracture4 ,it has a higher percentage of fixed carbon and correspondingly less of the volatile constituents1 than any of the other coals4 ,the coals form a completely graded series from peat to the hard anthracite4 ,comparison of the compositions of the coal materials at different stages shows clearly what has happened4 ,moisture has diminished1 certain volatile hydrocarbons have been eliminated as gases1 and oxygen has decreased4 ,on the other hand1 the residual fixed carbon1 sulphur1 and usually ash1 have remained in higher percentage4 ,this change in composition is graphically represented in ,figure #f4 ,during this process volume has been progressively reduced and density increased4 ,five feet of wood or plant may produce about one foot of bituminous coal1 or six-tenths of a foot of anthracite4 ,the exact physical conditions in the earth which determine the progressive changes in coals1 above outlined1 cannot be fully specified4 ,time is one of the factors--the longer the time1 the greater the opportunity for accomplishing these results4 ,another factor is undoubtedly pressure1 due to the weight of overlying sediments1 or to earth movements4 ,in peat condensational changes of this nature are accomplished artificially by the pressure of briquetting machines4 ,another factor is believed to be the heat developed by earth movements and vulcanism1 which presumably facilitates the elimination of volatile materials1 and thus accelerates the gradational changes above described4 ,this is suggested by the fact that in places where hot volcanic lavas have gone through coal beds they have locally produced coals of anthracitic and coke-like varieties4 ,in general1 however1 it has not been possible to determine the degree to which heat has been responsible for the changes4 ,coals which have been developed in different localities1 under what seem to be much the same heat conditions1 may show quite different degrees of progress toward the anthracite stage4 ,another factor that has been suggested as possibly contributing to the change1 is the degree of permeability of the rocks overlying the coal to the volatile materials which escape from the coal during its refinement4 ,it is argued that in areas of folding or of brittle rock where the cover is cracked1 volatile gases have a better chance to escape1 and that the change toward anthracite is likely to advance further here than elsewhere4 ,bacterial action is an important factor in the earlier stages1 in the partial decay of vegetable matter to form peat2 accumulation of waste products from this action1 however1 appears to inhibit further bacterial activity4 ,coal deposits have the primary shapes of sedimentary beds4 ,they are ordinarily thin and tabular1 and broadly lenticular1--on true scale being like sheets of thin paper4 ,at a maximum they seldom run over #ajj feet in thickness1 and they average less than #aj feet4 ,seldom is a workable coal bed entirely alone2 there are likely to be several superposed and overlapping seams of coal1 separated by sandstones1 shales1 or other rocks4 ,in ,illinois and ,indiana there are nine workable coal seams1 in ,pennsylvania in some places about twenty1 and in ,wales there are over one hundred1 many of which are worked4 ,some of the seams are of very limited extent2 others are remarkably persistent1 one seam in ,pennsylvania having an average thickness of #f to #aj feet over about #f1jjj square miles of its area4 ,only #b per cent of the coal-bearing measures of the eastern ,united ,states is actually coal4 ,even where not subsequently disturbed by deformation1 coal beds are not free from structural irregularity4 ,they are originally deposited in variable thicknesses on irregular surfaces4 ,during their consolidation there is a great reduction of volume1 resulting in minor faults and folds4 ,subsequent deformation by earth forces may develop further faults and folds1 with the result that the convolutions of a coal bed may be very complex4 ,the beds of a coal-bearing series are usually of differing thickness and competency1 and as a consequence they do not take the same forms under folding4 ,shearing between the beds may result in an intricate outline for one bed1 while the beds above and below may have much more simple outlines4 ,in short1 the following of a coal seam requires at almost every stage the application of principles of structural geology4 ,it is obvious1 also1 that the identification and location of sedimentary geologic horizons are essential1 and hence the application of principles of stratigraphy4 ,the folios of the ,united ,states ,geological ,survey on coal-bearing areas present highly developed methods of mapping and representing the geologic features of coal beds4 ,on the surface map are indicated the topography1 the geologic horizons1 and the lines of outcrop of the coal seams4 ,in addition1 there are indicated the sub-surface contours of one or more of the coal seams which are selected as datum horizons4 ,the sub-surface structure1 even though complex1 can be readily read from one of these surface maps4 ,with the addition of suitable cross sections and comparative columnar sections1 the story is made complete4 ,in the study of the occurrence of coal seams1 the reader cannot do better than familiarize himself with one or more of the ,geological ,survey folios4 ,the high-grade coals of the eastern and central ,united ,states are found in rocks of ,carboniferous age4 ,the very name ,carboniferous originated in the fact that the rocks of this geologic period contain productive coal beds in so many parts of the world4 ,the coal measures of ,great ,britain1 of ,germany1 ,belgium1 and northern ,france1 of ,russia1 and the largest coal beds of ,china are all of ,carboniferous age4 ,deposits of this period include the bulk of the world's anthracite and high-grade bituminous coal4 ,coal deposits of more recent age are numerous1 but in general they have had less time in which to undergo the processes of condensation and refinement1 and hence their general grade is lower4 ,in the western ,united ,states there are great quantities of subbituminous coal of ,cretaceous age1 and of ,tertiary lignites which have locally been converted by mountain upbuilding into bituminous and semibituminous coals4 ,jurassic coals are known in many parts of the world outside of ,north ,america1 and lignites of ,tertiary age are widely distributed through ,asia and ,europe4 ,,petroleum ,,economic ,,features ,petroleum is second only to coal as an energy resource4 ,the rapid acceleration in demand from the automobile industry and in the use of fuel oil for power seems to be limited only by the amounts of raw material available4 ,production and reserves4 ,the distribution by countries of the present annual production of petroleum1 the past total production1 and the estimated reserves1 is indicated in terms of percentages of the world's total in the table#ai on the opposite page4 ,this table indicates the great dominance of the ,united ,states both in present and past production of petroleum1 as well as the concentration of the industry in a few countries4 ,in addition the ,united ,states controls much of the ,mexican production as well as production in other parts of the world1 making its total control of production at least #gj per cent4 of the world's total4 ,notwithstanding its large domestic production1 the ,united ,states has recently consumed more oil than it produces4 ,imports of crude oil are about balanced by exports of kerosene1 fuel oils1 lubricants1 etc4 ,the per capita consumption of petroleum in the ,united ,states is said to be twenty times greater than in ,england4 ,on the other hand1 the remaining principal producers consume far less than they produce1 the excess being exported4 ,the oil from the ,united ,states1 ,russia1 the ,dutch ,east ,indies1 ,india1 ,roumania1 and ,galicia is for the most part treated at refineries near the source of supply or at tidewater1 and exports consist of refined products4 ,the ,mexican oil is largely exported in crude form to the ,united ,states though increasing quantities are being refined within ,mexico4 ,the figures shown in the table for oil reserves are of course the roughest approximations1 particularly for some of the less explored countries4 ,however1 they are compiled from the best available sources and may serve at least to show the apparent relative positions of the different countries at this time4 ,further exploration is likely to change the percentages and add very greatly to the totals4 ,the significant feature of these figures is the contrast which they indicate between distribution of reserves and distribution of past production4 ,particularly do they show that the reserves of the ,united ,states1 which are more closely estimated than those of any other country1 are in a far lower ratio to past production than are the reserves in other countries4 ,it was estimated in #aibj that about #dj per cent of the ,united ,states reserves are exhausted4#bj ,,present ,,and ,,past ,,production ,,and ,,reserves ,,of ,,oil1 ,,by ,,countries1 ,,in ,,terms ,,of ,,percentage ,,of ,,world',s ,,total ---------------------------------------- -------------------------- ,per cent ,per cent ,country ,per cent of of total of total production1 production1 oil #aiah #aheg-aiah resources ---------------------------------------- -------------------------- ,united ,states and ,alaska #fi4ae #fa4db #af4bf ,mexico #ab4dj #c4hj #aj4ea ,russia 7southeastern ,russia1 southwestern ,siberia1 region of the ,caucasus1 northern ,russia1 and ,saghalien7 #g4hf #bd4if #ae4fi ,east ,indies #b4eh #b4ea #g4jj ,roumania1 ,galicia1 and western ,europe #b4gi #d4jg #b4fd ,india #a4ee #a4da #b4ca ,persia and ,mesopotamia #a4dj 4#ai #ac4eb ,japan and ,formosa 4#dh 4#ea #b4hg ,egypt and ,algeria 4#dj 4#jg #b4ae ,germany 4#ad 4#bb -- ,canada 4#jf 4#cc #b4ca ,northern ,south ,america1 including ,peru1 ,trinidad and ,venezuela 4#ic 4#dc #ac4ca ,southern ,south ,america1 including ,bolivia and ,argentina 4#bf 4#jf #h4bd ,china -- -- #c4ai ,italy ,cuba 4#jb ,other countries ------ ------ ------ ,world total #ajj4jj #ajj4jj #ajj4jj ---------------------------------------- -------------------------- ,looking forward to the future1 it is clear that there will be considerable shifts in the centers of principal production of petroleum in the directions indicated by the reserve figures4 ,in particular1 conspicuous development of production may be expected in the immediate future in the countries bordering the ,caribbean ,sea and the ,gulf of ,mexico4 ,in the eastern hemisphere production is rapidly increasing in ,persia and ,mesopotamia2 and ,russia1 with the stabilization of political conditions1 may become ultimately the world's leading oil producer4 ,at the now indicated rate of production1 world reserves now estimated would be exhausted in eighty-six years and the peak of production would be passed earlier4 ,with continuing acceleration of production1 total reserves would be exhausted in considerably less time1--providing physical conditions would allow the oil to be pumped from the ground at the necessary speed1 which they probably will not4 ,these figures taken at face value are alarming2 but the earth offers such huge possibilities for further discoveries that the life of oil reserves above indicated is likely to be considerably extended4 ,at many times in the history of the mineral industry the end has apparently been in sight for certain products2 but with the increased demand for these products has come increased activity in exploration1 with the result that as yet no definite end has been approached for any one of them4 ,the more immediate problems of the petroleum industry seem to the writer to be of rather different nature3 first1 whether the discovery and winning of the oil can be made to keep pace with the enormous acceleration of demand2 and second1 the adjustment of political and financial control of oil resources1 the possession of which is becoming so increasingly vital to national prosperity4 ,in regard to the first question1 it is a much more difficult problem today to locate and develop a supply of oil to replace the annual world production 7recently half a billion barrels71 than it was twenty years ago1 when it was necessary for this purpose to find only one-fifth this amount2 and if the demand is unchecked1 it will be still more difficult to replace the three-quarters of a billion barrels of oil which will doubtless be required in a very few years4 ,regardless of the amount of oil actually in the ground1 it is entirely possible that physical limitations on its rate of discovery and recovery will prevent its being made available as fast as necessary to meet the increasing demand4 ,this fact is likely to make itself felt through increase of price4 ,other natural results should be the development of substitutes1 such as alcohol or benzol for gasoline2 the larger recovery of oil from oil shales2 and the general speeding up of conservational measures of various kinds4 ,these are all palliatives and not essential remedies4 ,to make enough alcohol to substitute for the gasoline now coming from oil would use a very considerable fraction of the world's food supply4 ,to make enough benzol 7a by-product of coke7 to replace gasoline would necessitate the manufacture of many times the amount of coke now required by the world's industries4 ,to develop the oil shale industry to a point where it could supply anything like the amount of oil now derived from oil pools would mean the building of great plants1 including towns1 railroads1 and other equipment1 equivalent to the plants of the coal mining industry4 ,to apply any one of the various conservational measures discussed on later pages would only temporarily alleviate the situation4 ,the question of political and financial control of oil supplies may be illustrated by particular reference to the ,united ,states4 ,on present figures it appears that within three to five years the peak of production in this country will be passed2 and at the present rate of production the life of the reserves may not be over seventeen to twenty years4 ,of course production could not continue to the end at this rate1 and the actual life will necessarily be longer4 ,again the doubtful factor is the possibility for further discoveries4 ,many favorable structures have been mapped which have not yet been drilled1 and there are considerable unexplored areas where the outcrops are so few that there is no clue at the surface to the location of favorable structures4 ,the future is likely to see a considerable amount of shallow drilling for the sole purpose of geological reconnaissance4 ,for upwards of ten years important parts of the public domain have not been available for exploration1 but ,congress has now enacted legislation which opens up vast territories for this purpose4 ,even with large allowance for these possibilities1 it seems unlikely that production in the ,united ,states can increase very long at the accelerating rate of the domestic demand1 which is already in excess of domestic production4 ,the supplies of ,mexico are in a large part controlled by ,american capital and are thus made available to the ,united ,states 7subject1 of course1 to political conditions72 but even with these added1 the ,united ,states is in a somewhat unfavorable situation as compared with certain other countries4 ,this situation is directing attention to the possibility of curtailment of oil exports1 and to the possibility of acquiring additional oil supplies in foreign countries4 ,in this quest the ,united ,states is peculiarly handicapped in that most foreign countries1 in recognition of the vital national importance of the oil resource1 have imposed severe restrictions on exploration by outsiders4 ,nationals of the ,united ,states are excluded from acquiring oil concessions1 or permitted to do so only under conditions which invalidate control1 in the ,british ,empire1 ,france1 ,japan1 ,netherlands1 and elsewhere1 and the current is still moving strong in the direction of further exclusion4 ,as the ,united ,states fields are yet open to all comers1 it has been suggested that some restriction by the ,united ,states might be necessary for purposes of self-protection1 or as an aid in securing access to foreign fields4 ,the activity of ,england during and since the war has increased the amount of oil controlled by that country from an insignificant quantity to potentially over half of the world's oil reserves4 ,the problem of future oil supplies for the ,united ,states presents an acute phase of the general question of government cooperation or participation in mineral industries1 which is further discussed in ,chapter ,,xviii4 ,the following table summarizes the distribution of the oil production in the ,united ,states1 together with the salient features of its geologic distribution and character4 ,this table1 in conjunction with ,fig4 #h below1 shows clearly that the bulk of the ,united ,states production of oil comes from two great sources--the ,pennsylvanian sandstones of the ,mid-,continent field in ,kansas and ,oklahoma1 and the ,cretaceous and ,tertiary sediments of the southern half of ,california4 ,phenomenal development of the ,central and ,north ,texas field in #aiai increased its yield to about one-sixth of the country's total4 ,the older ,appalachian oil field1 extending from ,new ,york to ,west ,virginia and ,tennessee1 was the earliest area discovered2 it is still one of the more productive fields1 though it has long since passed its maximum production4 ,the other principal sources of oil are the ,gulf ,coast field in ,louisiana and ,texas1 the ,north ,louisiana field1 the southern ,illinois field1 and the ,rocky ,mountain region4 ,this last region1 containing large amounts of government land recently opened to exploration1 bids fair to produce increasing quantities of oil for some time4 ,,past ,,production ,,of ,,petroleum ,,in ,,the ,,united ,,states4 7,,figures ,,from ,u4 ,s4 ,,geological ,,survey7 ---------------------------------------- -------------------------- ,total ,age of ,production production containing for #aiah including #aiah ,state rocks ,base 7barrels7 7barrels7 ---------------------------------------- -------------------------- ,alaska ,east-,low4 ,paraffin 7a7 7a7 ,tertiary ,west-,jurassic ,california ,cretaceous3 ,tertiary ,asphalt #ig1eca1iig #a1aaj1bbf1egf ,colorado ,pierre-,cretaceous,paraffin #adc1bhf #aa1cai1cgj ,illinois ,mississippian- ,paraffin #ac1cfe1igd #bih1bbe1chj ,pennsylvanian ,indiana ,east-,ordovician ,paraffin #hgg1eeh #ajf1aje1ehd 7,trenton7 ,west- ,pennsylvanian ,kansas ,pennsylvanian ,par4-,asph4 #de1dea1jag #adh1dej1bih ,kentucky1 ,mississippian ,paraffin #d1cgf1cdb #ah1bac1ahh ,tennessee ,louisiana ,cretaceous-,quat4 ,paraffin #af1jdb1fjj #aej1gfi1iaa ,cretaceous- ,eocene ,michigan1 ,carboniferous ,paraffin 7a7 7a7 ,missouri ,montana -- -- #fi1cbc #bac1fci ,new ,mexico ,carboniferous- -- 7a7 7a7 ,cretaceous ,new ,york1 ,devonian- ,paraffin #h1baf1fee #ghh1bjb1gag ,pennsylvania ,carboniferous ,ohio1 ,east ,ordovician- ,paraffin #g1bhe1jje #dfc1cfg1chf and ,west ,carboniferous ,oklahoma ,pennsylvanian ,paraffin #ajc1cdg1jgj #hea1cbj1deg ,texas ,pennsylvanian1 ,asph4-,par4 #ch1gej1jca #cbg1eej1jje ,cretaceous-,quat4 ,utah -- -- 7b7 7b7 ,west ,devonian- -- #g1hff1fbh #bid1dgd1gaj ,virginia ,carboniferous ,wyoming ,carboniferous- ,asph4-,par4 #ab1eif1bhg #dj1jai1egc ,cretaceous ,other -- -- #g1idc #aab1ibe ----------- ------------- #cee1ibg1gaf #d1fjh1ega1gai ---------------------------------------- -------------------------- 7a7 ,included in ,other4 7b7 ,included in ,wyoming4 ,illustration3 ,,fig4 #g4 ,chart showing the present tendency of the ,united ,states in respect to its unmined reserve of petroleum4 ,data from ,u4,s4 ,geological ,survey4 ,after ,gilbert and ,pogue4 ,methods of estimating reserves4 ,it may be of interest to inquire into the basis on which predictions are made of the life of an oil pool4 ,the process is essentially a matter of platting curves of production1 and of projecting them into the future with the approximate slopes exhibited in districts which are already approaching exhaustion4#ba ,while no two wells or two districts act exactly alike1 these curves have group characteristics which are used as a rough basis for interpreting the future4 ,illustration3 ,,fig4 #h4 ,the annual output of the principal oil fields of the ,united ,states for the last twenty years4 ,data from ,u4,s4 ,geological ,survey4 ,a less reliable method is to calculate from geologic data the volume and porosity of the oil-bearing reservoirs1 and to estimate the percentage of recovery on the basis of current practices and conditions4 ,complete data for this method are often not available2 but in the early years of a field1 before production curves are established1 this method may serve for a rough approximation4 ,illustration3 ,,fig4 #i4 ,curve showing the usual decline in oil field production after the period of maximum output is reached4 ,after ,ralph ,arnold4 ,the ,petroleum ,resources of the ,united ,states1 ,smithsonian report for #aiaf1 p4 #bhc4 ,compare this theoretical curve of final decrease with the production curve shown in ,fig4 #h4 ,classes of oils4 ,when crude petroleum is distilled1 it gives off in succession various substances and gradually thickens until it leaves a solid residue1 which may be largely either paraffin wax or asphalt4 ,the two main classes of oils are determined by the nature of this solid residual4 ,the products given off are natural gas and then liquid hydrocarbons of various kinds1 which evaporate in the order of their lightness4 ,petroleum is thus a mixture or mutual solution of different liquids1 gases1 and solids4 ,nearly one-fifth of the domestic consumption of crude petroleum is burned directly as fuel1 and four-fifths are refined4 ,the several principal primary products of refinement are gasoline1 kerosene1 fuel oil1 and lubricating oil2 but these may be broken up into other substances1 each the starting point of further refinements1 with the result that present commercial practice yields several hundred substances of commercial value4 ,with increasing chemical and technical knowledge these products are being multiplied4 ,the rapidly increasing demand for gasoline has led to the use of processes which extract a large proportion of this substance from the raw material1 by cracking or breaking up other substances2 but while1 under the stress of necessity1 there is possibility of slight modification of the proportions of principal substances extracted from the crude oil1 it is not possible to change these proportions essentially4 ,it is1 therefore1 a problem to adjust relative demands to supplies of the different products4 ,the domestic demand for gasoline is greater than the supply4 ,on the other hand1 the demand for kerosene1 which must be produced at the same time1 is much less than the domestic supply4 ,hence the importance of maintaining export markets for kerosene4 ,the nature or grade of the oil of various fields is an important matter in considering reserves for the future4 ,perhaps half of the ,united ,states reserves consist of the asphalt-base oils of the ,california and certain of the ,gulf fields1 which yield comparatively small amounts of gasoline and other valuable light products1 though they are very satisfactory for fuel purposes4 ,similarly the large reserve tonnages of oil in ,mexico and the ,caribbean countries1 in ,peru1 and probably in ,russia1 are essentially of the heavier1 lower grade oils4 ,the oils of the ,mid-,continental and eastern fields of the ,united ,states1 of ,ontario1 of the ,dutch ,east ,indies1 of ,burma1 and of ,persia and ,mesopotamia are reported to be largely of the paraffin base type1 which1 because of its larger yield of gasoline and light oils1 is at present considerably more valuable4 ,these generalizations are of course subject to qualifications1 in that the oils of a given region may vary considerably1 and that some oils are intermediate in character1 containing both asphalt and paraffin wax4 ,conservation of oil4 ,the rapid increase in demand for oil as compared with discovery of new sources is leading naturally to a more intensive study of the conservational aspects of the industry4 ,this is a complex and difficult subject which we shall not take up in detail1 but we may point out some of the phases of the problem which are receiving especial attention4 ,illustration3 ,,fig4 #aj4 ,chart showing the relative values of the principal petroleum products manufactured in the ,united ,states from #ahii to #aiad4 ,after ,gilbert and ,pogue4 ,note the decreasing importance of kerosene in sustaining the cost of refining1 and the necessity of exports for maintaining a balanced outlet of products4 ,data from ,story ,b4 ,ladd1 ,petroleum ,refining4 ,census of ,manufactures3 #aiad1 ,bureau of ,census1 ,washington1 #aiag1 p4 #aj4 ,about #ej per cent of the oil in the porous strata1 of oil pools is ordinarily not recovered1 because it clings to the rock4 ,efforts are being made along various lines to increase the percentage of recovery1--as1 for instance1 in preventing infiltration of water to the oil beds and in the use of artificial pressures and better pumping4 ,casing-head gasoline is being recovered to an increasing extent from the natural gas which was formerly allowed to dissipate in the air4 ,minute division of the ownership of a pool1 with consequent multiplication of wells and unrestricted competition1 tends to gross over-production and highly wasteful methods4 ,the more rapid exhaustion of one well than the others may result in the flooding of the oil sands by salt waters coming in from below4 ,various efforts have been made toward a more systematic and coordinated development of oil fields4 ,in general1 the organization and technique involved in the development of an oil field are improving in the direction of extracting a greater percentage of the total available oil4 ,better methods of refining the oil1 and the refining of a larger percentage of the crude oil1 make the oil more available for a greater variety of purposes and therefore more valuable4 ,great advances have been made along these lines1 particularly in the application of the cracking method for a greater recovery of the more valuable light oils at the expense of the less valuable heavy oils4 ,similarly1 modifications of internal combustion engines will probably permit the use1 in an increasing number of cases1 of products of lower volatility than gasoline4 ,one of the conservational advances in coming years will probably be a restriction in the amount of crude oil used directly for fuel and road purposes without refining4 ,these crude uses cut down the output of much desired products from the distillation of the oil4 ,various other restrictions in the use of oil have been proposed1 such as the curtailment of the use of gasoline in pleasure cars4 ,the gasless ,sundays during the war represented an attempt of this kind4 ,in general1 it seems likely that such restrictions will come mainly through increase in the price of oil products4 ,the substitution of oil from oil shales1 and of alcohol for gasolene1 already mentioned1 will be conservational so far as the oil is concerned1 though perhaps not so in regard to other elements of the problem4 ,,geologic ,,features ,organic theory of origin4 ,according to this theory1 accumulations of organic materials in sedimentary beds1 usually muds or marls1 have been slowly altered and distilled during geologic ages2 the products of distillation have migrated chiefly upward to porous strata like sandstones or cavernous limestones1 where1 under suitable conditions1 they have become trapped4 ,the original organic material is believed to have been plants of low order and animal organisms 7such as foraminifera7 which were deposited as organic detritus with mud and marl in the bottoms of ponds1 lakes1 estuaries1 and on the sea bottom1--in both salt and fresh waters4 ,bacteria are supposed to have played a part in the early stage of alteration1 sometimes called the biochemical stage4 ,when the organic matter was buried under later sediments and subjected to pressure1 physical conditions were responsible for further volatilization or distillation4 ,this stage is called the geochemical stage4 ,there is much in common as to origin between coal1 oil shales1 and petroleum4 ,according to ,white1#bb whether the ingredient organic matter1 be it plant or animal1 will be in part transformed to coal of the ordinary type1 to cannel1 to oil shale1 to the organic residues in so-called bituminous shales and carbonaceous shales1 or to petroleum and natural gas1 is dependent upon the composition of the ingredient organic debris1 the conditions of its accumulation or deposition1 and the extent of the microbian action4 ,white has further developed the important principle that1 in the geochemical stage of development1 both coal and oil react to physical influences in much the same way2 and that therefore when both are found in the same geologic series1 the degree of concentration of the coal1 measured by its percentage of carbon1 may be an indication of the stage of development of the oil4 ,more specifically where the coal contains more than #fe to #gj per cent of fixed carbon1 chances for finding oil in the vicinity are not good 7though commercial gaspools may be found71 probably for the reason that the geochemical processes of distillation have gone so far as to volatilize the oils1 leaving the solid residues in the rock4 ,white also finds that the lowest rank oils1 with considerable asphalt1 are found in regions and formations where the coal deposits are the least altered1 and the lighter1 higher rank oils1 on the whole1 where the coal has been brought to the correspondingly higher ranks2 in other words1 up to the point of complete elimination of the oil1 improvement in quality of the oil accompanies increased carbonization of the coal4 ,the principle1 therefore1 becomes useful in exploration in geologic series where oil is associated with coal4 ,where the coal is in one series and the oil in another1 separated by unconformity 7indicating different conditions of development71 the principle may not hold1 even though there is close geographical association4 ,the oil and gas distillates migrate upward under gas pressure and under pressure of the ground-water4 ,if there are no overlying impervious beds to furnish suitable trapping conditions1 or conditions to retard the flow1 the oil may be lost4 ,the conditions favorable for trapping are overlying impervious beds bowed into anticlines1 or other structural irregularities1 due either to secondary deformation or to original deposition1 which may arrest the oil in its upward course4 ,a dome-like structure or anticline may be due to stresses which have buckled up the beds1 or to unequal settling of sediments varying in character or thickness2 thus some of the anticlinal structures of the ,mid-,continent field may be due to settling of shaley sediments around less compressible lenses of sandstone which may act as oil reservoirs1 or around islands which stood above the seas in which the oil-bearing sediments were deposited and on the shores of which sands capable of acting as oil reservoirs were laid down4 ,favorable conditions for trapping the oil may be furnished by impervious clay gouges along fault planes1 or by dikes of igneous rock4 ,favorable conditions may also be merely differences in porosity of beds in irregular zones1 determined by differences either in original deposition or in later cementation4 ,the thickness of oil-producing strata may vary between #b or #c feet and #bjj feet4 ,the porosity varies between #e and #ej per cent4 ,in sandstones the average is from #e to #ae per cent4 ,in shales and clays1 which are commonly the impervious cap-rocks1 porosity may be equally high1 but the pores are too small and discontinuous to permit movement4 ,when the impervious capping is punctured by a drill hole1 gas is likely to be first encountered1 then oil1 and then water1 which is usually salty4 ,the gas pressure is often released with almost explosive violence1 which has suggested that this is an important cause of the underground pressures4 ,it has been supposed also that the pressures are partly those of artesian flows4 ,the vertical arrangement of oil1 gas1 and water under the impervious capping is the result of the lighter materials rising to the top4 ,in certain fields1 oil and gas have been found in the tops of anticlines in water-saturated rocks1 and farther down the flanks of folds or in synclines in unsaturated rocks4 ,the localization of oil pools is evidently determined partly by original organic deposition1 often in alignment with old shore lines1 and partly by the structural1 textural1 and other conditions which trap the oil in its migration from the source4 ,effect of differential pressures and folding on oil genesis and migration4 ,another organic hypothesis proposed somewhat recently#bc is that oil is formed by differential movement or shearing in bituminous shales1 which are often in close relationship with the producing sand of an oil field1 and that the movement of oil to the adjacent sands is accomplished by capillary pressure of water and not by ordinary free circulation of water under gravity4 ,the capillary forces have been shown to be strong enough to hold the oil in the larger pores against the influence of gravity and circulation4 ,the accumulation of the oil into commercial pools is supposed to take place in local areas where the oil-soaked shale1 due to jointing or faulting1 is in direct contact with the water of the reservoir rock4 ,this suggests lack of wide migration4 ,this hypothesis is based on experimental work with bituminous shales4 ,the general association of oil pools with anticlinal areas is explained on the assumption that anticlines on the whole are areas of maximum differential movement1 resulting in oil distillation1 and that they are ordinarily accompanied by tension joints or faults1 affording the conditions for oil migration4 ,data are insufficient1 however1 to indicate the extent to which the anticlinal areas are really areas of maximum shearing4 ,as regards the exact nature of the process1 it is not clear to what extent differential movement may involve increase in temperature which may be the controlling factor in distillation1--although in ,mc,coy's experiment oil was formed when no appreciable amount of heat was generated4 ,the development of petroleum by pressure alone acting on unaltered shale1 as shown by these experiments1 has been taken by ,white#bd to have a significant bearing on the geochemical processes of oil formation4 ,under differential stresses acting on fine-grained carbonaceous strata under sufficient load1 there is considerable molecular rearrangement1 as well as actual movement of the rock grains1--thus promoting the distillation of oil and gas from the organic matter in the rocks1 and the squeezing out of the oil1 gas1 and water into adjacent rocks1 such as coarse round-grained sandstones and porous limestones1 which are more resistant to change of volume under pressure4 ,migration1 concentration and segregation of the oil1 gas1 and water is supposed to be brought about1 partly through the effect of capillary forces--the water1 by reason of its greater capillary tension1 tending to seize and hold the smaller voids1 and thus driving the oil and gas into the larger ones--and partly through the action of gravity4 ,white also suggests that the process may go further where the parent carbonaceous strata are of such thickness and under such load of overlying rocks that they undergo considerable interior adjustment and volume change before yielding to stress by anticlinal buckling1--than where the strata yield quickly4 ,it is not clear to the writer that the interior adjustment assumed under this hypothesis is necessarily slowed up or stopped by anticlinal buckling4 ,interior stresses are inherent in any sedimentary formation1 when settling and consolidating and recrystallizing under gravity1 and these may be independent of regional thrusts from without4 ,the first oils evolved by pressure from the organic mother substance are probably heavy1 the later oils lighter1 and the oils from formations and regions where the alteration is approaching the carbonization limit are characteristically of the highest grade4 ,this is the reverse of the order of products obtained by heat distillation4 ,whether there is also a natural fractionation and improvement of the first heavy oils as they undergo repeated migrations is not known4 ,inorganic theory of origin4 ,another theory of the source of oil has had some supporters1 although they are much in the minority4 ,this is the so-called inorganic theory1 that oil comes from magmas and volcanic exhalations4 ,in support of this theory attention is called to the fact that igneous rocks and the gases associated with them frequently carry carbides or hydrocarbons2 that many oil fields have a suggestive geographic relationship with volcanic rocks2 and that certain of the oil domes1 as for instance in ,mexico1 are caused by plugs of igneous rocks from below4 ,it has been suggested that deep within the earth carbon is combined with iron in the form of an iron carbide1 and that from the iron carbide are generated the hydrocarbons of the oil1 either by or without the agency of water4 ,iron carbide is magnetic1 and significance has been attached to the general correspondence between the locations of oil in the western ,united ,states and regions of magnetic disturbance4 ,it seems not unlikely that some inorganic theory of this sort is necessary to explain the ultimate source of oil or of the substances which become oil1 but the evidence is overwhelming that organic agencies have been mainly responsible for the principal oil pools now known4 ,oil exploration4 ,a simple geographic basis for oil exploration is the fact that the major oil fields of the world are situated between #bj deg4 and #ej deg4 north latitude1 and that thus far there are no major oil areas within the tropics or within the southern hemisphere4 ,this broad generalization may have little value when exploration is carried further4 ,it has also been suggested that the geographic distribution of oil corresponds roughly with the average annual temperatures1 or isotherms1 between #dj deg4 and #gj4 deg4#be ,it is thought that this present distribution of temperatures may indicate roughly the temperatures of the past when the oil was accumulated2 and the inference is drawn that there was some sort of limitation of areal deposition within these temperature limits4 ,if this be true1 the only reasons why the southern hemisphere is not productive are the relatively small size of the land areas and the lack of exploration to date4 ,in approaching broadly the problem of oil exploration1 the geologist considers in a general way the kinds and conditions of rocks which are likely to be petroliferous or non-petroliferous4 ,schuchert#bf summarizes these conditions for ,north ,america as follows3 #a4 ,the impossible areas for petroliferous rocks4 7a7 ,the more extensive areas of igneous rocks and especially those of the ancient shields2 exception1 the smaller dikes4 7b7 ,all pre-,cambrian strata4 7c7 ,all decidedly folded mountainous tracts older than the ,cretaceous2 exceptions1 domed and block-faulted mountains4 7d7 ,all regionally metamorphosed strata4 7e7 ,practically all continental or fresh-water deposits2 relic seas1 so long as they are partly salty1 and saline lakes are excluded from this classification4 7f7 ,practically all marine formations that are thick and uniform in rock character and that are devoid of interbedded dark shales1 thin-bedded dark impure limestones1 dark marls1 or thin-bedded limy and fossiliferous sandstones4 7g7 ,practically all oceanic abyssal deposits2 these1 however1 are but rarely present on the continents4 #b4 ,possible petroliferous areas4 7a7 ,highly folded marine and brackish water strata younger than the ,jurassic1 but more especially those of ,cenozoic time4 7b7 ,cambrian and ,ordovician unfolded strata4 7c7 ,lake deposits formed under arid climates that cause the waters to become saline2 it appears that only in salty waters 7not over #d per cent87 are the bituminous materials made and preserved in the form of kerogen1 the source of petroleum2 some of the ,green ,river 7,eocene7 continental deposits 7the oil shales of ,utah and ,colorado7 may be of saline lakes4 #c4 ,petroliferous areas4 7a7 ,all marine and brackish water strata younger than the ,ordovician and but slightly warped1 faulted1 or folded2 here are included also the marine and brackish deposits of relic seas like the ,caspian1 formed during the later ,cenozoic4 ,the more certain oil-bearing strata are the porous thin-bedded sandstones1 limestones1 and dolomites that are interbedded with black1 brown1 blue1 or green shales4 ,coal-bearing strata of fresh-water origin are excluded4 ,series of strata with disconformities may also be petroliferous1 because beneath former erosional surfaces the top strata have induced porosity and therefore are possible reservoir rocks4 7b7 ,all marine strata that are1 roughly1 within #ajj miles of former lands2 here are more apt to occur the alternating series of thin and thick-bedded sandstones and limestones interbedded with shale zones4 ,the extent to which marine or brackish water conditions of sedimentation are requisite to the later formation of oil1 as is suggested in the above quotation1 has long been a debatable question4 ,it may be noted that certain oil shales formed in fresh water basins contain abundant organic matter which is undoubtedly suitable for the generation of oil and gas1 and that these shales on distillation yield oil essentially like that obtained from oil shales of marine origin2 that certain important oil-bearing sands of the younger ,appalachian formations were laid down in waters which are believed to have been only slightly saline2 that natural gas is present in fresh water basins2 and that it has not been demonstrated that salt in appreciable amounts is necessary for the geologic1 any more than for the artificial1 distillation of oil4 ,most of the great oil fields have been in regions of marine or other saline water deposits1 but it has not been proved that this is a necessary condition4 ,white#bg says3 ,at the present stage of our knowledge1 fresh-water basins appearing otherwise to meet the requirements should be wildcatted without prejudice4 ,the principal oil-bearing horizons in any locality are comparatively few1 and it is ordinarily easy to determine by stratigraphic methods the presence or absence of a favorable geologic horizon4 ,by knowing the succession and thicknesses of the beds in a given region it is possible to infer from surface outcrops the approximate depth below the surface at which the desired horizon can be found4 ,to do this1 however1 the conditions of sedimentation1 the initial irregularities of the beds1 the structural conditions1 including unconformities1 and other factors must be studied4 ,in exploration for oil the determination of the existence and location of the proper horizon is but an initial step4 ,for instance1 the oil of the ,midcontinent field of the ,united ,states is in the beds of the ,pennsylvanian1 which are known to occupy an enormous area extending from ,illinois and ,wyoming south to the ,gulf of ,mexico4 ,this information is clearly not sufficiently specific to limit the location of drill holes4 ,sometimes seepages of oil or showings of gas near the surface are sufficient basis for localizing the drill holes4#bh ,commonly1 however1 it is necessary to find some structural feature in the nature of a dome or anticline which suggests proper trapping conditions for an oil pool4 ,this is accomplished by geologic and topographic mapping of the surface4 ,levels and contours are run and outcrops are platted4 ,as the outcrops are usually of different geologic horizons1 it is necessary to select some one or more identifiable beds as horizon markers1 and to map their elevations at different points as a means of determining the structural contours of the beds4 ,when several key horizons are thus used1 their elevations must be reduced to the elevations of one common horizon by the addition or subtraction of the intervals between them4 ,for instance1 knowing the succession1 an outcrop of a certain sandstone may indicate that the marking horizon is #bjj feet below1 and the structural contour is then drawn accordingly4 ,observations of strike and dip at the surface are helpful2 but where the beds are but slightly flexed1 small irregularities in deposition may make strike and dip observations useless in determining major structures4 ,it is then necessary to have recourse to the elevations of the marking horizons4 ,in the selection of key horizons1 knowledge of the conditions of sedimentation is very important4 ,for example1 some of the oil fields occur in great delta deposits1 where successive advances and retreats of the sea have resulted in the interleaving of marine and land deposits4 ,the land-deposited sediments usually show great variations in character and thickness laterally and vertically2 and a given bed is likely to thin out and disappear when traced for a short distance1 rendering futile its use as a marker4 ,the marine sediments1 on the either hand1 show a much greater degree of uniformity and continuity1 and a bed of marine limestone may extend over a large area and be very useful as a key horizon4 ,over large areas outcrops and records of previously drilled water and oil wells may not be sufficient to give an indication of structure2 it then becomes necessary to secure cross sections by drilling shallow holes to some identifiable bed1 and to determine the structure from these cross sections1 in advance of deeper drilling through a favorable structure thus located4 ,the cooperative effort of the ,illinois ,state ,survey and private interests1 cited on page #cjf1 is a good illustration of this procedure4 ,this method is only in its infancy1 because well-drilling has not yet exhausted the possibilities of structures located from surface outcrops4 ,the so-called anticlinal structures1 which have been found by experience to be so favorable to the accumulation of oil1 are by no means symmetrical in shape or uniform in size4 ,they may be elongated arches with equal dip on the two sides1 or one side may dip and the other be nearly flat4 ,in a territory with a general dip in one direction1 a slight change in the angle1 though not in the direction of dip1 sometimes called an arrested dip1 may cause sufficient irregularity to produce the necessary trapping conditions4 ,in other cases the anticline may be of nearly equidimensional dome form4 ,the largest anticlines which have been found to act as specific reservoirs are rarely more than a few miles in extent1 and in many cases only a mile or two4 ,the closure of an anticline is the difference between the height of a given stratum at the highest point and at the edges of the structure4 ,a considerable number of productive anticlines are known in which the beds dip so gently as to give a closure of #bj feet or less4 ,after the structural outlines of beds near the surface have been determined1 all possible information should be used in projecting these structures downward to the oil-producing horizons4 ,where a number of wells have been previously drilled in the vicinity1 examination of their records may indicate certain lateral variations in the thickness of the beds between the horizon which has been mapped and the producing horizon4 ,the effect of such lateral variations may be either to accentuate the surface structure1 or to cause it to disappear entirely and thus to indicate lack of favorable trapping conditions4 ,the possibility of several oil-producing beds1 at different depths--a not uncommon condition in many fields--should also be kept in mind4 ,as already indicated1 anticlines are not always essential to make the necessary trapping conditions4 ,in the ,beaumont field of ,texas1 for instance1 it has been shown that irregular primary deposition of sediments differing in porosity both vertically and horizontally allowed the oil to migrate upward irregularly along the porous beds and parts of beds1 and to be trapped between the more impervious portions of the beds4 ,further questions to be considered in the exploration of an area are the content of organic matter in the sediments which may have served as a source of oil1 the presence of impervious cap-rocks or of variations in porosity sufficient to retain the oil1 the thickness of sediments and the extent to which they have undergone differential stresses1 the amount of erosion and the possibilities that oil1 if formed1 has escaped from the eroded edges of porous strata1 and1 where carbonaceous beds are present1 their degree of carbonization1 and many other similar matters4 ,each field in fact has its own habit1 determined by the interaction of several geologic factors4 ,this habit may be learned empirically4 ,geologists have often gone wrong in applying to a new district certain principles determined elsewhere1 without sufficient consideration of the complexity and relative importance of the sundry geologic factors which in the aggregate determine the local habit of oil occurrence4 ,geographically associated fields characterized by similarity of oil occurrence1 age1 and origin1 are known as petroliferous provinces4 ,the factors entering into the classification of fields are so numerous that more precise definition of a petroliferous province is hardly yet agreed upon4 ,the part played by the economic geologist in oil exploration and development is a large one for the obvious reasons given above4 ,probably no other single division of economic geology now employs so large a number of geologists4 ,practically no large oil company1 or large piece of oil exploration and development1 is now handled without geologic advice4 ,quoting from ,arnold3#bi ,it ought to be as obvious that exploration with the drill should be preceded by careful geologic studies as it is that railroad construction should be based on surveys4 ,these studies should include such subjects as topography1 stratigraphy1 structure1 and surface evidence of petroleum in the regions to be tested4 ,the work divides itself into two stages--preliminary reconnaissances and detailed surveys4 ,the preliminary reconnaissance should consist in procuring all the available published and hearsay evidence regarding the occurrence of oil or gas seepages or hydrocarbon deposits in the region2 in making preliminary geologic surveys to determine from which formations the oil is to come and the areal distribution of these formations2 in determining those general regions in which the surface evidence is supposed to be most favorable for the accumulation of hydrocarbons2 and in determining the best routes and methods of transportation4 ,the second stage includes detailed geologic surveys of those regions where the surface evidence indicates that petroleum is most likely to be found and the location of test holes at favorable points4 ,by working out the surface distribution and structure of the formations it is usually possible to select the areas offering the best chances of success4 ,geology should always be the dominant factor in determining the location of test holes1 although modifications to meet natural conditions must sometimes be made4 ,,oil ,,shales ,one of the sources of oil which is likely to become important in the future is oil shales1--that is1 shales from which oil product can be extracted by distillation4 ,these have already been referred to on previous pages4 ,such shales are now mined only in ,scotland and in ,france to a relatively small extent1 but there are immense reserves of these shales in various parts of the world which are likely to be drawn upon when commercial conditions require it4 ,in the ,united ,states alone it is estimated that the oil shales are a potential source of oil in amounts far greater than all the natural petroleum of this hemisphere4#cj ,the solution of the problem of extraction of oil from shales is fairly well advanced technically1 and the problem has now become principally one of cost4 ,in order to recover any large amount of oil from this source1 operations of stupendous magnitude1 approximately on the scale of the coal industry1 must be established4 ,as long as there are sufficient supplies of oil concentrated by nature to be drawn upon1 it is unlikely that oil shale will furnish any considerable percentage of the world's oil requirements4 ,with the great increase in world demand for oil1 however1 which may very possibly outstrip the available annual supply in the future1 and particularly with the increase in the ,united ,states demand relative to domestic supplies1 exhaustive surveys of the situation are being made with a view to development of oil shales when warranted by market conditions4 ,oil shales are sedimentary strata containing decomposed products of plants and animals4 ,locally they grade into cannel coal1 with which they are genetically related4 ,they may be regarded as representing the kinds of sediments from which the oil of oil pools has in the main originated4 ,the most extensive of the oil shales of the ,united ,states are found in the ,eocene beds of northwestern ,colorado1 northeastern ,utah1 and southwestern ,wyoming1 and in the ,miocene beds of northern ,nevada4 ,the largest known foreign deposits occur in ,brazil and ,russia4 ,,natural ,,gas ,,economic ,,features ,natural gas is used both for lighting and for fuel purposes4 ,in the ,united ,states it has become the basis of a great industry1 the value of the product ranging above that of lead and zinc4 ,the ,united ,states is the largest producer of natural gas4 ,other producers are ,canada1 ,dutch ,east ,indies1 ,mexico1 ,hungary1 ,japan1 and ,italy4 ,nearly all producing oil fields furnish also some natural gas4 ,in the ,united ,states nearly #dj per cent of the total production of natural gas comes from ,west ,virginia1 about #ag per cent from ,pennsylvania1 about #ag per cent from ,oklahoma1 and less than #aj per cent from each of ,ohio1 ,california1 ,louisiana1 ,kansas1 ,texas1 and several other states4 ,one of the recent interesting developments in this industry is the recovery of gasoline from the natural gas4 ,this is obtained by compression and condensation of the casing-head gas from oil wells1 and also1 more recently1 by an absorption process which is applied not only to wet gas from oil wells but also to so-called dry gas occurring independently of oil4 ,it is a high-grade product which in recent years has amounted to about #aj per cent of the total output of gasoline for the ,united ,states4 ,,geologic ,,features ,natural gas1 like oil1 originates in the distillation of organic substances in sediments1 and migrates to reservoirs capped by impervious strata4 ,it is commonly1 though not always1 associated with oil and coal4 ,the geologic features of its occurrence have so much in common with oil that a description would essentially duplicate the above account of the geologic features of oil4 ,,asphalt ,,and ,,bitumen ,,economic ,,features ,asphalt and bitumen are not used as energy resources1 but they have so much in common with oil in occurrence and origin that they are included in this chapter4 ,asphalt and bitumen find their main use in paving4 ,other important uses are in paints and varnishes1 in the manufacture of prepared roofing1 for various insulating purposes1 and in substitutes for rubber4 ,nearly the entire world's supply of natural asphalt comes from the ,british ,island of ,trinidad and from ,venezuela4 ,both of these deposits are under ,united ,states commercial control probably affiliated with ,dutch-,english interests4 ,prior to the war about half the product went to ,europe and half to the ,united ,states4 ,large amounts of asphaltic and bituminous rock1 used mainly in paving1 are normally produced in ,alsace1 ,france1 and in ,italy4 ,prior to the war both the ,alsatian and ,italian deposits were under ,german commercial control4 ,their output is practically all consumed in ,europe4 ,the ,united ,states takes a large part in the world's trade in natural asphalt1 by importation from ,trinidad and ,venezuela1 and by some reexportation chiefly to ,canada and ,mexico4 ,the ,united ,states also produces some natural asphalt and bituminous rock for domestic consumption4 ,deposits of natural asphaltic material are widely distributed through the ,united ,states1 but commercial production is limited to a few localities in ,kentucky1 ,texas1 ,utah1 ,colorado1 ,oklahoma1 and ,california4 ,the asphalt manufactured from petroleum constitutes a much larger tonnage than natural asphalt though it does not enter so largely into world trade4 ,the manufactured product is largely but not exclusively in ,american control4 ,large amounts are made in this country and will no doubt be made for the next decade1 from oil produced in the southwestern states and in ,mexico4 ,at the present time as much or more asphalt is made in the ,united ,states from ,mexican as from domestic crude oil4 ,the refineries are located near the ,gulf coast so that exports can avoid overland shipments4 ,the relative merits of natural asphalt and asphalt manufactured from oil may be subject to some discussion2 but it is perfectly clear that the manufactured material is sufficient1 both in quantity and variety1 to make the ,united ,states entirely independent and have an exportable surplus4 ,,geologic ,,features ,natural asphalt and similar products are in the main merely the residuals of oil and gas distillation accumulated by nature under certain conditions already described in connection with oil 7pp4 #adj-add74 ,in some cases the asphaltic material is found as impregnations of sediments1 and appears to have remained in place while the lighter organic materials were volatilized and migrated upward4 ,in other cases it occurs in distinct fissure veins2 the fissures and cavities apparently were once filled with liquid petroleum1 which has subsequently undergone further distillation4 ,the original liquid character of some of these bitumens is shown by occasional fragments of unworn country rock imbedded in the veins4 ,the effect of surface waters1 carrying oxidizing materials and sulphuric acid1 is believed to have contributed to the drying out and hardening of these veins or dikes4 ,asphalts and bitumens include a wide variety of hydrocarbon materials1 such as gilsonite1 grahamite1 elaterite1 ozokerite1 etc41 which are used for somewhat different purposes4 ,the deposits of the ,united ,states show much variety in form1 composition1 age1 and geologic associations4 ,the important ,kentucky deposits occur as impregnations of ,carboniferous sandstones at the base of the ,coal ,measures of that state4 ,the ,trinidad asphalt comes from the famous pitch lake1 which is a nearly circular deposit covering about a hundred acres #aej feet above sea level1 and which is believed to fill the crater of an old mud volcano4 ,the so-called pitch consists of a mixture of bitumen1 water1 mineral and vegetable matter1 the whole inflated with gas1 which escapes to some extent and keeps the mass in a state of constant ebullition4 ,the surface of the lake is hard1 and yet the mass as a whole is plastic and tends to refill the excavations4 ,the lake is believed to be on the outcrop of a petroleum-bearing stratum1 and the pitch to represent the unevaporated residue of millions of tons of petroleum which have exuded from the oil-sands4 ,the pitch is refined by melting1--the heat expelling the water1 the wood and other light impurities rising1 and the heavy mineral matter sinking to the bottom4 ,the asphalt of ,venezuela is similar in nature1 but the pitch lake is here covered with vegetation and the soft pitch wells up at certain points as if from subterranean springs4 ,,footnotes3 #ag ,for more detailed treatment of international coal movements before the war and of coal movements within the ,united ,states1 see the ,u4 ,s4 ,geological ,survey's ,world ,atlas of ,commercial ,geology1 ,pt4 #a1 #aiba1 pp4 #aa-af4 #ah ,campbell1 ,marius ,r41 ,the coal fields of the ,united ,states3 ,prof4 ,paper #ajj-;,a1 ,u4 ,s4 ,geol4 ,survey1 #aiag1 pp4 #e1 #f1 #g4 #ai ,compiled from tables quoted by ,white1 ,david1 ,the petroleum resources of the world3 ,annals ,am4 ,acad4 ,social and ,political ,sci41 vol4 #hi1 #aibj1 pp4 #abc and #abf4 #bj ,white1 ,david1 loc4 cit41 p4 #aac4 #ba ,see ,arnold1 ,ralph1 ,petroleum resources of the ,united ,states3 ,econ4 ,geol41 vol4 #aj1 #aiae1 p4 #gjg4 #bb ,white1 ,david1 ,late theories regarding the origin of oil3 ,bull4 ,geol4 ,soc4 ,am41 vol4 #bh1 #aiag1 p4 #gcb4 #bc ,mc,coy1 ,a4 ,w41 ,notes on principles of oil accumulation3 ,jour4 ,geol41 vol4 #bg1 #aiai1 pp4 #beb-bfb4 #bd ,white1 ,david1 ,genetic problems affecting search for new oil regions3 ,mining and ,metallurgy1 ,am4 ,inst4 of ,min4 ,engrs41 ,no4 #aeh1 ,sec4 #ba1 ,feb41 #aibj4 #be ,mehl1 ,m4 ,g41 ,some factors in the geographic distribution of petroleum3 ,bull4 ,sci4 ,lab41 ,denison ,univ41 vol4 #ai1 #aiai1 pp4 #ee-fc4 #bf ,schuchert1 ,charles1 ,petroliferous provinces3 ,bull4 #aee1 ,am4 ,inst4 ,mining and ,metallurgical ,engrs41 #aiai1 pp4 #cjei-cjfj4 #bg ,loc4 cit41 p4 #bj4 #bh ,seepages or residual bituminous matter near the surface may be due to upward escape of oil material through joints in the rocks capping a reservoir1 and productive pools may be found directly below such showings4 ,in other regions similar surface indications may mean that the stratum in the outcrop of which they are found is oil-bearing2 but accumulations of oil1 if present1 may be several miles down the dip1 at places where the structural conditions have been favorable4 ,in still other cases the seepage may have been in existence for such a long time as to exhaust the reservoir4 ,it must also be remembered that gas seeps are common in sloughs and marshes where vegetation is decaying1 and may be of no significance in the search for petroleum4 #bi ,arnold1 ,ralph1 ,conservation of the oil and gas resources of the ,americas3 ,econ4 ,geol41 vol4 #aa1 #aiaf1 pp4 #cba-cbb4 #cj ,oil shales may also be made to yield large quantities of fuel and illuminating gas1 and of ammonia 7see pp4 #aja-ajb74 ,,chapter ,,ix ,,minerals ,,used ,,in ,,the ,,production ,,of ,,iron ,,and ,,steel 7,,the ,,ferro-,,alloy ,,group7 ,,general ,,features ,iron and steel and their alloys are the most generally used of the metals4 ,the raw materials necessary for their manufacture include a wide variety of minerals4 ,iron is the principal element in this group2 but in the manufacture of iron and steel1 manganese1 chromium1 nickel1 tungsten1 molybdenum1 vanadium1 zirconium1 titanium1 aluminum1 uranium1 magnesium1 fluorine1 silicon1 and other substances play important parts1 either as accessories in the furnace reactions or as ingredients introduced to give certain qualities to the products4 ,nearly all parts of the world are plentifully supplied with iron ores for an indefinite period in the future1 but their abundant use has thus far been confined mainly to the countries bordering the ,north ,atlantic1--the ,united ,states1 ,germany1 and ,england1--which1 possessing ample coal supplies1 have had the initiative to develop great iron and steel industries4 ,china has abundant coal1 moderate quantities of iron ore1 and a large population1 but a low per capita consumption of iron and steel products4 ,development of its iron and steel industry is just beginning4 ,japan has neither coal nor iron in sufficient quantities1 and hence the ,japanese effort in recent years to control the mineral resources of ,china and other countries4 ,as a result of the war ,germany has been largely deprived of its iron ores1 and ,france may assume somewhat the rank in iron ore production once held by ,germany4 ,sweden and ,spain have been considerable producers of iron ore1 but both lack coal1 with the result that their ores have been largely exported to ,england and ,germany4 ,with increase of per capita consumption in outlying parts of the world1 iron and steel industries are beginning to develop locally on a small scale1 as in ,india1 ,south ,africa1 and ,australia4 ,russia has had sufficient supplies of coal and iron1 but the stage of industrial development in that country has not called for great expansion of its iron and steel industry4 ,there has been a tendency for iron and steel manufacture to become concentrated at a comparatively few places on the globe favored by the proper combinations of coal1 iron1 transportation1 proximity to consuming populations1 initiative and capacity to take advantage of a situation1 and other factors4 ,even though on paper conditions may seem to be favorable in outlying territories for the development of additional plants1 this development is often held back by competition from the established centers4 ,on the west coast of the ,united ,states1 there are raw materials for an iron and steel industry and there has been discussion for years as to the possibilities of starting a successful large scale steel industry4 ,the consuming power of the local population for all kinds of iron and steel would seem to be great enough to warrant such action4 ,however1 the demand is for an extremely varied assortment of iron and steel products2 and to start an industry1 making only a few of the cruder products such as pig iron and semi-finished forms1 would not meet this demand4 ,all varieties of finishing plants and associated factories would also need to be started in order to meet the situation4 ,this would require large capital4 ,furthermore the local demand for some of the accessory finished products might not warrant the establishment of the accessory plants4 ,throughout the history of the iron and steel business there has been a marked tendency for the iron ore to move to regions of coal production rather than for the coal to move to the iron ore regions4 ,the coal or energy factor seems ultimately to control4 ,this is due in considerable part to the fact that coal furnishes the basis of a great variety of industries for which iron ore is only one of the feeders1 and which are so interrelated that it is not always easy to move the iron and steel industry to a spot near the sources of iron ore where iron and steel alone could be produced4 ,in regard to iron ore supplies of proper grade and quantity1 the ,united ,states is more nearly self-sufficing than any of its competitors4 ,it imports minor amounts of ore from ,cuba and ,canada1 and even from ,chile and ,sweden1 to border points1 in the main merely because these imported ores can compete on a price basis with the domestic ores4 ,the entire exclusion of these ores1 however1 would make comparatively little difference in the total volume of our iron and steel industry2 though it would probably make some difference in distribution1 to the disadvantage of plants along the coast4 ,there is only one kind of iron ore in which the ,united ,states has anything approaching deficiency1 and that is ore extremely low in phosphorus1 adapted to making the so-called low-phosphorus pig which is needed for certain special steels4 ,ordnance requirements during the war put a premium on these steels4 ,while some of these extremely low-phosphorus ores are mined in the ,united ,states1 additional quantities have been required from ,spain and ,canada and to a lesser extent from ,north ,africa and ,sweden4 ,also the ,spanish pyrite1 imported ordinarily for its sulphur content1 on roasting leaves a residue of iron oxide extremely low in phosphorus which is similarly used4 ,the elimination of pyrite imports from ,spain during the war1 therefore1 was a considerable contributing factor to the stringency in low-phosphorus iron ores4 ,war experience showed that the ,united ,states was dependent on foreign sources for #dj per cent or upwards of its needs in this regard4 ,certain developments in progress1 notably the project for concentration of siliceous eastern ,mesabi ,range ores1 make it likely that future domestic production will more nearly be able to meet the requirements4 ,the equivalent of #ae per cent of the iron ore mined in the ,united ,states is exported as ore to ,canadian ports on the ,great ,lakes and in the form of crude iron and steel products to many parts of the world4 ,england and ,germany are almost the sole competitors in the export trade4 ,when we turn to the minerals used for making the alloys of iron and as accessories in the manufacture of iron1 it appears that no one of the principal iron and steel producing countries of the world is self-supporting1 but that these sweeteners must be drawn in from the far corners of the earth4 ,the importance of these minor constituents is altogether out of proportion to their volume4 ,for instance1 only fourteen pounds of manganese are necessary in the making of a ton of steel1 yet a ton of steel cannot be made without manganese4 ,the increasing specialization in iron and steel products1 and the rapidly widening knowledge of the qualities of the different alloys1 are constantly shifting the demand from one to the other of the ferro-alloy minerals4 ,each one of the ferro-alloy minerals may be regarded as being in the nature of a key mineral for the iron and steel industry1 and the control of deposits of these minerals is a matter of international concern4 ,control is not a difficult matter1 in view of the fact that the principal supplies of practically every one of the alloy minerals are concentrated in comparatively few spots on the globe1--as indicated on succeeding pages4 ,nature has not endowed the ,united ,states1 nor in fact the ,north ,american continent1 with adequate high-grade supplies of the principal ferro-alloy minerals1--with the exception of molybdenum1 and with the exception of silica1 magnesite1 and fluorspar1 which are used as accessories in the process of steel making4 ,with plenty of iron ore and coal1 and with an iron and steel capacity amounting to over #ej per cent of the world's total1 the ,united ,states is very largely dependent on other countries for its supplies of the ferro-alloy minerals4 ,the war brought this fact home4 ,with the closing of foreign sources of supplies1 it looked at one time as if our steel industry was to be very greatly hampered2 and extraordinary efforts were made to keep channels of importation open until something could be done in the way of development1 even at excessive cost1 of domestic supplies4 ,the result of war efforts was a very large development of domestic supplies of practically all the ferro-alloy minerals2 but in no case1 with the exceptions noted above1 did these prove sufficient to meet the total requirements4 ,this development was at great cost and at some sacrifice to metallurgical efficiency1 due to the low and variable grades of the raw materials4 ,with the post-war reopening of importation much of the domestic production has necessarily ceased1 and large amounts of money patriotically spent in the effort to meet the domestic requirements have been lost4 ,these circumstances have resulted in the demand in ,congress from producers for direct financial relief and in demand for protective tariffs1 in order to enable the new struggling industries to exist1 and to permit of development of adequate home supplies4 ,such tariffs might be beneficial to these particular domestic industries if wisely planned2 but also1 in view of the limited amounts of these particular ores in this country1 their general low grade1 and the high cost of mining1 tariffs might very probably hasten exhaustion of our limited supplies and might handicap our metallurgical industries both in efficiency and cost 7see pp4 #cfe-cff1 #cic-cid74 ,,iron ,,ores ,,economic ,,features ,technical and commercial factors determining use of iron ore minerals4 ,popularly1 an iron ore is an iron ore1 and there is little realization of its really great complexity of composition and the difficulty of determining what is or is not a commercial ore4 ,percentage of iron is of course an important factor2 but an ore in which the iron is in the mineral hematite is more valuable than one with an equivalent percentage of iron which is in the form of magnetite4 ,substances present in the ore in minor quantities1 such as phosphorus1 sulphur1 and titanium1 have a tendency to make the iron product brittle1 either when it is cold or when it is being made1 so that excessive amounts of these substances may disqualify an ore4 ,excessive quantities of silica1 lime1 or magnesia may make the ore undesirable4 ,where an acid substance1 like silica1 is balanced by basic constituents like lime and magnesia1 considerable amounts of both may be used4 ,excessive moisture content may spoil an ore because of the amount of heat necessary to eliminate it in smelting4 ,the metallurgical processes of the iron and steel industry are essentially adapted to the principal grades of ore available4 ,the cheapest of the steel-making processes1 called the acid ,bessemer process1 requires a very low-phosphorus ore 7usually below 4#jej per cent in the ,united ,states and below 4#jcj per cent in ,england47 ,the basic open-hearth processes1 making two-thirds of the steel in the ,united ,states1 allow higher percentages of phosphorus1 but not unlimited amounts4 ,the basic ,bessemer 7,thomas7 process1 used for the minette ores of western ,europe and the ,swedish magnetites1 may use an ore with any amount of phosphorus over #a4e per cent4 ,the phosphatic slag from this process is used as fertilizer4 ,the supply of low-phosphorus ,bessemer ore in the ,united ,states is at present limited as compared with that of the non-,bessemer ores1 with the result that steel-plant construction for many years past has been largely open-hearth4 ,the open-hearth process is favored also because it allows closer control of phosphorus content in the steel4 ,small but increasing amounts of steel are also made in the electric furnace2 for the most part1 however1 this process is more expensive than the others1 and it is used principally for special alloy steels4 ,iron ores are seldom so uniform in quality that they can be shipped without careful attention to sampling and grade4 ,in the ,lake ,superior region the ores are sampled daily as mined1 and the utmost care is taken to mix and load the ore in such a way that the desired grades can be obtained4 ,ordinarily a single deposit produces several grades of ore4 ,when ores are put into the furnace for smelting the mixtures are selected with great care for the particular purpose for which the product is to be used4 ,the mixture is compounded as carefully as a druggist's prescription4 ,an ore salesman1 after ascertaining the nature of the iron and steel products of a plant1 has to use great skill in offering particular ores for sale which not only will meet the desired grade in regard to all elements1 but also will meet competition in price4 ,in some respects1 the marketing of different grades of iron ore is as complex as the marketing of a miscellaneous stock of merchandise4 ,with ores1 as with merchandise1 custom and sentiment play their part1--with the result that two ores of identical grade mineralogically and chemically may have quite a different vogue and price1 simply because of the fact that furnace men are used to one and not to the other and are not willing to experiment4 ,the geologist is ordinarily concerned merely with finding an ore of as good a general grade as possible2 but he often finds to his surprise that his efforts have been directed toward the discovery of something which1 due to some minor defect in texture1 in mineralogical composition1 or in chemical composition1 is difficult to introduce on the market4 ,there is here a promising field1 intermediate between geology 7or mineralogy7 and metallurgy1 for the application of principles of chemistry1 metallurgy1 and mineralogy1 which is occupied at the present time mainly by the ore salesman4 ,both the mineralogist and metallurgist touch the problem but they do not cover it4 ,with increasingly precise and rapidly changing metallurgical requirements1 this field calls for scientific development4 ,geographic distribution of iron ore production4 ,iron ores are widely distributed over the world1 but are produced and smelted on a large scale only in a few places where there is a fortunate conjunction of high grades1 large quantity1 proximity of coal1 cheap transportation to markets1 and manufacturing enterprise4 ,over #ij per cent of the iron ore production of the world is in countries bordering the ,north ,atlantic basin4 ,the ,united ,states produces about #dj per cent1 ,france about #ab per cent1 ,england about #aj per cent1 ,germany before the war #ae to #bj per cent1 and ,spain1 ,russia1 and ,sweden each about #e per cent4 ,lesser producing countries are ,luxemburg1 ,austria-,hungary1 ,cuba1 ,newfoundland1 and ,algeria2 and insignificant amounts are produced in many other parts of the world4 ,of the world's iron and steel manufacturing capacity1 the ,united ,states has about #ec per cent1 ,germany #af per cent1 ,england #ad per cent1 ,france #aj per cent1 the remainder of ,europe 7chiefly ,russia1 ,austria-,hungary1 and ,belgium7 #g per cent4 ,the absence of important iron ore production and of iron and steel manufacture either in the southern hemisphere or in any of the countries bordering the ,pacific is a significant feature1 when we remember what part iron plays in modern civilization4 ,japan1 however1 is beginning to develop a considerable iron and steel industry1 which promises to use a large amount of ore from ,china1 ,manchuria1 and ,korea1 and possibly to compete in ,american ,pacific ,coast markets4 ,in the ,united ,states about #he per cent of the production1 or one-third of the world's production1 comes from the ,lake ,superior region1 a large part of the remainder from the ,birmingham district1 ,alabama1 and smaller quantities from the ,adirondacks4 ,for the rest of the ,north ,american continent1 the only largely producing deposit is that at ,belle ,isle1 ,newfoundland1 which is the basis of the iron industry of eastern ,canada4 ,cuba supplies some ore to the east coast of the ,united ,states4 ,in ,europe there are only three large sources of high-grade iron ore which have heretofore been drawn on largely1--the magnetite deposits of northern ,sweden1 the hematites and siderites of the ,bilbao and adjacent districts of northern ,spain1 and the magnetite-hematite deposits of southern ,russia4 ,the first two of these ores have been used to raise the percentage of iron in the low-grade ores which are the principal reliance of western ,europe4 ,the ,swedish ores have also been necessary in order to raise the percentage of phosphorus and thus make the ores suitable for the ,thomas process2 on the other hand the ,spanish ores and a small part of the ,swedish material have been desired because of their low phosphorus content1 adapted to the acid ,bessemer process and to the manufacture of low-phosphorus pig4 ,the ,russian ores have largely been smelted in that country4 ,the largest of the western ,european low-grade deposits is a geographic and geologic unit spreading over parts of ,lorraine1 ,luxemburg1 and the immediately adjacent ,briey1 ,longwy1 and ,nancy districts of ,france4 ,the ores of this region are called minette ores4 ,this unit produces about a fourth of the world's iron ore4 ,low-grade deposits of a somewhat similar nature in the ,cleveland1 ,lincolnshire1 and adjacent districts of ,england form the main basis for the ,british industry4 ,there is minor production of iron ores in other parts of ,france and ,germany1 in ,austria-,hungary1 and in ,north ,africa 7these last being important because of their low phosphorus content74 ,comparison of figures of consumption and production of iron ores indicates that the ,united ,states1 ,france1 ,russia1 and ,austria-,hungary are self-supporting so far as quantity of materials is concerned4 ,certain ores of special grades1 and ores of other minerals of the ferro-alloy group required in steel making1 however1 must be imported from foreign sources2 this matter has been discussed above4 ,great ,britain and ,germany appear to be dependent on foreign sources1 even under pre-war conditions1 for part of the material for their furnaces4 ,during the war there was considerable development of the low-grade ,english ores1 but this does not eliminate the necessity for importing high-grade ores for mixture4 ,belgium produces a very small percentage of her ore requirements and is practically dependent on the ,lorraine-,luxemburg field4 ,the principal effect of the war on iron ore production was the occupation of the great ,french mining and smelting field by the ,germans1 thereby depriving the ,french of their largest source of iron ore4 ,since the war the situation has been reversed1 ,france now possessing the ,lorraine field1 which formerly supplied ,germany with #gj per cent of its iron ore4 ,as the ,german industrial life is largely based on iron and steel manufacture1 the problem of ore supplies for ,germany is now a critical one4 ,it has led to ,german activity in ,chile and may lead to ,german developments in eastern ,europe and western ,asia1 particularly in the large and favorably located reserves of southern ,russia4 ,it seems likely1 however1 that arrangements will also be made to continue the export of ore from the ,lorraine field down the ,rhine to the principal ,german smelting centers4 ,france needs the ,german coal for coking as badly as ,germany needs the ,french iron ore4 ,the ,rhine valley is the connecting channel for a balanced movement of commodities determined by the natural conditions4 ,these basic conditions are likely in the long run to override political considerations4 ,the ,lake ,superior deposits1 the ,swedish magnetites1 the ,spanish hematites1 and the ,russian ores carry #ej to #fe per cent of metallic iron4 ,the ,birmingham deposits of southeastern ,united ,states1 the main ,british supplies1 and the main ,french and ,german supplies contain about #ce per cent or less4 ,it is only where ores are fortunately located with reference to consuming centers that the low-grade deposits can be used4 ,for outlying territories only the higher-grade deposits are likely to be developed1 and even there many high-grade deposits are known which are not mined4 ,the largest single group not yet drawn on is in ,brazil4 ,others in a very early stage of development are in ,north ,africa and ,chile4 ,world reserves and future production of iron ore4 ,the average rate of consumption of iron ore for the world in recent years has been about #agj million tons per year4 ,at this rate the proved ore reserves would last about #ahj years4 ,if it be assumed that consumption in the future will increase at about the same rate as it has in the past1 the total measured reserve would still last about a century4 ,these calculations of life1 however1 are based only on the known reserves2 and when potential reserves are included the life is greatly increased4 ,and this is not all2 for beyond the total reported reserves 7both actual and potential71 there are known additional large quantities of lower-grade ores1 at present not commercially available1 but which will be available in the future1--to say nothing of expected future discoveries of ores of all grades in unexplored territories4 ,both geological inference and the history of iron ore exploration seem to make such future discoveries practically certain4 ,iron ore constitutes about #d per cent of the earth's shell and it shows all stages of concentration up to #gj per cent4 ,only those rocks are called iron ores which have a sufficiently high percentage of iron to be adapted to present processes for the extraction of iron4 ,when economic conditions demand it1 it may be assumed that iron-bearing rocks not now ordinarily regarded as ores may be used to commercial advantage1 and therefore will become ores4 ,not only is an indefinitely long life assured for iron ore reserves as a whole1 but the same is true of many of the principal groups of deposits4 ,the question of practical concern to us1 therefore1 is not one of total iron ore reserves1 but one of degrees of availability of different ores to the markets which focus our requirements for iron4 ,the annual production of ore from a given district is roughly a measure of that ore's ability to meet the competitive market1 and therefore1 of its actual immediate or past availability4 ,annual production is the net result of the interaction of all of the factors bearing on availability4 ,it may be argued that there are ores known and not yet mined which are also immediately available4 ,on the whole1 they seem to be less available than ores actually being produced2 otherwise general economic pressure would require their use and actual production4 ,in considering the future availability of iron ores1 it is obvious that tables of past production afford only a partial basis for prediction4 ,presumably districts which have produced largely in the past may be expected to continue as important factors4 ,in these cases production has demonstrated availability4 ,continued heavy production may thus be expected from the ores of the ,lake ,superior region1 from the ,clinton hematites of ,alabama1 from the ores of the ,lorraine-,luxemburg-,briey district1 from the ,cleveland ores of ,england1 from the ,bilbao ores of ,spain1 from the high-grade magnetites of northern ,sweden1 and 7assuming political stability7 from the ores of southern ,russia4 ,similarly1 also1 recent increases in production from certain districts are probably significant of increased use of such ores in the future4 ,among these developments are the increasing production of ,swedish ores and their importation into ,england and ,germany1 and the increasing use of ,clinton hematites and ,adirondack magnetites in the ,united ,states4 ,low-grade ores from the great reserves of ,cuba are being mined and brought to the east coast of the ,united ,states in increasing amounts1 and it is highly probable that they will take a larger share of the market4 ,a similar project in ,chile1 which lay dormant during the war because of restricted shipping facilities1 is expected in the near future to yield important shipments to the ,united ,states4 ,in none of these cases will production be limited in the near future by ore reserves4 ,increased production and use of iron ores are also to be looked for in ,newfoundland1 ,north ,africa1 ,china1 ,india1 ,australia1 and ,south ,africa4 ,on the commercial horizon are ores of still newer districts1 the availability of which may not be read from tables of production4 ,their availability must be determined by analysis and measurement of the factors entering into availability4 ,availability of iron ore is determined by percentage of iron1 percentages of impurities1 percentages of advantageous or deleterious minor constituents1 physical texture1 conditions for profitable mining1 adaptability to present furnace practice1 distance from consuming centers1 conditions and costs of transportation1 geographical and transportational relation to the coal and fluxes necessary for smelting1 trade relations1 tariffs and taxes1 inertia of invested capital1 and other considerations4 ,all of these factors are variable4 ,a comparison of ores on the basis of any one of these factors or of any two or three of them is likely to be misleading4 ,a comparison based on the quantitative consideration of all of the several factors seems to be made practically impossible by the difficulty of ascertaining accurately the quantitative range and importance of each factor1 and by the difficulty of integrating all of the factors even if they should be determined4 ,however1 their combined effect is expressed in the cost of bringing the product to market2 and comparison of costs furnishes a means of comparing availability of ores4 ,a high-grade ore1 cheaply mined and favorably located with reference to the points of demand1 will command a relatively high price at the point of production4 ,the same ore so located that its transportation costs are higher will command a lower price2 or it may be so located that the costs of mining and bringing it to places where it can be used are so high that there is no profit in the operation4 ,there are known high-grade iron ores which1 because of cost1 are not available under present conditions4 ,the availability of an ore1 then1 depends on its relation to a market1--whether1 after meeting the cost of transportation1 it can be sold at prevailing market prices at the consuming centers1 and can still leave a fair margin of profit for the mining operation4 ,the price equilibrium between consuming centers affords a reasonably uniform basis against which to measure availability of ores4 ,figures of cost are obtainable as a basis for comparison of availability of iron ores of certain of the districts1 but not enough are at hand for comparison of the ores of all districts4 ,careful study of costs has demonstrated the availability in the near future of the ,brazilian high-grade ,bessemer hematites2 and projects which are now under way for exportation to ,england and the ,united ,states will doubtless make this enormous reserve play an important part in the iron industry4 ,iron ore is known but not yet mined in many parts of the western ,united ,states and western ,canada4 ,with the increasing population along the west coast of ,north ,america1 projects for smelting the ore there are becoming more definite4 ,establishment of smelters on the west coast would make available a large reserve of ore 7see also1 however1 p4 #aee74 ,the list of changes now under way or highly probable for the future might be largely extended4 ,the use of iron and steel is rapidly spreading through populous parts of the world which have heretofore demanded little of these products4 ,this increased use is favoring the development of local centers of smelting1 which will make available other large reserves of iron ore4 ,the growth of smelting in ,india1 ,china and ,australia illustrates this tendency4 ,iron ore reserves are so large1 so varied1 and so widely distributed over the globe1 that they will supply demands upon them to the remote future4 ,reserves become available and valuable only by the expenditure of effort and money4 ,ores are the multiplicand and man the multiplier in the product which represents value or availability4 ,iron ore can be made available1 when needed1 almost to any extent1 but at highly varying cost and degree of effort4 ,the highest grade ores1 requiring minimum expenditure to make them available1 are distinctly limited as compared to total reserves4 ,any waste in their utilization will lead more quickly to the use of less available ores at higher cost4 ,one of the significant consequences of the exhaustion of the highest grade reserves will be an increased draft upon fuel resources for the smelting of the lower grade ores4 ,availability of iron ores is limited1 not by total reserves1 but by economic conditions4 ,,geologic ,,features ,iron rarely exists in nature as a separate element4 ,it occurs mainly in minerals which represent combinations of iron1 oxygen1 and water1 the substances which make up iron rust4 ,very broadly1 most of the iron ores might be crudely classified as iron rust4 ,in detail this group is represented by several mineral varieties1 principal among which are hematite 7,fe#b,o#c71 magnetite 7,fe#c,o#d71 and limonite 7hydrated ferric oxide74 ,iron likewise combines with a considerable variety of substances other than oxygen2 and some of these compounds1 as for instance iron carbonate 7siderite71 iron silicate 7chamosite1 glauconite1 etc471 and iron sulphide 7pyrite71 are locally mined as iron ores4 ,while an ore of iron may consist dominantly of some one of the iron minerals1 in few cases does it consist exclusively of one mineral4 ,most ores are mixtures of iron minerals4 ,fully nine-tenths of the iron production of the world comes from the so-called hematite ores1 meaning ores in which hematite is the dominant mineral1 though most of them contain other iron minerals in smaller quantities4 ,about #e per cent of the world's iron ores are magnetites1 and the remainder are limonites and iron carbonates4 ,iron ores are represented in nearly all phases of the metamorphic cycle1 but the principal commercial values have been produced by processes of weathering and sedimentation at and near the surface4 ,sedimentary iron ores4 ,over #ij per cent of the world's production of iron ore is from sedimentary rocks4 ,the deposits consist in the main either of beds of iron ore which were originally deposited as such and have undergone little subsequent alteration1 or of those altered portions of lean ferruginous beds which since their deposition have been enriched or concentrated sufficiently to form ores4 ,a minor class of iron ores in sediments consists of deposits formed by secondary replacement of limestones by surface waters carrying iron in solution4 #a4 ,deposits of the first class1--originally laid down in much their present form1--are usually either oolitic1 i4 e41 containing great numbers of flat rounded grains of iron minerals like flaxseeds1 or consist in large part of fossil fragments of sea shells1 replaced by iron minerals4 ,the ,clinton ores of the ,birmingham district1 the ,wabana ores of ,newfoundland1 the minette ores of the ,lorraine district in central ,europe1 and the oolitic ores of northern ,england are all of these types4 ,their principal iron mineral is hematite1 although the ,english ores also contain considerable iron carbonate or siderite4 ,the cementing or gangue materials are chiefly calcite and quartz1 in variable proportions4 ,the large reserves of high-grade hematite in the ,minas ,geraes district of ,brazil are also original sediments1 but lack the oolitic texture4 ,an insignificant proportion of the world's iron is obtained from bog ores1 which are sedimentary deposits of hydrated iron oxide in swamps and lakes4 ,these ores have been used only on a small scale and chiefly in relatively undeveloped countries4 ,they are of particular interest from a genetic standpoint in that they show the nature of some of the processes of iron ore deposition as it is actually going on today4 ,none of the ores of this class1 with the exception of the iron carbonates1 have undergone any considerable surface enrichment since their primary deposition4 ,neither1 with the exception of the ,brazilian ores1 have they undergone any deep-seated metamorphism4 ,the shapes1 sizes1 and distribution of the deposits may be traced back to the conditions of original deposition4 ,in ,england and western ,europe the principal deposits have been only slightly tilted by folding4 ,in the ,united ,states the ,clinton ores have partaken in the ,appalachian folding4 ,in ,brazil1 the ores have undergone close folding and anamorphism4 #b4 ,deposits of the second class1 which owe much of their value to further enrichment since deposition1 are represented by the hematite ores of the ,lake ,superior district4 ,these may be thought of as the locally rusted and leached portions of extensive iron formations1 in which oxidation of the iron1 and the leaching of silica and other substances by circulating waters1 have left the less soluble iron minerals concentrated as ores4 ,the ,lake ,superior iron formations now consist near the surface mainly of interbanded quartz 7or chert7 and hematite1 called jasper or ferruginous chert or taconite4 ,these are similar in composition to the leaner iron ores of ,brazil1 called itabirite1 but differ in that the silica is in the form of chemically deposited chert1 rather than fragmental quartz grains4 ,illustration3 ,,fig4 #aa4 ,alteration of ,lake ,superior iron formation to iron ore by the leaching of silica4 ,when originally deposited the iron was partly hematite 7perhaps some magnetite7 and largely in the form of iron carbonate 7siderite7 and iron silicate 7greenalite71 interbanded with chert4 ,the original condition is indicated by the facts that deep below the surface1 in zones protected from weathering solutions1 siderite and greenalite are abundant1 and that they show complete gradation to hematite in approaching the surface4 ,the ore has been concentrated in the iron formation almost solely by the process of leaching of silica by surface or meteoric waters1 leaving the hematite in a porous mass4 ,figure #aa illustrates this change as calculated from analyses and measurements of pore space4 ,during this process a very minor amount of iron has been transported and redeposited4 ,in short1 the ,lake ,superior iron ores are residual deposits formed by exactly the same weathering processes as cause the accumulation of clays1 bauxites1 and the oxide zones of sulphide deposits4 ,the development of an iron ore rather than of other materials as an end-product is due merely to the peculiar composition of the parent rock4 ,the solution of silica on such an immense scale as is indicated by these deposits has sometimes been questioned on the general ground that silica minerals are insoluble4 ,however1 there is plenty of evidence that such minerals are soluble in nature2 and the assumption of insolubility1 so often made in geologic discussions1 is based on the fact that most other minerals are more soluble than silica minerals1 and that in the end-products of weathering silica minerals therefore usually remain as important constituents4 ,iron oxide1 on the other hand1 is less soluble even than silica1--with the result that when the two occur together1 the evidence of leaching of silica from the mixture becomes conspicuous4 ,the fact that these deposits are almost exclusively residual deposits formed by the leaching of silica has an important bearing on exploration4 ,if they have been formed by the transportation and deposition of iron from the surrounding rocks1 there is no reason why they should not occasionally be found in veins and dikes outside of the iron formation4 ,as a matter of fact they do not transgress a foot beyond the limits of the iron formation4 ,failure to recognize the true nature of the concentration of these ores has sometimes led to their erroneous classification as ores derived from the leaching and redeposition of iron from the surrounding rocks4 ,the distribution and shapes of ore deposits of this class are far more irregular and capricious than those of the primary sediments1 as would be expected from the fact that their concentration has taken place through the agency of percolating waters from the surface1 which worked along devious channels determined by a vast variety of structural and lithological conditions4 ,the working out of the structural conditions for the different mines and districts constitutes one of the principal geologic problems in exploration4 ,these conditions have been fully discussed in the ,united ,states ,geological ,survey reports1 and are so various that no attempt will be made to summarize them here4 ,one of the interesting features of the concentration of ,lake ,superior iron ores is the fact that it took place long ago in the ,keweenawan period1 preceding the deposition of the flat-lying ,cambrian formations1 at a time when the topography was mountainous and the climate was arid or semi-arid4 ,these conditions made it possible for the oxidizing and leaching solutions to penetrate very deeply1 how deeply is not yet known1 but certainly to a depth below the present surface of #b1ejj feet4 ,at present the water level is ordinarily within #ajj feet of the surface1 and oxidizing solutions are not going much below this depth4 ,this region1 therefore1 furnishes a good illustration of the intermittent and cyclic character of ore concentration which is now coming to be recognized in many ore deposits4 ,subsequent changes far beneath the surface have folded1 faulted1 and metamorphosed some of the ,lake ,superior iron ores but have not enriched them4 ,the same processes have recrystallized and locked together the minerals of some of the lean iron formations1 making them hard and resistant1 so that subsequent exposure and weathering have had little effect in enriching them to form commercial ores4 ,the weathering of limestones containing minor percentages of iron minerals originally deposited with the limestones may result in the residual concentration of bodies of limonite or brown ores associated with clays near the surface4 ,this process is similar in all essential respects to the concentration of the ,lake ,superior ores4 ,such limonitic ores are found rather widely distributed through the ,appalachian region and in many other parts of the world4 ,because of the ease with which they can be mined and smelted on a small scale they have been used since early times1 but have furnished only a very small fraction of the world's iron4 #c4 ,in a third class of sedimentary ores1 the iron minerals are supposed to have been introduced as replacements of limestones subsequent to sedimentation4 ,such ores are not always easy to discriminate from ores resulting primarily from sedimentation4 ,this class is represented by the high-grade deposits of ,bilbao1 ,spain1 ,austrian deposits1 and by smaller deposits in other countries4 ,the ,bilbao ores consist mainly of siderite1 which near the surface has altered to large bodies of oxide minerals4 ,they occur in limestones and shales and are not associated with igneous rocks4 ,the deposits are believed to have been formed by ordinary surface waters carrying iron in solution1 and depositing it in the form of iron carbonate as replacements of the limestones4 ,the original source of the iron is believed to have been small quantities of iron minerals disseminated through the ordinary country rocks of the district4 ,the action of surface waters1 in thus concentrating the iron in certain localities which are favorable for precipitation1 is similar to the formation of the lead and zinc ores of the ,mississippi valley1 referred to in the next chapter4 ,deposits formed in this manner may be roughly tabular and resemble bedded deposits1 or they may be of very irregular shapes4 ,the sedimentary iron ores in general evidently represent an advanced stage of katamorphism1 and illustrate the tendency of this phase of the metamorphic cycle toward simplification and segregation of certain materials4 ,the exact conditions of original sedimentation present one of the great unsolved problems of geology1 referred to in ,chapter ,,iii4 ,iron ores associated with igneous rocks4 ,about five per cent of the world's production of iron ore is from bodies of magnetite formed in association with igneous rocks4 ,these are dense1 highly crystalline ores1 in which the iron minerals are tightly locked up with silicates1 quartz1 and other minerals1 suggestive of high temperature origin4 ,the largest of these deposits is at ,kiruna in northern ,sweden2 in fact this is the largest single deposit of high-grade ore of any kind yet known in the world4 ,here the magnetite forms a great tabular vertical body lying between porphyry and syenite4 ,in the ,adirondack ,mountains of ,new ,york and in the highlands of ,new ,jersey1 magnetites are interbedded and infolded with gneisses1 granites1 and metamorphic limestones4 ,in the western ,united ,states there are many magnetite deposits1 not yet mined1 at contacts between igneous intrusives and sedimentary rocks1 particularly limestones 7so-called contact-metamorphic deposits74 ,the ores of the ,cornwall district of ,pennsylvania and some of the ,chilean1 ,chinese1 and ,japanese ores are of the same type4 ,magnetites containing titanium1 which prevents their use at the present time1 are known in many parts of the world as segregations in basic igneous rocks4 ,they are actually parts of the igneous rock itself 7p4 #cd74 ,among the large deposits of this nature are certain titaniferous ores of the ,adirondacks1 of ,wyoming1 and of the ,scandinavian peninsula4 ,in all of these cases1 it is clear that the origin of the ores is in some way related to igneous processes1 and presumably most of the ores are deposited from the primary hot solutions accompanying and following the intrusion of the igneous rocks2 but thus far it has been difficult to find definite and positive evidence as to the precise processes involved4 ,none of these deposits have undergone any important secondary enrichment at the surface4 ,their sizes1 shapes1 and distribution are governed by conditions of igneous intrusion1 more or less modified1 as in the ,adirondacks1 by later deformation4 ,iron ores due to weathering of igneous rocks4 ,a small part of the world's iron ores1 less than #a per cent of the total production1 are the result of surface alteration of serpentine rocks4 ,these ores are mined principally in ,cuba 7,fig4 #ab74 ,here they have been developed on a plateau-like area on which erosion is sluggish4 ,the process of formation has been one of oxidation of the iron minerals and leaching of most of the other constituents1 leaving the iron concentrated near the surface in blanket-like deposits4 ,the minerals of the original rock contained alumina1 which1 like the iron1 is insoluble under weathering conditions1 and hence the ,cuban iron ores are high in alumina4 ,they also contain small quantities of nickel and chromium which have been concentrated with the iron4 ,a large part of the iron minerals1 especially where close to the surface1 have been gathered into small shot-like nodules called pisolites4 ,it is thought that the solution and redeposition of the iron by organic acids from plant roots may be at least a contributing cause in the formation of this pisolitic texture4 ,illustration3 ,,fig4 #ab4 ,representing in terms of weight the mineralogical changes in the katamorphism of serpentine rock to iron ore1 on the assumption that alumina has remained constant1 eastern ,cuba4 ,the ,cuban iron ores are similar in their origin to laterites1 which are surface accumulations of clay1 bauxite1 and iron oxide minerals1 resulting from the weathering of iron-bearing1 commonly igneous1 rocks4 ,the typical laterites carry more clay and bauxite than the ,cuban iron ores1 but this is due merely to the fact that the original rocks commonly carry more materials which weather to clay4 ,in fact the ,cuban iron ores are themselves1 broadly speaking1 laterites4 ,iron ores due to weathering of sulphide ores4 ,a relatively minute portion of the world's iron ore comes from the gossans or iron caps over deposits of iron sulphides4 ,the gossans are formed by oxidation and leaching of other minerals from the deposits1 leaving limonite or hematite in concentrated masses 7see pp4 #df-dg74 ,,manganese ,,ores ,,economic ,,features ,manganese ores are used mainly in the manufacture of steel1 the alloys spiegeleisen and ferromanganese being added to the molten steel after treatment in the ,bessemer converter and open-hearth furnace in order to recarburize and purify the metal4 ,the alloy ferromanganese is also used in the production of special manganese steels4 ,manganese ore is used in relatively small amounts in dry batteries1 in the manufacture of manganese chemicals1 in glass making1 and in pigments4 ,steel uses #ie per cent of the total manganese consumed1 batteries and chemicals #e per cent4 ,on an average each ton of steel in the ,united ,states requires #ad pounds of metallic manganese1 equivalent to #dj pounds of manganese ore4 ,with manganese ores1 as with iron ores1 the percentage of minor constituents1--phosphorus1 silica1 sulphur1 etc41--determines to a large extent the manner of use4 ,low-grade manganese ores1 ranging from #aj to #ce per cent in manganese1 #bj to #ce per cent in iron1 and containing less than #bj per cent of silica1 are used mainly in the production of the low-grade iron-manganese alloy called spiegeleisen or spiegel 7#af to #cb per cent manganese74 ,the higher-grade ores1 ranging from #ce to #ee per cent in manganese1 are used mainly in the production of the high-grade alloy called ferromanganese or ferro1 in which the manganese constitutes #fe to #hj per cent of the total4 ,to a very limited extent manganese is smelted directly with iron ores1 thus lessening the amount to be introduced in the form of alloys2 this1 however1 is regarded as wasteful use of manganese1 since its effectiveness as so used is not very great4 ,steel makers usually prefer to introduce manganese in the form of ferromanganese rather than as spiegel4 ,on the other hand1 the ores of the ,united ,states as a whole are better adapted to the manufacture of spiegel4 ,with the shutting off of foreign high-grade supplies during the war1 resulting in the increased use of local ores1 it became necessary to use larger amounts of the spiegel which could be made from these ores4 ,metallurgists stated that it was theoretically possible to substitute spiegel for the higher grade alloy up to #gj per cent of the total manganese requirement1 but in actual practice this substitution did not get much beyond #ah per cent4 ,the principal manganese ore-producing countries in normal times are ,russia1 ,india1 and ,brazil4 ,relatively little ore is used in these countries1 most of it being sent to the consuming countries of ,europe and to the ,united ,states4 ,the ,indian ore has been used largely by ,british steel plants1 but much of it also has gone to the ,united ,states1 ,belgium1 ,france1 and ,germany4 ,the ,russian ore has been used by all five of these countries1 ,germany having a considerable degree of commercial control and receiving the largest part2 a small quantity is also used in ,russia4 ,brazilian ore has gone mainly to the ,united ,states1 and in part to ,france1 ,germany1 and ,england4 ,smaller amounts of manganese ore have been produced in ,germany1 ,austria-,hungary1 ,spain1 and ,japan4 ,this production has had little effect on the world situation4 ,that produced in ,austria-,hungary and ,germany is used in the domestic industry4 ,that from ,spain and ,japan is in large part exported4 ,the highest grade of manganese ore comes from the ,russian mines1 especially those in the ,caucasus region4 ,most of the ore used for the manufacture of dry batteries and in the chemical industry1 where high-grade ores are required1 has come from ,russia4 ,by far the larger part of the ,russian production1 however1 has gone into steel manufacture4 ,indian and ,brazilian ores have likewise been used mainly in the steel industry4 ,some ,japanese ore also is of high grade and is used for chemical and battery purposes4 ,nature has not endowed the ,united ,states very abundantly with manganese ores1 and such as are known are widely scattered1 of relatively small tonnage1 and of a wide range of grade4 ,the principal producing districts are the ,philipsburg district of ,montana and the ,cuyuna ,range of ,minnesota2 there are also scattering supplies in ,virginia1 ,arizona1 ,california1 and many other states4 ,the use of domestic ores has sometimes been unsatisfactory1 because of frequent failure of domestic producers to deliver amounts and grades contracted for4 ,it has been1 on the whole1 cheaper1 easier1 and more satisfactory for the large consumers to purchase the imported ore1 which is delivered in any desired amount and in uniform grades1 rather than to try to assemble usable mixtures from various parts of the country4 ,before the ,european ,war1 the ,united ,states produced only #a to #b per cent of its needed supply of manganese1 the rest being imported mainly from ,india1 ,russia1 and ,brazil1 in the form of ore1 and from ,england in the form of ferromanganese 7about half of the total requirement74 ,the partial closing of the first two and the fourth of these sources of supply under war conditions made it necessary to turn for ore to ,brazil and also to ,cuba1 where ,american interests developed a considerable industry in medium-grade ores4 ,at the same time steps were taken to develop domestic resources2 and with the high prices imposed by war conditions1 the domestic production1 both of high- and low-grade ore1 was increased largely1 but still was able to supply only #ce per cent of the total requirements of manganese4 ,at the close of the war sufficient progress had been made--in the discovery of many new deposits in the ,united ,states1 in the use of low-grade domestic ores1 which before had not been able to compete with imported ores1 and in the increased use of spiegel1 allowing wider use of low-grade ores1--to demonstrate that1 if absolutely necessary1 and at high cost1 the ,united ,states in another year or two could have been nearly self-sufficing in regard to its manganese requirements4 ,the release of shipping from war demands resulted immediately in larger offerings of foreign manganese ore and of ferromanganese from ,england1 at prices which would not allow of competition from much of the domestic or ,cuban ore production or from the domestic manufacture of alloys4 ,the result was a rather dramatic closing down of the manganese industry1 with much financial loss1 the passage of a bill for reimbursement of producers1 and a demand on the part of the producers1 though not of consumers1 for a protective tariff4 ,in the questions thus raised it is desirable that geologists and engineers professionally connected with the industry thoroughly understand the basic facts2 for they are liable to be called upon for advice1 not only on questions relating to domestic supplies affected by possible future foreign policies1 but on the formulation of the policies themselves4 ,conservation1 cheaper steel1 and future trade relations of the ,united ,states all require consideration1 before action is taken to protect this one of several similarly situated mineral industries1 in the effort to make the country self-supporting4 ,these questions are further dealt with in ,chapters ,,xvii and ,,xviii4 ,manganese production was also developed during the war in the ,gold ,coast of ,west ,africa1 in ,costa ,rica1 in ,panama1 in ,java1 and elsewhere2 but with the possible exception of ,java and ,chile1 none of these sources are likely to be factors in the world situation4 ,the war-developed manganese production of ,italy1 ,france1 ,sweden1 and ,united ,kingdom is also unlikely to continue on any important scale4 ,,geologic ,,features ,like iron ores1 manganese ores consist principally of the oxides of manganese 7pyrolusite1 psilomelane1 manganite1 wad1 and others71 and rarely the carbonate of manganese 7rhodochrosite74 ,they are similar in their geologic occurrence to many of the iron ores and are often mixed with iron ores as manganiferous iron ores and ferruginous manganese ores4 ,the higher grade manganese ores are of two general types4 ,those of the ,caucasus district in ,russia are sedimentary beds1 oolitic in texture1 which were originally deposited as rather pure manganese oxides1 and which have undergone little secondary concentration4 ,they are mined in many places in much the same manner as coal4 ,those of ,india and ,brazil are chiefly surface concentrations of the manganese oxides1 formed by the weathering of underlying rocks which contain manganese carbonates and silicates4 ,the origin of the primary manganese minerals in the ,indian and in some of the ,brazilian deposits is obscure4 ,in others of the ,brazilian ores1 the manganese was deposited in sedimentary layers interbedded with siliceous iron formations1 and the whole series has subsequently been altered and recrystallized4 ,the manganese ores of ,philipsburg1 ,montana1 the principal large high-grade deposits mined in the ,united ,states1 were derived by surface weathering from manganese carbonates which form replacements in limestone near the contact with a great batholith of granodiorite4 ,the primary manganese minerals probably owe their origin to hot magmatic solutions1 as suggested by the close association of the ores with the igneous rock1 the presence of minerals containing chlorine1 fluorine1 and boron1 and the development in the limestone of dense silicates and mineral associations characteristic of hot-water alteration4 ,the manganese ores are mined principally in the oxidized zone4 ,rich silver ores are found below the water table1 but mainly in veins independent of the manganese deposits4 ,at ,butte1 ,montana1 a little high-grade manganese material has been obtained from the unoxidized pink manganese carbonate1 which is a common mineral in some of the veins4 ,it is associated with quartz and metallic sulphides and is similar in origin to the copper ores of the same district 7pp4 #bja-bjb74 ,the lower-grade and the more ferruginous manganese ores are of a somewhat similar origin to the principal high-grade ores1 in that they represent surface concentrations of the oxides from smaller percentages of the carbonates and silicates in the rocks below4 ,deposits of this nature have been derived from a wide variety of parent rocks--from contact zones around igneous intrusions1 from fissure veins of various origins1 from calcareous and clayey sediments1 and from slates and schists4 ,the manganese and manganiferous iron ores of the ,cuyuna district of ,minnesota1 the largest source of low-grade ores in this country1 were formed by the action of weathering processes on sedimentary beds of manganese and iron carbonates constituting iron formations4 ,the process is the same as the concentration of ,lake ,superior iron ores described elsewhere4 ,manganese1 like iron1 is less soluble than most of the rock constituents1 and tends to remain in the outcrop under weathering conditions4 ,to some extent also it is dissolved and reprecipitated1 and is thus gathered into concretions and irregular nodular deposits in the residual clays4 ,in some cases it is closely associated with iron minerals2 in others1 due to its slightly greater solubility1 it has been separated from the iron and segregated into relatively pure masses4 ,with manganese1 as with iron1 katamorphic processes are responsible for the concentration of most of the ores4 ,the ores are in general surface products1 and rarely extend to depths of over a hundred feet4 ,,chrome 7,,or ,,chromite7 ,,ores ,,economic ,,features ,the principal use of chrome ores is in the making of the alloy ferrochrome 7#fj to #gj per cent chromium71 used for the manufacture of chrome1 chrome-nickel1 and other steels4 ,these steels have great toughness and hardness1 and are used for armor-plate1 projectiles1 high-speed cutting tools1 automobile frames1 safe-deposit vaults1 and other purposes4 ,chrome ore is used also both in the crude form and in the form of bricks for refractory linings in furnaces1 chiefly open-hearth steel furnaces2 and as the raw material for bichromates and other chemicals1 which are used in paints and in tanning of leather4 ,in the ,united ,states in normal times about #ce per cent of the total chromite consumed is used in the manufacture of ferrochrome1 and about #ce per cent for bichromate manufacture1 leaving #cj per cent for refractory and other purposes4 ,in the higher commercial grades of chrome ore the percentage of chromic oxide is #de to #ee per cent1 but under war conditions ore as low as #cj per cent in ,cr#b,o#c was mined4 ,recovery of chrome from slags resulting from the smelting of chromiferous iron ores was one of the war-time developments4 ,the principal chromite-producing countries in normal times are ,new ,caledonia1 and ,rhodesia 7controlled by ,french and ,british interests71 and to a somewhat lesser extent ,russia and ,turkey 7,asia ,minor74 ,small amounts of chromite are mined in ,greece1 ,india1 ,japan1 and other countries4 ,the ,indian deposits in particular are large and high-grade but have been handicapped by inadequate transportation4 ,the production of chrome ore in ,new ,caledonia1 ,rhodesia1 ,russia1 and ,turkey has usually amounted to more than #ij per cent of the total world's production4 ,the ore from ,new ,caledonia has been used by ,france1 ,germany1 ,england1 and to some extent by the ,united ,states4 ,rhodesian ore has been used by the ,united ,states and the principal ,european consumers4 ,latterly more ,rhodesian ore has gone to ,europe and more ,caledonian ore to the ,united ,states4 ,the ,russian ore has been in part used in ,russia and in part exported1 probably going mainly to ,france and ,germany4 ,the ,turkish ore has been exported to the ,united ,states1 ,england1 and ,germany2 it probably supplied most of ,germany's chromite requirements during the war4 ,during the war the ,united ,states was temporarily an important producer1 as were also ,canada1 ,brazil1 ,cuba1 and to a minor degree ,guatemala4 ,the richest chrome ore mined at present comes from ,guatemala1 but the mines are relatively inaccessible4 ,the ,new ,caledonian1 ,rhodesian1 ,russian1 ,turkish1 and ,indian ores are also of high grade4 ,the ores mined in the ,united ,states1 ,canada1 ,brazil1 ,cuba1 ,greece1 and ,japan are of lower grade4 ,the use of domestic chromite supplies in the ,united ,states presents much the same problem as does manganese4 ,the ore bodies are small1 scattered1 and of a generally law grade4 ,war-time experience showed that they could be made to meet a large part of the ,united ,states requirements1 but at high cost and at the risk of early exhaustion of reserves4 ,california and ,oregon are the principal sources1 and incidental amounts have been produced in ,washington1 ,wyoming1 and some of the ,atlantic states4 ,with the resumption of competition from foreign high-grade ores at the close of the war1 the domestic mining industry was practically wiped out2 the consequences being financial distress1 partial direct relief from ,congress1 and consideration of the possibilities of a protective tariff1--which in this case would have to be a large one to accomplish the desired results 7see ,chapters ,,xvii and ,,xviii74 ,,geologic ,,features ,the principal chrome mineral is chromite1 an oxide of chromium and iron4 ,chromite is a common minor constituent of basic igneous rocks of the peridotite and pyroxenite type4 ,in these rocks it occurs both as disseminated grains1 and as stringers1 and large irregular masses which probably represent magmatic segregations4 ,alteration1 and weathering of the parent rock1 forming first serpentine and then residual clays1 make the chromite bodies progressively richer and more available1 by leaching out the soluble constituents of the rock leaving the chromite as residual concentrates4 ,all the important chromite deposits of the world are associated in somewhat this manner with serpentine or related rocks4 ,they are formed in the same way as the lateritic iron ores of ,cuba1 and from the same sort of rocks 7pp4 #aga-agc74 ,chromite is very insoluble1 and the mechanical breaking down of deposits and transportation by streams frequently forms placers of chrome sands and gravels4 ,such placers have not been worked to any extent4 ,katamorphic processes give the important values to chromite deposits4 ,,nickel ,,ores ,,economic ,,features ,the principal use of nickel is in the manufacture of nickel steel1 the most important of all alloy steels4 ,ordinary nickel steels carry about #c-a_/b per cent nickel4 ,nickel is used in all gun and armor-plate steels1 and in practically all other good steels except tool steels4 ,it is also extensively alloyed with other metals1 particularly with copper to form the strong non-corrosive metal 7monel metal7 used for ship propellers and like purposes4 ,nickel is also used for electroplating1 for nickel coins1 for chemicals1 etc4 ,of the total production about #fj per cent is used in steels1 #bj per cent in non-ferrous alloys and #bj per cent in miscellaneous uses4 ,the ores mined range from #b to #f per cent in metallic nickel4 ,canada 7,sudbury1 ,ontario7 produces over three-fourths of the world's nickel and is likely to have an even greater share of the future production4 ,the ,french supply from ,new ,caledonia is second in importance1 and minor amounts are produced in ,norway and in several other countries4 ,the control and movement of the ,canadian and ,new ,caledonian supplies are the salient features of the world nickel situation4 ,nickel leaves the producing countries mostly as matte4 ,canadian matte has been refined mainly in the ,united ,states1 but the tendency is toward refining a larger proportion in ,canada4 ,in ,europe there are refineries in ,france1 ,england1 ,belgium1 ,germany1 and ,norway1 which normally treat the bulk of the ,new ,caledonian and some of the ,canadian production4 ,small quantities of ,new ,caledonian matte or ore are also refined in ,japan1 and during the war considerable amounts came to the ,united ,states4 ,the ,united ,states now produces perhaps #aj per cent of its normal requirements of nickel from domestic sources1 principally as a by-product of copper refining4 ,however1 the ,united ,states has a large financial interest in the ,canadian deposits1 and refines most of the matte produced from ,sudbury ores in a ,new ,jersey refinery4 ,shipments to ,europe of ,canadian nickel refined in the ,united ,states have been a feature of the world's trade in the past4 ,the nickel-bearing iron ores of ,cuba1 consumed in the ,united ,states1 constitute a potential nickel supply of some importance1 if processes of preparation become commercially perfected4 ,known supplies of nickel in ,canada and ,new ,caledonia are ample for a considerable future1 and geologic conditions promise additional discoveries at least in the former field4 ,the probable reserves of the ,sudbury district have been estimated to be fully #ajj1jjj1jjj tons1 which would supply the world's normal pre-war requirements for about a hundred years4 ,in recent years the ,british and ,canadian governments have taken an active interest in the nickel industry4 ,they organized a joint commission for its investigation1 the report#ca of which furnishes the most comprehensive view of the world nickel situation yet available4 ,the ,british government has directly invested in shares of the ,british-,american ,nickel ,company1 and has negotiated ,european contracts for sale of nickel for this company4 ,the ,canadian government has exerted some pressure toward larger refining of nickel matte in ,canada4 ,,geologic ,,features ,the principal ore minerals are the nickel sulphides and arsenides 7particularly pentlandite1 but also millerite1 niccolite1 and others71 which are found at ,sudbury intergrown with the iron and copper sulphides1 pyrrhotite and chalcopyrite2 and the hydrated nickel-magnesium silicates 7garnierite and genthite71 which are products of weathering4 ,the richer ores of ,canada contain about #e or #f per cent of nickel1 the ,new ,caledonian ores less than #b per cent4 ,the ,sudbury ores carry also an average of about #a4e per cent of copper4 ,nickel1 while present in the average igneous rock in greater amounts than copper1 lead1 or zinc1 is apparently not so readily concentrated in nature as the other metals and is rarely found in workable deposits4 ,the few ore bodies known have been formed as the result of unusual segregation of the nickel in highly magnesian igneous rock of the norite or gabbro type1 at the time of its solidification or soon after2 and in some cases1 in order to produce the nickel ore1 still further concentration by the agency of weathering has been necessary4 ,thus there are two main types of deposits4 ,the first1 the sulphide type1 is represented by the great ore bodies of the ,sudbury district4 ,these are situated in the basal portions of a great norite intrusive1 and are ascribed to segregation of the sulphides as the rock solidified4 ,to some extent the segregation was aided by mineralizing solutions following the crystallization of the magma1 but in general there is little evidence that the ores were deposited from vagrant solutions of this kind 7see pp4 #cd-ce74 ,these ores owe their value to primary concentration2 secondary transportation and reprecipitation by surface waters has not been important4 ,a small amount of the green arsenate1 annabergite or nickel bloom1 has been developed by oxidation at the surface4 ,the second1 the garnierite or lateritic type of nickel ores1 is somewhat more common and is represented by the deposits of ,new ,caledonia4 ,in this locality the original rock is a peridotite1 relatively low in nickel1 which has been altered to serpentine4 ,weathering has concentrated the more resistant nickel at the expense of the more soluble minerals1 and has produced extensive blanket deposits of clay1 which in their lower portions contain nickel in profitable amounts4 ,similar processes1 working on material of a somewhat different original composition1 have produced the nickel-bearing and chrome-bearing iron ores of ,cuba 7pp4 #aga-agc74 ,,tungsten 7,,wolfram7 ,,ores ,,economic ,,features ,the principal use of tungsten is in the making of high speed tool steels4 ,it is added either as the powdered metal or in the form of ferrotungsten1 an alloy containing #gj to #ij per cent of tungsten4 ,tungsten is also used for filaments in incandescent lamps1 and in contacts for internal combustion engines1 being a substitute for platinum in the latter use4 ,of late years tungsten alloys have also been used in valves of airplane and automobile engines4 ,the average grade of tungsten ores mined in the ,united ,states is less than #c per cent of the metal2 before smelting they are concentrated to an average grade of #fj per cent tungsten oxide4 ,germany through its smelting interests controlled the foreign tungsten situation prior to the war2 two-thirds of its excess output of ferrotungsten was consumed by ,england and the balance principally by the ,united ,states and ,france4 ,other consumers in the main satisfied their requirements by imports of tool steel from these four countries4 ,the bulk of the tungsten ore consumed in ,europe prior to #aiad came from ,british possessions2 these were principally the ,federated ,malay ,states1 ,burma1 ,australia1 and ,new ,zealand4 ,the ,united ,states1 ,portugal1 ,bolivia1 ,japan1 ,siam1 ,argentina1 and ,peru were also producers4 ,the great demand for tungsten created by the war added ,china to the list of important producers and greatly increased the production from ,burma and ,bolivia4 ,smelting works were established in ,england and those of the ,united ,states and ,france were greatly enlarged4 ,england is at present in a position to dominate the world tungsten situation4 ,the question of control of the ores obtainable in ,china1 ,korea1 ,siam1 ,portugal1 and western ,south ,america is likely to be an important one for the future4 ,of the annual pre-war world production1 the ,united ,states used about one-fifth4 ,three-fourths of this requirement was met by domestic production4 ,the balance was obtained by importation1 chiefly from ,germany1 from ,portugal and ,spain1 and from ,england1 both of concentrates and of ferrotungsten4 ,to the considerable demand for high speed tool steels occasioned by munitions manufacture1 production in the ,united ,states responded quickly4 ,supplies of tungsten came chiefly from ,california1 ,colorado1 ,arizona1 ,nevada1 and ,south ,dakota4 ,at the same time importation largely increased1 chiefly from the west coast of ,south ,america and the ,orient4 ,consumption reached a half of the world's total4 ,considerable amounts of ferrotungsten were exported to the ,allies4 ,the end of the war created a possible tungsten shortage in this country into a tungsten surplus4 ,in so far as actual domestic consumption is concerned there has been a return to something like pre-war conditions1 as the only known new use to which tungsten may be put--the manufacture of die steel--does not involve the use of any large amount of ferrotungsten4 ,the richer mines of the two chief tungsten-producing districts in the ,united ,states have shown impoverishment and at present no important new deposits are known4 ,the grade of the producing deposits is on an average low4 ,the domestic production of tungsten ore will doubtless decrease1 owing to the importation of cheaper foreign ores1 unless a high tariff wall is erected4 ,importation from the ,orient and the west coast of ,south ,america should continue in reduced amounts1 depending upon the ability of domestic manufacturers to obtain and hold foreign markets for ferrotungsten and high speed tool steel4 ,in the commercial control of tungsten ores the ,united ,states has at present a strong position1 second only to that of ,england4 ,,geologic ,,features ,tungsten ores contain tungsten principally in the form of the minerals scheelite 7calcium tungstate71 ferberite 7iron tungstate71 huebnerite 7manganese tungstate71 and wolframite 7iron-manganese tungstate74 ,all these minerals are relatively insoluble and have high specific gravity1 and as a consequence they are frequently accumulated in placers1 along with cassiterite and other stable1 heavy minerals4 ,a large part of the world's tungsten production in the past has been won from such deposits4 ,placers are still important producers in ,china1 ,siam1 and ,bolivia1 although in these countries vein deposits are also worked4 ,with the exhaustion of the more easily worked placer deposits1 increasing amounts of tungsten are being obtained from the primary or fixed deposits4 ,these are found almost exclusively in association with granitic rocks1 and have a variety of forms4 ,the most productive deposits are in the form of veins1 cutting the granites and the surrounding rocks into which the granites were intruded1 and containing quartz1 metallic sulphides1 and in some cases minerals of tin1 gold1 and silver4 ,the deposits of the two most important districts in the ,united ,states1 in ,boulder ,county1 ,colorado1 and at ,atolia1 ,california1 are of this general nature4 ,the close association of such deposits with plutonic igneous rocks1 and the characteristic mineral associations 7see pp4 #cg-da7 suggest strongly that the deposits were formed by hot solutions deriving their material from a magmatic source4 ,other tungsten deposits1 which only recently became of importance1 are of the contact-metamorphic type--in limestones which have been invaded by hot aqueous and gaseous solutions near the borders of granitic intrusions4 ,in these occurrences the tungsten mineral is almost invariably scheelite1 and is associated with calcite1 garnet1 pyroxene1 and other silicates4 ,a magmatic origin of the tungsten is probable4 ,some of the deposits of the ,great ,basin area and of ,japan are of this nature1 and it is believed that important deposits of this type may be discovered in many other countries4 ,tungsten is likewise found in original segregations in igneous rocks and in pegmatite dikes1 but these deposits are of comparatively small commercial importance4 ,in some tungsten deposits a hydrated oxide called tungstite has been formed as a canary-yellow coating at the surface4 ,on the whole1 however1 tungsten minerals are very resistant to weathering1 and in all their deposits secondary concentration by chemical action at the surface has not played any appreciable part4 ,the disappearance of tungsten minerals from alluvial materials which are undergoing laterization1 which has been described in ,burma1#cb seems to indicate that the tungsten is dissolved in surface waters to some extent2 but in the main it is probably carried completely out of the vicinity and not reprecipitated below4 ,,molybdenum ,,ores ,,economic ,,features ,the main use of molybdenum is in the manufacture of high-speed tool steels1 in which it has been used as a partial or complete substitute for tungsten4 ,its steel-hardening qualities are more effective than those of tungsten1 but it is more difficult to control metallurgically4 ,it has been used in piston rods and crank shafts for ,american airplanes4 ,its use in tool steel is mainly confined to ,europe1 where its metallurgical application is in a more advanced stage than in the ,united ,states4 ,molybdenum is added to steel either as powdered molybdenum or in the form of ferromolybdenum1 an alloy containing #fj to #gj per cent of the metal4 ,molybdenum chemicals are essential reagents in iron and steel analysis and other analytical work2 they are also used as pigments4 ,molybdenum metal has been used to a small extent in incandescent lamps and as a substitute for platinum in electric contacts and resistances4 ,molybdenum ores range from considerably less than #a per cent to about #e per cent in molybdenum4 ,the world's principal sources of molybdenum ores in approximate order of importance are the ,united ,states1 ,canada1 ,norway1 ,australia1 ,korea1 ,austria1 ,peru1 and ,mexico4 ,about half of the world's supply is produced in the ,united ,states4 ,production of molybdenum in this country practically began in #aiad4 ,most of the production has come from ,colorado and ,arizona4 ,it is believed that the ,united ,states contains reserves more than sufficient to meet any possible future demand4 ,thus far the demand has not kept up with capacity for production4 ,the principal consuming countries are ,england1 ,france1 and ,germany4 ,,geologic ,,features ,the chief ore minerals are molybdenite 7molybdenum sulphide7 and wulfenite 7lead molybdate74 ,the larger part of the world's production is from the molybdenite ores4 ,molybdenite occurs principally in association with granitic rocks1--in pegmatite dikes1 in veins1 and in contact-metamorphic deposits1--in all of which associations its origin is traced to hot solutions from the magma4 ,it is frequently present as an accessory mineral in sulphide deposits containing ores of gold1 copper1 silver1 lead1 and zinc4 ,at ,empire1 ,colorado1 one of the principal producing localities1 it is found in veins1 associated with pyrite1 and filling the interstices between brecciated fragments of a wall rock composed of alaskite 7an acid igneous rock74 ,in molybdenite deposits secondary concentration has not been important4 ,wulfenite is rather common in the upper oxidized zone of deposits which contain lead minerals and molybdenite4 ,it is probably always secondary4 ,deposits of wulfenite have been worked on a small scale in ,arizona4 ,,vanadium ,,ores ,,economic ,,features ,vanadium is used mainly in steel1 to which it gives great toughness and torsional strength4 ,vanadium steels are used in locomotive tires1 frames1 and springs1 in those parts of automobiles that must withstand special bending strains1 in transmission shafts1 and in general in forgings which must stand heavy wear and tear4 ,vanadium is also used in high-speed tool steels1 its use materially reducing the amount of tungsten necessary4 ,it is added in the form of ferrovanadium1 carrying #ce to #dj per cent of vanadium4 ,another use of vanadium is in chrome-vanadium steels for armor-plate and automobiles4 ,minor amounts are used in making bronzes1 in medicine1 and in dyeing4 ,the low-grade ores of the ,united ,states range from #a to #h per cent of vanadium oxide1 the general mean being nearer the lower figure4 ,the high-grade ores of ,peru contain from about #aj to as high as #ej per cent of the oxide2 the roasted ore as shipped averages about #ce to #dj per cent4 ,two-thirds of the world's supply of vanadium comes from ,peru1 where the mines are under ,american control4 ,the concentrates are all shipped to the ,united ,states and some of the ferrovanadium is exported from this country to ,europe4 ,the ,germans during the war supplied their needs for vanadium from the minette iron ores in the ,briey district in ,france1 and presumably the ,french will in the future utilize this source4 ,an unrecorded but small quantity is obtained by the ,english from lead-vanadate mines in ,south ,africa4 ,there are some fairly large deposits of vanadium minerals in ,asiatic ,russia1 which may ultimately become an important source4 ,the ,united ,states supplies less than one-half of its normal needs of vanadium1 from southwestern ,colorado and southeastern ,utah4 ,the grade of these deposits is low and the quantity in sight does not seem to promise a long future4 ,through its commercial control of the ,peruvian deposits1 the ,united ,states dominates the world's vanadium situation4 ,,geologic ,,features ,the ,minasragra vanadium deposit of ,peru contains patronite 7vanadium sulphide7 associated with a peculiar nickel-bearing sulphide and a black carbonaceous mineral called quisqueite1 in a lens-shaped body of unknown depth1 enclosed by red shales and porphyry dikes4 ,the origin is unknown4 ,the patronite has altered at the surface to red and brown hydrated vanadium oxides4 ,the deposits of ,colorado and ,utah are large lens-shaped bodies containing roscoelite 7a vanadium-bearing mica7 in fissures and brecciated zones and replacing the cementing materials of flat-lying sandstones4 ,locally the sandstones contain as much as #bj per cent of the roscoelite4 ,the deposits contain small amounts of fossil wood which may have been an agent in the precipitation of the vanadium4 ,there is considerable doubt as to their origin1 but it is generally supposed that they represent concentrations by surface waters of minute quantities of material originally scattered through the surrounding sediments2 it has also been suggested that certain igneous dikes in this region may have had some connection with the mineralization4 ,deposits of carnotite1 a potassium-uranium vanadate1 which have been worked for their content of uranium and radium and from which vanadium has been obtained as a by-product1 are found as impregnations of the sandstone in these same localities 7p4 #bfe74 ,there are other deposits containing small amounts of vanadium which are not at present available as ores4 ,vanadinite1 a lead-vanadate1 and descloizite1 a vanadate of copper or lead1 are found in the oxide zones of a number of lead and copper deposits in the southwestern ,united ,states and ,mexico4 ,titaniferous iron ores1 extensive deposits of which are known in many places1 usually contain a small percentage of vanadium4 ,outside of the ,peruvian deposit1 the affiliations of which are doubtful1 the vanadium deposits of economic importance owe their positions and values mainly to the action of surface processes1 rather than to igneous activity4 ,,zirconium ,,ores ,,economic ,,features ,the oxides of zirconium have high refractory properties which make them useful for refractory bricks and shapes for furnace linings1 for chemical ware1 and for other heat1 acid1 and alkali resisting articles4 ,for these purposes they find a limited market4 ,experimental work seems to show possibilities of a very considerable use of zirconium as a steel alloy2 indeed1 results are so suggestive that during the war the government conducted an active campaign of investigation with a view to using it in ordnance and armor steel4 ,for such purposes the alloy ferrozirconium is used1 which carries #be to #ce per cent zirconium metal4 ,the principal known deposits of zirconium ores1 in order of commercial importance1 are in ,brazil1 in ,india1 and in the ,united ,states 7,pablo ,beach1 ,florida74 ,the ,brazilian and ,indian deposits are also the principal sources of monazite 7pp4 #bhh-bhi74 ,the ,united ,states controls one of the important ,brazilian deposits4 ,germany before the war controlled the ,indian deposits1 and is reported to have taken much interest in the development of zirconium steels4 ,during the war ,german influence in ,india was effectively broken up4 ,the use of zirconium has been in an experimental state1 and known sources of supply have been ample for all requirements4 ,,geologic ,,features ,the zirconium silicate1 zircon1 is a fairly common accessory constituent of granitic rocks and pegmatite veins4 ,from these rocks it is separated by weathering1 disintegration1 and stream transportation1 and1 having a high specific gravity1 it becomes concentrated in placers4 ,the deposits of southern ,india1 of the coast of ,brazil1 and of ,pablo ,beach1 ,florida1 all contain zircon along with ilmenite1 garnet1 rutile1 monazite1 and other insoluble1 heavy minerals1 in the sands of the ocean beaches4 ,smaller deposits of zircon-bearing sands exist in rivers and beaches in other parts of the ,united ,states and in other countries1 but none of these deposits has thus far proved to be of commercial importance4 ,the largest and most important zirconium deposits are on a mountainous plateau in eastern ,brazil and are of a unique type1 entirely different from those just described4 ,they contain the natural zirconium oxide1 baddeleyite or brazilite1 mixed with the silicate1 the ore as produced carrying about #hj per cent zirconia 7,zr,o#b74 ,the ores consist both of alluvial pebbles and of extensive deposits in place4 ,the latter are associated with phonolite 7igneous7 rocks1 and seem to owe their origin to the agency of hot mineralizing solutions from the igneous rocks4 ,,titanium ,,ores ,,economic ,,features ,titanium is sometimes used in steel manufacture to take out occluded gases and thus to increase the strength and wearing qualities4 ,its effect is to cure certain evils in the hardening of the molten steel1 and it is not ordinarily added in amounts sufficient to form a definite steel alloy4 ,aluminum is frequently used in place of titanium4 ,titanium is added in the form of ferrotitanium1 containing either about #ae per cent titanium and #f to #h per cent carbon1 or about #be per cent titanium and no carbon4 ,titanium compounds are also used in pigments1 as electrodes for arc-lights1 and by the army and navy for making smoke-clouds4 ,the ,united ,states has domestic supplies of titanium sufficient for all requirements4 ,production has come chiefly from ,virginia4 ,additional quantities have been imported from ,canada and ,norway4 ,the recently developed deposits of ,pablo ,beach1 ,florida1 may produce important amounts of titanium minerals along with the output of zircon and monazite4 ,,geologic ,,features ,the principal titanium minerals are rutile 7titanium oxide7 and ilmenite 7iron titanate74 ,these minerals are formed mainly under high temperatures1 either during the original solidification of igneous rocks1 or as constituents of the pegmatites which follow the crystallization of the main igneous masses4 ,the ,virginia production comes from pegmatite dikes cutting through gabbros1 syenites1 and gneisses4 ,the deposits contain rutile in amounts as high as #cj per cent of the mass1 but averaging #d or #e per cent1 in addition to varying amounts of ilmenite4 ,titaniferous magnetites1 formed in many basic igneous rocks by the segregation of certain iron-bearing materials into irregular masses1 contain large quantities of ilmenite which are not commercially available under present metallurgical processes4 ,rutile and ilmenite both have high specific gravity and are little affected by weathering4 ,consequently they are not decomposed at the surface1 but when carried away and subjected to the sorting action of streams and waves1 they form placer deposits4 ,both of these minerals are recovered from the sands at ,pablo ,beach1 ,florida4 ,,magnesite ,,economic ,,features ,the most important use of magnesite is as a refractory material for lining furnaces and converters4 ,it is also used in the manufacture of ,sorel cement for stucco and flooring1 in making paper1 in fire-resisting paint1 in heat insulation1 and as a source for carbon dioxide4 ,small amounts are used in ,epsom salts and other chemicals4 ,as taken from the ground the ore consists principally of the mineral magnesite or magnesium carbonate1 with minor impurities 7#a to #ab per cent7 of lime1 iron1 silica1 and alumina4 ,in making magnesite bricks1 it is calcined or dead-burned to drive out the carbon dioxide4 ,austria-,hungary and ,greece are the large ,european producers of magnesite and ,scotland supplies a little4 ,most of the ,european production is consumed in ,england and the ,central ,european countries1 but part has been sent to ,america4 ,outside the ,united ,states there are ,american supplies in ,canada1 and recent developments in ,venezuela and ,mexico 7,lower ,california74 ,magnesite is produced in considerable quantities in the ,united ,states1 in ,california and ,washington4 ,some material is imported from ,canada1 and a small amount comes from ,scotland as return cargo for ballast purposes4 ,before the war only about #e per cent of the ,united ,states requirements of magnesite were met by domestic production4 ,the country was practically dependent on imports from various ,european countries2 chiefly from ,austria-,hungary and ,greece ,the ,austrian magnesite 7controlled in large part by ,american capital7 was considered especially desirable for lining open-hearth steel furnaces1 because of the presence of a small percentage of iron which made the material slightly more fusible than the pure mineral4 ,when the shipments from this source were discontinued during the war and prices rose to a high figure1 experiments were made with ,american magnesite1 and the deposits on the ,pacific ,coast were developed on a large scale4 ,a process of treatment was perfected by which the ,washington magnesite was made as desirable for lining furnaces as the ,austrian material4 ,at the same time large amounts were imported from ,canada and ,venezuela and lesser amounts from ,lower ,california4 ,under the high prices which prevailed during the war1 dolomite was to some extent substituted for magnesite4 ,dolomite1 which may be thought of as a magnesite rock high in lime1 occurs in large quantities close to many points of consumption4 ,it is cheaper but less satisfactory than magnesite1 and is not likely to be used on any large scale4 ,while the ,united ,states has undoubtedly sufficient reserves of magnesite to supply the domestic demands for many years1 the mines are far from the centers of consumption and it is expensive to transport the material4 ,since the war1 magnesite shipped from ,canada and overseas has again replaced the ,american product in the eastern market to some extent4 ,the ,canadian magnesite is of lower grade than the domestic and ,european magnesite and is consequently less desirable4 ,deposits in ,venezuela are also expected to furnish some material for the eastern furnaces1 in competition with those of ,austria and ,greece4 ,austrian magnesite1 however1 will be likely to dominate the market in the future if delivered at anything like pre-war prices4 ,this situation has led to agitation for a protective tariff on magnesite4 ,,geologic ,,features ,magnesite1 as noted above1 is the name of a mineral1 the composition of which is magnesium carbonate4 ,the principal magnesite deposits are of two types1 of different modes of origin and of somewhat different physical characteristics4 ,the large magnesite deposits of ,austria and of ,washington1 as well as those of ,quebec1 occur as lenses in beds of dolomite 7calcium-magnesium carbonate74 ,they are in fairly close proximity to igneous rocks1 and magnesia-bearing solutions issuing from these rocks are believed to have dissolved out the calcium carbonate of the dolomite and replaced it with magnesium carbonate4 ,in these deposits the material is coarsely crystalline and forms fairly large1 continuous bodies1 which are worked by quarrying4 ,the ,washington deposits closely resemble marble1 and had sometimes been mistaken for that rock until war-time needs resulted in their more thorough investigation4 ,the commoner type of magnesite deposits is represented by those of ,greece1 ,california1 ,venezuela1 and many other countries4 ,these consist of veins and replacements in serpentine4 ,the original rock was a highly magnesian igneous rock of the peridotite type1 which is very unstable under weathering conditions1 and rapidly alters to serpentine4 ,magnesite is formed both by this process and by the further breaking down of the serpentine itself4 ,the processes are those of katamorphism4 ,under these circumstances the magnesite is characteristically fine-grained or massive1 and occurs in veins1 lenses1 and irregular bodies in cavities and fractured zones4 ,it is usually worked by open cuts4 ,magnesite is also reported to occur in sedimentary beds in which it was primarily deposited in its present form and has not undergone later alteration4 ,such deposits are not important commercially4 ,,fluorspar ,,economic ,,features ,the chief use of fluorspar is as a flux in the manufacture of open-hearth steel4 ,minor uses are in chemical and enameling industries1 in the smelting of copper1 lead1 and iron1 and in the manufacture of the ferro-alloys in the electric furnace4 ,in order to be used in steel-making1 the fluorspar after being concentrated should contain at least #he per cent calcium fluoride and less than #d per cent silica4 ,chemical and enameling industries require material with #ie to #ih per cent calcium fluoride and less than #a per cent silica4 ,the chief foreign producer of fluorspar is ,great ,britain1 and much of this product comes to the ,united ,states4 ,canada produces a small amount1 some of which also comes to the ,united ,states4 ,several thousand tons are produced yearly in ,germany and ,france1 and are largely consumed there4 ,the production of fluorspar in the ,united ,states is several times that of any other country4 ,the ore mined comes principally from the southern ,illinois and western ,kentucky field1 and is used largely for fluxing purposes in open-hearth steel furnaces4 ,minor amounts are produced in ,colorado1 ,new ,mexico1 and other states4 ,the ,united ,states has sufficient supplies of fluorspar to meet all its own demands for this material4 ,small amounts1 however1 are imported for use in eastern furnaces because the material can be brought over from ,england very cheaply4 ,the domestic fluorspar is suitable for practically all purposes for which fluorspar is used except for lenses in optical instruments4 ,for this use very small quantities of material imported from ,japan have been used1 but recently fluorspar of a grade suitable for optical purposes has been found in ,illinois1 ,kentucky1 ,new ,hampshire1 and other states4 ,for fluxing purposes domestic fluorspar is superior to the foreign product4 ,,geologic ,,features ,fluorspar is the trade name for the mineral fluorite1 which is composed of calcium fluoride4 ,this is a common mineral in veins and replacements which carry ores of zinc1 lead1 silver1 gold1 copper1 and tin4 ,it is formed under a variety of conditions1 but is always ascribed to solutions coming from nearby igneous rocks4 ,the large fluorspar deposits of ,illinois and ,kentucky contain fluorite with calcite1 barite1 and metallic sulphides1 in wide veins filling fissures in limestones and sandstones and replacing the fissure walls4 ,into these sediments there are intruded certain peridotite dikes4 ,the fluorite and associated minerals were probably deposited by hot solutions bringing the material from some large underlying igneous mass of which the dikes are off-shoots4 ,in the western ,united ,states many metalliferous deposits carry large amounts of fluorite1 which is treated as a gangue or waste mineral1 but which could be profitably extracted if there were local markets4 ,in ,england1 fluorite is obtained in this manner as a by-product from lead and zinc mines4 ,,silica ,,economic ,,features ,silicon and its oxide1 silica1 find important applications in the manufacture of iron and steel4 ,silicon1 like manganese1 is an important constituent of many steels1 the alloy ferrosilicon being added to deoxidize and purify the metal and thus to increase its tensile strength4 ,like titanium1 it is added chiefly for its curative effect rather than as a useful ingredient4 ,on an average #d pounds of #ej to #ee per cent ferrosilicon are used in the ,united ,states for each ton of steel produced4 ,a higher grade of ferrosilicon 7#hj to #he per cent7 is used for certain special steels1 and during the war considerable quantities were used in making hydrogen gas for balloons4 ,lower grades 7#aj to #ae per cent silicon7 are practically a high silicon pig iron4 ,silica has an important use in the form of silica brick or ganister for lining furnaces and converters in which acid slags are formed4 ,for this purpose siliceous rocks1 chiefly quartzites and sandstones1 are ground up1 mixed with lime as a binder1 and fused and pressed into bricks and shapes4 ,for the most satisfactory results the rock should contain #if per cent or more of silica1 and very little of the alkali materials1 which increase the fusibility4 ,in addition to its applications to the iron and steel industry1 silica finds an almost universal use in a wide variety of structural and manufacturing operations4 ,the extensive use of sand and gravel--composed chiefly of silica--for road materials and railway ballast is well known4 ,in construction work silica is used in the form of stone1 sand-lime brick1 cement1 mortar1 concrete1 etc4 ,large quantities of sand1 or silica1 are used for molds in foundries1 for abrasives1 for the manufacture of glass1 for filters1 and for a great variety of other purposes which readily suggest themselves 7see pp4 #hd1 #bfg74 ,for most uses of silica there are local supplies available4 ,for certain purposes requiring material of a particular chemical composition or texture1 however1 satisfactory deposits are known in only a few places4 ,for example1 the material for silica refractories is obtained in the ,united ,states chiefly from certain regions in ,pennsylvania1 ,missouri1 and ,wisconsin4 ,the ,united ,states has ample domestic supplies of silica for practically all requirements4 ,ferrosilicon of the higher grades is manufactured principally in electric furnaces at ,niagara ,falls4 ,the capacity is ample to meet all demands1 but cheap ferrosilicon from ,canada also enters ,united ,states markets4 ,,geologic ,,features ,silicon and oxygen1 making up the compound silica1 are the two most abundant elements in the earth's crust1 and quartz 7,si,o#b7 is a very abundant mineral4 ,the processes of weathering and transportation everywhere operative on the surface of the earth tend to separate quartz from other materials1 and to concentrate it into deposits of sand4 ,katamorphism is primarily responsible for most of the deposits of silica which are commercially used4 ,anamorphism--cementing and hardening the sands into sandstones and quartzites--has created additional value for certain uses1 as in refractories1 building stones1 and abrasives 7see pp4 #hd1 #bfg74 ,,footnotes3 #ca ,report of the ,royal ,ontario ,nickel ,commission4 ,printed by order of the ,legislative ,assembly of ,ontario1 ,toronto1 #aiag4 #cb ,campbell1 ,j4 ,morrow1 ,tungsten deposits of ,burma and their origin1 ,econ4 ,geol41 vol4 #ae1 #aibj1 p4 #eaa4 ,,chapter ,x ,,copper1 ,,lead1 ,,and ,,zinc ,,minerals ,,copper ,,ores ,,economic ,,features ,the electrical industry is the largest consumer of copper4 ,the manufacture of brass1 bronze1 and other copper alloys constitutes another chief use for the metal4 ,considerable quantities of copper sheets1 tubes1 and other wares are used outside of the electrical industry1 as for instance in roofing1 plumbing1 and ship bottoms4 ,copper is also used in coinage1 particularly in ,china1 where it is the money standard of the working population4 ,the average grade of all copper ores mined in the ,united ,states in recent years has been about #a4g per cent metallic copper4 ,ores containing as low as #j4f per cent have been mined in the ,lake ,superior country1 and bonanza deposits containing #bj to #fj per cent have been found and worked in some places1 notably in ,alaska and ,wyoming4 ,the lower-grade ores1 carrying #a to #c per cent copper1 are usually concentrated before smelting1 while the richer ores1 carrying #c to #e per cent or more1 are generally smelted direct4 ,many of the ores contain values in gold and silver1 and also in lead and zinc4 ,an average of about #dj;c4 worth of gold and silver per ton is obtained from all the copper ores of the ,united ,states4 ,in other countries the average grade of copper ores mined is somewhat higher than in the ,united ,states1--where large scale operations1 particularly the use of steam-shovel methods on extensive bodies of disseminated or porphyry copper ores1 as well as improvements in concentrating and metallurgical processes1 have made possible the use of low-grade ore4 ,the principal sources of copper are the ,north ,american continent1 ,chile and ,peru1 ,japan1 south and central ,africa1 ,australia1 and ,spain and ,portugal4 ,smaller quantities are produced in ,russia1 ,germany1 ,norway1 ,cuba1 ,serbia1 and a number of other countries4 ,the ,united ,states normally produces nearly two-thirds of the world's copper and consumes only about one-third4 ,in addition the great bulk of the ,south ,american1 ,mexican1 and ,canadian crude copper comes to the ,united ,states for refining4 ,through financial interests abroad and by means of refining facilities1 the ,united ,states controls a quantity of foreign production which1 together with the domestic production1 gives it control of about #gj per cent of the world's copper4 ,no other country produces one-sixth as much copper as the ,united ,states4 ,england1 because of production in the ,british ,empire 7mainly ,africa and ,australia7 and ,british financial control of production in various foreign countries1 is not dependent upon the ,united ,states for supplies of raw copper4 ,japan1 ,spain1 ,portugal1 and ,norway are able to produce from local mines enough copper for their own needs and for export4 ,but ,france1 ,italy1 ,russia1 ,germany1 and the rest of ,europe normally are dependent upon foreign sources1 chiefly the ,united ,states4 ,south ,america1 ,mexico1 ,canada1 ,africa1 and ,australia are exporters of copper4 ,the control of these countries over their production in each case is political and not financial1 except in the case of ,canada1 where about half the financial control is also ,canadian4 ,it is in these countries and in ,spain that the ,united ,states and ,england have financial control of a large copper supply4 ,before the war ,german interests had a considerable control over the ,american copper industry through close working arrangements with electrolytic refineries4 ,germany was the largest foreign consumer of copper1 and ,german companies bought large quantities of the raw copper in the ,united ,states1 ,canada1 ,mexico1 and ,south ,america1 had it refined1 and sold the finished material in both the ,american and foreign markets4 ,during the war this control was broken up4 ,in view of the importance of copper metal as a raw material1 particularly in the electrical industry1 the strength of the ,united ,states in copper as a key resource ranks even above its control of petroleum4 ,in the ,united ,states in recent years about #dj per cent of the annual production of copper has come from ,arizona1 chiefly from the ,bisbee1 ,globe1 ,ray-,miami1 ,jerome1 and ,morenci-,metcalf districts2 about #ah per cent has come from the ,butte district of ,montana2 about #ab to #ae per cent from ,keweenaw ,point1 ,michigan2 and about #ab per cent from ,bingham1 ,utah4 ,from #c to #e per cent of the country's output comes from each of the states of ,new ,mexico1 ,nevada1 ,alaska1 and ,california4 ,all other states together produce only a little over #b per cent of the total4 ,the so-called porphyry coppers in ,utah1 ,arizona1 ,nevada1 and ,new ,mexico1 described below1 are the source of about #ce per cent of the present production of the ,united ,states4 ,the deep mines of ,butte and ,michigan are responsible for about #cj per cent of the production1 and the ore bodies of ,arizona 7other than porphyry7 and of ,alaska produce about #be per cent4 ,reserves of copper ore are such as to give no immediate concern about shortage1 nor to indicate any large shift in the distribution of production in the near future4 ,development is on the whole considerably in advance of present demands4 ,the principal measured reserves are in the so-called porphyry coppers of the ,united ,states and ,chile4 ,in the ,united ,states the life of these reserves now estimated is approximately #be years4 ,the reserves of the ,chile ,copper ,company are the largest of any known copper deposit in the world1 and the ,braden copper reserve 7also in ,chile7 is among the largest4 ,for the deep mines of the ,united ,states1 the developed reserves have a life of perhaps only five years1 but for most of these mines the life will be greatly extended by further and deeper development4 ,the porphyry coppers1 because of their occurrence near the surface and the ease with which they may be explored by drilling1 disclose their reserves far in advance4 ,the deep mines are ordinarily developed for only a few years in advance of production4 ,,geologic ,,features ,the principal copper minerals may be classified into the sulphide group1 the oxide group1 and native copper4 ,native copper1 mined in the ,lake ,superior region1 is the source of #h to #aj per cent of the world's copper supply4 ,the oxide group of minerals--including the copper carbonates1 azurite and malachite2 the silicate1 chrysocolla2 the oxide1 cuprite2 the sulphates1 chalcanthite and brochantite2 and some native copper associated with these minerals--probably supplies another #e per cent4 ,the remaining #he per cent is derived from the sulphide group4 ,of the sulphide group by far the most important mineral is chalcocite 7cuprous sulphide71 which supplies the bulk of the values in the majority of the mining camps of the western hemisphere4 ,locally1 as at ,butte1 enargite 7copper-arsenic sulphide7 is of great value4 ,other minerals of considerable importance in some districts are chalcopyrite and bornite 7copper-iron sulphides71 tetrahedrite 7copper-antimony sulphide71 and covellite 7cupric sulphide74 ,very commonly the copper sulphides are associated with large quantities of the iron sulphide1 pyrite1 as well as with varying amounts of lead and zinc sulphides and gold and silver minerals4 ,the principal copper ores originate in the earlier stages of the metamorphic cycle1 in close association with igneous activity4 ,katamorphism or weathering1 in place1 has played an important part in enriching them4 ,the processes of transportation and sedimentary deposition1 which have done so much toward making valuable iron ore deposits1 have contributed little to the formation of copper ores4 ,copper deposits associated with igneous flows4 ,the copper ores of the ,lake ,superior district1 and of a few small deposits in the eastern ,united ,states1 contain small percentages of native copper in pre-,cambrian volcanic flows or in sediments between the flows4 ,the ore bodies have the form of long sheets parallel to the bedding1 the copper and associated minerals filling amygdaloidal openings and small fissures in the flows1 and replacing conglomeratic sediments which lie between the flows4 ,the copper was probably deposited by hot solutions related to the igneous rocks1 either issuing from the magmas or deriving heat and dissolved material from them4 ,secondary concentration has not been important4 ,there is practically none of it near the present erosion surface2 but it appears in one part of the district near an older erosion surface covered by ,cambrian sediments1 suggesting a different climatic condition at that time4 ,the ,kennecott copper deposits of ,alaska have a number of resemblances to the ,lake ,superior copper deposits1 suggesting similarity in origin4 ,the ,kennecott deposits occur exclusively in limestone1 which rests conformably on a tilted surface of igneous flows 7greenstones7 not unlike those of ,lake ,superior4 ,the flows carry native copper and copper sulphides in minutely disseminated form and in amygdules1 but apparently not in quantities sufficiently concentrated to mine4 ,the flows are supposed to be the original source of the copper now in the limestone4 ,the primary copper mineral in the limestone is chalcocite1 in exceptionally rich and solid masses1 showing no evidence of having replaced earlier sulphides4 ,it is regarded as a product of primary deposition1 under the influence of hot solutions related in some way to the igneous flows2 but whether the solutions were magmatic1 originating in the lavas or below1 or whether they were meteoric waters rendered hot by contact with the extrusives1 and thereby made effective in leaching copper from them1 is not clear4 ,the oxidation of the ,kennecott copper ores is not extensive4 ,it presents an interesting feature1 in that since glacial time the ground has been frozen and the moisture is now present in the form of ice4 ,the oxidation clearly took place before glacial time4 ,abundant fragments of both the oxide and the sulphide ores are mined from the lateral moraine of a nearby glacier4 ,this is a good illustration of the cyclic nature of secondary concentration which is coming to be recognized in so many camps4 ,the ,boleo copper deposits of ,lower ,california occur in volcanic tuffs and associated conglomerates of ,tertiary age4 ,they have certain peculiar mineralogic associations--the ores containing large quantities of all the common copper oxide minerals1 and a number of rare oxide minerals of copper1 lead1 silver1 and cobalt1 together with gypsum1 sulphur1 and much iron and manganese oxide4 ,the copper oxides and carbonates are in places gathered into rounded concretions called boleos 7balls74 ,sulphides are present in the lowest beds and may represent the form in which the copper was originally deposited4 ,the copper-bearing beds have been much silicified1 and it has been suggested that mineralization was accomplished by hot-spring waters1 probably of igneous origin4 ,these deposits have a few marked similarities to the ,lake ,superior copper ores4 ,copper veins in igneous rocks4 ,a second group of copper ores in igneous rocks is made up of deposits in distinct fissure veins and as replacements along such veins4 ,the chief deposits of this type are at ,butte1 ,montana--which is1 from the standpoint of both past and present production1 the greatest single copper district in the world4 ,here a large batholith of ,tertiary granite was intruded by porphyry dikes2 and faulting1 accompanying and following the intrusions of the dikes1 developed numerous fissures4 ,the fissures were mineralized with copper sulphides and arsenides1 iron sulphides1 and locally with zinc sulphide and manganese carbonate1--all in a matrix of quartz4 ,at the same time the wall rocks were extensively mineralized and altered2 the fissure veins grade off into the wall rock1 and in fact the larger part of the ore is simply altered granite with disseminated sulphides4 ,the solutions which deposited the ores are inferred to have been hot from the nature of the wall-rock alterations1 from the presence of hot-water minerals like fluorite1 cassiterite1 and others1 and from the general association of the ores in time and place with the porphyry intrusions4 ,the solutions are believed to have originated from the porphyry and possibly from other intrusives4 ,in the ,butte district1 and in the great majority of copper sulphide vein ores throughout the world1 secondary concentration by surface waters has played a considerable part in developing ores of commercial value4 ,near the surface the copper is leached out and carried down by waters containing various solvents1 particularly sulphuric acid from the oxidation of pyrite4 ,a leached zone is formed containing the ordinary products of rock weathering1--rusty quartz and clay1 sometimes black with manganese oxides4 ,a small part of the copper remains in this zone as oxides1 carbonates1 and silicates4 ,below the oxidized and leached zone there is evidence of deposition of a large amount of secondary copper sulphide in the form of chalcocite4 ,this is supposed to have been formed by the leaching of copper from above as soluble copper sulphate1 and its precipitation below by iron and other sulphide minerals which the solutions meet on their downward course--a reaction which has been demonstrated experimentally4 ,it was formerly supposed that most of the chalcocite was of this origin2 but as chalcocite is found in important amounts with enargite and chalcopyrite to great depths 7now #c1ejj feet71 where the veins are still rich and strong1 it begins to appear that much of the chalcocite is of primary origin4 ,the fissures along which the ,butte ores occur are in three main sets1 which in order of age strike roughly east-west1 northwest-southeast1 and northeast-southwest4 ,two-thirds of the ore is in the first set1 about #cj per cent in the second1 and the remainder in the third4 ,the mineralization of the several vein systems cannot be discriminated1 and it is thought that it was accomplished as a more or less continuous and progressive process4 ,there is some evidence1 also1 that the fracturing in the several fracture systems was likewise a nearly continuous progressive process1 contemporaneous with the ore deposition1 and perhaps developing under a single great shear which caused more or less simultaneous and overlapping systems of fractures in the various directions4 ,porphyry coppers4 ,another type of copper deposits in igneous rocks is the disseminated or porphyry deposits4 ,the term porphyry as commonly used includes true porphyries1 monzonites1 granites1 and other igneous rocks4 ,ores of this type are represented by the great deposits of ,bingham1 ,utah2 ,ray1 ,miami1 and the ,new ,cornelia mine of ,arizona2 ,ely1 ,nevada2 ,santa ,rita1 ,new ,mexico2 ,cananea1 ,sonora1 ,mexico2 northern ,chile2 and many other districts of importance4 ,they form the greatest known reserves of copper ore4 ,these deposits contain copper minerals1 usually in the marginal portions of acid porphyries1 in many irregular1 closely spaced veins1 and in minute seams and spots disseminated through the mass of the rock4 ,in the ,ray and ,miami and other districts the mineralization has spread largely through adjacent schists1 but these deposits are included with the porphyry copper deposits in commercial parlance4 ,the porphyry deposits are of an undulating blanket form of considerable areal extent and shallow depth4 ,at the surface is a leached and weathered zone1 often containing more or less of the oxides1 carbonates1 and silicates of copper1 ranging in thickness up to #a1jjj feet1 but averaging #bjj feet or less4 ,below this is a zone carrying copper in the form of chalcopyrite1 enriched by chalcocite deposition from above1 ranging in thickness up to #djj feet4 ,the ore in this zone varies from one-half of #a per cent to #f per cent of copper and ordinarily averages between #a and #b per cent4 ,the use of ore of this grade is made possible by the large quantities and by the cheap and efficient mining and metallurgical practices4 ,the ore body grades below into a zone characterized by lean chalcopyrite1 which is supposed to represent original or primary deposition from hot waters associated with the porphyry intrusion4 ,this primary ore1 or protore1 was clearly formed after the solidification of the igneous rocks1 though soon after1 by solutions from igneous sources which followed fractured and shattered zones4 ,copper in limestone near igneous contacts4 ,another great group of copper deposits occurs as replacements of limestone adjacent to porphyry or granitic intrusives4 ,this type is illustrated by some of the deposits at ,bingham1 ,utah1 and at ,bisbee1 ,arizona4 ,the primary deposition was of chalcopyrite and other copper sulphides1 together with garnet1 diopside1 and other minerals known to have required high temperature in their formation4 ,the ore fills fissures and replaces extensive masses of the limestone4 ,it is likely to show a fairly sharp contact on the side toward the intrusive1 and to grade off into the country rock on the other side with numerous embayments and irregularities4 ,these deposits have been enriched by weathering in the same manner as indicated above for the porphyry coppers1 but to highly varying degrees4 ,in the ,bisbee deposits large values were found in the weathered zone1 and secondary sulphide enrichment below this zone is also important4 ,in the ,bingham camp1 on the other hand1 the weathered zone is insignificant and most of the ore beneath is primary4 ,the weathering of the silicated limestone gangue results in great masses of clay which are characteristic features of the oxide zones of these deposits4 ,copper deposits in schists4 ,other copper deposits1 as at ,jerome1 ,arizona1 in the ,foothill and ,shasta ,county districts of ,california1 at ,ducktown1 ,tennessee1 etc41 are irregular lenticular bodies in schists and other rocks1 but all show relationship to igneous rocks4 ,the ,rio ,tinto ores of ,spain and ,portugal1 which belong in this group1 have been referred to on page #ajh4 ,in the ,jerome or ,verde district of central ,arizona1 folded pre-,cambrian greenstones and sediments were invaded by masses of quartz-porphyry1 and after further deformation1 rendering many of the rocks schistose1 were intruded by an augite-diorite4 ,contact metamorphism along both the quartz-porphyry and the diorite contacts was practically lacking4 ,the ore bodies were formed as irregular pipe-like replacements of the schists1 being localized in one case by a steeply pitching inverted trough of impervious diorite1 and in other cases by shear zones which favored vigorous circulation4 ,a later series of small diorite or andesite dikes cut the ore bodies4 ,the primary ores consist of pyrite1 chalcopyrite1 and other sulphides1 with large amounts of jaspery quartz and some calcite and dolomite4 ,they were clearly formed by replacement of the schists particle by particle1 as shown by the frequent preservation of the schist structure in a banding of the sulphide minerals1 the residual shreds of unreplaced schist material in the ores1 and the usual gradual transition from unreplaced schists to those completely replaced by massive sulphides4 ,the localization of the most important mineralization in an inverted trough is good evidence that the solutions came from below1 and the nature of the mineral associations suggests an origin through the work of hot waters associated with igneous intrusives4 ,the diorite1 being most closely related in time and space with the ore bodies1 seems the most logical source of the ore materials4 ,secondary concentration of the ,jerome ores has proceeded along the general lines previously outlined 7pp4 #df-ej1 #bjb74 ,here again the evidence is clear that the ores were concentrated in an earlier period1 in this case in pre-,cambrian times1 probably during the long interval required for the base-leveling of the pre-,cambrian mountains4 ,since ,cambrian times the deposits have been for the most part buried by later sediments4 ,some of the deposits are still protected by this overlying blanket and mining has not yet reached the zone of altogether primary sulphides4 ,others have been faulted up and again exposed by erosion2 but since being uncovered1 steep slopes and rapid erosion have apparently favored the scattering of the copper rather than its concentration and enrichment4 ,in the ,united ,verde ,mine1 oxidizing conditions at present prevail to the bottom of the chalcocite zone4 ,the very large reserves of the ,katanga copper belt of the ,belgian ,congo are in the form of tabular masses in schistose and highly metamorphosed ,paleozoic sediments4 ,the ore bodies are roughly parallel to the bedding1 but in instances follow the schistosity which cuts across the bedding4 ,they consist dominantly of the oxide minerals1 though in several ore bodies sulphides have been shown by diamond-drilling4 ,the ores have a high content of cobalt and also carry precious metals4 ,the origin of the deposits is not known1 but has been ascribed to granitic masses intrusive into the schists4 ,sedimentary copper deposits4 ,in the later phases of the metamorphic cycle1 the agencies of transportation 7in solution7 and sedimentary deposition have resulted in some low-grade deposits of copper sulphides in sedimentary rocks4 ,deposits of this type are found in the ,rocky ,mountain region1 where they are referred to as the ,red ,beds coppers1 but are of no commercial importance4 ,similar deposits in ,germany1 the ,mansfield copper-bearing shales1 have been worked for some time1 and during the war were ,germany's main source of copper4 ,on ,keweenaw ,point1 ,michigan1 deposits of native copper formed in this manner in the ,nonesuch beds have been worked on a commercial scale4 ,other copper ores on ,keweenaw ,point are replacements of conglomerate beds between igneous flows1 and are of a different origin already described 7p4 #bjj74 ,while much of the copper of sedimentary beds gives evidence that it was deposited from solution in cracks and as replacements of the wall rocks1 often through the agency of abundant organic material in the beds1 and while also comparatively little of this copper can be identified as having been deposited in detrital flakes or fragments along with the other mineral fragments1 there is1 nevertheless1 considerable evidence that some of these deposits were formed essentially during the sedimentation of the enclosing beds and as incidents to this process4 ,such evidence consists of a close limitation of the copper to certain beds1 its wide and uniform distribution within these beds1 its absence in similar beds near at hand1 the absence of evidence of feeding and escape channels of the kind which would be necessary in case the solutions were introduced long afterward1 and often a minute participation of the copper minerals in the minor structures of bedding1 false-bedding1 and ripple-marks1 which would be difficult to explain as due to secondary concentration4 ,the ,corocoro copper deposits of ,bolivia occur in beds of sandstone with no igneous rocks in the vicinity4 ,however1 they are all closely associated with a fault plane1 igneous rocks occur at distances of a few miles1 and the general mineralization is coextensive with the belt of igneous rocks2 the deposits are therefore ascribed to a magmatic source rather than to sedimentary processes4 ,toward the surface the copper is in part in the form of sulphides1 somewhat altered to oxide minerals1 and farther down it is entirely native copper1 associated with gypsum4 ,this is the only district outside of ,lake ,superior where native copper has been mined on an important scale4 ,general comments4 ,in general1 the commercially prominent copper deposits show a close relationship to igneous rocks in place1 time1 and origin4 ,seldom do the ores extend more than #a1jjj feet away from the igneous rock4 ,the common downward order in sulphide deposits is3 first1 a weathered zone1 originally formed mainly above the water table1 consisting above of a leached portion and below of oxides and carbonates of copper in a gangue of quartz or clay2 second1 a zone of secondary sulphide enrichment1 characterized by chalcocite coatings1 chalcopyrite1 and pyrite1 with a gangue of quartz and igneous rock or limestone2 and third1 a zone of primary deposition with similar gangue1 characterized by chalcopyrite1 and at ,butte by enargite and chalcocite4 ,the oxide zone as a whole may be rich or lean in values1 depending on the nature of the associated gangue material and country rock4 ,when these are more soluble than the copper--as is commonly the case in limestone--the copper may be residually concentrated1 notwithstanding the fact that much copper originally present has been carried off in solution4 ,when the associated gangue and country rock are less soluble than the copper--as is common with quartz and igneous rocks--the oxide zone is likely to be depleted of values4 ,the zones formed by weathering and secondary enrichment are extremely irregular1 both in distribution and depth1 in any one deposit1 and they overlap and grade into one another in a very complex fashion4 ,in many places the primary zone is too lean to be mined to commercial advantage2 but in other places1 as at ,butte1 and in the limestone deposits of ,bingham1 the primary ores are of considerable importance4 ,when evidence of secondary sulphide enrichment was first recognized there was a tendency to magnify its effectiveness1 and to assume that in most cases the values were due to this process2 that the primary zones would be found to be valueless4 ,in recent years the emphasis is being somewhat changed because of the recognizing in many camps of rich primary zones4 ,while some chalcocite is clearly the result of secondary enrichment from above1 other chalcocite seems to have been related closely to the primary deposition4 ,the quantitative discrimination of the two is a matter of great difficulty4 ,it has come to be recognized that the zonal arrangement caused by enrichment from the surface has been imposed usually on a zonal arrangement caused by the primary hot solutions and not related to the surface but to the source of the solutions4 ,in some districts1 as illustrated by ,butte and ,bingham1 the copper-bearing minerals seem to have been deposited nearest the igneous source1 while the lead1 zinc1 gold1 and silver minerals have been deposited farther away1--suggesting the cooling of the solutions with increasing distance from the igneous source4 ,the further investigation of this primary zonal arrangement promises interesting results with a practical bearing on exploration and development4 ,one of the newer features of the investigation of copper deposits has been the recognition of the cyclic nature of the secondary concentration4 ,this process has been related not only to the present erosion surface1 but to older surfaces now partly buried under later rocks4 ,ransome's#cc summary of conditions at the ,ray-,miami camp has a somewhat general application4 ,supergene enrichment has generally been treated as a continuously progressive process4 ,there is considerable probability1 however1 that it is essentially cyclic1 although the cyclic character may not be patent in all deposits4 ,a full development of the cycle can take place only under a certain equilibrium of a number of factors1 including climate1 erosion1 topography1 and character of rock4 ,the essential fact appears to be that as enrichment progresses and chalcocite increases the process of enrichment becomes slower in action1 and erosion may1 in some circumstances1 overtake it4 ,with the removal of some of the protecting zone of chalcocite the protore is again exposed to oxidation and a second cycle of enrichment begins4 ,although much of the enriched ore is now below ground-water level1 it probably was once above that level1 and enrichment is believed to have taken place mainly in the zone of rock above any general water table4 ,where the old erosion surface roughly coincides with the present erosion surface1 the deposits follow more or less the topography4 ,where the old erosion surface pitches below later sediments1 the ores pitch with it1 and therefore do not follow the present topography4 ,the recognition of the cyclic nature of secondary concentration is obviously of great significance in exploration and development4 ,although a vast amount of study has been devoted to the origin and enrichment of copper deposits1 and although the general conditions and processes are pretty well understood1 the results thus far have been largely qualitative rather than quantitative4 ,,lead ,,ores ,,economic ,,features ,the most prominent uses of lead are in the manufacture of alloys1 such as type-metal1 bearing metal1 shot1 solder1 and casting metal2 as the oxide1 red lead1 and the basic carbonate1 white lead1 in paints2 for lead pipe1 cable coverings1 and containers of acid active material2 and in lead compounds for various chemical and medical uses4 ,of the lead consumed in the ,united ,states before the war about #ch per cent was utilized in pigments1 #cj per cent in alloys other than shot1 #ae per cent in pipe1 #aj per cent in shot1 and #g per cent in all other uses4 ,during the war much larger quantities were used in munitions1 such as shot and shrapnel4 ,the lead content of commercial ores varies widely4 ,it ranges from as low as 4#be per cent in the ,joplin district of ,missouri1 to about #ae per cent in the ,broken ,hill deposits of ,australia1 and over #bj per cent in the ,bawdwin mines of ,burma4 ,in the ,coeur d',alene district of ,idaho and the southeastern district of ,missouri1 the two greatest lead producers in the ,united ,states1 the average grades are about #aj per cent and about #c-a_/b per cent respectively4 ,the grade of ore which may be profitably worked depends not only upon the economic factors1--such as nearness to consuming centers1 and the price of lead1--but also upon the amenability of the ore to concentration1 the content of other valuable metals1 and the fact that lead is very useful in smelting as a collector of gold and silver4 ,most lead ores contain more or less zinc1 and lead is obtained as a by-product of most zinc ores4 ,argentiferous lead ores form one of the principal sources of silver1 and also yield some gold4 ,lead and copper are produced together from certain ores4 ,thus the separation of many ores into hard and fast classes1 as lead1 or zinc1 or copper1 or silver1 or gold ores1 cannot be made2 in some of the mineral resource reports of the ,united ,states ,geological ,survey the statistics of these five metals are published together4 ,the main sources of lead ore1 named in order of their importance1 are the ,united ,states1 ,australia1 ,spain1 ,germany1 and ,mexico1 which account for over #hj per cent of the world's production4 ,most of the countries of ,europe outside of ,spain and ,germany produce small amounts of lead1 but are largely dependent on imports4 ,spain exports argentiferous lead and pig lead mainly to ,england and ,france1 with minor quantities to other countries of ,europe and to ,argentina4 ,before the war ,germany1 which was the largest ,european consumer1 utilized all its own production of lead ores and imported an additional #aj per cent of the world's ores for smelting1 as well as considerable amounts of pig lead4 ,its principal deposits were those of ,silesia2 under the ,peace ,treaty they may possibly be lost to ,poland1 leaving ,german smelters largely dependent on imports4 ,australia before the war normally shipped lead concentrates and pig lead to ,england and also to ,belgium1 ,germany1 and ,japan4 ,england1 the second largest ,european consumer1 before the war had insufficient smelting capacity within the ,british ,empire and was partly dependent on foreign-smelted lead4 ,during the war1 however1 ,england contracted for the entire ,australian output1 and enlarged its smelting capacity accordingly4 ,this may mean permanent loss to ,belgium1 which had depended mainly on the ,australian ores for its smelting industry before the war4 ,in ,north ,africa there is a small but steady production of lead1 most of which goes to ,france4 ,recent developments in ,burma have shown large reserves of high-grade lead-zinc-silver-copper ores1 and this region may be expected to become an important producer4 ,there are also large reserves of lead in the ,altai ,mountains of southwestern ,siberia and in the ,andes ,mountains of ,south ,america4 ,england1 through control of ,australian and ,burman lead mines and smelters1 domestic smelting facilities1 and some financial control in ,spain1 ,mexico1 and elsewhere1 and ,france1 through financial control of ,spanish and ,north ,african mines and ,spanish1 ,belgian1 and domestic smelters1 have adequate supplies of lead4 ,the ,united ,states produces about a third of the world's lead and twice as much as any other country4 ,normally the domestic production is almost entirely consumed in this country4 ,mexico sends large quantities of bullion and ore to the ,united ,states to be smelted and refined in bond4 ,mexican lead refined and exported by the ,united ,states equals in amount one-sixth of the domestic production4 ,small quantities of ore or bullion from ,canada1 ,africa1 and ,south ,america are also brought into the ,united ,states for treatment4 ,through domestic production1 smelting facilities for ,mexican ore1 and commercial ownership in ,mexico and elsewhere1 the ,united ,states controls over #de per cent of the world's lead production4 ,before the war ,germany1 through the ,lead ,convention or ,international ,sales ,association1 and through smelting and selling contracts with large producing mines1 practically controlled the ,european lead market as well as exports from ,mexico and the ,united ,states and from ,australia4 ,during the war ,german foreign influence was practically destroyed4 ,in the ,united ,states about a third of the production of lead comes from southeastern ,missouri and about a fourth from the ,coeur d',alene district of ,idaho4 ,the five states1 ,missouri1 ,idaho1 ,utah1 ,colorado and ,oklahoma1 produce about nine-tenths of the country's total output4 ,reserves of lead ore are not large in proportion to demand1 contrasting in this regard with zinc ore4 ,,geologic ,,features ,the principal lead mineral is the sulphide1 galena1 from which the great bulk of the world's lead is derived4 ,cerussite 7lead carbonate7 and anglesite 7lead sulphate7 are mined in some places in the upper part of sulphide deposits1 and supply a small fraction of the world's output4 ,the ores of lead are of two general classes3 ,the first class1 the so-called soft lead ores1 nearly free from copper and precious metals1 and commonly associated with zinc ores1 are found in sedimentary beds independent of igneous intrusion4 ,they are of world-wide distribution1 were the first to be extensively exploited1 were at one time the dominant factor in world production of lead1 and at present produce about #cj per cent of the world's total4 ,they are represented by the deposits of the ,mississippi ,valley1 of ,silesia1 and some of the ,spanish deposits4 ,the general description of the origin of the zinc ores of the ,mississippi ,valley on pp4 #baf-bah applies to this class of lead ores4 ,it should be noted1 however1 that in the principal ,united ,states lead-producing district1 that of southeastern ,missouri1 the lead ores occur almost to the exclusion of the zinc ores1 and are more disseminated through the limestone than is characteristic of the zinc ores4 ,ores of this type have been found extending only to shallow depths 7not over a few hundred feet71 and because of the absence of precious metals their treatment is comparatively simple4 ,the second class consists of ores more complex in nature1 which are found in association with igneous rocks1 and which usually contain some or all of the metals1 zinc1 silver1 gold1 copper1 iron1 manganese1 antimony1 bismuth1 and rare metals1 with various gangue minerals among which quartz1 siderite1 and silicates are important4 ,today these ores are the source of about #gj per cent of the world's lead4 ,they are represented by the lead deposits of the ,rocky ,mountain region 7,coeur d',alene1 ,idaho2 ,leadville1 ,colorado2 ,bingham1 ,utah2 etc472 of ,broken ,hill1 ,new ,south ,wales2 of ,burma2 and of many other places4 ,they are all related to the earlier stages of the metamorphic cycle and occur in close genetic association with igneous activity4 ,they include deposits in the body of igneous rocks1--in the form of well-defined veins1 replacements along zones of fissuring and shearing1 and disseminated masses1--as well as veins and replacements in the rocks1 particularly in limestones1 adjoining igneous intrusions4 ,the deposits present a wide variety of shapes depending on the courses of the solutions by which they were formed4 ,the materials of the ore minerals are believed to have been derived from the igneous rocks and to have been deposited by hot solutions4 ,the source of the solutions--whether magmatic or meteoric--presents the same problems which have been discussed elsewhere 7pp4 #da-db74 ,the ores are frequently mined to great depths4 ,because of their complexity they require involved processes of treatment to separate out the values4 ,ores of this nature have already been referred to in the discussion of the copper ores of ,bingham and ,butte1 and will be referred to in connection with the zinc-lead-silver ores of ,leadville1 ,colorado4 ,special reference may be made here to the ,coeur d',alene district of ,idaho1 which is the second largest producer of lead in the ,united ,states4 ,the ,coeur d',alene deposits are almost unique in that they contain galena as vein-fillings and replacements in quartzite1 with a gangue of siderite 7iron carbonate74 ,quartzite 7instead of limestone7 is an unusual locus of replacement ores1 and siderite is an unusual gangue4 ,these ores are believed to owe their origin to acid igneous intrusives1 because of the close association of the ores with some of these intrusives1 and because of the content of high-temperature minerals4 ,some of the ore bodies are found far from intrusives1 but it is supposed that in such cases further underground development may disclose the intrusives below the surface4 ,secondary concentration has been insignificant4 ,in general1 weathering of lead ores at the surface and secondary sulphide enrichment below are not so extensive as in the case of copper and zinc4 ,galena is fairly stable in the oxide zone1 and even in moist climates it is found in the outcrop of many veins4 ,weathering removes the more soluble materials and concentrates the lead sulphide with the residual clay and other gangue4 ,in some districts cerussite and a little anglesite are also found in the oxide zone4 ,the carrying down of lead in solution and its deposition below the water table as a secondary sulphide is not proved on any extensive scale4 ,in this respect it contrasts with zinc2 and when the two minerals occur together1 lead is likely to be more abundant in the oxide zone1 and zinc in the sulphide zone below4 ,such a change in composition with depth is also found in some cases as the result of primary vertical variations in the mineralization4 ,,zinc ,,ores ,,economic ,,features ,zinc metal has commonly gone under the name of spelter4 ,brass and galvanized iron contain zinc as an essential ingredient4 ,of the total ,united ,states zinc consumption in normal times1 about #fj per cent is used in galvanizing iron and steel objects to protect them from rust1 #bj per cent is used in the manufacture of brass and other alloys1 #aa per cent goes into the form of rolled sheets for roofing1 plumbing1 etc41 #a per cent is employed in desilverizing lead bullion1 and the remaining #h per cent is used for pigments1 electrodes1 and other miscellaneous purposes4 ,during the war the use in brass-making was greatly increased4 ,the zinc content of the ores mined today ranges from a little over #a-a_/b per cent in the ,joplin district of ,missouri1 to #be per cent and higher in some of the deposits of the ,coeur d',alene and other western camps1 and over #dj per cent in certain bonanzas in ,british ,columbia and ,russia4 ,the ores usually contain both zinc and lead in varying proportions1 and sometimes gold1 silver1 and copper are present4 ,of the zinc produced in the ,united ,states1 about #gc per cent is obtained from ores containing zinc as the principal element of value1 about #be per cent from zinc-lead ores1 and #b per cent from copper-zinc and other ores4 ,the average grade of the straight zinc ores is about #b-a_/b per cent4 ,of the world's zinc ore1 the ,united ,states produces in normal times about one-third1 ,germany about one-fifth1 ,australia about #ae per cent1 ,italy1 ,north ,africa and ,spain each about #e per cent4 ,the remaining #ae to #bj per cent comes from a large number of scattered sources1 including ,japan1 ,east ,asia1 ,norway and ,sweden1 ,canada1 ,mexico1 ,austria1 ,france1 ,greece1 ,siberia1 and ,russia4 ,in the near future the ,bawdwin mines of ,burma will probably be increasingly important producers4 ,large reserves of zinc also exist in the ,altai ,mountains of southwestern ,siberia1 and in the ,cordilleran region of ,south ,america4 ,in short1 zinc is one of the most widely distributed of metallic resources2 there is consequently less necessity for great international movements than in the case of many other commodities4 ,the smelting of zinc concentrates is in general carried on close to the points of consumption and where skilled labor is available1 rather than at the mines1--although smelters to handle part of the output have recently been built in ,australia and in ,burma4 ,in ,europe the great smelting countries have been ,germany and ,belgium1 and to a lesser extent ,england and ,france4 ,before the war these four countries with the ,united ,states produced over nine-tenths of the world's spelter4 ,belgium did principally a custom business1 and a large part of its exports went to ,england4 ,australian and ,tasmanian zinc ores were the basis of the ,belgian and ,english smelting industries1 and also supplied about one-third of the ,german requirements4 ,since the war ,england has contracted to take practically the entire ,australian output4 ,this fact1 in connection with war-time destruction of ,belgian smelters1 leaves the future of the ,belgian zinc industry in some doubt4 ,germany may possibly lose to ,poland its richest zinc mines1 those of ,silesia4 ,german activity in the rich deposits of ,mexico is to be expected4 ,france controls the deposits of ,north ,africa and satisfies a considerable part of its requirements from that source4 ,smaller movements of zinc include exports from ,italy to ,england1 and a complex interchange among the lesser producers of ,europe4 ,english and ,french zinc-smelting capacity was expanded during the war1 and the industry in these countries is in a strong position4 ,japan also developed a considerable smelting industry during the war1 importing ores from eastern ,asia and ,australia4 ,the ,united ,states normally smelts and consumes all its large production of zinc ores and does not enter foreign markets to any extent4 ,small amounts of zinc concentrates are brought in from ,mexico and ,canada to be smelted in bond4 ,during the war1--when the ,allies were cut off by enemy operations from the customary ,belgian and ,german supplies of spelter1 and by shortage of ships from ,australian zinc ores1--,australian1 ,spanish1 ,italian1 and other ores were imported into the ,united ,states1 and large quantities of spelter were exported from this country to ,europe4 ,mine and smelter capacities were greatly increased1 over-production ensued1 and with the cessation of hostilities many plants were obliged to curtail or cease operations4 ,the ,united ,states has now about #dj per cent of the zinc-smelting capacity of the world4 ,for the present at least the capacity is far in excess of the domestic requirements4 ,before the war ,german control of the international zinc market was even stronger than in the case of lead4 ,the ,german ,zinc ,syndicate1 through its affiliations1 joint share-holdings1 ownership of mines and smelters1 and especially through smelting and selling contracts1 controlled directly one-half of the world's output of zinc and three-fourths of the ,european production4 ,it regulated the ,australian exports by means of long-term contracts1 and had considerable influence in the ,united ,states4 ,to some extent it was able to so manipulate the market that zinc outside the syndicate was also indirectly controlled4 ,during the war political jurisdiction was used by the ,allied countries to destroy this ,german influence4 ,in the ,united ,states the principal zinc-producing regions are the ,joplin and adjacent districts of ,missouri1 ,oklahoma1 ,kansas1 and ,arkansas1 furnishing about one-third of the country's output2 the ,franklin ,furnace district of ,new ,jersey1 and the ,butte district of ,montana1 each yielding about one-sixth of the total supply2 and the ,upper ,mississippi ,valley district of ,wisconsin1 ,iowa1 and ,illinois1 the ,leadville district of ,colorado1 and the ,coeur d',alene district of ,idaho1 each producing between one-tenth and one-twentieth of the total4 ,smaller quantities are produced in ,tennessee1 ,new ,mexico1 ,nevada1 and several other states4 ,reserves of zinc are ample for the future4 ,they are now developed considerably in advance of probable requirements1 a fact which causes keen competition for markets and renders zinc-mining more or less sensitive to market changes4 ,,geologic ,,features ,the most important mineral of zinc is the sulphide1 sphalerite or zinc blende4 ,the minerals of the oxide zone are smithsonite 7zinc carbonate7 and calamine 7hydrous zinc silicate71 which yield minor amounts of zinc and are especially productive at ,leadville1 ,colorado4 ,zincite 7zinc oxide7 and willemite 7zinc silicate7 are the important minerals in the deposits of ,franklin ,furnace1 ,new ,jersey4 ,the association of most deposits of zinc with more or less lead has been noted4 ,the ores of zinc are of two general classes1 corresponding to the two classes of lead ores 7pp4 #baa-bab74 ,zinc ores of the first type are in veins and replacements in sedimentary rocks at shallow depths1 independent of igneous association1 and are supposed to have been formed by cold solutions4 ,they are found in the ,mississippi ,valley1 in ,silesia1 and in many of the smaller ,european deposits4 ,they were formerly the leading zinc-producers1 and now produce about #de per cent of the world's total4 ,zinc ores of the second type consist of veins and replacements related to intrusive rocks1 sometimes extending to considerable depths1 and of more complex composition4 ,they include most of the deposits of the ,american ,cordilleran region 7,butte1 ,coeur d',alene1 ,leadville1 etc471 of ,franklin ,furnace1 of ,australia1 of ,burma1 and of many other places4 ,the zinc-lead ores of the type found in the ,mississippi ,valley are of special interest1 in that they are sulphide ores of an origin apparently independent of igneous agencies4 ,these ores occur as fissure-fillings and replacements1 mainly in nearly flat-lying ,paleozoic limestones and dolomites--the ,bonne ,terre dolomitic limestone of southeastern ,missouri1 the ,boone formation of southwestern ,missouri and ,oklahoma1 the ,galena dolomite of ,wisconsin and ,illinois4 ,they are variously associated with a gangue of dolomite1 calcite1 quartz1 iron pyrite1 barite1 and chert4 ,not infrequently they are spread out both in sheets and in disseminated form along carbonaceous layers within or at the base of the limestone4 ,the source of the primary sulphides has been a subject of much discussion4 ,all are agreed that they were first deposited with the sediments in minutely dispersed form1 through the agency of the organic contents of the sediments1 and that such deposition was somewhat generally localized by estuarine conditions which favored the accumulation of organic remains4 ,many years ago1 before the evidence of estuarine deposition was recognized1 ,chamberlin suggested an ingenious hypothesis for the northern ,mississippi ,valley1--that the organic material had been localized by ocean's currents forming something in the nature of a ,sargasso sea4 ,differences of opinion become acute1 however1 when the attempt is made to name the precise sedimentary horizon1 out of several available horizons1 in which for the most part this primary concentration occurred4 ,judging from the organic contents of the several beds1 the primary source may have been below1 within1 or above the present ore-bearing horizons4 ,if the ore came from the lower horizons1 it was introduced into its present situation by an artesian circulation1 for which the structural conditions are favorable4 ,if the ore was derived from overlying horizons1 downward moving solutions accompanying erosion did the work4 ,if the primary source was within the horizon of present occurrence of the ores1 both upward and downward moving waters may have modified and transported them locally4 ,for each of these hypotheses a plausible case can be made2 but much of the evidence can be used interchangeably for any one of them4 ,in spite of the wealth of data available1 it is astonishingly difficult to arrive at a conclusion which is exclusive of other possibilities4 ,without attempting to argue the matter in detail the writer merely records his view1 based on some familiarity with these districts1 that1 on the whole1 the evidence favors the accumulation of these deposits by downward moving meteoric solutions during the weathering of overlying strata2 but that it is by no means certain that a part of the ores has not been derived from lower horizons4 ,the great area of the producing districts in comparison with their depth1 the uniform association of the ore-bearing zone with the surface regardless of geologic horizon uncovered by erosion1 the failure of the ores to extend in quantity under cappings of later formations1 and the known efficacy of oxidizing waters in local downward transfers of zinc and lead1 seem to suggest concentrating agencies which are clearly related to surface conditions4 ,it is of interest to note that in many places in the limestones of ,missouri and ,virginia1 and elsewhere in the ,paleozoic rocks1 there are sinks of limonite and clay near the surface1 which are likewise believed to have originated through downward movement of waters deriving their mineral contents from the erosion and stripping of overlying sediments4 ,still further1 the primary deposition of ,clinton iron ores in many parts of the ,mississippi ,valley and eastward to the ,appalachians took place in stratigraphic horizons not far removed from the horizons of lead and zinc deposition4 ,when the peculiar conditions controlling the deposition of the ,clinton ores are understood 7see pp4 #eb-ec7 it is entirely possible that they may throw some light on the genesis of the lead and zinc ores4 ,since the ores were introduced into essentially their present locations1 secondary concentration has produced an oxide zone of clay1 chert1 and iron oxide1 with varying amounts of zinc carbonate1 zinc silicate1 lead sulphide1 and rarely lead carbonate4 ,this zone is obviously developed above water level1 and is seldom as much as #ajj feet thick4 ,zinc1 and to a less extent lead1 have been taken into solution as sulphates1 with the aid of sulphuric acid resulting from the oxidation of the associated pyrite4 ,zinc has been carried away from the weathered zone in solution faster than lead1 leaving the lead more or less concentrated near the surface4 ,some of the zinc carried down has been redeposited secondarily as zinc sulphide4 ,evidences of this secondary sulphide enrichment can be seen in many places2 yet certain broad quantitative considerations raise a doubt as to whether this process has been responsible for the main portion of the values of the sulphide zone4 ,if downward secondary enrichment had been a dominant process1 it might be expected that the ores would be richer in places where erosion had cut away more than half the limestone formation carrying the ore1 than in places where it had barely cut into the formation4 ,this is not the fact1--which suggests that erosion in its downward progress has carried a large part of the zinc completely out of the vicinity4 ,zinc ores of this same general character are also found in ,paleozoic rocks 7,knox dolomite7 in ,virginia and ,tennessee4 ,their manner of occurrence suggests the same problem of origin as in ,missouri and ,wisconsin1 but no decisive evidence of their source has been discovered4 ,of the zinc ores associated with igneous intrusions1 those of the ,butte and ,coeur d',alene districts are described in connection with copper and lead ores on pp4 #bja-bjc1 #bjh1 and #bab-bac4 ,zinc constitutes about #ge per cent by weight of the recoverable metals of the ,leadville district of ,colorado4 ,about two-thirds of the zinc occurs as the sulphide and about one-third as the carbonate resulting from weathering of the sulphide4 ,the zinc sulphide is associated with lead1 iron1 and copper sulphides and gold and silver minerals4 ,in the oxide zone the zinc carbonate is associated with oxides and carbonates of various metals1 including those of lead1 copper1 iron1 and manganese4 ,the iron and manganese oxides are mined in considerable tonnage as a flux4 ,it is an interesting fact that1 although mining has been carried on in this district for upwards of forty years1 only within the last decade has the existence of zinc ores in the oxide zone been recognized4 ,this has been due largely to the fact that the iron and manganese oxides effectively stain and mask the zinc carbonate4 ,the ,leadville ores occur as replacements and vein-fillings in a gently faulted and folded ,carboniferous limestone1 in deposits of a general tabular shape1 parallel to the bedding but with very irregular lower surfaces4 ,the limestone is intruded by numerous sheets of porphyry1 mainly parallel to the bedding but sometimes cutting across it1 against the under sides of which most of the ore occurs4 ,the primary sulphides are believed to be genetically related in some fashion to these porphyries4 ,the older view was that the agents of deposition were aqueous solutions from the surface above1 which derived their mineral content chiefly from the porphyries4 ,later views favor solutions coming directly from the porphyries or deeper igneous sources4 ,while in form and association these ores are characteristic igneous contact deposits1 they lack the high-temperature silicates which are so distinctive of many ores of this type4 ,the zinc ores of ,franklin ,furnace1 ,new ,jersey1 belong in the group associated with igneous agencies1 but have certain unique features4 ,they consist of willemite and zincite1 together with large amounts of franklinite 7an iron-manganese oxide7 and silicates1 in a pre-,cambrian white crystalline limestone near its contact with a coarse-grained granite-gneiss4 ,the origin of the ores is obscured by later shearing and metamorphism1 but it seems best explained by replacement of the limestone by heated solutions coming from the granitic mass4 ,the view has also been advanced that the ores originated in the limestone before the advent of the igneous rocks4 ,secondary concentration is not apparent4 ,,footnotes3 #cc ,ransome1 ,frederick ,leslie1 ,the copper deposits of ,ray and ,miami1 ,arizona3 ,prof4 ,paper #aae1 ,u4,s4 ,geol4 ,survey1 #aiai1 pp4 #ab-ac4 ,,chapter ,,xi ,,gold1 ,,silver1 ,,and ,,platinum ,,minerals ,,gold ,,ores ,,economic ,,features ,the principal and most essential use of gold is as a standard of value and a medium of exchange4 ,gold has been prized since the earliest times because of its luster1 color1 malleability1 and indestructibility1 and has long been used as a trading medium4 ,at present little of the metal is actually circulated from hand to hand4 ,stocks of gold1 however1 accumulated by governments and banking interests1 form the essential foundation of paper currency and of the vast modern system of credit relations4 ,in the settlement of international trade balances considerable quantities of gold frequently move from debtor to creditor nations4 ,although the amounts thus shipped are frequently great in value1 they are very small in volume4 ,it is interesting to note that the entire accumulated gold stocks of the world's governments--about nine billion dollars--cast in a solid block1 with the horizontal dimensions of the ,washington monument1 would be only about #ab feet high4 ,other uses of gold are in dentistry1 and in the arts for jewelry1 gilding1 and other forms of ornamentation4 ,consumption for these purposes has been increasing of late years and now takes a third or more of the world's annual production4 ,in the ,united ,states1 before war-time restrictions were adopted1 the consumption for jewelry and similar uses exceeded the consumption in coinage4 ,since the war it has exceeded the total domestic production of gold4 ,an interesting problem for the future is how an adequate supply of gold is to be distributed between monetary uses and the arts4 ,the curve of increase in the requirements of the arts indicates that1 unless there is greatly increased production1 all the world's gold will be necessary for the arts in a comparatively few years4 ,to retain it for monetary purposes would require government restrictions4 ,of all the mineral commodities1 gold has played perhaps the most important and certainly the most romantic part in the world's history4 ,the lure of gold has taken men to the remotest corners of the globe4 ,it has been the moving force in the settlement and colonization of new countries1 in numerous wars1 and in many other strenuous activities of the human race4 ,about two-thirds of the annual gold production of the world comes from the ,british ,empire--from ,south and ,west ,africa1 ,australasia1 ,canada1 and ,india4 ,a single colony1 the ,transvaal1 produces about #dj per cent of the world's total4 ,british capital1 which seems to have a particular affinity for investments in gold mines1 controls not only the larger part of the output from the colonies1 but also important mines in ,siberia1 ,mexico1 ,south ,america1 and the ,united ,states4 ,russia1 ,mexico1 and ,japan have small gold production4 ,the chief deposits of ,russia are those of ,siberia1 which have had an important output and have apparent great possibilities of increase4 ,other foreign districts are numerous and widely scattered1 but1 with the exception of ,colombia and ,korea1 no one of them yields #a per cent of the world's gold4 ,french interests control about a tenth of the production of the ,transvaal1 and minor supplies in ,mexico and ,south ,america--in all about #f per cent of the world's production4 ,germany and ,austria control less than #a per cent of the total gold production4 ,german interests formerly had extensive holdings in ,south ,africa and ,australia1 but during the war this control was eliminated4 ,the ,united ,states1 the second largest gold-producing country1 supplies about #bj per cent of the world's total4 ,commercially it controls production of another #e per cent in foreign countries1 chiefly in ,canada1 ,mexico1 ,south ,america1 and ,korea4 ,about one-fourth of the ,united ,states production comes from ,california4 ,other producing states in order of importance are ,colorado1 ,alaska1 ,south ,dakota1 ,nevada1 ,arizona1 ,montana1 and ,utah4 ,these eight states supply #ie per cent of the country's output1 and most of the remainder is obtained from other western states4 ,international movements of gold depend chiefly upon its use in the settlement of trade balances1 and are not governed by the considerations which control ordinary mineral commodities4 ,imports and exports vary with changing foreign trade balances4 ,large amounts of gold normally go to ,london1 because ,great ,britain requires all gold produced in the colonies to be sent to ,england2 but since ,england ordinarily has an unfavorable balance of trade1 much of this gold is reexported4 ,the ,united ,states up to a few years ago was also a debtor nation1 and more gold was exported than was imported4 ,during the war1 however1 this country became the greatest of the creditor nations and imports of gold1 chiefly from ,europe1 were several times the exports4 ,the total world's gold production up to #aibj has been upwards of #ai billions of dollars1 of which about #aj billions have gone into the arts or been hidden and lost1 leaving #i billions in monetary reserve4 ,at the present writing the ,united ,states government holds an unusually large fraction of the world's gold reserve1 about #bh per cent or #b billion dollars1--an amount equal to two-thirds of the aggregate production of the ,united ,states to date4 ,other large stocks of gold are held1 in order1 by ,great ,britain1 ,france1 and ,russia1 these three with the ,united ,states holding over a half of the world's total gold reserve4 ,germany has about #a-a_/b per cent of the total reserve1 and1 with its tremendous debt and no sources of new production1 is of course in a particularly unfavorable position4 ,the total amount of gold now 7#aibj7 accounted for by governments as money is not more than #aj per cent of the value of the notes and currency issued against this gold4 ,before the war it was #fj per cent4 ,in the ,united ,states the pre-war percentage was #ii-a_/b per cent4 ,since the war it has been #de per cent4 ,the ratio of gold to currency is now so small that the gold standard is hardly a physical fact1 but is to be regarded rather more as a profession of faith4 ,notwithstanding the recent falling off in gold production1 an increment of approximately #cej million dollars is potentially available each year to be added to the gold reserves4 ,whether this increment1 or a larger increment which may come from new discoveries1 is sufficient to maintain a reasonable proportion between gold stocks and the necessary normal increase in paper currency1 has been1 and doubtless will continue to be1 a subject of vigorous discussion and speculation4 ,during and immediately following the war1 the gold production of the world showed rather an alarming progressive decrease4 ,about #aiae the group of three greatest producers--,south ,africa1 ,united ,states1 and ,australia1--reached the acme of its production1 and output then fell off4 ,simultaneously there was a marked decrease of production in many of the less important districts4 ,this general decline was due in considerable part to the fact that during the war the price of gold was fixed and its use restricted to monetary purposes4 ,the price of gold1 which is itself the standard of value1 could not rise to offset growing mining costs and to maintain profits1 as was the case with iron1 copper1 and the other metals1--with the result that the margin of profit in gold mining became so small as materially to affect exploration and production4 ,another important cause of decreased production was the actual exhaustion of certain mines1 and the lowering of the grades of ore available in many others4 ,new discoveries did not supply these deficiencies4 ,in the ,united ,states1 for instance1 physical conditions of one kind or another were responsible for lessening of production from ,alaska1 ,cripple ,creek1 and ,california4 ,minor causes included conflicts in ,california between agricultural and mining interests over water rights1 and a succession of dry seasons which did not afford enough water for the working of placers2 and in ,alaska difficulties due to litigation over the oil-flotation process of recovering gold from its ores4 ,as a result of all these conditions1 many of the smaller mines were closed down1 others continued operations only by curtailing exploration and by mining solely the richest and most accessible ore bodies1 and there was a general discouragement and lack of inducement to engage in gold mining4 ,the gold situation has become a matter of great concern to the various governments1 since national financial stability and the confidence of the public in the national credit are based largely upon the acquirement of an adequate gold reserve4 ,both in ,england and in the ,united ,states1 committees of experts have been appointed to make exhaustive investigations and present recommendations for measures to stimulate production4 ,the report of the joint committee from the ,united ,states ,bureau of ,mines and ,geological ,survey gives a comprehensive review of the conditions in the gold-mining industry4#cd ,during the war there was vigorous demand by gold miners both in the ,united ,states and ,south ,africa for a bonus on gold4 ,these demands received serious consideration on the part of the governments1 but were denied on the general ground of the doubtful adequacy of such a measure to meet the situation1 and the danger of upsetting the gold standard of value4 ,in the ,united ,states1 for instance1 a bonus of #aj per ounce was asked for4 ,it did not appear likely that this could increase the annual production from the ,united ,states by more than #aj per cent1 in face of the physical conditions being met in gold mining4 ,the bonus would have had to be paid on all the gold mined1 which would make the increment of production very expensive2 to secure an added production of ten million dollars would have cost in the neighborhood of forty millions4 ,ten millions is only one-third of #a per cent of the gold reserve already held by this country1 and it would obviously have taken a long time for this small increase in annual production to make itself felt in the size of the gold reserves4 ,since the war gold has gone to a considerable premium in ,england1 due to the action of the ,british government in establishing a free market1--that is1 abandoning the restriction that gold marketed in ,london should be offered to the government or the ,bank of ,england at the fixed statutory price for monetary purposes4 ,with the pound sterling at a considerable discount outside of ,england1 other countries could afford to bid1 in terms of ,british currency1 far above the ,british mint price4 ,the result is that the ,south ,african miner of gold receives a premium due to depreciation of sterling exchange1 while the ,american miner still receives the regular mint price4 ,the agitation for a bonus therefore continues in the ,united ,states4 ,however1 with the removal of war-time restrictions gold has been allowed to go to the arts1 the demand from which is already equal to one-third of the world's gold production1 is rapidly increasing1 and is temporarily acute due to the accumulation of requirements resulting from war restrictions4 ,this situation has a general tendency to improve the position of the gold miner1 though the outlook is still far from bright4 ,it is an interesting fact that ,india is absorbing a good half of the free gold4 ,india1 in regard to its demand for precious metals and stones1 has been described as an abyss from which there is no return4 ,this is an important contributing cause of the shortage of gold in the rest of the world4 ,looking forward to the future1 it seems that increased exploration1 which is resulting from the present premium on gold1 is likely to bring in new reserves to increase production4 ,because of lack of important discoveries in recent years1 there is pessimism in some quarters as to the possibilities of large increase of production2 but1 considering the history of gold discoveries1 and the amount of ground still to be explored both areally and vertically1 this pessimism does not seem to be wholly justified from the geologic standpoint4 ,curves representing the world's gold production in past years show periods of increasing annual production as new fields are discovered1 followed by periods of decreasing production when no new ore bodies are coming in to replace dwindling reserves4 ,it is entirely possible that in recent years the gold-mining industry has been merely in one of these temporary stagnant periods4 ,there are many regions1 both in the vicinity of worked-out lodes and in unsettled and poorly explored countries1 where gold may still be discovered2 there may be far greater resources of this metal still covered up than all those which man has thus far uncovered4 ,a single new deposit or district may make a great difference in the world's production1 as suggested by the experience of the past4 ,regions which are especially attractive for exploration and the discovery of new deposits are in ,siberia and ,south ,america1 which in the opinion of many engineers may eventually rival ,south ,africa4 ,mexico1 with the establishment of a stable government1 should also have a greatly increased production4 ,,geologic ,,features ,the principal gold mineral is native or metallic gold4 ,this occurs in nature in small scales1 crystals1 and irregular masses1 and also in microscopic particles mechanically mixed with pyrite and other sulphides4 ,chemically1 gold is very inactive and combines with but few other elements4 ,a small part of the world's supply is obtained from the gold-silver tellurides--calaverite1 sylvanite1 krennerite1 and petzite4 ,gold deposits are of two general classes--placers1 and veins or lodes4 ,placers1 which are in general the more easily discovered and more easily worked deposits1 have in the past been the chief source of the world's gold supply4 ,it is estimated that in the first twenty-seven years of the modern era of gold-mining1 beginning with the discovery of gold in ,california in #ahdh1 #hg per cent of the world's production was obtained from placers4 ,at present the placers of recent geologic age supply a tenth to a fifth of the gold1 and ancient or fossil placers in the ,transvaal supply another two-fifths4 ,in the ,united ,states about a fourth of the gold production comes from placers1 mainly from ,california and ,alaska4 ,placers are detrital or fragmental sediments containing the ore in mechanical fragments1 which are derived from the erosion and transportation of solid-rock veins or lodes1 sometimes called the mother lode4 ,during the process of transportation and deposition there is more or less sorting1 because of differing density of the mineral fragments1 resulting in the segregation or concentration of the ore minerals in certain layers or channels4 ,gold1 because of its weight1 tends to work down toward bedrock1 or into scoured or excavated portions of stream channels4 ,in a few cases it is carried in some quantity to the sea and concentrated in beach sands4 ,the processes are not unlike the mechanical concentration of ores by crushing and water sorting4 ,seldom1 however1 do the processes go far enough in nature to produce an ore which can be used directly without some further mechanical sorting4 ,ore minerals concentrated in placers are those which resist abrasion and chemical solution during the processes of weathering and transportation1 and which have a density sufficiently high so that they are partially sorted out and concentrated from the accompanying quartz and other minerals4 ,to warrant their recovery they must also be of such high intrinsic value that it pays to mine small quantities4 ,the most important of such minerals are gold1 tin1 platinum1 and the precious stones4 ,iron1 copper1 lead1 and zinc minerals are often somewhat concentrated as placers1 but their intrinsic value is not high enough to warrant the attempt to recover them in the large amounts necessary to make them commercially available4 ,placers are forming now and have formed at all stages of the earth's history4 ,early placers may be reworked and further concentrated by renewal of the proper erosional and transportational conditions4 ,old placers may be buried beneath younger rocks1 cemented1 and more or less recrystallized4 ,fossil placers of this kind are best represented by deposits in the ,black ,hills of ,south ,dakota and probably by the ,south ,african gold deposits4 ,in the ,witwatersrand deposits of ,south ,africa1 the gold is concentrated in the lower parts of large conglomerate and quartz sand layers of great areal extent4 ,pebbles of the conglomerate are mainly quartz and quartzite4 ,the gold1 in particles hardly visible to the eye1 is in a sandy matrix and is associated with chloritoid1 sericite1 calcite1 graphite1 and other minerals4 ,the origin of the gold deposits of this district is not entirely agreed on1 but the evidence seems on the whole to favor their placer origin4 ,some investigators of these ores believe them to have been introduced into the conglomerate and sand by later solutions1 possibly by hot solutions related to certain diabase intrusions that cut the beds4 ,in the vein or lode or hard-rock deposits1 the gold is mainly metallic gold1 and to a minor extent is in the form of gold tellurides4 ,it is usually closely associated with iron pyrite in a matrix or gangue of quartz4 ,seldom is a gold deposit free from important values in other minerals4 ,about #hd per cent of the gold mined in vein or lode deposits of the ,united ,states is associated with silver minerals1 the combined value averaging about #f per ton2 about #ac per cent comes from copper ores which have an average yield of gold and silver of #ej;c4 per ton2 and #c per cent comes from zinc and lead ores1 with an average gold and silver yield ranging from #a to #f per ton4 ,the geologic occurrence of gold in the copper1 lead1 and zinc ores has already been referred to in the discussions of these ores4 ,reference will be made here only to the vein deposits in which gold1 with silver1 constitutes the principal values4 ,because of their common gangue of quartz these are often called dry or siliceous ores4 ,their principal occurrence is in distinct fissure veins in igneous rocks1 with more or less replacement of the wall rock4 ,the igneous rocks are commonly acid intrusives of a granite or porphyry type1 less commonly intrusives of gabbro and diabase and surface lavas of rhyolite and basalt4 ,in a few cases the ores are contact-metamorphic deposits of the type described under copper ores4 ,in still rarer cases they are in pegmatites4 ,gold is commonly associated with minerals and wall-rock alterations indicating deposition by hot solutions1 which are inferred to have come from the igneous rocks4 ,because of the resistant nature both of ore minerals and gangue1 weathering and secondary concentration have had little effect in enriching gold deposits4 ,so far as there has been any noticeable effect on the gold content of the ores1 it has been due to the leaching out of other constituents1 principally pyrite and other sulphides1 leaving the gold present in slightly larger proportions4 ,locally there is evidence of solution of gold in weathered zones and its deposition in the sulphide zones below4 ,solution is believed to be accomplished by chloride solutions1 and is favored by the presence of manganese which delays precipitation4 ,the precipitating agent below may be ferrous sulphate1 various sulphides1 native metals1 or organic matter4 ,of the vein or lode gold ores in the ,united ,states some of the most productive and best known have the following geologic features3 ,the ,california gold belt extends north and south along the west slope of the ,sierra ,nevada ,mountains4 ,the ore is in a series of parallel and overlapping veins striking with the trend of the range1 associated with granodiorite intrusives in schist and slate4 ,there is no pronounced secondary concentration4 ,these deposits are the source of most of the great placer deposits of ,california1 hence the name ,mother ,lode applied to a part of them4 ,the principal ore deposits are somewhat removed from the main mass of intrusive which forms the crest of the ,sierra ,nevada range1 and are more closely related to the smaller similar intrusive masses farther down the slope4 ,the gangue is mainly quartz4 ,at ,juneau1 ,alaska1 great dikes of albite-diorite intrude greenstones and schists1 and low-grade gold ores occur in shattered portions of the diorite4 ,these ores were mined on a great scale at the ,treadwell ,mine4 ,another famous low-grade deposit is the ,homestake ,mine in the ,black ,hills of ,south ,dakota1 where pre-,cambrian slates and schists of sedimentary origin are impregnated with gold1 associated with quartz1 dolomite1 calcite1 pyrite1 and other minerals4 ,the origin is supposed to have some connection with intrusives into the schists2 but the relations of the ores to intrusives1 both in age and in place1 present many puzzling questions which make conclusion as to origin very difficult4 ,in the ,cripple ,creek district of ,colorado1 a volcanic neck two or three miles in diameter breaks through pre-,cambrian granites1 gneisses1 and schists4 ,the volcanic rocks consist mainly of tuffs and breccias cut by basic dikes4 ,the ore bodies are in fissures and sheeted zones1 principally in the granitic rocks1 but associated with these dikes4 ,the ore is mainly gold telluride1 in a gangue of quartz together with pyrite and a variety of minerals characteristic of hot-water solutions4 ,also the wall rocks have the characteristic hot-water alterations4 ,there is slight enrichment near the surface4 ,at ,goldfield1 ,nevada1 native gold is found in surface igneous flows of a dacite type1 which have undergone extensive hydrothermal alterations characterized by the development of alunite 7a potassium-aluminum sulphate71 quartz1 and pyrite4 ,the ore fills fissures to some extent1 but is mainly a replacement of the wall rock4 ,association with typical hot-water minerals and hydrothermal alterations of the wall rock are again believed to indicate the origin of the ores through ascending hot solutions from a deep source4 ,one of the interesting features of this occurrence is the abundance of alunite4 ,sulphate minerals are commonly formed by oxidizing solutions4 ,the abundant presence1 therefore1 of a sulphate mineral with minerals of a primary deep-seated source has led to much discussion of origin4 ,the hypothesis was developed that these minerals result from the interaction of deep-seated sulphide-bearing solutions with surface oxidizing solutions4#ce ,it may be noted that in recent years other sulphate minerals have been occasionally regarded as primary1 including gypsum1 anhydrite1 barite1 and others4 ,it has been suggested that if igneous emanations contain free oxygen and sulphur1 or sulphur dioxide1 it would be expected that as they become cool sulphur trioxide would be formed which would result in the sulphate at suitable temperature4#cf ,other deposits containing gold are discussed in connection with silver on following pages4 ,,silver ,,ores ,,economic ,,features ,silver has two important uses--in money and in the arts4 ,as money1 it is used in the ,united ,states and ,europe for subsidiary coinage1--silver coins normally circulating at more than their intrinsic value1--but its greatest monetary use is in ,india and ,china1 where it has been the basis for the settlement of foreign exchange balances4 ,in ,china also it is the money standard of the country4 ,in the arts1 silver is employed chiefly in the making of articles of luxury1 such as jewelry and tableware4 ,in the ,orient this use is closely related to its use as money1 since the natives invest their savings both in silver jewelry and silver coins4 ,there is some consumption of silver by certain chemical industries1 and quantities of increasing importance are used in the form of silver salts by the photographic and moving picture industries4 ,it has been estimated that before #aiad about two-thirds of the new silver produced went into the arts and one-third into money4 ,during the war1 however1 increasing amounts were used in coinage1 and less than one-fifth of the output was used in the arts4 ,demands for silver for monetary purposes will probably continue to take the larger part of the world's production for some time4 ,in this connection it may be noted that ,india has adopted a gold standard1 but that the conservative habits of the population will doubtless continue to call for large amounts of silver4 ,about half of the silver production of the world comes from the dry or siliceous silver ores1 which are mined solely for that metal and the associated gold2 and about half of the production is obtained as a by-product in the mining of other metals1 principally copper and lead4 ,the average grades of these ores1 in combined values of gold and silver1 were referred to on p4 #bbh4 ,while the aggregate amount of silver obtained as a by-product of other ores is large1 the percentage of silver in the copper or lead in any mine is ordinarily very small4 ,consequently the world output of silver depends to a considerable extent upon conditions in the copper- and lead-mining industries4 ,of the total world output of silver1 normally about #ge per cent comes from ,north ,america4 ,of this the ,united ,states and ,mexico each produce about two-fifths and ,canada one-fifth1 and minor amounts are produced in ,central ,america4 ,in late years1 political disturbances in ,mexico reduced that country's production to less than half the normal figure1 and the ,united ,states took the place which ,mexico had held for many years as the leading silver producer4 ,the ,united ,states and ,mexican supply is obtained from the ,rocky ,mountain belt1 and the ,canadian production comes chiefly from the ,cobalt1 ,ontario1 district4 ,outside of ,north ,america the principal producing areas are ,australia1 ,south ,america 7,peru and to a less extent ,bolivia and ,chile71 ,europe 7chiefly from ,spain1 ,germany1 and ,austria-,hungary1 but with smaller amounts from all the other countries71 and ,japan4 ,thus1 while there are sources of silver in many places1 the great bulk of the world's output comes from ,north ,america4 ,in the financial ownership of mines1 including ownership in other countries1 the ,united ,states controls over half the world's silver1 ,great ,britain about a third1 and ,germany about a tenth 7principally in ,mexico74 ,all the silver mined in the ,united ,states is smelted and refined by domestic plants2 and in addition much of the ,canadian1 ,mexican1 and ,south and ,central ,american silver is exported to the ,united ,states as ore and base bullion1 to be treated in this country4 ,the ,united ,states is therefore the great silver-selling country of the world4 ,the great silver-consuming countries are ,india and ,china1 and normally about a half of the world's output goes to these two countries4 ,this major movement of silver1 from ,america to the ,far ,east1 takes place through the ,london market1 since ,england has been the chief nation trading in the ,orient4 ,the balance of the world's silver consumption is widely distributed among the countries of ,europe and ,south ,america and the ,united ,states 7which consumes about one-tenth of the total74 ,for the ,european trade most of the silver also goes through ,london1 which is the great clearing-house and the market where prices are fixed4 ,in the later years of the war and immediately after1 the demands for silver were probably twice the world's output4 ,the resulting rise in price was unprecedented4 ,silver actually became worth more as bullion than as currency1 and in ,europe much trouble was experienced because of its withdrawal from currency to be melted up4 ,this condition was later followed by an equally striking drop in price as supply caught up with demand4 ,in the ,united ,states1 as in many other countries1 it was desired during the war to accumulate large stocks of gold as a basis of credit for the flotation of government loans1 and the export of gold was prohibited4 ,consequently in the settlement of foreign trade balances1 particularly with the nations of the ,orient1 very large amounts of silver bullion had to be used4 ,current production proved inadequate1 and it was necessary to utilize the stocks of silver dollars in the ,united ,states ,treasury4 ,to this end the ,pittman ,silver ,act1 passed in ,april1 #aiah1 authorized the melting down and conversion into bullion of #cej1jjj1jjj dollars out of the ,treasury stock1 and the retirement of a corresponding number of silver certificates and the issue of ,federal ,reserve bank notes4 ,in this manner old stocks of silver1 ,manila dollars1 etc41 were called into service--though the stage was not reached1 as it was in ,germany1 where it became necessary to melt down silver plate and ornaments4 ,the silver used for exchange and export was to be replaced by the purchase of bullion from ,american producers at #a per ounce1 and its coining into new dollars4 ,a minimum price of #a per ounce was thus established for silver bullion4 ,the immediate result was to increase the price of silver at the mine2 but with the continued rise in demands for silver1 the price in the open market went far above this figure1 the maximum being reached in #aibj when the price of silver went to #a4ci per ounce4 ,naturally1 but little silver was then offered to the government at the fixed price of #a under the ,pittman ,act4 ,with the more recent slump in the general market for silver to a price below #a1 offers to the government under the ,pittman ,act have been renewed4 ,that part of the silver production which is a by-product of copper production has been low since the war1 because of the stagnation in the copper industry4 ,the production from lead ores1 on the other hand1 was not handicapped by lack of demand for lead4 ,with the restoration of order in ,mexico1 a presumption of large silver production in that country may be expected4 ,increases may probably be expected also from new mines in ,burma and from ,bolivia4 ,on the whole1 no large increase in world production can be assumed from present known resources4 ,new discoveries will be necessary to make any considerable change4 ,of the mine production of silver in the ,united ,states1 about two-thirds of the total comes from the states of ,montana1 ,utah1 ,idaho1 and ,nevada4 ,other considerable producers are ,colorado1 ,arizona1 ,california1 ,alaska1 and ,new ,mexico4 ,all the other states together produce less than #e per cent of the total4 ,the most important single districts are the ,butte district of ,montana1 the ,coeur d',alene district of ,idaho1 and the ,tonopah district of ,nevada1 supplying respectively about one-fifth1 one-eighth1 and one-tenth of the country's total silver output4 ,,geologic ,,features ,the most important mineral of silver is the sulphide1 argentite or silver glance4 ,other minerals which yield a minor percentage of the total silver produced are the silver-antimony sulphides1 pyrargyrite or ruby silver1 stephanite or black silver1 and polybasite2 the silver-arsenic sulphides1 proustite or light ruby silver and pearcite2 and the silver antimonide1 dyscrasite4 ,in the oxide zone the most abundant minerals are cerargyrite 7silver chloride7 and native or horn silver4 ,in addition to these definite mineral forms1 silver is present in many ores in an undetermined form in other sulphides1 notably in galena1 sphalerite1 and pyrite4 ,silver differs from gold in that it is chemically active and forms many stable compounds1 of which only the more important have been mentioned4 ,the fact that half the world's silver is obtained as a by-product in the mining of other metals has been referred to4 ,in the ,united ,states about a third of the production comes from dry or siliceous ores1 over a third from lead and zinc ores1 and a fourth to a third from copper ores4 ,a fraction of #a per cent of the total is obtained as a by-product of gold placers1 and all the remainder is won from lode or hard-rock deposits4 ,the general geologic features of the silver-bearing copper and lead ores1 and of the dry or siliceous gold and silver ores1 have been described on previous pages4 ,the ,philipsburg district has been referred to in connection with manganese ores1 and the ,bolivian tin-silver ores will be described in connection with tin4 ,we shall consider here only a few of the more prominent districts which have been primarily silver producers4 ,the ,cobalt district of northern ,ontario is the most productive silver district in ,north ,america4 ,the ores are found in numerous short1 narrow veins1 principally in pre-,cambrian sediments near a thick quartz-diabase sill4 ,locally they penetrate the sill4 ,native silver and various silver sulphides1 arsenides1 and antimonides are associated with minerals of cobalt1 nickel1 bismuth1 lead1 and zinc1 in a gangue of calcite and some quartz4 ,the ore is of very high grade4 ,the ore minerals are believed to have been deposited by hot solutions emanating from deep magmatic sources after the intrusion of the diabase4 ,the present oxidized zone is very shallow1 but may have been deeper before being stripped off by glaciation2 it is characterized by native silver and arsenates of nickel and cobalt in the form of the green nickel bloom and the pink cobalt bloom4 ,the silver minerals are distinctly later in origin than the cobalt and nickel in the unoxidized zone1 as evidenced by the relations of the mineral individuals when seen under the microscope4 ,this fact1 together with the abundance of native silver in the oxide zone1 has suggested downward concentration of the silver by surface waters2 but recent studies have indicated the probability that some of the silver at least was deposited by the later ascending solutions of magmatic origin4 ,in the ,tintic district of central ,utah1 ,paleozoic limestones have been intruded by monzonite 7an acid granitic or porphyritic igneous rock71 and covered by surface flows1 the flows for the most part having been removed by subsequent erosion4 ,the sediments have been much folded and faulted1 and the ore bodies occur as fissure veins which locally widen into chimneys or pipes in fracture zones1 accompanied by much replacement of limestone4 ,there is a rough zonal arrangement of the ore minerals around the intrusive1 gold and copper minerals 7chiefly enargite and chalcopyrite7 being more prominent near the intrusive1 and argentiferous galena and zinc blende richer at greater distances4 ,silver constitutes the principal value4 ,the gangue is mainly fine-grained quartz or jasperoid1 and barite4 ,the water table is at unusually great depths 7#b1djj feet7 and there is a correspondingly deep oxidized zone1 which is characterized by lead and zinc oxide minerals much as at ,leadville 7p4 #bai74 ,the ,comstock ,lode at ,virginia ,city1 ,nevada1 on the east slope of the ,sierra ,nevadas1 was one of the most famous bonanza deposits of gold and silver in the world4 ,while the richer ore has all been extracted1 lower-grade material is still being mined and the fissure is still being followed1 in the hope of some day striking another fabulously rich ore body4 ,the lode occupies a fault fissure parallel to the trend of the range and dipping about #dj degrees to the east1 which can be traced about two and a half miles along the strike1 with igneous rocks forming both hanging and foot walls4 ,there are no sedimentary rocks in the district4 ,the high-grade part of the vein is several hundred feet in thickness1 with many irregular branches2 the great thickness has been thought to be at least in part due to the tremendous pressure exerted by growing quartz crystals4 ,the wall rocks have undergone a propylitic alteration1 with development of chlorite1 epidote1 and probably sericite1 much as at ,butte4 ,the ore contains rich silver sulphide minerals and native gold1 in a gangue composed almost entirely of quartz4 ,the ore was doubtless formed by hot solutions1 but the exact nature of these solutions1 whether magmatic or meteoric1 has not been proven4 ,the hypothesis was early developed that the ores were deposited by surface waters1--which are supposed to have fallen on the summits of the ,sierra ,nevadas1 to have sunk to great depths where they were heated1 enabling them to pick up metallic constituents from the diabase forming one wall of the ore body1 and to have risen under artesian pressure along the fault plane1 where loss of heat and pressure resulted in deposition4 ,later studies have emphasized the similarity of the ore-depositing conditions with those in other districts where the ores are believed to have come directly from magmatic sources1 and this origin is now generally favored for the ,comstock ,lode4 ,however1 the earlier theory has not been disproved4 ,the ,tonopah1 ,nevada1 district is very similar to the ,goldfield district 7p4 #bcj74 ,silver and gold are found in veins and replacements in a series of ,tertiary volcanic flows and tuffs1 all of which have been complexly faulted4 ,silver is the dominant constituent of value4 ,the formation of fissures and faults accompanying and caused by the intrusion and cooling of lavas was first clearly shown in this district4 ,evidences of origin through the work of hot solutions1 probably magmatic1 are the close association of the ores in place and in time with the igneous rocks--ore deposition in most of the flows having taken place before the next overlying flows were put down1--the presence of fluorine1 the nature of the wall-rock alterations1 the fact that both hot and cold springs are found close together underground 7indicating unusual sources for the hot springs71 the contrast in composition between the ores and the country rock1 and the general relation of these ores to a large number of similar occurrences in ,tertiary lavas in the same general area4 ,under weathering conditions1 the silver sulphide minerals in general are oxidized to form native silver and cerargyrite1 which are relatively insoluble and remain for the most part in the oxide zone4 ,silver is less soluble than copper and zinc1 but more soluble than gold2 and to some extent it is removed in solution1 particularly where the oxidation of pyrite forms ferric sulphate4 ,farther down it may be reprecipitated as native silver1 argentite1 and the sulpho-salts1 by organic matter or by various sulphides4 ,the secondarily enriched ores are in a few districts1 as at ,philipsburg1 ,montana1 the most valuable portions of the deposits4 ,in other cases1 sulphide enrichment does not appear to have contributed greatly to the values4 ,the zones of oxide ores1 secondary sulphide ores1 and primary or protores are in most silver deposits much less regular and much less definitely marked than in the case of copper ores4 ,,platinum ,,ores ,,economic ,,features ,the principal uses of platinum are3 as a catalytic agent in the contact process for the manufacture of sulphuric acid1 and in the making of nitric acid from ammonia2 for chemical laboratory utensils that must be resistant to heat and acids2 for electrical contacts for certain telephone1 telegraph1 and electrical control instruments1 and for internal combustion engines2 in dental work2 and for jewelry4 ,in normal times before the war1 it is estimated that in the ,united ,states the jewelry and dental industries used #ge per cent of the platinum metals consumed1 the electrical industry #bj per cent1 and the chemical industry #e per cent4 ,during the war1 with the extraordinary expansion of sulphuric and nitric acid plants1 these proportions were reversed and the chemical and electrical industries consumed about two-thirds of the platinum4 ,substitutes have been developed1 particularly for the electrical uses1 and the demand from this quarter may be expected to decrease4 ,about #ij per cent of the world's crude platinum produced annually comes from the ,ural ,mountains in ,russia4 ,the deposits next in importance are those of ,colombia4 ,small amounts are produced in ,new ,south ,wales1 ,tasmania1 ,new ,zealand1 ,borneo1 ,british ,columbia1 ,united ,states1 ,india1 and ,spain2 and as a by-product in the electrolytic refining of the ,sudbury1 ,canada1 nickel ores4 ,the extension of this method of refining to all of the ,sudbury ores would create an important supply of platinum4 ,the ,colombian output has been increasing rapidly since #aiaa4 ,meanwhile the ,russian production has declined2 and from the best information available1 it is not likely that ,russia will be able to maintain production for many more years4 ,estimates of the life of the ,russian fields are from #ab to #bj years at the pre-war rate of production4 ,the platinum situation is commercially controlled by buying and mine-operating agencies1--the ,french having1 before the war1 practically dominated the ,russian industry1 while ,american interests controlled in ,colombia4 ,the situation is further influenced by four large refineries1 in ,england1 ,germany1 ,united ,states1 and ,france4 ,before the war the ,united ,states produced less than #a per cent of the new platinum it consumed annually4 ,production comes principally from ,california1 with smaller amounts from ,oregon1 ,alaska1 and ,nevada4 ,the many efforts which have been made to develop an adequate domestic supply of this metal do not indicate that the ,united ,states can ever hope to become independent of foreign sources for its future supplies of platinum4 ,there is little reason to doubt that the ,colombia field1 commercially dominated by the ,united ,states1 holds great promise for the future4 ,the output has come largely from native hand labor1 and with the installation of dredges can probably be greatly increased4 ,during the war1 the need for platinum for war manufactures was so urgent and the production so reduced1 that restrictions against its use in jewelry were put into force in all the allied countries4 ,the ,united ,states government secured quantities of platinum which would have been sufficient for several years' use if war had continued4 ,with the cessation of hostilities restrictions on the use of platinum were removed1 and the accumulated metal was released by the government from time to time in small quantities2 but the demands for platinum in the arts were so great that prices for a time tended to even higher levels than during the war4 ,more recently supply is again approaching demand4 ,,geologic ,,features ,platinum1 like gold1 occurs chiefly as the native metal4 ,this is usually found alloyed with iron and with other metals of the platinum group1 especially iridium1 rhodium1 and palladium4 ,most of the platinum as used in jewelry and for electrical purposes contains iridium1 which serves to harden it4 ,paladium-gold alloys are a substitute for platinum1 chiefly in dental uses4 ,the original home of platinum is in basic igneous rocks1 such as peridotites1 pyroxenites1 and dunites1 where it has been found in small1 scattered crystals intergrown with olivine1 pyroxene1 and chromite4 ,platinum is very dense and highly resistant to oxidation and solution4 ,in the breaking up and washing away of the rocks1 therefore1 it is concentrated in small grains and scales in stream and beach placers4 ,of the world production of platinum over #ii per cent has been derived from placers4 ,the ,ural ,mountain deposits of ,russia are gold- and platinum-bearing placers1 in streams which drain areas of dunite rock containing minute quantities of native platinum4 ,the deposits of ,colombia and ,australasia are placers of a similar character4 ,in the ,united ,states small quantities of platinum are recovered from the gold-bearing gravels of ,california and ,oregon1 where the streams have come from areas of serpentine and peridotite4 ,a platinum arsenide1 called sperrylite1 is sometimes found associated with sulphide minerals in basic igneous rocks4 ,at ,sudbury1 ,ontario1 this mineral1 together with palladium arsenide1 is found in the nickel ores1 especially in the weathered zone where it is concentrated by removal of more soluble materials4 ,it has also been found in the copper mines of ,rambler1 ,wyoming4 ,in the ,yellow ,pine district of southern ,nevada1 metallic gold-platinum-palladium ore shoots are found in association with copper and lead ores1 in a fine-grained quartz mass which replaces beds of limestone near a granitic dike4 ,no basic intrusives are known in the district4 ,the deposit is unusual in that it has a comparatively high content of platinum 7nearly an ounce to the ton71 and is probably genetically related to acid intrusives4 ,from all these deposits1 only small quantities of platinum are mined4 ,,footnotes3 #cd ,report of a joint committee appointed from the ,bureau of ,mines and the ,united ,states ,geological ,survey by the ,secretary of the ,interior to study the gold situation3 ,bull4 #add1 ,u4 ,s4 ,bureau of ,mines1 #aiai4 ,see also ,report of ,special ,gold ,committee to ,secretary of the ,treasury1 ,february #aa1 #aiai4 #ce ,ransome1 ,f4 ,l41 ,the geology and ore deposits of ,goldfield1 ,nevada3 ,prof4 ,paper #ff1 ,u4,s4 ,geol4 ,survey1 #aiji1 p4 #aic4 #cf ,butler1 ,b4 ,s41 ,loughlin1 ,g4 ,f41 ,heikes1 ,v4 ,c41 and others1 ,the ore deposits of ,utah3 ,prof4 ,paper #aaa1 ,u4,s4 ,geol4 ,survey1 #aibj1 p4 #aie4 ,,chapter ,,xii ,,miscellaneous ,,metallic ,,minerals ,,aluminum ,,ores ,,economic ,,features ,bauxite 7hydrated aluminum oxide7 is the principal ore of aluminum4 ,over three-fourths of the world's bauxite production and #fe per cent of the ,united ,states production is used for the manufacture of aluminum4 ,on an average six tons of bauxite are required to make one ton of metallic aluminum4 ,other important uses of bauxite are in the manufacture of artificial abrasives in the electric furnace1 and in the preparation of alum1 aluminum sulphate1 and other chemicals which are used for water-purification1 tanning1 and dyeing4 ,relatively small but increasingly important quantities are used in making bauxite brick or high alumina refractories for furnace-linings4 ,aluminum is used principally in castings and drawn and pressed ware1 for purposes in which lightness1 malleability1 and unalterability under ordinary chemical reagents are desired4 ,thus it is used in parts of airplane and automobile engines1 in household utensils1 and recently in the framework of airplanes4 ,aluminum wire has been used as a substitute for copper wire as an electrical conductor4 ,aluminum is used in metallurgy to remove oxygen from iron and steel1 and also in the manufacture of alloys4 ,powdered aluminum is used for the production of high temperatures in the ,thermite process1 and is a constituent of the explosive1 ammonal1 and of aluminum paints4 ,deposits of bauxite usually contain as impurities silica 7in the form of kaolin or hydrous aluminum silicate71 iron oxide1 and titanium minerals1 in varying proportions4 ,bauxites to be of commercial grade should carry at least #ej per cent alumina1 and for the making of aluminum should be low in silica though the content of iron may be fairly high4 ,for aluminum chemicals materials low in iron and titanium are preferred2 and for refractories which must withstand high temperatures1 low iron content seems to be necessary4 ,the abrasive trade in general uses low-silica high-iron bauxites4 ,the only large producers of bauxite are the ,united ,states and ,france1 which supplied in normal times before the war over #ie per cent of the world's total4 ,small amounts are produced in ,ireland1 ,italy1 ,india1 and ,british ,guiana4 ,during the war a great deal of low-grade bauxite was mined in ,austria-,hungary and possibly in ,germany2 but on account of the large reserves of high-grade material in other parts of the world1 it is doubtful whether these deposits will be utilized in the future4 ,bauxites of good grade have been reported from ,africa1 ,australia1 and many localities in ,india4 ,from geologic considerations it is practically certain that there are very large quantities available for the future in some of these regions4 ,the international movements and the consumption of bauxite are largely determined by the manufacture of aluminum1 and to a lesser extent by the manufacture of abrasives and chemicals4 ,the principal foreign producers of aluminum are ,france1 ,switzerland 7works partly ,german-owned71 ,norway 7works controlled by ,english and ,french capital71 ,england1 ,canada1 ,italy1 ,germany1 and ,austria4 ,french bauxite has normally supplied the entire ,european demands1--with the exceptions that ,italy procures part of her requirements at home1 and that the ,irish deposits furnish a small fraction of the ,english demand4 ,the deposits of southern ,france1 controlled largely by ,french but in part by ,british capital1 have large reserves and will probably continue to meet the bulk of ,european requirements4 ,france also has important reserves of bauxite in ,french ,guiana4 ,the ,united ,states produces about half of the aluminum of the world1 and is the largest manufacturer of artificial abrasives and probably of aluminum chemicals4 ,most of these are made from domestic bauxite4 ,prior to the war1 the ,united ,states imported about #aj per cent of the bauxite consumed1 but these imports were mainly high-grade ,french bauxite which certain makers of chemicals preferred to the domestic material4 ,the small production of ,guiana is also imported into the ,united ,states4 ,bauxite is exported to ,canadian makers of aluminum and abrasives4 ,during the war period domestic deposits were entirely capable of supplying all the domestic as well as ,canadian demands for bauxite1 although these demands increased to two and one-half times their previous figure4 ,at the same time considerable amounts of manufactured aluminum products were exported to ,europe1 whereas aluminum had previously been imported from several ,european countries4 ,the ,united ,states production of bauxite comes mainly from ,arkansas1 with smaller amounts from ,tennessee1 ,alabama1 and ,georgia4 ,the reserves are large but are not inexhaustible4 ,most of the important deposits are controlled by the large consumers of bauxite1 principally the ,aluminum ,company of ,america and its subsidiaries1 though certain chemical and abrasive companies own some deposits4 ,the ,aluminum ,company of ,america also controls immense deposits of high-grade bauxite in ,dutch and ,british ,guiana1 and further exploration by ,american interests is under way4 ,with the return to normal conditions since the war1 some of the domestic bauxite deposits probably can not be worked at a profit1 a situation which is likely to require the development of the tropical ,american deposits4 ,,geologic ,,features ,aluminum is the third most abundant element in the common rocks and is an important constituent of most rock minerals2 but in its usual occurrence it is so closely locked up in chemical combinations that the metal cannot be extracted on a commercial scale4 ,in the crystalline form aluminum oxide constitutes some of the most valuable gem stones4 ,many ordinary clays and shales contain #be to #ce per cent alumina 7,al#b,o#c71 and the perfection of a process for their utilization would make available almost unlimited aluminum supplies4 ,the principal minerals from which aluminum is recovered today are hydrous aluminum oxides1 the most prominent of which are bauxite1 gibbsite1 and diaspore--the aggregate of all these minerals going commercially under the name of bauxite4 ,prior to the discovery of bauxite ores1 cryolite1 a sodium-aluminum fluoride obtained from pegmatites in ,greenland1 was the chief source of aluminum4 ,it is only within about the last thirty-five years that bauxite has been used and that aluminum has become an important material of modern industry4 ,cryolite is used today to form a molten bath in which the bauxite is electrolytically reduced to aluminum4 ,bauxite deposits in general are formed by the ordinary katamorphic processes of surface weathering1 when acting on the right kind of rocks and carried to an extreme4 ,in the weathering of ordinary rocks the bases are leached out and carried away1 leaving a porous mass of clay 7hydrous aluminum silicates71 quartz1 and iron oxide4 ,in the weathering of rocks high in alumina1 and low in iron minerals and quartz1 deposits of residual clay or kaolin nearly free from iron oxide and quartz are formed4 ,under ordinary weathering conditions the kaolin is stable2 but under favorable conditions1 such as obtain in the weathered zones of tropical climates1 it is broken up1 the silica is taken into solution and carried away1 and hydrous aluminum oxides remain as bauxite ores4 ,this extreme type of weathering is sometimes called lateritic alteration 7see pp4 #agb-agc74 ,impurities of the bauxite ores are the small quantities of iron and titanium present in the original rocks1 together with the kaolin which has not been broken up4 ,the deposits usually form shallow blankets over considerable areas1 with irregular lower surfaces determined by the action of surface waters--which work most effectively where joints or other conditions favor the maximum circulation and alteration4 ,a certain degree of porosity in the original rock is also known to favor the alteration4 ,a complete gradation from the unaltered rock through clay to the high-grade bauxite1 with progressive decrease in bases and silica1 concentration of alumina and iron oxide1 and increase of moisture and pore space1 is frequently evident 7see ,fig4 #ac74 ,the bauxite is earthy1 and usually shows a concretionary or pisolitic structure similar to that observed in residual iron ores 7p4 #agb74 ,near the surface there may be an increase in silica1--probably due to a reversal of the usual conditions by a slight leaching of alumina1 thus concentrating the denser masses of kaolin which have not been decomposed4 ,the ,arkansas bauxite deposits1 the most important in the ,united ,states1 are surface deposits overlying nepheline-syenite1 an igneous rock with a high ratio of alumina to iron content4 ,the most valuable deposits are residual1 and some parts have preserved the texture of the original rock1 though with great increase in pore space2 most of the ore1 however1 has the typical pisolitic structure4 ,near the surface the pisolites are sometimes loosened by weathering1 yielding a gravel ore1 and some of the material has been transported a short distance to form detrital ores interstratified with sands and gravels4 ,the complete gradation from syenite to bauxite has been shown4 ,illustration3 ,,fig4 #ac4 ,diagram showing gradation from syenite to bauxite in terms of volume4 ,the columns represent a series of samples from a single locality in ,arkansas4 ,after ,mead4 ,in the ,appalachian region of ,tennessee1 ,alabama1 and ,georgia1 bauxite occurs as pockets in residual clays above sedimentary rocks1 chiefly above shales and dolomites4 ,its origin has probably been similar to that described4 ,the bauxite deposits of southern ,france occur in folded limestones1 and have been ascribed by ,french writers to the work of ascending hot waters carrying aluminum sulphate4 ,they present some unusual features1 and evidence as to their origin is not conclusive4 ,at the present time bauxite is doubtless forming in tropical climates1 where conditions are favorable for deep and extreme weathering of the lateritic type4 ,the breaking up of kaolin accompanied by the removal of silica is not characteristic of temperate climates1 though many clays in these climates show some bauxite4 ,it is possible that1 at the time when the bauxite deposits of ,arkansas and other temperate regions were formed1 the climate of these places was warmer than it is today4 ,in studying the origin of bauxites1 it should not be overlooked that they have much in common with clays1 certain iron ores1 and many other deposits formed by weathering4 ,,antimony ,,ores ,,economic ,,features ,antimony is used mainly for alloying with other metals4 ,over one-third of the antimony consumed in the ,united ,states is alloyed with tin and copper in the manufacture of babbitt or bearing-metal4 ,other important alloys include type-metal 7lead1 antimony1 and tin71 which has the property of expanding on solidification2 hard lead1 a lead-antimony alloy used in making acid-resisting valves2 ,britannia or white metal 7antimony1 tin1 copper1 zinc71 utilized for cheap domestic tableware2 and some brasses and bronzes1 solders1 aluminum alloys1 pattern metals1 and materials for battery plates and cable coverings4 ,antimony finds a very large use in war times in the making of shrapnel bullets from antimonial lead4 ,antimony oxides are used in white enameling of metal surfaces1 as coloring agents in the manufacture of glass1 and as paint pigments2 the red sulphides are used in vulcanizing and coloring rubber1 as paint pigments1 in percussion caps1 and in safety matches2 and other salts find a wide variety of minor uses in chemical industries and in medicine4 ,antimony ores vary greatly in grade1 the ,chinese ores carrying from #bj to #fd per cent of the metal4 ,the presence of arsenic and copper in the ores is undesirable4 ,several of the more important antimony districts owe their economical production of that metal to the presence of recoverable values in gold4 ,some lead-silver ores contain small quantities of antimony1 and antimonial lead1 containing #ab to #ah per cent antimony1 is recovered in their smelting4 ,china is by far the most important antimony-producing country in the world1 and normally supplies over half the world's total4 ,chinese antimony is exported in part as antimony crude 7lumps of needle-like antimony sulphide71 and in part as antimony regulus1 which is about #ii per cent pure metal4 ,france was the only other important source of antimony before the war 7#be to #cj per cent of the world production71 and ,mexico and ,hungary produced small amounts4 ,the large demand for antimony occasioned by the war1 besides stimulating production in these countries1 brought forth important amounts of antimony ore from ,algeria 7,french control7 and from ,bolivia and ,australia 7,british control71 as well as smaller quantities from several other countries4 ,of the war-developed sources1 only ,algeria and perhaps ,australia are expected to continue production under normal conditions4 ,before the war1 antimony was smelted chiefly in ,china1 ,england1 and ,france1 and to a lesser extent in ,germany4 ,british and ,french commercial and smelting interests dominated to a considerable extent the world situation1 and ,london was the principal antimony market of the world4 ,during the war ,chinese antimony interests were greatly strengthened1 and facilities for treating the ore in that country were increased4 ,japan also became important as a smelter and marketer of ,chinese ore1 and increasing quantities of antimony were exported from ,china and ,japan directly to the ,united ,states4 ,english exports ceased entirely and were replaced in this country by ,chinese and ,japanese brands4 ,the ,united ,states normally consumes about one-third of the world's antimony4 ,before the war the entire amount was secured by importation1 two-thirds from ,great ,britain and the rest from the ,orient1 ,france1 and other ,european countries4 ,domestic production of ore and smelting of foreign ores were negligible4 7,these statements refer only to the purer forms of antimony2 the ,united ,states normally produces considerable amounts of antimonial lead1 equivalent to somewhat less than #e per cent of the country's total lead production1 but this material cannot be substituted for antimony regulus in most of its uses47 ,during the war1 under the stimulus of rising prices1 mining of antimony was undertaken in the ,united ,states and several thousand tons of metal were produced--principally from ,nevada1 with smaller amounts from ,alaska1 ,california1 and other western states4 ,the great demands for antimony1 however1 were met chiefly by increased importation4 ,imports were mainly of regulus from ,chinese and ,japanese smelters of ,chinese antimony2 but about a third was contained in ores1 including most of the production of ,mexico which had formerly gone to ,england1 and about #ae per cent of the ,bolivian output4 ,antimony smelters were developed in the ,united ,states to handle these ores4 ,at the close of hostilities there had accumulated in the ,united ,states large surplus stocks of antimony and antimonial materials4 ,with a very dull market and low prices1 domestic mines and smelters were obliged to close down4 ,the dependence of the ,united ,states on foreign sources of antimony and the importance of the metal for war purposes led to some agitation for a protective tariff--in addition to the present import duty of #aj per cent on antimony metal--in order to encourage home production 7see pp4 #cfe-cff1 #cic-cid74 ,in summary1 the ,united ,states is almost entirely dependent upon outside sources for its antimony1 although there are inadequately known reserves in this country which might be exploited if prices were maintained at a high level4 ,the future of ,united ,states smelters is problematical4 ,china1 the world's chief source of antimony1 at present dominates the market in this country1 largely due to the low cost of production and favorable ,japanese freight rates4 ,,geologic ,,features ,the antimony sulphide1 stibnite1 is the source of most of the world's production of this metal4 ,antimony oxides1 including senarmontite1 cervantite1 and others1 are formed near the surface1 and in some of the deposits of ,mexico and ,algeria they supply a large part of the values recovered4 ,jamesonite1 bournonite1 and tetrahedrite 7sulphantimonides of lead and copper71 when found in lead-silver deposits1 are to some extent a source of antimony in the form of antimonial lead4 ,stibnite is found in a variety of associations and is present in small quantities in many types of deposits4 ,in the commercial antimony deposits1 it is in most cases accompanied by minor quantities of other metallic sulphides--pyrite1 cinnabar1 sphalerite1 galena1 arsenopyrite1 etc4--in a gangue of quartz and sometimes calcite4 ,many of the deposits contain recoverable amounts of gold and silver4 ,the deposits of the ,hunan ,province of southern ,china occur as seams1 pockets1 and bunches of stibnite ore in gently undulating beds of faulted and fissured dolomitic limestone4 ,in the vicinity of the most important mines no igneous rocks have been observed1 and the origin of the ores has not been worked out4 ,in the ,central ,plateau of ,france the numerous antimony deposits are stibnite veins cutting granites and the surrounding schists and sediments4 ,an origin related in some way to hot ascending solutions seems probable4 ,the deposits of the ,national district of western ,nevada1 the most important war-developed antimony deposits of the ,united ,states1 consist of stibnite veins with a gangue of fine-grained drusy quartz1 cutting through flows of rhyolite and basalt4 ,they are intimately related to certain gold- and silver-bearing veins1 and all are closely associated with dikes of rhyolite1 which were the feeders to the latest extrusion in the district4 ,the wall rocks have undergone alteration of the propylitic type4 ,these relations1 and the presence of the mercury sulphide1 cinnabar1 in some of the ores 7see pp4 #beh-bei71 suggest an origin through the work of ascending hot waters or hot springs4 ,these waters probably derived their dissolved matter from a magmatic source1 and worked up along vents near the rhyolite dikes soon after the eruption of this rock4 ,in the weathering of antimony deposits1 the stibnite usually alters to form insoluble white or yellowish oxides1 which are sometimes called antimony ocher4 ,these tend to accumulate in the oxide zone through the removal of the more soluble accompanying minerals4 ,secondary sulphide enrichment of antimony deposits1 if it occurs at all1 is negligible4 ,,arsenic ,,ores ,,economic ,,features ,about two-thirds of the arsenic consumed in recent years has been used in agriculture1 where various arsenic compounds--arsenic trioxide or white arsenic1 ,paris green1 lead arsenate1 etc4--are used as insecticides and weed killers4 ,arsenic compounds are also used in cattle-dips for killing vermin4 ,the only other large use of arsenic is in the glass industry1 arsenic trioxide being added to the molten glass to purify and decolorize the product4 ,small quantities of arsenic compounds are used in the preparation of drugs and dyeing materials1 and metallic arsenic is used for hardening lead in shot-making4 ,the principal arsenic-producing countries are the ,united ,states1 ,germany1 ,france1 ,great ,britain1 ,canada1 and ,mexico4 ,spain1 ,portugal1 ,japan1 and ,china are also producers1 and recent trouble with the prickly-pear pest in ,queensland1 ,australia1 has led to local development of arsenic mining in that country4 ,for the most part1 ,european production has been used in ,europe and ,american production in the ,united ,states4 ,arsenic is recovered almost wholly as a by-product of smelting ores for the metals4 ,the potential supply is ample in most countries where smelting is conducted1 but owing to the elaborate plant required to recover the arsenic1 apparatus is not usually installed much in advance of the demand for production4 ,rapid expansion is not possible4 ,before the war the arsenic needs of the ,united ,states 7chiefly agricultural7 were supplied by a few recovery plants in the ,united ,states1 ,mexico1 and ,canada4 ,several large smelters had not found it profitable to install recovery plants1 as the market might have been oversupplied and prices were low4 ,during the war1 with the extensive demand for insecticides for gardening1 there was a considerable deficiency of arsenic supplies4 ,with rising prices production was stimulated1 but was still unable to meet the increased demand4 ,this situation resulted in regulation of the prices of white arsenic by the ,food ,administration4 ,production of arsenic in the ,united ,states comes chiefly from smelters in ,colorado1 ,washington1 ,utah1 ,montana1 and ,new ,jersey4 ,small amounts are produced by arsenic mines in ,virginia and ,new ,york4 ,a ,mexican plant at ,mapimi has been shipping important quantities to the ,united ,states4 ,the plant at ,anaconda1 ,montana1 is expected to produce an ample supply in the future4 ,the ,united ,states is entirely independent in arsenic supplies and will probably soon have an exportable surplus4 ,export trade1 after the reconstruction period1 will probably meet competition from ,france and ,germany where production was formerly large4 ,,geologic ,,features ,arsenic-bearing minerals are numerous and rather widely distributed1 but only a few of them are mined primarily for their content of arsenic4 ,arsenopyrite or mispickle 7iron-arsenic sulphide7 has been used intermittently as a source of white arsenic in various places1--notably at ,brinton1 ,virginia1 and near ,carmel1 ,new ,york4 ,the former deposits contain arsenopyrite and copper-bearing pyrite impregnating a mica-quartz-schist1 adjacent to and in apparent genetic relation with aplite or pegmatite intrusives4 ,in the latter locality arsenopyrite is found associated with pyrite in a gangue of quartz1 forming a series of parallel stringers in gneiss close to a basic dike4 ,the orange-red sulphides of arsenic1 orpiment and realgar1 are formed both as primary minerals of igneous source and as secondary products of weathering4 ,they are rather characteristic of the oxide zones of certain arsenical metallic ores1 and are believed in many cases to have formed from arsenopyrite4 ,they are mined on a commercial scale in ,china4 ,the great bulk of the world's arsenic1 as previously stated1 is obtained as a by-product of smelting operations4 ,the enargite of the ,butte copper ores 7pp4 #bja-bjc7 contains a considerable amount of arsenic1 a large part of which will be recovered from the smelter fumes by new processes which are being installed4 ,the gold-silver ores of the ,tintic district 7pp4 #bce7 also yield important amounts1 the arsenic-bearing minerals being enargite and tennantite 7copper-arsenic sulphides7 and others4 ,the silver ores of the ,cobalt district of ,ontario 7pp4 #bcd-bce71 containing nickel and cobalt arsenides1 produce considerable arsenic4 ,many other metallic ores contain notable amounts of arsenic1 which are at present allowed to escape through smelter flues1 but which could be recovered under market conditions which would repay the cost of installing the necessary apparatus4 ,,bismuth ,,ores ,,economic ,,features ,bismuth metal is used in alloys1 to which it gives low fusibility combined with hardness and sharp definition4 ,bismuth alloys are employed in automatic fire sprinklers1 in safety plugs for boilers1 in electric fuses1 in solders and dental amalgams1 and in some type and bearing metals4 ,bismuth salts find a considerable application for pharmaceutical purposes1 especially in connection with intestinal disorders1 and the best grades of bismuth materials are used for this purpose4 ,the salts are also used in porcelain painting and enameling and in staining glass4 ,bolivia is the most important producer of bismuth ore4 ,the output is controlled entirely by ,british smelting interests4 ,an important deposit exists in ,peru1 the output of which is limited by the same ,british syndicate4 ,considerable bismuth is produced in ,australia1 ,tasmania1 and ,new ,zealand1 all of which likewise goes to ,england4 ,germany before the war had three smelters which produced bismuth from native ores in ,saxony2 bismuth was one of the few metals of which ,germany had an adequate domestic supply4 ,recently southern ,china is reported to be mining increasing amounts of bismuth4 ,the ,united ,states produces the larger part of its bismuth requirements1 chiefly from plants installed at two lead refineries4 ,a further installation would make this country entirely independent of foreign supplies if occasion required4 ,imports1 from ,england and ,south ,america1 have been steadily declining1 but during the war were somewhat increased4 ,the ,united ,states does not export bismuth so far as known4 ,,geologic ,,features ,the principal minerals of bismuth are bismuthinite 7bismuth sulphide71 bismutite 7hydrated carbonate71 bismite or bismuth ocher 7hydrated oxide71 and native bismuth4 ,the native metal and the sulphide are believed to be formed mainly as primary minerals of igneous origin4 ,in the deposits of ,new ,south ,wales they are found associated with molybdenite in quartz gangue1 in pipe-like deposits in granite4 ,the oxide and the carbonate are probably products of surface weathering4 ,the ,bolivian deposits contain the native metal1 the oxide1 and the carbonate1 associated with gold1 silver1 and tin minerals1 in one locality in slates and in another locality in porphyry4 ,the origin is not well known4 ,in the ,united ,states1 the sulphide1 bismuthinite1 is found in the siliceous ores of ,goldfield1 ,nevada 7p4 #bcj71 and in minor amounts in a great number of the sulphide ores of the ,cordilleran region4 ,the ores of the ,leadville and ,tintic districts 7pp4 #bai and #bce7 yield the larger part of the ,united ,states production1 the bismuth being recovered as by-product from the electrolytic refining of the lead bullion4 ,large amounts of bismuth pass out of the stacks of smelters treating other western ores1 and while it would not be cheap nor easy to save the bismuth thus lost1 it could probably be done in case of necessity4 ,,cadmium ,,ores ,,economic ,,features ,cadmium is used in low melting-point alloys--as1 for example1 those employed in automatic fire-extinguishers and electric fuses1--in the manufacture of silverware1 and in dental amalgams4 ,during the war the critical scarcity of tin led to experiments in the substitution of cadmium for tin in solders and anti-friction metals4 ,results of some of these experiments were promising1 but the war ceased and demands for tin decreased before the cadmium materials became widely used4 ,future developments in this direction seem not unlikely4 ,cadmium compounds are used as pigments1 particularly as the sulphide cadmium yellow1 and to give color and luster to glass and porcelain4 ,cadmium salts are also variously used in the arts1 in medicine1 and in electroplating4 ,practically the entire cadmium output of the world comes from ,germany and the ,united ,states4 ,in addition1 ,england produces a very small quantity4 ,before the war ,germany produced about two-thirds of the world's total1 and supplied the ,european as well as a considerable part of the ,united ,states consumption4 ,during the war the ,united ,states production increased three to four fold1 imports ceased1 and considerable quantities were exported to the allied nations in ,europe and to ,japan4 ,at present the ,united ,states is entirely independent as regards cadmium supplies4 ,production is sufficient to supply all the home demand and to permit exports of one-third of the total output4 ,a considerable number of possible cadmium sources are not being used1 and the production is capable of extension should the need arise4 ,,geologic ,,features ,nearly the only cadmium mineral known is the sulphide1 greenockite1 but no deposits of this mineral have been found of sufficient volume to be called cadmium ores4 ,sphalerite almost always contains a little cadmium1 probably as the sulphide2 and in zinc deposits crystals of sphalerite in cavities are frequently covered with a greenish-yellow film or coating of greenockite4 ,these coatings have probably been formed by the decomposition of cadmium-bearing zinc sulphide in the oxide zone1 the carrying down of the cadmium in solution1 and its precipitation as secondary cadmium sulphide4 ,the zinc oxide minerals in the surficial zone also are sometimes colored yellow by small amounts of greenockite4 ,in the zinc ores of the ,joplin district of ,missouri1 cadmium is present in amounts ranging from a trace to #a per cent and averaging #j4c per cent4 ,germany's cadmium is produced by fractional distillation of the ,silesian zinc ores1 which contain at most #j4c per cent cadmium4 ,in the ,united ,states there are large potential sources in the zinc ores of the ,mississippi valley1 and considerable cadmium is recovered in roasting them4 ,much of the ,american cadmium is also obtained from bag-house dusts at lead smelters4 ,the general geologic conditions of the cadmium-bearing ores are indicated in the discussion of lead and zinc deposits in an earlier chapter4 ,,cobalt ,,ores ,,economic ,,features ,cobalt finds its largest use in the form of cobalt salts1 employed in coloring pottery and glass and in insect poisons4 ,cobalt is also used in some of the best high-speed tool steels4 ,stellite1 which is used to a limited extent in non-rusting tools of various sorts1 and in considerable quantity to replace high-speed tool steels1 is an alloy of cobalt1 chromium1 and small quantities of other metals4 ,considerable experimental work has been done on the properties and uses of cobalt alloys1 and their consumption is rapidly on the increase4 ,cobalt is an item of commerce of insignificant tonnage4 ,there are only two countries1 ,canada 7,ontario7 and the ,belgian ,congo1 which produce noteworthy amounts4 ,the ,katanga district in the ,congo produces blister copper that contains as much as #d per cent of cobalt1 though usually less than #b per cent4 ,this product formerly went to ,germany1 and now goes entirely to ,great ,britain4 ,just how much cobalt is saved is unknown1 but probably several hundred tons annually4 ,it is probable that most of the cobalt in these ores will be lost on the installation of a leaching process for recovery of the copper4 ,canada exports most of its product to the ,united ,states1 though the amount is small4 ,domestic production in this country has been too small to record4 ,the ,united ,states has been dependent on imports from ,canada4 ,,geologic ,,features ,the principal cobalt minerals are smaltite 7cobalt arsenide71 cobaltite 7cobalt-arsenic sulphide71 and linnaeite 7cobalt-nickel sulphide74 ,under weathering conditions these minerals oxidize readily to form asbolite1 a mixture of cobalt and manganese oxides1 and the pink arsenate1 erythrite or cobalt bloom4 ,cobalt minerals are found principally in small quantities disseminated through ores of silver1 nickel1 and copper4 ,the production of ,canada is obtained mainly as a by-product of the silver ores of the ,cobalt district 7described on pp4 #bcd-bce71 and smaller amounts are recovered from the ,sudbury nickel ores 7pp4 #ahj-ahb74 ,the cobalt of ,belgian ,congo is obtained from rich oxidized copper ores which impregnate folded sediments 7p4 #bje74 ,,mercury 7,,quicksilver7 ,,ores ,,economic ,,features ,uses of mercury are characterized by their wide variety and their application to very many different phases of modern industry2 they will be named here in general order of decreasing importance4 ,about one-third of the mercury consumed in this country goes into the manufacture of drugs and chemicals1 such as corrosive sublimate1 calomel1 and glacial acetic acid4 ,mercury fulminate is used as a detonator for high explosives and to some extent for small-arms ammunition--a use which was exceedingly important during the war1 but is probably of minor consequence in normal times4 ,mercuric sulphide forms the brilliant red pigment1 vermilion1 and mercuric oxide is becoming increasingly important in anti-fouling marine paint for ship-bottoms4 ,either as the metal or the oxide1 mercury is employed in the manufacture of electrical apparatus 7batteries1 electrolyzers1 rectifiers1 etc471 and in the making of thermostats1 gas governors1 automatic sprinklers1 and other mechanical appliances4 ,mercuric nitrate is used in the fabrication of felt hats from rabbits' fur4 ,in the extraction of gold and silver from their ores by amalgamation1 large amounts of metallic mercury have been utilized1 but of late years the wide application of the cyanide process has decreased this use4 ,minor uses include the making of certain compounds for preventing boiler-scale1 of cosmetics1 and of dental amalgam4 ,the ores of mercury vary greatly in grade4 ,spanish ores yield an average in the neighborhood of #g per cent1 ,italian ores #j4i per cent1 and ,austrian ores #j4fe per cent of metallic mercury4 ,in the ,united ,states the ores of ,california yield about #j4d per cent and those of ,texas range from about #j4e to #d per cent4 ,in almost all cases the ores are treated in the immediate vicinity of the mines1 and fairly pure metal is obtained by a process of sublimation and condensation4 ,this is usually marketed in iron bottles or flasks containing #ge pounds each4 ,the large producers of mercury are1 in order of normal importance1 ,spain1 ,italy1 ,austria1 and ,united ,states4 ,mexico1 ,russia1 and all other countries produce somewhat less than #e per cent of the world's total4 ,the largest quicksilver mines of the world are those of ,almaden in central ,spain1 which are owned and operated by the ,spanish government4 ,this government1 after reserving a small amount for domestic use1 sells all the balance of the production through the ,rothschilds of ,london4 ,in addition ,british capital controls some smaller mines in northern ,spain4 ,england thus largely controls the ,european commercial situation in this commodity1 and ,london is the world's great quicksilver market1 where prices are fixed and whence supplies go to all corners of the globe4 ,reserves of the ,almaden ore bodies are very large4 ,sufficient ore is reported to have been developed to insure a future production of at least #dj1jjj metric tons--an amount equivalent to the entire world requirements at pre-war rates of consumption for #ajj years4 ,the mercury deposits of the ,monte ,amiata district of central ,italy were in large part dominated by ,german capital1 but during the war were seized by the ,italian government4 ,the mines of ,idria1 ,austria-,hungary1 were owned by the ,austrian government and their ultimate control is at present uncertain4 ,reserves are very large1 being estimated at about one-half those of ,almaden4 ,although ,england has had a considerable control over the prices and the market for mercury1 the ,italian and ,austrian deposits have provided a sufficient amount to prevent any absolute monopoly4 ,english interests have now secured control of the ,italian production1 and it is expected that they will also control the ,austrian production--thus giving ,england control of something over three-fourths of the world's mercury4 ,in the ,united ,states about two-thirds of the mercury is produced in the ,coast ,range district of ,california1 and most of the remainder in the ,terlingua district of ,texas4 ,smaller quantities come from ,nevada1 ,oregon1 and a few other states4 ,the output before the war was normally slightly in excess of domestic demand and some mercury was exported to various countries4 ,due to the exhaustion of the richer and more easily worked deposits1 however1 production was declining4 ,during the war1 with increased demands and higher prices1 production was stimulated1 the ,united ,states became the largest mercury-producing country in the world1 and large quantities were exported to help meet the military needs of ,england and ,france4 ,with the end of war prices and with high costs of labor and supplies1 production in the ,united ,states has again declined4 ,many of the mines have passed their greatest yield1 and though discovery of new ore bodies might revive the industry1 production is probably on the down grade4 ,future needs of this country will probably in some part be met by imports from ,spain1 ,italy1 and ,austria1 where the deposits are richer and labor is cheaper4 ,this situation has caused much agitation for a tariff on imports4 ,the present tariff of #aj per cent is not sufficient to keep out foreign mercury4 ,outside of the ,united ,states large changes in distribution of production of quicksilver are not expected for some time4 ,the reserves of the ,european producers are all large and are ample to sustain present output for a considerable number of years4 ,it is reported that there will be a resumption of mining in the once very productive ,huancavelica ,district of ,peru and in ,asia ,minor1 and with restoration of political order there may be an increase in output from ,mexico and ,russia1--but these districts will be subordinate factors in the world situation4 ,on geologic grounds1 new areas of mercury ores may be looked for in regions of recent volcanic activity1 such as the east coast of ,asia1 some islands of ,oceania1 the shores of the ,mediterranean1 and the ,cordilleras of ,north and ,south ,america1--but no such areas which are likely to be producers on a large scale are now known4 ,,geologic ,,features ,the chief mineral of mercury1 from which probably over #ie per cent of the world's mercury comes1 is the brilliant red sulphide1 cinnabar4 ,minor sources include the black or gray sulphide1 metacinnabar1 the native metal1 and the white mercurous chloride1 calomel4 ,the ores are commonly associated with more or less iron sulphide1 and frequently with the sulphides of antimony and arsenic1 in a gangue consisting largely of quartz and carbonates 7of calcium1 magnesium1 and iron74 ,the precious metals and the sulphides of the base metals are rare4 ,mercury deposits are in general related to igneous rocks1 and have associations which indicate a particular type of igneous activity4 ,they are not found in magmatic segregations1 in pegmatites1 nor in veins which have been formed at great depths and under very high temperatures4 ,on the contrary1 the occurrence of many deposits in recent flows which have not been eroded1 their general shallow depth 7large numbers extending down only a few hundred feet71 and the association of some deposits with active hot springs now carrying mercury in solution1 suggest an origin through the work of ascending hot waters near the surface4 ,the mercury minerals are believed to have been carried in alkaline sulphide solutions4 ,precipitation from such solutions may be effected by oxidation1 by dilution1 by cooling1 or by the presence of organic matter4 ,being near the surface1 it is a natural assumption that the waters doing the work were not intensely hot4 ,at ,sulphur ,bank ,springs1 in the ,california quicksilver belt1 deposition of cinnabar by moderately hot waters is actually taking place at present2 also these waters are bleaching the rock in a manner often observed about mercury deposits4 ,the ,coast ,ranges of ,california contain a great number of mercury deposits extending over a belt about #djj miles long4 ,the ore bodies are in fissured zones in serpentine and ,jurassic sediments1 and are related in general to recent volcanic flows4 ,a considerable amount of bituminous matter is found in the ores1 and is believed to have been an agent in their precipitation4 ,the ,terlingua ores of ,texas are found in similar fractured zones in ,cretaceous shales and limestones associated with surface igneous flows4 ,the occurrence of a few ore bodies in vertical shoots in limestone1 apparently terminating upward at the base of an impervious shale1 furnishes an additional argument for their formation by ascending waters4 ,in the few deposits 7e4 g41 those of ,almaden1 ,spain1 and of the deep mines of ,new ,almaden and ,new ,idria1 ,california17 where there is no such clear relation to volcanic rocks as generally observed1 but where the ores contain the same characteristic set of minerals1 it is concluded that practically the same processes outlined above have been active in their formation2 and that the volcanic source of the hot solutions either failed to reach the surface or has been removed by erosion4 ,the same line of reasoning is carried a step further1 and in many gold-quartz veins in volcanic rocks1 where cinnabar and its associated minerals are present1 it is believed that waters of a hot-spring nature have again been effective4 ,thus cinnabar1 when taken with its customary associations1 is regarded as a sort of geologic thermometer4 ,in the weathering of mercury deposits1 cinnabar behaves somewhat like the corresponding silver sulphide1 argentite4 ,in the oxide zone1 native mercury and the chloride1 calomel1 are formed4 ,in the ,texas deposits a red oxide and a number of oxychlorides are also present4 ,the carrying down of the mercury and its precipitation as secondary sulphide may have taken place in some deposits1 but this process is unimportant in forming values4 ,,tin ,,ores ,,economic ,,features ,the largest use of tin is in the manufacture of tin-plate1 which is employed in containers for food1 oil1 and other materials4 ,next in importance is its use in the making of solder and of babbitt or bearing metal4 ,tin is also a constituent of certain kinds of brass1 bronze1 and other alloys1 such as white metal and type metal4 ,minor uses include the making of tinfoil1 collapsible tubes1 wire1 rubber1 and various chemicals4 ,tin oxide is used to some extent in white enameling of metal surfaces4 ,roughly a third of the tin consumed within the ,united ,states goes into tin-plate1 a third into solder and babbitt metal1 and a third into miscellaneous uses4 ,the ores of tin in general contain only small quantities of the metal4 ,tin has sufficient value to warrant the working of certain placers containing only a half-pound to the cubic yard1 although the usual run is somewhat higher4 ,the tin content of the vein deposits ranges from about #a per cent to #dj per cent1 and the average grade is much closer to the lower figure4 ,great ,britain has long controlled the world's tin ores1 producing about half of the total and controlling additional supplies in other countries4 ,the production is in small part in ,cornwall1 but largely in several ,british colonies--the ,malay ,states1 central and south ,africa1 ,australia1 and others4 ,the ,malay ,states furnish about a third of the world's total4 ,another third is produced in immediately adjacent districts of the ,dutch ,east ,indies1 ,siam 7,british control71 and ,china1 and some of the concentrates of these countries are handled by ,british smelters1 especially at ,singapore4 ,tin is easily reduced from its ores and most of the tin is smelted close to the sources of production4 ,considerable quantities1 however1 have gone to ,england for treatment4 ,london has been the chief tin market of the world1 and before the war the larger portion of the tin entering international trade went through this port4 ,during the war a good deal of the export tin from ,straits ,settlements was shipped direct to consumers rather than via ,london1 but it is not certain how future shipments may be made4 ,significant features of the tin situation in recent years have been a decline of production in the ,malay ,states1 and a large and growing production in ,bolivia4 ,malayan output has decreased because of the exhaustion of some of the richer and more accessible deposits2 certain governmental measures have also had a restrictive effect4 ,bolivian production now amounts to over a fifth of the world's total and bids fair to increase4 ,about half the output is controlled by ,chilean1 and small amounts by ,american1 ,french1 and ,german interests4 ,a large portion of the ,bolivian concentrates formerly went to ,germany for smelting1 but during the war ,american smelters were developed to handle part of this material2 large quantities are also smelted in ,england4 ,the ,united ,states produces a small fraction of #a per cent of the world's tin1 and consumes a third to a half of the total4 ,the production is mainly from the ,seward ,peninsula of northwestern ,alaska4 ,for ,american tin smelters1 ,bolivia is about the only available source of supplies2 metallic tin can be obtained from ,british possessions1 but no ore1 except by paying a #cc-a_/c per cent export tax4 ,the ,united ,states exports tin-plate in large amounts1 and in this trade has met strong competition from ,english and ,german tin-plate makers4 ,a world shortage of tin during the war required a division of available supplies through a central international committee4 ,somewhat later1 with the removal of certain restrictions on the distribution of tin1 considerable quantities which had accumulated in the ,orient found their way into ,europe and precipitated a sensational slump in the tin market4 ,,geologic ,,features ,the principal mineral of tin is cassiterite 7tin oxide74 ,stannite1 a sulphide of copper1 iron1 and tin1 is found in some of the ,bolivian deposits but is rare elsewhere4 ,about two-thirds of the world's tin is obtained from placers and one-third from vein or lode deposits4 ,over #ij per cent of the tin of southeastern ,asia and ,oceania is obtained from placers4 ,tin placers1 like placers of gold1 platinum1 and tungsten1 represent concentrations in stream beds and ocean beaches of heavy1 insoluble minerals--in this case chiefly cassiterite--which were present in the parent rocks in much smaller quantities1 but which have been sorted out by the classifying action of running water4 ,the original home of cassiterite is in veins closely related to granitic rocks4 ,it is occasionally found in pegmatites1 as in certain small deposits of the ,southern ,appalachians and the ,black ,hills of ,south ,dakota1 or is present in a typical contact-metamorphic silicated zone in limestone1 as in some of the deposits of the ,seward ,peninsula of ,alaska4 ,in general1 however1 it is found in well-defined fissure veins in the outer parts of granitic intrusions and extending out into the surrounding rocks4 ,with the cassiterite are often found minerals of tungsten1 molybdenum1 and bismuth1 as well as sulphides of iron1 copper1 lead1 and zinc1 and in some cases there is evidence of a rough zonal arrangement4 ,the deposits of ,cornwall and of ,saxony show transitions from cassiterite veins close to the intrusions into lead-silver veins at a greater distance4 ,the gangue is usually quartz1 containing smaller amounts of a number of less common minerals--including lithium mica1 fluorite1 topaz1 tourmaline1 and apatite4 ,the wall rocks are usually strongly altered and in part are replaced by some of the above minerals1 forming coarse-grained rocks which are called greisen4 ,the origin of cassiterite veins1 in view of their universal association with granitic rocks1 is evidently related to igneous intrusions4 ,the occurrence of the veins in distinct fissures in the granite and in the surrounding contact-metamorphic zone indicates that the granite had consolidated before their formation1 and that they represent a late stage in the cooling4 ,the association with minerals containing fluorine and boron1 and the intense alteration of the wall rocks1 indicate that the temperature must have been very high4 ,it is probable that the temperature was so high as to cause the solutions to be gaseous rather than liquid1 and that what have been called pneumatolytic conditions prevailed2 but evidence to decide this question is not at present available4 ,the most important deposits of tin in veins are those of ,bolivia1 some of which are exceptionally rich4 ,these are found in granitic rocks forming the core of the high ,cordillera ,real and in the adjacent intruded sediments1 in narrow fissure veins and broader brecciated zones containing the typical ore and gangue minerals described above1 and also1 in many cases1 silver-bearing sulphides 7chiefly tetrahedrite74 ,there appear to be all gradations in type from silver-free tin ores to tin-free silver ores1 although the extremes are now believed to be rare4 ,in the main the tin ores1 with abundant tourmaline1 appear to be more closely related to the coarse-grained granites1 and to indicate intense conditions of heat and pressure1 while the more argentiferous ores1 with very little or no tourmaline1 are found in relation to finer-grained quartz porphyries and even rhyolites1 and seem to indicate less intense conditions at the time of deposition4 ,the ores of the whole area1 which is a few hundred miles long1 have been supposed to represent a single genetic unit1 and the sundry variations are believed to be local facies of a general mineralization4 ,processes of secondary enrichment have in places yielded large quantities of oxidized silver minerals and wood tin near the surface1 with accumulations of ruby silver ores at greater depths4 ,the only other vein deposits which are at present of consequence are those of ,cornwall4 ,here batholiths of granite have been intruded into ,paleozoic slates and sandstones1 and tin ores occur in fissures and stockworks in the marginal zones4 ,with the exhaustion of the more easily mined placers1 the lode deposits will doubtless be of increasing importance4 ,cassiterite is practically insoluble and is very resistant to decomposition by weathering4 ,oxide zones of tin deposits are therefore enriched by removal of the more soluble minerals4 ,stannite probably alters to wood tin1 a fibrous variety of cassiterite4 ,secondary enrichment of tin deposits by redeposition of tin minerals is negligible4 ,,uranium ,,and ,,radium ,,ores ,,economic ,,features ,radium salts are used in various medical treatments--especially for cancer1 internal tumors1 lupus1 and birth marks--and in luminous paints4 ,during the latter part of the war it is estimated that over nine-tenths of the radium produced was used in luminous paints for the dials of watches and other instruments4 ,in addition part of the material owned by physicians was devoted to this purpose1 and it is probable that the accumulated stocks held by the medical profession were in this way reduced by one-half4 ,the greatly extended use of radium1 together with the distinctly limited character of the world's known radium supplies1 has led to some concern2 and considerable investigation has been made of the possibilities of mesothorium as a substitute for radium in luminous paints4 ,low-grade radium residues are used to some extent as fertilizers4 ,uranium has been used as a steel alloy1 but has not as yet gained wide favor4 ,uranium salts have a limited use as yellow coloring agents in pottery and glass4 ,the principal use of uranium1 however1 is as a source of radium1 with which it is always associated4 ,european countries first developed the processes of reduction of radium salts from their ores4 ,most of the ,european ores are obtained from ,austria1 where the mines are owned and operated by the ,austrian government1 and small quantities are mined in ,cornwall1 ,england1 and in ,germany4 ,production is decreasing4 ,the ,european hospitals and municipalities have acquired nearly all of the production4 ,the ,united ,states has the largest reserves of radium ore in the world1 and the ,american market has in recent years been supplied from domestic plants4 ,before the war1 radium ores were shipped to ,europe for treatment in ,germany1 ,france1 and ,england1 and radium salts were imported from these countries4 ,there are now radium plants in the ,united ,states capable of producing annually from domestic ores an amount several times as large as the entire production of the rest of the world4 ,practically all the production has come from ,colorado and ,utah4 ,known reserves are not believed to be sufficient for more than a comparatively few years' production1 but it is not unlikely that additional deposits will be found in the same area4 ,,geologic ,,features ,uranium is one of the rarer metals4 ,radium is found only in uranium ores and only in exceedingly small quantities4 ,the maximum amount which can be present in a state of equilibrium is about one part of radium in #c1jjj1jjj parts of uranium4 ,the principal sources of uranium and radium are the minerals carnotite 7hydrous potassium-uranium vanadate7 and pitchblende or uraninite 7uranium oxide74 ,the deposits of ,joachimsthal1 ,bohemia1 contain pitchblende1 along with silver1 nickel1 and cobalt minerals and other metallic sulphides1 in veins associated with igneous intrusions4 ,the important commercial deposits of ,colorado and ,utah contain carnotite1 together with roscoelite 7a vanadium mica7 and small amounts of chromium1 copper1 and molybdenum minerals1 as impregnations of flat-lying ,jurassic sandstones4 ,the ores carry up to #ce per cent uranium oxide 7though largely below #b per cent71 and from one-third as much to an equal amount of vanadium oxide4 ,the ore minerals are supposed to have been derived from a thick series of clays and impure sandstones a few hundred feet above1 containing uranium and vanadium minerals widely disseminated1 and to have been carried downward by surface waters containing sulphates4 ,the ore bodies vary from very small pockets to deposits yielding a thousand tons or so1 and are found irregularly throughout certain particular beds without any special relation to present topography or to faults4 ,the association of many of the deposits with fossil wood and other carbonaceous material suggests that organic matter was an agent in their precipitation1 but the exact nature of the process is not clear4 ,in a few places in ,utah the beds dip at steep angles1 and the carnotite appears in spots along the outcrops and generally disappears as the outcrops are followed into the hillsides2 this suggests that the carnotite may be locally redissolved and carried to the surface by capillary action1 forming rich efflorescences4 ,because of the nature of the deposits no large amount of ore is developed in advance of actual mining2 but estimates based on past experience indicate great potentialities of this region for future production4 ,in eastern ,wyoming is a unique deposit of uranium ore in a quartzite which lies between mica-schist and granite4 ,the principal ore mineral is uranophane1 a hydrated calcium-uranium silicate1 which is believed to be an oxidation product of pitchblende4 ,some of the ore runs as high as #d per cent uranium oxide1 and the ore carries appreciable amounts of copper but very little vanadium4 ,very recently radium ores have been discovered in the ,white ,signal mining district of ,new ,mexico1 which was formerly worked for gold1 silver1 copper1 and lead4 ,the radium-bearing minerals are torbernite and autunite 7hydrous copper-uranium and calcium-uranium phosphates71 and are found in dark felsite dikes near their intersections with east-west gold-silver-quartz veins4 ,the possibilities of this district have not yet been determined4 ,pitchblende has been found in gold-bearing veins in ,gilpin ,county1 eastern ,colorado1 and in pegmatite dikes in the ,appalachians1 but these deposits are of no commercial importance4 ,pitchblende is grayish-black1 opaque1 and so lacking in distinctive characteristics that it may readily be overlooked2 hence future discoveries in various regions would not be surprising4 ,,chapter ,,xiii ,,miscellaneous ,,non-,,metallic ,,minerals ,,natural ,,abrasives ,,economic ,,features ,natural abrasives are less important commercially in the ,united ,states than artificial abrasives1 but a considerable industry is based on the natural abrasives4 ,silica or quartz in its various crystalline forms constitutes over three-fourths of the tonnage of natural abrasives used in the ,united ,states4 ,it is the chief ingredient of sand1 sandstone1 quartzite1 chert1 diatomaceous earth1 and tripoli4 ,from the sand and sandstone are made millstones1 buhrstones1 grindstones1 pulpstones1 hones1 oilstones1 and whetstones4 ,sand1 sandstone1 and quartzite are also ground up and used in sand-blasts1 sandpaper1 and for other abrasive purposes4 ,chert or flint constitutes grinding pebbles and tube-mill linings1 and is also ground up for abrasives4 ,diatomaceous 7infusorial7 earth is used as a polishing agent and also as a filtering medium1 an absorbent1 and for heat insulation4 ,tripoli 7and rottenstone7 are used in polishing powders and scouring soaps as well as for filter blocks and many other purposes4 ,other important abrasives are emery and corundum1 garnet1 pumice1 diamond dust and bort1 and feldspar4 ,imports of abrasive materials into the ,united ,states have about one-third of the value of those locally produced4 ,while all of the various abrasives are represented in these imports1 the ,united ,states is dependent on foreign sources for important parts of its needs only of emery and corundum1 garnet1 pumice1 diamond dust and bort1 and grinding pebbles4 ,emery and corundum are used in various forms for the grinding and polishing of hard materials--steel1 glass1 stone1 etc4 ,the principal foreign sources of emery have been ,turkey 7,smyrna7 and ,greece 7,naxos7 where reserves are large and production cheap4 ,production of corundum has come from ,canada1 ,south ,africa1 ,madagascar1 and ,india4 ,the domestic production of emery is mainly from ,new ,york and ,virginia1 and corundum comes from ,north ,carolina4 ,domestic supplies are insufficient to meet requirements1 and cannot be substituted for the foreign material for the polishing of fine glass and other special purposes4 ,curtailment of imports during the war greatly stimulated the development of artificial abrasives and their substitution for emery and corundum4 ,garnet is used chiefly in the form of garnet paper for working leather1 wood1 and brass4 ,garnet is produced mainly in the ,united ,states and ,spain4 ,the ,united ,states is the only country using large amounts of this mineral and imports most of the ,spanish output4 ,the domestic supply comes mainly from ,new ,york1 ,new ,hampshire1 and ,north ,carolina4 ,pumice is used in fine finishing and polishing of varnished and enameled surfaces1 and in cleaning powders4 ,the world's principal source for pumice is the ,lipari ,islands1 ,italy4 ,there is a large domestic supply of somewhat lower-grade material 7volcanic ash7 in the ,great ,plains region1 and there are high-grade materials in ,california and ,arizona4 ,under war conditions these supplies were drawn on1 but normally the high-quality ,italian pumice can be placed in ,american markets more cheaply4 ,diamond dust is used for cutting gem stones and other very hard materials1 and borts or carbonadoes 7black diamonds7 for diamond-drilling in exploration4 ,most of the black diamonds come from ,brazil1 and diamond dust comes from ,south ,africa1 ,brazil1 ,borneo1 and ,india4 ,chert or flint pebbles for tube-mills are supplied mainly from the extensive deposits on the ,french and ,danish coasts4 ,the domestic production has been small1 consisting principally of flint pebbles from the ,california beaches1 and artificial pebbles made from rhyolite in ,nevada and quartzite in ,iowa4 ,war experience demonstrated the possibility of using the domestic supply in larger proportion1 but the grade is such that in normal times this supply will not compete with importations4 ,feldspar as an abrasive is used mainly in scouring soaps and window-wash4 ,domestic supplies are ample4 ,the principal use of feldspar is in the ceramic industry and the mineral is discussed at greater length in the chapter on common rocks 7p4 #hf74 ,for the large number of abrasives produced from silica1 outside of flint pebbles1 domestic sources of production are ample4 ,siliceous rocks are available almost everywhere4 ,for particular purposes1 however1 rocks possessing the exact combinations of qualities which make them most suitable are in many cases distinctly localized4 ,millstones and buhrstones1 used for grinding cereals1 paint ores1 cement rock1 fertilizers1 etc41 are produced chiefly in ,new ,york and ,virginia2 partly because of trade prejudice and tradition1 about a third of the ,american requirements are imported from ,france1 ,belgium1 and ,germany4 ,grindstones and pulpstones1 used for sharpening tools1 grinding wood-pulp1 etc41 come mainly from ,ohio and to a lesser extent from ,michigan and ,west ,virginia2 about #e per cent of the consumption is imported from ,canada and ,great ,britain4 ,hones1 oilstones1 and whetstones are produced largely from a rock called novaculite in ,arkansas1 and also in ,indiana1 ,ohio1 and ,new ,england2 imports are negligible4 ,flint linings for tube-mills were formerly imported from ,belgium1 but ,american products1 developed during the war in ,pennsylvania1 ,tennessee1 and ,iowa1 appear to be wholly satisfactory substitutes4 ,diatomaceous earth is produced in ,california1 ,nevada1 ,connecticut1 and ,maryland1 and tripoli and rottenstone in ,illinois1 ,missouri1 and ,oklahoma2 domestic sources are sufficient for all needs1 but due to questions of back-haul and cost of rail transportation there has been some importation from ,england and ,germany4 ,,geologic ,,features ,the geologic features of silica 7quartz71 feldspar1 and diamonds are sufficiently indicated elsewhere 7,chapter ,,ii2 pp4 #hd1 #aif1 #hf1 #bia-bib74 ,diatomaceous earth is made up of remains of minute aquatic plants4 ,it may be loose and powdery1 or coherent like chalk4 ,it is of sedimentary origin1 accumulated originally at the bottoms of ponds1 lakes1 and in the sea4 ,tripoli and rottenstone are light1 porous1 siliceous rocks which have resulted from the leaching of calcareous materials from various siliceous limestones or calcareous cherts in the process of weathering4 ,grinding pebbles are derived from the erosion of limestone or chalk formations which contain concretions of extremely fine-grained and dense chert4 ,under stream and wave action they are rounded and polished4 ,the principal sources are ocean beaches4 ,corundum as an abrasive is the mineral of this name--made up of anhydrous aluminum oxide4 ,emery is an intimate mechanical mixture of corundum1 magnetite1 and sometimes spinel4 ,corundum is a product of contact metamorphism and also a result of direct crystallization from molten magma4 ,canadian corundum occurs as a constituent of syenite and nepheline-syenite in ,lower ,ontario4 ,in ,north ,carolina and ,georgia1 the corundum occurs in vein-like bodies at the contact of peridotite with gneisses and schists1 and also in part in the peridotite itself4 ,in ,new ,york the emery deposits are segregations of aluminum and iron oxides in norite 7a basic igneous rock74 ,the emery of ,greece and ,turkey occurs as lenses or pockets in crystalline limestones1 and is the result of contact metamorphism by intrusive granites4 ,garnets result mainly from contact metamorphism1 and commonly occur either in schists and gneisses or in marble4 ,the principal ,american occurrences are of this type4 ,being heavy and resistant to weathering1 they are also concentrated in placers4 ,the ,spanish garnets are reported to be obtained by washing the sands of certain streams4 ,pumice is solidified rock froth formed by escape of gases from molten igneous rocks at the surface4 ,it is often closely associated with volcanic ash1 which is also used for abrasive purposes4 ,in general1 the geologic processes entering into the formation of abrasives cover almost the full range from primary igneous processes to surface alterations and sedimentation4 ,,asbestos ,,economic ,,features ,the principal uses of asbestos are in high-pressure packing in heat engines1 in thermal and electrical insulation1 in fire-proofing1 and in brake-band linings4 ,the largest producers of asbestos are ,canada 7,quebec7 and1 to a considerably less extent1 ,russia4 ,united ,states interests have financial control of about a fourth of the ,canadian production1 and practically the entire export trade of ,canada goes to the ,united ,states4 ,russia exports nearly all her product to ,germany1 ,austria1 ,united ,kingdom1 ,belgium1 and the ,netherlands4 ,previous to the war the output was largely controlled by a ,german syndicate4 ,there is a considerable recent production in ,south ,africa1 which is taken by ,england and the ,united ,states1 and small amounts are produced in ,italy1 ,cyprus1 and ,australia4 ,the ,united ,states has been a large importer of asbestos1 from ,canada and some other sources4 ,domestic production is relatively insignificant1 and exports depend chiefly on an excess of import4 ,georgia is the principal local source4 ,arizona and ,california are also producers1 their product being of a higher grade4 ,the ,united ,states is the largest manufacturer of asbestos goods1 and exports go to nearly all parts of the world4 ,so long as the abundant ,canadian material is accessible on reasonable conditions1 the ,united ,states is about as well situated as if independent4 ,some ,canadian proposals of restriction during the war led to a study of other supplies and showed that several deposits1 such as those in ,russia and ,africa1 might compete with the ,canadian asbestos4 ,,geologic ,,features ,asbestos consists mostly of magnesium silicate minerals--chrysotile1 anthophyllite1 and crocidolite4 ,the term asbestos covers all fibrous minerals with some tensile strength which are poor conductors and can be used for heat-protection4 ,like talc1 they are derived principally from the alteration of olivine1 pyroxene1 and amphibole1--or more commonly from serpentine1 which itself results from the alteration of these minerals4 ,chrysotile is the most common1 and because of the length1 fineness1 and flexibility of its fibers1 enabling it to be spun into asbestos ropes and fabrics1 it is the most valuable4 ,anthophyllite fibers1 on the other hand1 are short1 coarse1 and brittle1 and can be used only for lower-grade purposes4 ,crocidolite or blue asbestos is similar to chrysotile but somewhat inferior in fire-resisting qualities4 ,asbestos deposits occur chiefly as veinlets in serpentine rock1 which is itself the alteration of some earlier rock like peridotite4 ,they are clearly formed in cracks and fissures through the agency of water1 but whether the waters are hot or cold is not apparent4 ,the veinlets have sometimes been interpreted as fillings of contraction cracks1 but more probably are due to recrystallization of the serpentine1 proceeding inward from the cracks4 ,in ,quebec the chrysotile asbestos 7which is partly of spinning and partly of non-spinning grade7 forms irregular veins of this nature in serpentine1 the fiber making up #b to #f per cent of the rock4 ,in ,georgia the asbestos1 which is anthophyllite1 occurs in lenticular masses in peridotite associated with gneiss4 ,it is supposed to have formed by the alteration of olivine and pyroxene in the igneous rocks4 ,in ,arizona chrysotile is found in veins in cherty limestone1 associated with diabase intrusives4 ,here it is believed to be an alteration product of diopside 7lime-magnesia pyroxene7 in a contact-metamorphic silicated zone4 ,crocidolite is mined on a commercial scale only in ,cape ,colony1 ,south ,africa4 ,the deposits occur in thin sedimentary layers interbedded with jaspers and ironstones4 ,their origin has not been worked out in detail4 ,the deposits of ,russia1 the ,transvaal1 ,rhodesia1 and ,australia are of high-grade chrysotile1 probably similar in origin to the ,quebec deposits4 ,the asbestos of ,italy and ,cyprus is anthophyllite1 more like the ,georgia material4 ,,barite 7,,barytes7 ,,economic ,,features ,barite is used chiefly as a material for paints4 ,for this purpose it is employed both in the ground form and in the manufacture of lithopone1 a widely used white paint consisting of barium sulphate and zinc sulphide4 ,ground barite is also used in certain kinds of rubber goods and in the making of heavy glazed paper4 ,lesser amounts go into the manufacture of barium chemicals1 which are used in the preparation of hydrogen peroxide1 in softening water1 in tanning leather1 and in a wide variety of other applications4 ,germany is the world's principal producer of barite and has large reserves of high grade4 ,great ,britain also has extensive deposits and produces perhaps one-fourth as much as ,germany4 ,france1 ,italy1 ,belgium1 ,austria-,hungary1 and ,spain produce smaller but significant amounts4 ,before the war the ,united ,states imported from ,germany nearly half the barite consumed in this country1 and produced the remainder4 ,under the necessities of war times1 adequate domestic supplies were developed and took care of nearly all the greatly increased demands4 ,production has come from fourteen states1 the large producers being ,georgia1 ,missouri1 and ,tennessee4 ,during the war1 also1 an important movement of barite-consuming industries to the middle west took place1 in order to utilize more readily and cheaply the domestic product4 ,for this reason it is not expected that ,german barite will play as important a part as formerly in ,american markets1--although it can undoubtedly be put down on the ,atlantic seaboard much more cheaply than domestic barite1 which requires long rail hauls from southern and middle-western states4 ,,geologic ,,features ,the mineral barite is a heavy white sulphate of barium1 frequently called barytes or heavy spar4 ,witherite1 the barium carbonate1 is a much rarer mineral but is found with barite in some veins4 ,all igneous rocks contain at least a trace of barium1 which is probably present in the silicates1 and these small quantities are the ultimate source of the more concentrated deposits4 ,barite itself is not found as an original constituent of igneous rocks or pegmatites1 but is apparently always formed by deposition from aqueous solutions4 ,it is a common gangue mineral in many deposits of metallic sulphides1 both those formed in relation to igneous activity and those which are independent of such activity1 but in these occurrences it is of little or no commercial importance4 ,the principal deposits of barite are found in sedimentary rocks1 and especially in limestones and dolomites4 ,in these rocks it occurs in veins and lenses very similar in nature to the lead and zinc deposits of the ,mississippi valley 7p4 #baa et seq471 and1 like them1 probably deposited by cold solutions which gathered together small quantities of material from the overlying or surrounding rocks4 ,the ,missouri deposits are found in limestones in a region not far from the great southeastern ,missouri lead district1 and vary from the lead deposits in relative proportions rather than in kind of minerals2 the veins consist chiefly of barite1 with minor quantities of silica1 iron sulphide1 galena1 and sphalerite4 ,the deposits of the southern ,appalachians occur as lenses in limestones and schists4 ,barite is little affected by surface weathering1 and tends to remain behind while the more soluble minerals of the associated rock are dissolved out and carried away4 ,a limited amount of solution and redeposition of the barite takes place1 however1 resulting in its segregation into nodules in the residual clays4 ,most of the barite actually mined comes from these residual deposits1 which owe their present positions and values to katamorphic processes4 ,the accompanying clay and iron oxide are removed by washing and mechanical concentration4 ,certain investigators of the deposits of the ,mississippi valley are extremely reluctant to accept the idea that the ores are formed by surface waters of ordinary temperatures1 and are inclined to appeal to heated waters from a hypothetical underlying magmatic source4 ,the fact that barite is a characteristic mineral of many igneous veins1 and the fact that in this same general region it is found in the ,kentucky-,illinois fluorspar deposits1--where a magmatic source is generally accepted1--together with doubts as to the theoretical efficacy of meteoric waters to transport the minerals found in the barite deposits1 have led certain writers to ascribe to these barite deposits a magmatic origin4 ,the magmatic theory has not been disproved2 but on the whole the balance of evidence seems strongly to indicate that the barite deposits as well as the lead and zinc ores1 which are essentially the same in nature though differing in mineral proportions1 have been concentrated from the adjacent sediments by ordinary surface waters4 ,,borax ,,economic ,,features ,borax-bearing minerals are used almost entirely in the manufacture of borax and boric acid4 ,fully a third of the borax consumed in the ,united ,states is used in the manufacture of enamels or porcelain-like coatings for such objects as bathtubs1 kitchen sinks1 and cooking utensils4 ,other uses of borax or of boric acid are as a flux in the melting and purification of the precious metals1 in decomposing chromite1 in making glass1 as a preservative1 as an antiseptic1 and as a cleansing agent4 ,recent developments indicate that the metal1 boron1 may play an important part in the metallurgy of various metals4 ,it has been used in making very pure copper castings for electrical purposes1 in aluminum bronzes1 and in hardening aluminum castings2 and an alloy1 ferroboron1 has been shown experimentally to act on steel somewhat like ferrovanadium4 ,the bulk of the world's borax comes from the ,western ,hemisphere1 the ,united ,states and ,chile being the two principal producers4 ,there are additional large deposits in northern ,argentina1 southern ,peru1 and southern ,bolivia1 which have thus far been little drawn on because of their inaccessibility4 ,english financial interests control most of these ,south ,american deposits4 ,the only large ,european producer of borax is ,turkey4 ,italy and ,germany produce small amounts4 ,there has also been small production of borax in ,thibet1 brought out from the mountains on sheep-back4 ,the ,united ,states supplies of borax are sufficient for all domestic requirements and probably for export4 ,small quantities of boric acid are imported1 but no borax in recent years4 ,the domestic production comes entirely from ,california1 though in the past deposits in ,nevada and ,oregon have also been worked4 ,,geologic ,,features ,the element boron is present in various complex boro-silicates1 such as datolite and tourmaline1 the latter of which is used as a precious stone 7pp4 #bij1 #bic74 ,none of these are commercial sources of borax4 ,the principal boron minerals are borax or tincal 7hydrated sodium borate71 colemanite 7hydrated calcium borate71 ulexite 7hydrated calcium-sodium borate71 and boracite 7magnesium chloro-borate74 ,commercially the term borax is sometimes applied to all these materials4 ,these minerals appear in nature under rather widely differing modes of origin4 ,the borax production of ,italy is obtained from the famous soffioni or fumaroles of ,tuscany4 ,these are volcanic exhalations1 in which jets of steam carrying boric acid and various borates1 together with ammonium compounds1 emerge from vents in the ground4 ,the boric acid material is recovered by a process of condensation4 ,borates1 principally in the form of borax1 occur in hot springs and in lakes of volcanic regions4 ,the ,thibet deposits1 and those formerly worked at ,borax ,lake1 ,california1 are of this type4 ,certain of the hot-spring waters of the ,california coast ranges and of ,nevada carry considerable quantities of boron1 together with ammoniacal salts1 and in some places they deposit borax along with sulphur and cinnabar4 ,it seems probable 7see p4 #dj7 that these waters may come from an igneous source not far beneath4 ,most of the borax deposits of ,california1 ,nevada1 and ,oregon1 though not at present the largely producing ones1 and probably most of the ,chilean and adjacent ,south ,american deposits1 are formed by the evaporation of desert lakes4 ,they are products of desiccation1 and in ,chile are associated with the great nitrate deposits 7pp4 #ajb-ajd71 which are of similar origin4 ,the salts contained in these deposits are mainly borax1 ulexite1 and colemanite4 ,the sources of these materials are perhaps deposits of the type mentioned in the last paragraph1 or1 in ,california1 certain ,tertiary borate deposits described below4 ,whatever their source1 the borates are carried in solution by the waters of occasional rains to shallow basins1 which become covered with temporary thin sheets of water or playa lakes4 ,evaporation of these lakes leaves broad flats covered with the white salts4 ,these may subsequently be covered with drifting sands and capillary action may cause the borates to work up through the sands1 becoming mixed with them and efflorescing at the surface4 ,one of the largest of the ,california deposits of this general class is that at ,searles ,lake1 from which it has been proposed to recover borax along with the potash 7pp4 #aac-aad74 ,the deposits which at present constitute the principal source of domestic borax are not the playa deposits just described1 but are masses of colemanite in ,tertiary clays and limestones with interbedded basaltic flows4 ,the principal deposits are in ,death ,valley and adjacent parts of ,california4 ,the colemanite occurs in irregular milky-white layers or nodules1 mingled with more or less gypsum4 ,the deposits are believed to be of the replacement type1 rather than ones formed contemporaneously with the sediments4 ,whether they are due to magmatic solutions carrying boric acid from the associated flows1 or to surface waters carrying materials leached from other sediments1 is not clear4 ,the crude colemanite as mined carries an average of about #be per cent ,b#b,o#c2 it is treated with soda in the manufacture of borax1 or with sulphuric acid in making boric acid4 ,boron is present in minute quantities in sea water4 ,when such water evaporates1 it becomes concentrated1 along with the magnesium and potassium salts1 in the mother liquor2 and upon complete evaporation1 it crystallizes out as boracite and other rarer minerals4 ,thus the ,stassfurt salts of ,germany 7p4 #aac7 contain borates of this type in the carnallite zone of the upper part of the deposits4 ,this is the only important case known of borate deposits of marine origin4 ,,bromine ,,economic ,,features ,bromine finds a considerable use in chemistry as an oxidizing agent1 in separating gold from other metals1 and in manufacturing disinfectants1 bromine salts1 and aniline colors4 ,the best known and most widely used bromine salts are the silver bromide1 used in photography1 and the potassium bromide1 used in medicine to depress the nervous system4 ,during the war1 large quantities of bromine were used in asphyxiating and lachrymating gases4 ,the chief center of the bromine industry in ,europe prior to #aiad was ,stassfurt1 ,germany4 ,no other important commercial source in foreign countries is known1 though small quantities have been obtained from the mother liquors of ,chile saltpeter and from the seaweed1 kelp1 in various countries4 ,india has been mentioned as a possible large producer in the future4 ,the ,united ,states is independent of foreign sources for bromine4 ,the entire domestic tonnage is produced from brines pumped in ,michigan1 ,ohio1 ,west ,virginia1 and ,pennsylvania4 ,a large part of the output is not actually marketed as bromine1 but in the form of potassium and sodium bromides and other salts4 ,during the war considerable quantities of bromine materials were exported to ,great ,britain1 ,france1 and ,italy4 ,,geologic ,,features ,bromine is very similar chemically to chlorine1 and is found under much the same conditions1 though usually in smaller quantities4 ,the natural silver bromide 7bromyrite7 and the combined silver chloride and bromide 7embolite7 are fairly common in the oxide zones of silver ores1 but are not commercial sources of bromine4 ,bromine occurs in sea water in appreciable amounts1 as well as in some spring waters and many natural brines4 ,when natural salt waters evaporate1 bromine is one of the last materials to be precipitated1 and the residual mother liquors or bitterns frequently show a considerable concentration of the bromine4 ,where complete evaporation takes place1 as in the case of the ,stassfurt salt deposits 7p4 #aac71 the bromine salts are crystallized out in the final stages along with the salts of sodium1 magnesium1 and potassium4 ,the larger part of the world's bromine has come from the mother liquor resulting from the solution and fractional evaporation of these ,stassfurt salts4 ,the bromine obtained from salt deposits in the eastern ,united ,states is doubtless of a similar origin4 ,it is produced as a by-product of the salt industry1 the natural or artificial brines being pumped from the rocks 7p4 #bie71 and the bromides being extracted either from the mother liquors or directly from the unconcentrated brines4 ,,fuller',s ,,earth ,,economic ,,features ,fuller's earth is used chiefly for bleaching1 clarifying1 or filtering mineral and vegetable oils1 fats1 and greases4 ,the petroleum industry is the largest consumer4 ,minor uses are in the manufacture of pigments for printing wall papers1 in detecting coloring matters in certain food-products1 and as a substitute for talcum powder4 ,fuller's earths are in general rather widely distributed4 ,the principal producers are the ,united ,states1 ,england1 and the other large consuming countries of ,europe4 ,the only important international trade in this commodity consists of exports from the ,united ,states to various countries for treating mineral oils1 and exports from ,england for treating vegetable oils4 ,there is a large surplus production in the ,united ,states of fuller's earth of a grade suitable for refining mineral oils1 but an inadequate production of material for use in refining edible oils1 at least by methods and equipment now in most general use4 ,however1 the imports needed from ,england are more than offset by our exports to ,europe of domestic earth particularly adapted to the petroleum industry4 ,production in the ,united ,states comes almost entirely from the southern states2 ,florida produces over three-fourths of the total and other considerable producers are ,texas1 ,georgia1 ,california1 and ,arkansas4 ,imports from ,england are normally equivalent to about a third of the domestic production4 ,,geologic ,,features ,fuller's earth is essentially a variety of clay having a high absorptive power which makes it useful for decolorizing and purifying purposes4 ,fuller's earths are in general higher in water content and have less plasticity than most clays1 but they vary widely in physical and chemical properties4 ,chemical analyses are of little value in determining whether a given clay will serve as fuller's earth1 and an actual test is the only trustworthy criterion4 ,deposits of fuller's earth may occur under the same variety of conditions as deposits of other clays4 ,the deposits of ,florida and ,georgia consist of beds in slightly consolidated flat-lying ,tertiary sediments1 which are worked by open cuts4 ,the ,arkansas deposits are residual clays derived from the weathering of basic igneous rocks1 and are worked through shafts4 ,,graphite 7,,plumbago7 ,,economic ,,features ,crystalline graphite is used principally in the manufacture of crucibles for the melting of brass1 bronze1 crucible steel1 and aluminum4 ,about #de per cent of the quantity and #gj per cent of the value of all the graphite consumed in the ,united ,states is employed in this manner4 ,both crystalline and amorphous graphite are used in lubricants1 pencils1 foundry facings1 boiler mixtures1 stove-polishes and paint1 electrodes1 and fillers or adulterants for fertilizers4 ,the most important use of amorphous graphite is for foundry facings1 this application accounting for about #be per cent of the total ,united ,states consumption of graphite of all kinds4 ,artificial graphite is not suitable for crucibles or pencils but is adapted to meet other uses to which natural graphite is put4 ,it is particularly adapted to the manufacture of electrodes4 ,the grade of graphite deposits varies widely1 their utilization being largely dependent on the size of the grains and the ease of concentration4 ,some of the richest deposits1 those of ,madagascar1 contain #bj per cent or more of graphite4 ,the ,united ,states deposits contain only #c to #aj per cent4 ,the graphite situation is complicated by the differences in the quality of different supplies4 ,crucibles require coarsely crystalline graphite1 but pencils1 lubricants1 and foundry facings may use amorphous and finely crystalline material4 ,the largest production of high-grade crucible graphite has come from ,ceylon1 under ,british control1 and about two-thirds of the output has come to the ,united ,states4 ,the mines are now worked down to water-level and costs are increasing4 ,in later years a rival supply has come from the ,french island of ,madagascar1 where conditions are more favorable to cheap production1 and where reserves are very large4 ,french1 ,british1 and ,belgian interests are concerned in the development of these deposits4 ,the quality of graphite is different from the ,ceylon product2 it has not found favor in the ,united ,states but is apparently satisfactory to crucible makers in ,europe4 ,most of the output is exported to ,great ,britain and ,france1 and smaller amounts to ,germany and ,belgium4 ,less satisfactory supplies of crystalline graphite are available in many countries1 including ,bavaria1 ,canada1 and ,japan4 ,large deposits of crystalline material have been reported in ,greenland1 ,brazil1 and ,roumania1 but as yet have assumed no commercial importance4 ,amorphous graphite is widely distributed1 being produced in about twenty countries1--chiefly in ,austria1 ,italy1 ,korea1 and ,mexico4 ,certain deposits have been found to be best for special uses1 but most countries could get along with nearby supplies4 ,a large part of the world's needs of crucible graphite will probably continue to be met from ,ceylon and ,madagascar1 while a large part of the amorphous graphite will come from the four sources mentioned4 ,the ,united ,states has been largely dependent upon importations from ,ceylon for crucible graphite4 ,domestic supplies are large and capable of further development1 but for the most part the flake is of such quality that it is not desired for crucible manufacture without large admixture of the ,ceylon material4 ,restrictions during the war required crucible makers to use at least #bj per cent of domestic or ,canadian graphite in their mixtures1 with #hj per cent of foreign graphite4 ,this created a demand for domestic graphite which caused an increased domestic output4 ,most of the production in the ,united ,states comes from the ,appalachians1 particularly from ,alabama1 ,new ,york1 and ,pennsylvania1 and smaller amounts are obtained from ,california1 ,montana1 and ,texas4 ,one of the permanently beneficial effects of the war was the improvement of concentrating practice and the standardization of output1 to enable the domestic product to compete more effectively with the well-standardized imported grades4 ,whether the domestic production will hold its own with foreign competition under peace conditions remains to be seen4 ,domestic reserves are large but of low grade4 ,the ,madagascar graphite1 in the shape and size of the flakes1 is more like the ,american domestic graphite than the ,ceylon product4 ,small amounts have been used in this country1 but ,american consumers appear in general to prefer the ,ceylon graphite in spite of its greater cost4 ,the ,madagascar product can be produced and supplied to eastern ,united ,states markets much more cheaply than any other large supply2 and1 in view of the possible exhaustion of the ,ceylon deposits1 it may be desirable for ,american users to adapt crucible manufacture to the use of ,madagascar material as has already apparently been done in ,europe4 ,expansion of the ,american graphite industry during the war1 and its subsequent collapse1 have resulted in agitation for a duty on imports of foreign graphite4 ,amorphous graphite is produced from some deposits in the ,united ,states 7,colorado1 ,nevada1 and ,rhode ,island71 but the high quality of ,mexican graphite1 which is controlled by a company in the ,united ,states1 makes it likely that imports from this source will continue4 ,since the war the ,mexican material has practically replaced the ,austrian graphite in ,american markets4 ,the output of ,korea is divided between the ,united ,states and ,england4 ,artificial graphite1 in amounts about equal to the domestic production of amorphous graphite1 is produced from anthracite or petroleum coke at ,niagara ,falls4 ,,geologic ,,features ,the mineral graphite is a soft1 steel-gray1 crystalline form of carbon4 ,ceylon graphite occurs in veins and lenses cutting gneisses and limestones4 ,usually the veins consist almost entirely of graphite1 but sometimes other minerals occur in important amounts1 especially pyrite and quartz4 ,the association of graphite with these minerals1 and also with feldspar1 pyroxene1 apatite1 and other minerals1 suggests that the veins are of igneous origin1 like some of the pegmatite veins in the ,adirondacks of ,new ,york4 ,the graphite is mined from open pits and shafts1 and sorted by hand and mechanically4 ,the product consists of angular lumps or chips with a relatively small amount of surface in proportion to their volume4 ,in ,madagascar the graphite is mainly disseminated in a graphitic schist1 though to some extent it is present in the form of veins and in gneiss4 ,most of the graphite is mined from a weathered zone near the surface1 and the material is therefore soft and easily concentrated4 ,the product is made up of flakes or scales1 and in the making of crucibles requires the use of larger amounts of clay binder than the ,ceylon graphite4 ,the flake graphite of the ,united ,states1 principally in the ,appalachian region1 occurs in crystalline graphitic schists1 resulting from the anamorphism of sedimentary rocks containing organic matter4 ,certain beds or zones of comparatively narrow width carry from #c to #aj per cent of disseminated graphite4 ,the graphite is recovered by mechanical processes of sorting4 ,the graphite is believed to be of organic origin1 the change from organic carbon to graphite having been effected by heat and pressure accompanying mountain-building stresses4 ,some of the graphite also occurs in pegmatite intrusives and adjacent wall rocks4 ,this graphite is considered to be of inorganic origin1 formed by the breaking up of gaseous oxides of carbon in the original magma of the pegmatites4 ,the ,montana graphite is similar in origin4 ,this inorganic graphite in pegmatite veins resembles ,ceylon graphite1 in breaking into large lumps and chips1 but supplies are very limited4 ,amorphous graphite is formed in many places where coal and other carbonaceous materials have undergone extreme metamorphism4 ,it represents simply a continuation in the processes by which high grade coals are formed from plant matter 7pp4 #abc-abg74 ,the ,mexican deposits are of this type1 and occur in beds up to #bd feet in thickness interbedded with metamorphosed sandstones4 ,in general1 graphite is primarily concentrated both by igneous processes in dikes1 and by sedimentary processes in beds4 ,in the latter case anamorphism is necessary to recrystallize the carbon into the form of graphite4 ,,gypsum ,,economic ,,features ,the principal use of gypsum is in structural materials4 ,about two-thirds of the gypsum produced in the ,united ,states is used in the manufacture of various plasters--wall plaster1 plaster of ,paris1 and ,keene's cement 7for statuary and decorative purposes71--and about a fifth is used as a retarder in ,portland cement4 ,another important structural use is in the manufacture of plaster boards1 blocks1 and tile for interior construction4 ,gypsum is used as a fertilizer under the name of land plaster1 and with the growing recognition of the lack of sulphur in various soils an extension of its application is not unlikely4 ,minor uses are in the polishing of plate glass1 in the manufacture of dental plaster1 in white pigments1 in steampipe coverings1 and as a filler in cotton goods4 ,the world's gypsum deposits are widely distributed4 ,of foreign countries1 ,france1 ,canada1 and the ,united ,kingdom are the principal producers4 ,germany1 ,algeria1 and ,india produce comparatively meager amounts4 ,the ,united ,states is the largest producer of gypsum in the world4 ,in spite of its large production1 the ,united ,states normally imports quantities equivalent to between one-fifteenth and one-tenth of the domestic production1 mainly in the crude form from ,nova ,scotia and ,new ,brunswick for consumption by the mills in the vicinity of ,new ,york4 ,this material is of a better grade than the eastern domestic supply1 and is cheaper than the western supply for eastern consumption4 ,during the war this importation was practically stopped because of governmental requisition of the carrying barges for the coal-carrying trade1 but with the return of normal conditions it was resumed4 ,there is no prospect of importation of any considerable amount from any other sources4 ,the domestic supply is ample for all demands4 ,production of gypsum in the ,united ,states comes from eighteen states4 ,four-fifths of the total comes from ,new ,york1 ,iowa1 ,michigan1 ,ohio1 ,texas1 and ,oklahoma4 ,there are extensive deposits in some of the western states1 the known reserves in ,wyoming alone being sufficient for the entire world demands for many decades4 ,the ,united ,states exports a small amount of crude gypsum to ,canada1 principally for use in ,portland cement manufacture4 ,this exportation is due to geographic location4 ,the ,united ,states is the largest manufacturer of plaster boards1 insulating materials1 and tile1 and exports large quantities of these products to ,cuba1 ,australia1 ,japan1 and ,south ,america4 ,,geologic ,,features ,gypsum is a hydrated calcium sulphate4 ,it is frequently associated with minor quantities of anhydrite1 which is calcium sulphate without water1 and under the proper natural conditions either of these materials may be changed into the other4 ,common impurities in gypsum deposits include clay and lime carbonate1 and also magnesia1 silica1 and iron oxide4 ,in the material as extracted1 impurities may range from a trace to about #be per cent4 ,gypsite1 or gypsum dirt1 is an impure mixture of gypsum with clay or sand found in ,kansas and some of the western states2 it is believed to have been produced in the soil or in shallow lakes1 by spring waters carrying calcium sulphate which was leached from gypsum deposits or from other rocks4 ,gypsum deposits1 like deposits of common salt1 occur in beds which are the result of evaporation of salt water4 ,calcium makes up a small percentage of the dissolved material in the sea1 and when sea waters are about #cg per cent evaporated it begins to be precipitated as calcium sulphate4 ,conditions for precipitation are especially favorable in arid climates1 in arms of the sea or in enclosed basins which may or may not once have been connected with the sea4 ,simultaneously with the deposition of gypsum1 there may be occasional inwashings of clay and sand1 and with slight changes of conditions organic materials of a limey nature may be deposited4 ,further evaporation of the waters may result in the deposition of common salt4 ,thus gypsum beds are found interbedded with shales1 sandstones1 and limestones1 and frequently1 but not always1 they are associated with salt beds4 ,the nature of these processes is further discussed under the heading of salt 7pp4 #bie-bih74 ,the anhydrite found in gypsum deposits is formed both by direct precipitation from salt water and by subsequent alteration of the gypsum4 ,the latter process involves a reduction of volume1 and consequently a shrinkage and settling of the sediments4 ,the hydration of anhydrite to form gypsum1 on the other hand1 involves an increase of volume and may result in the doming up and shattering of the overlying sediments4 ,gypsum is fairly soluble in ground-water1 and sink-holes and solution cavities are often developed in gypsum deposits4 ,these may allow the inwash of surface dirt and also may interfere with the mining4 ,all the important commercial gypsum deposits are believed to have been formed by evaporation of salt water in the manner indicated4 ,small quantities of gypsum are formed also when pyrite and other sulphides oxidize to sulphuric acid and this acid acts on limestone4 ,thus gypsum is found in the oxide zones of some ore bodies4 ,these occurrences are of no commercial significance4 ,,mica ,,economic ,,features ,the principal use of sheet mica is for insulating purposes in the manufacture of a large variety of electrical equipment4 ,the highest grades are employed particularly in making condensers for magnetos of automobile and airplane engines and for radio equipment1 and in the manufacture of spark plugs for high tension gas engines4 ,sheet mica is also used in considerable amounts for glazing1 for heat insulation1 and as phonograph diaphragms4 ,ground mica is used in pipe and boiler coverings1 as an insulator1 in patent roofing1 and for lubricating and decorative purposes4 ,india1 ,canada1 and the ,united ,states are the important sheet mica-producing countries1 before the war accounting for #ih per cent of the world's total4 ,india has long dominated the sheet mica markets of the world1 and will probably continue to supply the standard of quality for many years4 ,the bulk of the ,indian mica is consumed in the ,united ,states1 ,great ,britain1 and ,germany4 ,the mica of ,india and the ,united ,states is chiefly muscovite4 ,canada is the chief source of amber mica 7phlogopite71 though other deposits of potential importance are known in ,ceylon and ,south ,africa4 ,canadian mica is produced chiefly in ,quebec and ,ontario1 and is exported principally to the ,united ,states4 ,important deposits of mica 7principally muscovite7 are also known in ,brazil1 ,argentina1 and ,german ,east ,africa4 ,large shipments were made from the two former countries during the war1 both to ,europe and the ,united ,states1 and ,brazil particularly should become of increasing importance as a producer of mica4 ,the deposits in ,german ,east ,africa were being quite extensively developed immediately before the war and large shipments were made to ,germany in #aiac4 ,the ,united ,states is the largest consumer of sheet mica and mica splittings1 absorbing normally nearly one-half of the world's production4 ,approximately three-fifths of this consumption is in the form of mica splittings1 most of which are made from muscovite in ,india and part from amber mica in ,canada4 ,due to the cheapness of labor in ,india and the amenability of ,indian mica to the splitting process1 ,india splittings should continue to dominate the market in this country4 ,amber mica is a variety peculiarly adapted to certain electrical uses4 ,there are no known commercial deposits of this mica in the ,united ,states1 but ,american interests own the largest producing mines in ,canada4 ,shipments of ,brazilian mica are not of such uniformly high quality as the ,indian material1 but promise to become of increasing importance in ,american markets4 ,of the sheet mica consumed annually1 the ,united ,states normally produces about one-third4 ,war conditions1 although stimulating the production of domestic mica very considerably1 did not materially change the situation in this country as regards the dependence of the ,united ,states on foreign supplies for sheet mica4 ,about #gj per cent of the domestic mica comes from ,north ,carolina and #be per cent from ,new ,hampshire4 ,the deposits are small and irregular1 and mining operations are small and scattered4 ,these conditions are largely responsible for the heterogeneous nature of the ,american product4 ,it is hardly possible for any one mine to standardize and classify its product1 although progress was made in this direction during the war by the organization of associations of mica producers4 ,this lack of standardization and classification is a serious handicap in competition with the standard grades and sizes which are available in any desired amounts from foreign sources4 ,for ground mica1 the domestic production exceeds in tonnage the total world production of sheet mica1 and is adequate for all demands4 ,,geologic ,,features ,mica is a common rock mineral1 but is available for commerce only in igneous dikes of a pegmatite nature1 where the crystallization is so coarse that the mica crystals are exceptionally large4 ,muscovite mica occurs principally in the granitic pegmatite dikes4 ,the phlogopite mica of ,canada occurs in pyroxenite dikes4 ,the distribution of mica within the dikes is very erratic1 making predictions as to reserves hazardous4 ,the associated minerals1 mainly quartz and feldspar1 are ordinarily present in amounts greater than the mica4 ,also1 individual deposits are likely to be small4 ,for these reasons mining operations cannot be organized on a large scale1 but are ordinarily hand-to-mouth operations near the surface4 ,a large amount of hand labor is involved1 and the ,indian deposits are favored by the cheapness of native labor4 ,the output of a district is from many small mines rather than from any single large one4 ,pegmatites which have been subjected to dynamic metamorphism are often not available as a source of mica1 because of the distortion of the mica sheets4 ,the mining of a mica is facilitated by weathering1 which softens the associated feldspar1 making it an easier task to take out the mica blocks4 ,on the other hand1 iron staining by surface solutions during weathering may make the mica unfit for electrical and certain other uses4 ,scrap or ground mica is obtained as a by-product of sheet mica and from deposits where the crystals are not so well developed4 ,black mica 7biotite7 and chlorite minerals1 which are soft and flexible but not elastic and are found extensively developed in certain schists1 have been used to a limited extent for the same purposes4 ,,monazite 7,,thorium ,,and ,,cerium ,,ores7 ,,economic ,,features ,the mineral monazite is the source of the thorium and cerium compounds which1 glowing intensely when heated1 form the light-giving material of incandescent gas mantles4 ,welsbach mantles consist of about #ii per cent thorium oxide and #a per cent cerium oxide4 ,cerium metal1 alloyed with iron and other metals1 forms the spark-producing alloys used in various forms of gas lighters and for lighting cigars1 cigarettes1 etc4 ,mesothorium1 a by-product of the manufacture of thorium nitrate for gas mantles1 is used as a substitute for radium in luminous paints and for therapeutic purposes4 ,the alloy ferrocerium is used to a small extent in iron and steel4 ,the world's supply of monazite is obtained mainly from ,brazilian and ,indian properties4 ,before the war ,german commercial interests controlled most of the production1 as well as the manufacture of the thorium products4 ,during the war ,german control was broken up4 ,the ,united ,states has a supply of domestic monazite of lower grade than the imports1 but is dependent under normal conditions on supplies from ,brazil and ,india4 ,the ,american deposits are chiefly in ,north and ,south ,carolina1 and have been worked only during periods of abnormally high prices or of restriction of imports4 ,known reserves are small and the deposits will probably never be important producers4 ,during the war1 however1 the ,united ,states became the largest manufacturer of thorium nitrate and gas mantles and exported these products in considerable quantity4 ,an effort is now being made to secure protective legislation against ,german thorium products4 ,,geologic ,,features ,monazite is a mineral consisting of phosphates of cerium1 lanthanum1 thorium1 and other rare earths in varying proportions4 ,the content of thorium oxide varies from a trace up to #cj per cent1 and commercial monazite sands are usually mixed so as to bring the grade up to at least #e per cent4 ,yellowish-brown crystals of monazite have been found scattered through granites1 gneisses1 and pegmatites1 but in quantities ordinarily too small to warrant mining4 ,in general the mineral is recovered on a commercial scale only from placers1 where it has been concentrated along with other dense1 insoluble minerals such as zircon1 garnet1 ilmenite1 and sometimes gold4 ,the ,indian and ,brazilian monazite is obtained principally from the sands of ocean beaches1 in the same localities from which zircon is recovered 7p4 #ahi74 ,the ,north and ,south ,carolina monazite has been obtained chiefly from stream beds1 and to a slight extent by mining and washing the rotted underlying rock1 which is a pegmatized gneiss4 ,monazite1 together with a small amount of gold1 is also known in the stream gravels of the ,boise ,basin1 ,idaho1 where a large granitic batholith evidently carries the mineral sparsely distributed throughout4 ,these deposits have not been worked4 ,,precious ,,stones ,,economic ,,features ,precious stones range high in the world's annual production of mineral values4 ,a hundred or more minerals are used to some degree as precious stones2 but those most prized1 representing upwards of #ij per cent of the total production value1 are diamond1 pearl1 ruby1 sapphire1 and emerald4 ,in total value the diamonds have an overwhelming dominance4 ,over a ton of diamonds is mined annually4 ,diamonds come mainly from ,south ,africa1 which produces over #ii per cent of the total4 ,pearls come chiefly from the ,indian and ,pacific oceans4 ,burma is the principal source of fine rubies4 ,siam is the principal producer of sapphires4 ,colombia is the principal source of fine emeralds4 ,the ,united ,states produces small amounts of sapphires 7in ,montana7 and pearls 7from fresh-water molluscs74 ,diamonds1 rubies1 and emeralds are practically absent on a commercial scale4 ,of other precious and semi-precious gem stones produced in the ,united ,states1 the principal ones are quartz1 tourmaline1 and turquoise4 ,on the other hand1 the ,united ,states absorbs by purchase over half of the world's production of precious stones4 ,it is estimated roughly that there are now in the ,united ,states nearly one billion dollars' worth of diamonds1 or over one-half of the world's accumulated stock1 and probably the proportions for the other stones are not far different4 ,value attaches to a precious stone because of its qualities of beauty1 coupled with endurance and rarity1 or because of some combination of these features which has caught the popular fancy4 ,no one of these qualities is sufficient to make a stone highly prized2 neither does the possession of all of them insure value4 ,some beautiful and enduring stones are so rare that they are known only to collectors and have no standard market value4 ,others fail to catch the popular fancy for reasons not obvious to the layman4 ,while the intrinsic qualities go far in determining the desirability of a stone1 it is clear that whim and chance have been no small factors in determining the demand or lack of demand for some stones4 ,as in other minerals1 value has both its intrinsic and extrinsic elements4 ,for the leading precious stones above named1 the values are more nearly standard throughout the world than for any other minerals1 with the exception of gold and possibly platinum4 ,highly prized everywhere and easily transported1 the price levels show comparatively little variation over the world when allowance is made for exchange and taxes4 ,the valuation of precious stones is a highly specialized art1 involving the appraisal not only of intrinsic qualities1 but of the appeal which the stone will make to the buying public4 ,in marking a sale price for some exceptional stone not commonly handled in the trade1 experts in different parts of the world often reach an almost uncanny uniformity of opinion4 ,it is estimated that the world stock of precious stones approximates three billion dollars1 or a third of the world's monetary gold reserve4 ,because of small bulk and standard value1 this wealth may be easily secreted1 carried1 and exchanged4 ,when the economic fabric of civilization is disturbed by war or other conditions1 precious stones become a medium of transfer and exchange of wealth of no inconsiderable importance4 ,the beauty of a stone may arise from its color or lack of color1 from its translucency or opaqueness1 from its high refraction of light1 and from the manner of cutting and polishing to bring out these qualities4 ,hardness and durability are desirable qualities4 ,the diamond is the hardest known mineral and the sapphire1 ruby1 and emerald rank high in this regard4 ,on the other hand the pearl is soft and fragile and yet highly prized4 ,,geologic ,,features ,the principal precious stones above named are of simple composition4 ,diamond is made of carbon2 the pearl is calcium carbonate2 ruby and sapphire are aluminum oxide--varieties of the mineral corundum2 the emerald is silica and alumina1 with a minor amount of beryllia4 ,minute percentages of chromite1 iron1 manganese1 and other substances are often responsible for the colors in these stones4 ,carbon also constitutes graphite and is the principal element in coal4 ,lime carbonate is the principal constituent of limestone and marble4 ,alumina is the principal constituent of bauxite1 the ore of aluminum1 and of the natural abrasives1 emery and corundum4 ,silica1 the substance of common quartz1 also constitutes gem quartz1 amethyst1 opal1 agate1 onyx1 etc4 ,most of the world's diamonds come from the ,kimberley and ,transvaal fields of ,south ,africa1 where they are found in a much decomposed volcanic rock called blue ground4 ,this is a rock of dull1 greasy appearance consisting largely of serpentine4 ,it was originally peridotite1 occurring in necks or plugs of old volcanoes penetrating carbonaceous sediments4 ,when the rock is mined and spread at the surface1 it decomposes in the course of six months or a year1 allowing it to be washed and mechanically sorted for its diamond content4 ,the amount of ground treated in one of the large mines is about equal to that handled in operating the huge porphyry copper deposit of ,bingham1 ,utah2 the annual production of diamonds from the same mine could be carried in a large suit-case4 ,the diamonds were clearly formed at high temperatures and pressures within the igneous rocks4 ,it has been suggested that the igneous magma may have secured the carbon by the melting of carbonaceous sediments through which it penetrated1 but proof of this is difficult to obtain4 ,artificial diamonds of small size have been made in the electric furnace under high-pressure conditions not unlike those assumed to have been present in nature4 ,weathering and transportation of rocks containing diamonds have resulted in the development of diamond-bearing placers4 ,the ,south ,african diamonds were first found in stream placers1 leading to a search for their source and its ultimate discovery under a blanket of soil which completely covered the parent rock4 ,the proportion of diamonds now mined from placers is very small4 ,the diamonds of ,brazil come from placer deposits4 ,this is the principal source of the black diamond so largely used in diamond-drilling4 ,the ,united ,states produces no diamonds on a commercial scale4 ,small diamonds have been found in peridotite masses in ,pike ,county1 ,arkansas1 but these are of very little commercial value4 ,a few diamonds have been found in the glacial drift of ,wisconsin and adjacent states1 indicating a possible diamond-bearing source somewhere to the north which has not yet been located 7p4 #cag74 ,pearls are concretions of lime carbonate of organic origin1 and are found in the shells of certain species of molluscs4 ,their color or luster is given by organic material or by the interior shell surface against which the pearl is formed4 ,the principal supply comes from the ,indian and ,pacific ,oceans1 but some are found in the fresh water mussels of ,north ,america1 in the ,caribbean1 and on the western coast of ,mexico and ,central ,america4 ,from the beginning of history the principal source of rubies has been upper ,burma1 where the stones are found in limestone or marble near the contact with igneous rocks1 associated with high-temperature minerals4 ,the weathering of the rock has developed placers from which most of the rubies are recovered4 ,siam is also an important producer4 ,in the ,united ,states rubies have been found in pegmatites in ,north ,carolina1 but these gems are of little commercial importance4 ,sapphires are of the same composition as rubies and are found in much the same localities4 ,most of the sapphires of the best quality come from ,siam1 where they are found in sandy clay of placer origin4 ,in the ,united ,states sapphires are recovered from alluvial deposits along the ,missouri ,river near ,helena1 ,montana1 where they are supposed to have been derived from dikes of andesite rocks4 ,in ,fergus ,county1 ,montana1 they are mined from decomposed dikes of lamprophyre 7a basic igneous rock74 ,in ,north ,carolina sapphire has been found in pegmatite dikes4 ,the principal source of fine emeralds is in the ,andes in ,colombia4 ,their occurrence here is in calcite veins in a bituminous limestone1 but little seems to be known of their origin4 ,the only other emerald locality of commercial importance is in the ,ural ,mountains of ,siberia4 ,emeralds have been found in pegmatite dikes in ,north ,carolina and ,new ,england1 but the production is insignificant4 ,tourmaline is a complex hydrous silicate of aluminum and boron1 with varying amounts of magnesium1 iron1 and alkalies4 ,it is a rather common mineral in silicated zones in limestones near igneous contacts1 but gem tourmalines are found principally in pegmatite dikes4 ,they have a wide variety of colors1 the red and green gems being the most prized4 ,maine1 ,california1 and ,connecticut are the principal ,american producers4 ,turquoise is a hydrated copper-aluminum phosphate4 ,it is found in veinlets near the surface in altered granites and other igneous rocks4 ,it is usually associated with kaolin and frequently with quartz1 and is believed to have been formed by surface alterations4 ,in the ,united ,states it is produced chiefly in ,nevada1 ,arizona1 and ,colorado4 ,in general the principal gem minerals1 except pearl and turquoise1 occur as original constituents in igneous intrusives1 usually of a pegmatite or peridotite nature4 ,sapphire1 ruby1 emerald1 and tourmaline result also from contact metamorphism of sediments in the vicinity of igneous rocks4 ,weathering softens the primary rocks1 making it possible to separate the gem stones from the matrix4 ,when eroded and transported the gems are concentrated in placers4 ,,salt ,,economic ,,features ,the principal uses of salt are in the preserving and seasoning of foods and in chemical industries4 ,chemical industries require salt for the manufacture of many sodium compounds1 and also as a source of hydrochloric acid and chlorine4 ,a minor use of salt is in the making of glazes and enamel on pottery and hardware4 ,because of the wide distribution of salt in continental deposits and because of the availability of ocean and salt-lake brines as other sources1 most countries of the world either possess domestic supplies of salt adequate for the bulk of their needs1 or are able to obtain supplies from nearby foreign countries4 ,certain sea salts preferred by fish packers and other users are1 however1 shipped to distant points4 ,about a fifth of all the salt consumed in the world annually is produced in the ,united ,states1 and other large producers are ,great ,britain1 ,germany1 ,russia1 ,china1 ,india1 and ,france4 ,the ,united ,states produces almost its entire consumption of salt1 which is increasing at a very rapid rate4 ,salt is produced in fourteen states1 but over #he per cent of the total output comes from ,michigan1 ,new ,york1 ,ohio1 and ,kansas4 ,reserves are practically inexhaustible4 ,exports and imports of salt form a very minor part of the ,united ,states industry1 each being equivalent to less than #e per cent of the domestic production4 ,a large part of the imported material is coarse solar-evaporated sea salt1 which is believed by fish and pork packers to be almost essential to their industry4 ,imports of this salt come from ,spain1 ,italy1 ,portugal1 and the ,british and ,dutch ,west ,indies2 during the war1 on account of ship shortage1 they were confined chiefly to the ,west ,indies4 ,a considerable tonnage of specially prepared kiln-dried salt1 desired by butter-makers1 is imported from ,liverpool1 ,england4 ,there are also some small imports from ,canada1 probably because of geographic location4 ,exports of domestic salt go chiefly to ,canada1 ,cuba1 and ,new ,zealand1 with smaller amounts to practically all parts of the world4 ,salt is recovered from salt beds in two ways4 ,about a fourth of the salt produced in the ,united ,states is mined through shafts in the same manner as coal1 the lumps of salt being broken and sized just as coal is prepared for the market4 ,the larger part of the ,united ,states production1 however1 is derived by pumping water down to the beds to dissolve the salt1 and pumping the resulting brine to the surface where it is then evaporated4 ,a considerable amount of salt1 also1 is recovered from natural brines--which represent the solution of rock salt by ground-waters--and from the waters of salt lakes and the ocean4 ,,geologic ,,features ,common salt constitutes the mineral halite1 the composition of which is sodium chloride4 ,it is rarely found perfectly pure in nature1 but is commonly mixed with other saline materials1 such as gypsum and anhydrite1 and occasionally with salts of potassium and magnesium4 ,the general grade of rock-salt deposits1 where not admixed with clay1 is perhaps #if to #ii per cent of sodium chloride4 ,the ultimate source of salt deposits is the sodium and chlorine of igneous rocks4 ,in the weathering of these rocks the soda1 being one of the more soluble materials1 is leached out and carried off by ground-waters1 and in the end a large part of it reaches the sea4 ,the chlorine follows a similar course2 however1 the amount of chlorine in ordinary igneous rocks is so extremely small that1 in order to explain the amount of chlorine present in the sea1 it has been thought necessary to appeal to volcanic emanations or to some similar agency4 ,ocean water contains about #c4e per cent by weight of dissolved matter1 over three-fourths of which consists of the constituents of common salt4 ,chief among the other dissolved materials are magnesium1 calcium1 potassium1 and ,,so#d 7the sulphuric acid radical74 ,when sea water evaporates it becomes saturated with various salts1 according to the amounts of these salts present and their relative solubilities4 ,in a general way1 after #cg per cent of the water has evaporated gypsum begins to separate out1 and after #ic per cent has evaporated common salt begins to be deposited4 ,after a large part of the common salt has been precipitated1 the residual liquid1 called a bittern or mother liquid1 contains chiefly a concentration of the salts of magnesium and potassium4 ,still further evaporation will result in their deposition1 mainly as complex salts like those found in the ,stassfurt deposit 7p4 #aac74 ,the actual processes of concentration and precipitation in sea water or other salt waters are much more complex than is indicated by the above simple outline4 ,the solubility of each of the various salts present1 and consequently the rate at which each will crystallize out as evaporation proceeds1 depends upon the kinds and concentrations of all the other salts in the solution4 ,temperature1 pressure1 mass-action1 and the crystallization of double salts are all factors which influence the nature and rate of the processes and add to their complexity4 ,during a large part of the general process1 several different salts may be crystallizing out simultaneously4 ,it is evident that gypsum may be precipitated in some quantity1 and that external conditions may then change1 so that evaporation ceases or so that the waters are freshened1 before any common salt is crystallized out4 ,this fact may explain in part why gypsum beds are more widely distributed than beds of common salt4 ,at the same time the much greater amount of sodium chloride than of calcium sulphate in sea water may explain the greater thickness of many individual salt beds4 ,the evaporation of salt waters1 either from the ocean or from other bodies of water1 is believed to have been responsible for nearly all of the important deposits of common salt4 ,this process has been going on from ,cambrian time down through all the intervening geologic ages1 and can be observed to be actually operative today in various localities4 ,the beds of salt so formed are found interstratified with shales1 sandstones1 and limestones1 and are frequently associated with gypsum4 ,on a broad scale1 they are always lens-shaped1 though they vary greatly in extent and thickness4 ,the necessary conditions for the formation of extensive salt beds include arid climate and bodies of water which are essentially enclosed--either as lakes1 as lagoons1 or as arms of the sea with restricted outlets1--where evaporation exceeds the contributions of fresh water from rivers1 and where circulation from the sea is insufficient to dilute the water and keep it at the same composition as the sea water4 ,under such conditions the dissolved salts in the enclosed body become concentrated1 and precipitation may occur4 ,a change of conditions so that mud or sand is washed in or so that calcareous materials are deposited1 followed by a recurrence of salt-precipitation1 results in the interstratification of salt beds with shales1 sandstones1 and limestones4 ,for the formation of very thick beds of salt1 and especially of thick beds of fairly pure composition1 however1 this simple explanation of conditions is insufficient4 ,the deposits of ,michigan and ,new ,york occur in beds as much as #ba feet in thickness1 with a considerable number of separate beds in a section a few hundred feet thick4 ,beneath the potash salt deposits of ,stassfurt1 beds of common salt #cjj to #ejj feet in thickness are found1 and beds even thicker are known in other localities4 ,when we come to investigate the volume of salts deposited from a given volume of sea water1 we find it to be so small that for the formation of #ejj feet of salt over a given area1 an equivalent area of water #be1jjj feet deep would be required4 ,it has therefore been one of the puzzling problems of geology to determine the exact physical conditions under which deposition of these beds took place4 ,one of the most prominent theories1 the bar theory1 suggests that deposition may have taken place in a bay separated from the sea by a bar4 ,sea water is supposed to have been able to flow in over the bar or through a narrow channel1 so that evaporation in the bay was about balanced by inflow of sea water4 ,thus the salts of a very large quantity of sea water may have accumulated in a small bay4 ,as the process went on1 the salts would become progressively more concentrated1 and would be precipitated in great thickness4 ,a final complete separation of the basin from the sea1 for instance by the relative elevation of the land1 might result in complete desiccation1 and deposition of potassium-magnesium salts such as those found at ,stassfurt 7p4 #aac74 ,another suggestion to explain the thickness of some salt beds is that the salts in a very large basin of water may1 as the water evaporated and the basin shrank1 have been deposited in great thickness in a few small depressions of the basin4 ,other writers believe that certain thick salt deposits were formed in desert basins 7with no necessary connection with the sea71 through the extensive leaching of small quantities of salt from previous sediments1 and its transportation by water to desert lakes1 where it was precipitated as the lakes evaporated4 ,over a long period of time large amounts of salt could accumulate in the lakes1 and thick deposits could result4 ,such hypotheses also explain those cases where common salt beds are unaccompanied by gypsum1 since land streams can easily be conceived to have been carrying sodium chloride without appreciable calcium sulphate2 in ocean waters1 on the other hand1 so far as known both calcium sulphate and sodium chloride are always present1 and gypsum would be expected to accompany the common salt4 ,a partial explanation of some great thicknesses found in salt beds is that these beds1 especially when soaked with water1 are highly plastic and incompetent under pressure4 ,in the deformation of the enclosing rocks1 the salt beds will flow somewhat like viscous liquids1 and will become thinned on the limbs of the folds and correspondingly thickened on the crests and troughs4 ,the salt deposits of the ,gulf ,coast of ,texas and ,louisiana should be referred to because of their exceptional features4 ,they occur in low domes in ,tertiary and more recent sands1 limestones1 and clays4 ,vertical thicknesses of a few thousand feet of salt have been found1 but the structure is known only from drilling4 ,in some of these domes are also found petroleum1 gypsum1 and sulphur 7p4 #aaj74 ,no igneous rocks are known in the vicinity4 ,it has been thought by some that the deposits were formed by hot waters ascending along fissures from underlying igneous rocks1 and the upbowing of the rocks has been variously explained as due to the expanding force of growing crystals1 to hydrostatic pressure of the solutions1 and to laccolithic intrusions4 ,on the other hand1 the uniform association of other salt and gypsum deposits with sedimentary rocks1 and the absence of igneous rocks1 suggest that these deposits may have had essentially a sedimentary origin1 and that they have been modified by subsequent deformation and alteration4 ,the origin is still uncertain4 ,other mineral deposits formed under much the same conditions as salt are gypsum1 potash1 borax1 nitrates1 and minerals of bromine2 and in a study of the origin of salt deposits these minerals should also be considered4 ,,talc ,,and ,,soapstone ,,economic ,,features ,soapstone is a rock composed mainly of the mineral talc4 ,popularly the terms talc and soapstone are often used synonymously4 ,the softness1 greasy feel1 ease of shaping1 and resistance to heat and acids of this material make it useful for many purposes4 ,soapstone is cut into slabs for laundry tubs1 laboratory table tops1 and other structural purposes4 ,finer grades are cut into slate pencils and acetylene burners4 ,ground talc or soapstone is used as a filler for paper1 paint1 and rubber goods1 and in electrical insulation4 ,fine grades are used for toilet powder4 ,pyrophyllite 7hydrated aluminum silicate7 resembles talc in some of its properties and is used in much the same way4 ,fine ,english clays 7p4 #he7 are sometimes used interchangeably with talc as paper filler4 ,the ,united ,states produces nearly two-thirds of the world's talc4 ,the other large producers are ,france1 ,italy1 ,austria1 and ,canada 7,ontario74 ,the ,united ,states is independent of foreign markets for the bulk of its talc consumption1 but some carefully prepared talc of high quality is imported from ,canada1 ,italy1 and ,france4 ,italy is our chief source of talc for pharmaceutical purposes1 though recently these needs have been largely supplied by high-grade talc from ,california4 ,in the ,united ,states1 ,vermont and ,new ,york are the leading producers of talc and ,virginia of soapstone slabs4 ,reserves are large4 ,,geologic ,,features ,talc is hydrated magnesium silicate1 as is also serpentine1 a mineral with which talc is closely associated4 ,both are common alteration products of magnesian silicate minerals such as olivine1 pyroxene1 and amphibole4 ,talc is also derived from the recrystallization of magnesian carbonates4 ,talc deposits consist of lenses and bands in metamorphic limestones1 schists1 and gneisses of ancient age4 ,the talc itself is usually schistose like the wall rocks1 and is largely a product of mechanical mashing4 ,in some cases1 also1 talc results from the alteration of igneous rocks without mashing--as in the case of the large talc and soapstone deposits of ,virginia1 which are the result of rather complete alteration of basic igneous rocks such as peridotites and pyroxenites4 ,talc is known to result from the weathering of magnesian silicates under surface conditions1 but the common occurrence of the principal deposits1 in highly crystalline rocks which have undergone extensive deep-seated metamorphism1 is an indication that processes other than weathering have been effective4 ,it has been suggested that hot ascending solutions have been responsible for the work1 but without much proof4 ,a more plausible explanation for many deposits is that the talc results from the dynamic metamorphism or shearing of impure magnesian carbonates 7as in highly magnesian limestones71 the process resulting in elimination of the carbon dioxide and recrystallization of the residue4 ,certain talc deposits1 such as those of ,ontario1 show clearly traces of the original bedding planes of limestone crossing the cleavage of the talc1 and the rock bears all the evidence of having formed in the same manner as a common slate4 ,talc and slate are almost the only mineral products which owe their value principally to dynamic metamorphism4 ,,chapter ,,xiv ,,exploration ,,and ,,development ,,the ,,general ,,relations ,,of ,,the ,,geologist ,,to ,,exploration ,,and ,,development ,the economic geologist is more vitally concerned with exploration and development than with any other phase of his work4 ,this comes closest to being his special field4 ,here is a fascinating element of adventure and chance4 ,here is the opportunity to converge all his knowledge of geology and economics to a practical end4 ,the outcome is likely to be definite one way or the other1 thus giving a quantitative measure of the accuracy of scientific thinking which puts a keen edge on his efforts4 ,it is not enough merely to present plausible generalizations2 scientific conclusions are followed swiftly either by proof or disproof4 ,with this check always in mind1 the scientist feels the necessity for the most rigid verification of his data1 methods1 and principles4 ,the general success of the application of geology to exploration and development is indicated by the rapid increase in demand for such service in recent years1 and by the large part it plays in nearly all systematic and large-scale operations4 ,the argument is sometimes made that many mineral deposits have been found without geologic assistance1 and that therefore the geologist is superfluous4 ,the answer to this argument is that there are often hundreds of practical explorers in the field to one geologist1 and that in proportion to numbers the story is quite a different one4 ,the very fact that many large mining organizations1 as a result of their experience1 now leave these matters of exploration and development largely in the hands of geologists1 is a tribute to the usefulness of the science4 ,also1 it is to be remembered that not all applications of geology are made by geologists4 ,it is hard to find a prospector or explorer who has not absorbed empirically some of the elements of geology1 and locally this may be enough4 ,very often men who take pride in the title of practical prospectors are the ones with the largest stock of self-made geological theories4 ,during a prospecting boom it is not uncommon for speculators and promoters to attempt to discount geologic considerations where these run counter to their plans4 ,the catching phrase bet against the geologist has a broad appeal to an instinctive preference for the practical as opposed to the theoretical4 ,if the public would stop to note the character of the support behind the geologist1 including as it does the larger and more successful operators1 it would not be so ready to accept this implication4 ,another aspect of this question might be mentioned4 ,there is scarcely an oil field or mining camp in the world without a cherished tradition to the effect that1 prior to discovery1 the mineral possibilities had been reported on unfavorably by the geologists1--again implying that success has been due to the hard common sense of the horny-handed prospector4 ,these traditions persist in the face of favorable geological reports published before discovery2 they are natural expressions of the instinctive distrust of any knowledge which is beyond the field of empirical experience4 ,in many cases the discoveries were made long before geologists appeared on the scene4 ,in others1 possibly one or two geologic reports were unfavorable1 while many were favorable4 ,in the aggregate1 there can be no question that1 in proportion to the scale of its use1 geological advice has had more than its proportion of success4 ,even under the most favorable conditions1 the chances against the success of an individual drill hole or underground development are likely to be greater than the chances for it4 ,the geologist may not change this major balance2 but if he can reduce the adverse chances by only a few per cent1 his employment is justified on purely commercial grounds4 ,the above comments refer to sound geological work by competent scientists4 ,the geologic profession1 like many others1 is handicapped by numbers of ill-trained men and by many who have assumed the title of geologist without any real claim whatever1--who may do much to discredit the profession4 ,the very newness of the field makes it difficult to draw a sharp line between qualified and unqualified men4 ,with the further development of the profession this condition is likely to be improved 7see pp4 #dbg-dbh74 ,so new is the large-scale application of geology to exploration and development1 and so diverse are the scientific methods of approach1 that it is difficult to lay out a specific course for a student which will prepare him for all the opportunities he may have later4 ,in the writer's experience1 both in teaching and practice1 the only safe course for the student is to prepare broadly on purely scientific lines4 ,with this background he will be able later to adapt himself to most of the special conditions met in field practice4 ,,partly ,,explored ,,versus ,,virgin ,,territories ,in selecting an area to work1 the geologic explorer will naturally consider various factors mentioned in succeeding paragraphs2 but the natural first impulse is to start for some place where no one else has been1 and to keep away from the older principal mining camps1--on the assumption that such grounds have been thoroughly explored and that their geological conditions bearing on exploration are fully understood4 ,it is safe to say that very few mineral districts are thoroughly understood and explored4 ,numerous important discoveries of recent years have been in the extensions of old mines and old districts2 and when one considers the scale of even the most extensive mine openings in comparison with the vast body of rock available for exploration1 it is clear that this will continue to be the situation far into the future4 ,it is the writer's belief that the economic geologist stands at least as good a chance of success in exploration in the older districts as he does in new fields4 ,nature is exceedingly erratic and economical in providing places favorable for mineral production2 in a producing district the geologic conditions have been proved to be right1 and the explorer starts here with this general pragmatic advantage4 ,the explorer here has another great advantage1 that much essential information has been gathered which can be built into his plan of operations4 ,he can start1 scientifically and practically1 where the other man left off4 ,one of the best-known economic geologists has maintained that the more previous work done1 the better1 because it furnished him more tools to work with4 ,there is no such thing as skimming the cream from a geologic problem2 there is no end in sight in the search for more knowledge4 ,this attitude toward the problem of exploration has also proved advantageous on the business or financial side4 ,a successful backer of mineral enterprises once remarked that his best prospecting was done from the rear platform of a private car1--meaning that this mode of transportation had carried him to the center of important mining activities1 where the chances for large financial success showed a better percentage than in more general and miscellaneous exploration4 ,,the ,,use ,,of ,,all ,,available ,,information ,effective scientific exploration requires the use of all available information applying to the specific area4 ,this might seem to be too obvious to require mention1 yet observance of the methods of explorers seems to call for warning against the rather common tendency to go into a field unprepared with a thorough knowledge of preceding work4 ,it is easy to forget or overlook some investigation made many years previously2 or to assume that such work is out of date1 and of no special consequence in the application of new thought and method which is the basis of the faith and confidence of each new geologic explorer4 ,a study of the reports on an old camp shows how often the younger generations have ignored the results of the older4 ,many of the same elementary truths are rediscovered by successive generations1 after large efforts which could have been saved by means of proper care and investigation of the previous literature and mapping4 ,in outlying parts of the world1 the existing information bearing on exploration may be at a minimum4 ,in many of the older mining camps and throughout most civilized countries1 however1 careful investigation will usually disclose a considerable range of useful information bearing on the territory to be explored4 ,in the ,united ,states the natural course to be pursued is to hunt carefully through the reports of the ,u4 ,s4 ,geological ,survey1 the ,bureau of ,mines1 various state surveys1 universities1 and private organizations 7so far as these reports are available71 and through the technical journals and the reports of technical societies1 for something bearing on the district to be explored4 ,even if no specific report or map is to be found1 it is usually possible to locate general maps or accounts which are likely to be of use4 ,,cooperation ,,in ,,exploration ,competition in exploration often develops an atmosphere of suspicion and furtiveness which is highly unfavorable to cooperative efforts4 ,individuals and companies may handicap themselves greatly by a desire to play a lone hand1 and by failure to take advantage of an exchange of information4 ,this action may be based1 particularly on the part of strong mining companies1 on the assumption that they know all that is necessary about the problem1 and that an outsider has nothing to contribute4 ,financial and other conditions may require this attitude2 but in large part it is a result of temperament1 as clearly indicated by the difference in methods followed by different groups and in different mining districts4 ,from the scientific point of view this attitude can hardly be justified1 in view of the extremely narrow limits of human knowledge as compared with the scientific field to be explored4 ,the sum total of knowledge from all sources is only a small fraction of that necessary for the most effective results4 ,the mutual exchange of information and discussion is usually justified on the basis of self-interest alone1 to say nothing of the larger interest to the mineral district1 to the country1 or to science4 ,national and state survey organizations exercise considerable effort to secure records of drilling4 ,in some cases they have the legal power to command this information1 particularly in relation to appraisals for taxation and blue sky laws4 ,in a larger number of cases drill records are secured through voluntary cooperation with explorers4 ,a considerable number of records are nevertheless not filed with public agencies and some of these are permanently lost4 ,even where the records are turned in to a public organization1 they are in most cases not directly available to explorers4 ,public registration of all drilling records is a highly desirable procedure in the interests of the development of the mineral industry as a whole4 ,a vast amount of unnecessary duplication can thus be avoided4 ,the record of a drill hole1 even though barren1 may be of vast significance in the interpretation of future developments and should be recorded as carefully as an abstract of land title4 ,the property right of the explorer in such information can be and usually is protected by withholding the record from public inspection until sufficient time has elapsed to give him full opportunity to use the information to his own best advantage4 ,the opportunities for cooperation with specialists of public organizations are almost unlimited4 ,these organizations are likely to have an accumulation of data and experience extending through long periods and over large areas1 which the private explorer ordinarily cannot hope to duplicate4 ,with proper restrictions this information may be available for public use4 ,a good illustration of current cooperative effort of this kind is in the deep exploration for oil in the ,trenton limestone of ,illinois4 ,outcrops and other specific indications are not sufficient to localize this drilling2 but the information along broad geologic and structural lines which has been collected previously by the ,illinois ,survey is sufficient so that1 with a comparatively small amount of shallow drilling1 the locus of the more favorable structural conditions may be determined4 ,in this case the ,survey is directing the initial exploration1 which is financed by private capital4 ,,economic ,,factors ,,in ,,exploration ,the approach to the problem of exploration is very often determined by local requirements and conditions2 but if one were to come at the problem from a distance and to keep matters in broad perspective1 the first step would be a consideration of what might be called the economic factors4 ,let us suppose that the geologist is free to choose his field of exploration4 ,an obvious preliminary step is to eliminate from consideration mineral commodities which are not in steady or large demand and are much at the mercy of market conditions1 or which are otherwise not well situated commercially4 ,the underlying factors are many and complex4 ,they include the present nature and future possibilities of foreign competition1 the domestic competition1 the grades necessary to meet competition1 the cost of transportation1 the cost of mining under local conditions--including considerations of labor and climatic and topographic conditions1--the probability of increase or decrease in demand for the product1 the possible changes in metallurgical or concentrating practice 7such as those which made possible the mining of low-grade porphyry copper ores71 the size of already available reserves1 and the mining laws in relation to ownership and regulation4 ,most of these factors are discussed at some length on other pages4 ,after looking into the economic conditions limiting the chromite1 nickel1 or tin developments in the ,united ,states1 the explorer might hesitate to proceed in these directions1--for he would find that past experience shows little promise of quantities and grades equivalent to those available in other countries1 and that there is little likelihood of tariffs or other artificial measures to improve the domestic situation4 ,before and during the war1 commercial conditions might have shown the desirability of hunting for pyrite1 but more recent developments in the situation cast some doubt on this procedure4 ,to go ahead blindly in such a case1 on the assumption that the pyrite market would in some fashion readjust itself1 would not be reasoned exploration4 ,again1 in considering exploration for copper1 account should be taken in this country of the already large reserves developed far in advance of probable demand1 which require that any new discoveries be very favorably situated for competition4 ,in oil1 on the other hand1 a very brief survey of the economic factors of the situation indicates the desirability of exploration4 ,the comparative shortage of lead supplies at the present time suggests another favorable field for exploration4 ,in short1 before actual field exploration is begun1 intelligent consideration of the economic factors may go far toward narrowing the field and toward converging efforts along profitable lines4 ,looked at broadly1 this result is usually accomplished by the natural working of general laws of supply and demand2 but there are many individual cases of misdirected effort1 under the spell of provincial conditions1 which might easily be avoided by a broader approach to the problem4 ,,geologic ,,factors ,,in ,,exploration ,coming to the geological aspects of exploration1 the procedure in its early stages is again one of elimination4 ,oil and coal1 for instance1 are found in certain sediments of certain ages1 and one would not look for them in an area of granite4 ,for every mineral resource there are broad geologic conditions of this sort1 particularly the genetic1 structural1 and metamorphic conditions1 which make it possible to eliminate vast areas from consideration and to concentrate on relatively small areas4 ,after the elimination of unfavorable areas1 there comes the hunt for positively favorable geologic conditions--for a definite kind of sediment or igneous rock1 for a definite structure1 for the right kind of mineralogic and metamorphic conditions1 or for the right combination of these and other geologic elements4 ,the geologic considerations used in exploration for the various mineral deposits are so many and so diverse1 and they require so much adjustment and interpretation in their local application1 that one would be rash indeed to attempt anything in the nature of an exhaustive discussion4 ,it is hardly practicable to do more than to outline1 for illustrative purposes1 a few of the geologic factors most commonly used in exploration4 ,,mineral ,,provinces ,,and ,,epochs ,mineral deposits may be similar in their mineralogic and geologic characters and relations over a considerable area4 ,they may give evidence of having developed under the same general conditions of origin2 perhaps they may even be of the same geologic age4 ,the gold-silver deposits of ,goldfield1 of ,tonopah1 the ,comstock ,lode of ,virginia ,city1 and many other deposits through the ,great ,basin area of the southwestern ,united ,states and ,mexico have group characteristics which have led geologists to refer to this area as a metallogenic or metallographic province4 ,the gold-silver ores on the west slope of the ,sierra ,nevadas1 for nearly the entire length of ,california1 likewise constitute a metallogenic province4 ,the ,lake ,superior copper ores on the south shore of ,lake ,superior1 the silver ores on the north shore1 miscellaneous small deposits of copper1 silver1 and gold ores to the east of ,lake ,superior1 the nickel ores of ,sudbury1 and the silver-nickel-cobalt ores of the ,cobalt district are all characterized by similar groups of minerals 7though in highly differing proportions71 by similar geologic associations1 by similar age1 and probably by similar conditions of origin4 ,this area is a metallogenic province4 ,the lead and zinc ores of the ,mississippi ,valley constitute another such province4 ,the oil pools of the principal fields are characterized by common geologic conditions over great areas 7p4 #adi71 which may likewise be considered as forming mineral provinces2 for them the term petroliferous provinces has been used4 ,the list might be extended indefinitely4 ,knowledge of such group distributions of minerals is a valuable asset to the explorer1 in that it tends to localize and direct search for certain classes of ores in certain provinces2 also1 within a province1 it tells the explorer what is to be normally expected as regards kinds and occurrences of mineral deposits4 ,in searching for minerals of sedimentary origin1 the explorer will use stratigraphic methods in following definite sedimentary horizons4 ,in searching for ores related to igneous intrusions he will naturally hunt for the intrusions1 and then follow the periphery of the intrusions for evidences of mineralization1 taking into account possible features of zonal arrangement of minerals about the intrusives 7see pp4 #db-dd71 and the preference of the ores for certain easily replaced horizons like limestones1 or for certain planes or zones of fracturing4 ,just as minerals may be grouped by provinces1 they may be grouped by geologic ages4 ,such groupings are especially useful in the case of minerals which are closely related to certain stratigraphic horizons1 such as coal1 oil1 and iron4 ,the greater number of the productive coal deposits of the ,united ,states are of ,carboniferous age1 and the distribution of sediments of this age is pretty well understood from general geologic mapping4 ,the ,clinton iron ores all follow one general horizon in the lower-middle ,paleozoic4 ,the ,lake ,superior iron ores are pre-,cambrian1 and over three-fourths of them occur at one horizon in the pre-,cambrian4 ,gold deposits of the ,united ,states were formed mainly in the pre-,cambrian1 the early ,cretaceous1 and the ,tertiary4 ,copper deposits of the ,united ,states were formed chiefly in pre-,cambrian1 ,cretaceous1 and ,tertiary time4 ,while there are many exceptions and modifications to general classifications of this sort1 they seem to express essential geologic facts which can be made very useful in localizing exploration4 ,,classification ,,of ,,mineral ,,lands ,in recent years there has been considerable development of the practice of classifying mineral lands in given areas for purposes of exploration and valuation1 or for purposes of formulation and administration of government laws4 ,this has been done both by private interests and by the government4 ,these classifications take into account all of the geologic and economic factors ascertainable4 ,the classes of mineral land designated vary with the mineral1 the district1 and the purpose for which the classification is made4 ,common procedure for commercial exploration purposes is to divide the lands of a given territory into three groups--7#a7 lands which are definitely promising for mineral exploration1 7#b7 lands of doubtful possibilities1 and 7#c7 lands in which the mineral possibilities are so slight that they may be excluded from practical consideration4 ,each of these classes may be subdivided for special purposes4 ,another commonly used classification is1 7#a7 proved mineral lands1 7#b7 probable mineral lands1 usually adjacent to producing mines1 7#c7 possible mineral lands1 and 7#d7 commercially unpromising mineral lands4 ,the classification of the public mineral lands by government agencies is fully discussed by ,george ,otis ,smith and others in a bulletin of the ,united ,states ,geological ,survey4#cg ,the purposes1 methods1 and results of this classification should be familiar to every explorer4 ,nowhere else is there available such a vast body of information of practical value4 ,quoting from this report3 ,a study of the land laws shows the absolute necessity of some form of segregation of the lands into classes as a prerequisite to their disposition4 ,agricultural entry may not be made on lands containing valuable minerals1 nor coal entry on lands containing gold1 silver1 or copper2 lands included in desert entries or selected under the ,carey ,act must be desert lands2 enlarged-homestead lands must not be susceptible of successful irrigation2 placer claims must not be taken for their timber value or their control of watercourses2 and lands included in building-stone1 petroleum1 or salt placers must be more valuable for those minerals than for any other purpose4 ,so through the whole scheme of ,american land laws runs the necessity for determining the use for which each tract is best fitted4 ,for this purpose the ,geological ,survey has made extensive classification of coal lands1 oil and gas lands1 phosphate lands1 lands bearing potash and related salines1 metalliferous mineral lands1 miscellaneous non-metalliferous mineral lands1 and water resources4 ,the scope of the work may be indicated by the factors considered4 ,for instance coal is investigated in relation to its character and heat-giving qualities 7whence comes its value71 quantity1 thickness1 depth1 and other conditions that effect the cost of its extraction4 ,metalliferous mineral lands are considered in relation to general geology1 country rock1 intrusions and metamorphism1 structure1 outcrops and float of lodes1 prospects and mines1 samples1 and history of the region4 ,classifications of this kind have often proved useful to large holders of land as a basis for intelligent handling of problems of sale1 taxation1 and the granting of rights to explorers4 ,because of the lack of this elementary information1 there has been in some quarters timidity about dealing with large holdings1 for fear of parting with possible future mineral wealth1--with the result that such tracts are carried at large expense and practically removed from the field of exploration4 ,to the same cause may be attributed some of the long delays on the part of the government in opening lands for mineral entry or in issuing patents on land grants4 ,,outcrops ,,of ,,mineral ,,deposits ,many mineral deposits have been found because they outcrop at the surface2 the discoveries may have been by accident or they may have been aided by consideration of geologic factors4 ,there are still vast unexplored areas in which mineral deposits are likely to be found standing out at the surface4 ,for much of the world1 however1 the surface has been so thoroughly examined that the easy surface discoveries have been made1 and the future is likely to see a larger application of scientific methods to ground where the outcrops do not tell an obvious story4 ,mineral deposits may fail to outcrop because of covering by weathered rock or soil1 by glacial deposits1 or by younger formations 7surface igneous flows or sediments71 or the outcrop of a deposit may be so altered by weathering as to give little clue to the uninitiated as to what is beneath4 ,mineral deposits formed in older geologic periods have in most cases been deeply covered by later sediments and igneous rocks4 ,such deposits are in reach of exploration from the surface only in places where erosion has partly or wholly removed the later covering4 ,an illustration of this condition is furnished in the ,great ,basin district of ,nevada1 where ore bodies have been covered by later lava flows4 ,the ore-bearing districts are merely islands exposed by erosion in a vast sea of lava and surface sediments4 ,beyond reasonable doubt many more deposits are so covered than are exposed1 and it is no exaggeration to say that by far the greater part of the mineral wealth of the earth may never be found4 ,where a mineral-bearing horizon is exposed by erosion at the surface1 underground operations may follow this horizon a long way below the capping rocks2 but1 after all1 such operations are geographically small as compared with the vast areas over which the covering rocks give no clue as to what is beneath4 ,one of the principal problems of economic geology for the future is to develop means for exploration in territories of this sort4 ,a beginning has been made in various districts by the use of reconnaissance drilling1 combined with interpretation of all the geologic and structural features4 ,the discovery of one of the largest nickel deposits in the ,sudbury district of ,canada was made by reconnaissance drilling to ascertain the general geologic features1 in an area so deeply covered as to give little suggestion as to the proper location for attack4 ,,some ,,illustrative ,,cases ,the use of outcrops in oil exploration has been noted on other pages 7pp4 #adf-adg74 ,outcrops of coal seams may be found in folded or deeply eroded areas4 ,for the most part1 however1 and especially in areas of flat-lying rocks1 the presence of coal is inferred from stratigraphic evidence and from the general nature of the geologic section--which has been determined by outcrops of associated rocks or by information available at some distant point4 ,the structural mapping of coal beds on the basis of outcrops and drill holes has been referred to 7pp4 #abf-abg74 ,iron ores are very resistant to solution4 ,where hard and compact they tend to form conspicuous outcrops1 and where soft they may be pretty well covered by clay and soil4 ,in glaciated areas1 like the ,lake ,superior region1 outcrops of iron ore are much less numerous because of the drift covering4 ,certain of the harder iron ores of the ,marquette1 ,gogebic and ,menominee districts of ,michigan and of the ,vermilion district of ,minnesota project in places through the glacial drift1 and these ores were the first and most easily found4 ,much the greater number of iron ore deposits of ,lake ,superior1 including the great soft deposits of the ,mesabi range of ,minnesota1 fail to outcrop4 ,on the other hand the iron formation1 or mother rock of the ore1 is hard and resistant and outcrops are numerous4 ,the hematite ores of ,brazil have many features in common with the ,lake ,superior ores in age and occurrence1 but they have not been covered with glacial deposits4 ,outcrops of the iron ore are large and conspicuous1 and the surface in this territory gives one some idea of what the ,lake ,superior region may have looked like before the glaciers came along4 ,certain of the soft iron ores of the lateritic type1 as in ,cuba1 outcrop over great areas where their topographic situation is such that erosion has not swept them off4 ,on erosion slopes they are seldom found4 ,the ,clinton iron ores of the southeastern ,united ,states outcrop freely4 ,some of the lead and zinc deposits of the ,mississippi ,valley outcrop at the grass roots as varying mixtures of iron oxide1 galena1 chert1 and clay1 though they seldom project above the general surface4 ,the old lead ranges of ,wisconsin and ,illinois1 found at the surface a century ago by the early explorers and traders1 have served as starting points for deeper exploration which has located the zinc deposits4 ,erosion channels have freely exposed these ore bodies1 and in the ,wisconsin-,illinois deposits most of the ores thus far found are confined to the vicinity of these channels4 ,the greater number of the lead and zinc deposits of the ,mississippi ,valley1 however1 are covered with weathered material or with outliers of overlying sediments1 with the result that underground exploration is necessary to locate them4 ,sulphide deposits in general1 including those carrying gold1 silver1 copper1 lead1 zinc1 and other metals1 have many common features of outcrop4 ,the iron sulphide commonly present in these ore bodies is oxidized to limonite at the surface1 with the result that prospectors look for iron-stained rocks4 ,these iron-stained rocks are variously called the gossan1 the iron capping1 the colorado1 or the eiserner ,hut 7iron hat74 ,the gossan is likely to resist erosion and to be conspicuous at the surface1--though this depends largely on the relative resistance of the wall rocks1 and on whether the gangue is a hard material like quartz1 or some material which weathers more rapidly like limestone or igneous rock4 ,the gossan does not often carry much value1 though it may show traces of minerals which suggest what may be found below4 ,gold1 silver1 and lead are not easily leached out of the surface outcrops4 ,copper and zinc are much more readily leached1 and in the outcrop may disclose their existence only by traces of staining4 ,it happens not infrequently1 therefore1 that copper and zinc deposits are found through the downward exploitation of oxidized gold1 silver1 and lead ores4 ,the veins at ,butte were first worked for silver1 and the ore bodies at ,bingham1 ,utah1 and ,jerome1 ,arizona1 were first mined for gold4 ,exceptionally1 copper ore in enriched1 oxidized form outcrops1 as at ,bisbee1 ,arizona4 ,it is not always true that valuable sulphide deposits have an iron-stained outcrop1 for in some of them iron sulphide or pyrite is so scarce that the surface outcrops may be light-colored clayey and siliceous rocks4 ,silver is often represented in the outcrop by silver chloride or cerargyrite1 which may be easily identified4 ,the prospecting for such surface ores is sometimes called chloriding4 ,the presence in the outcrop of dark manganese oxides associated with vein quartz sometimes indicates the presence below of copper and zinc and other minerals1 as at ,butte4 ,extensive alterations of the country rock in the way of silicification and sericitization1 and the presence of minerals like garnet1 tourmaline1 diopside1 and others1 known to be commonly deposited by the same hot solutions which make many ore deposits1 may furnish a clue for exploration below4 ,these characteristics of the country rock1 however1 are likely to be masked at the outcrop by later weathering1 which superposes a kaolinic or clayey alteration4 ,,topography ,,and ,,climate ,,as ,,aids ,,in ,,searching ,,for ,,mineral ,,outcrops ,the topographic expression of a mineral deposit depends upon its hardness and resistance to erosion as compared with the adjacent rocks4 ,if more resistant it will stand out at the surface2 if less resistant1 it will form a depression4 ,the conditions determining resistance are exceedingly variable1 and no broad generalization can be made2 but within a local province a given group of mineral deposits may characteristically form depressions or ridges1 and thus topographic criteria may be very useful in exploration4 ,even with such limitations1 the variations of the topographic factor may be so great as to require much care in its use4 ,sulphide ores in quartzites are likely to develop depressions under erosion4 ,in limestones they are more likely to stand out in relief1 because of the softer character of the limestone1 though this does not always work out4 ,crystalline magnetite and hematite are more resistant to erosion than almost any other type of rock1 and stand out at the surface with proportional frequency4 ,climatic conditions may determine the locus of search for certain surface minerals4 ,bauxite and lateritic iron ores1 for instance1 are known to favor tropical climates4 ,in exploration for these minerals1 the climatic factor must be applied in connection with the topographic considerations already mentioned1 and both1 in turn1 in connection with the character of the country rock as determined by general geologic surveys4 ,a combination of climatic1 topographic1 and other physiographic conditions may be used also in exploration for certain types of residual clays4 ,,size ,,and ,,depth ,,of ,,ore ,,bodies ,,as ,,determined ,,from ,,outcrop ,where the ore body is harder than the surrounding rock1 it stands out in conspicuous outcrops and is likely to show a narrowing below4 ,where it is softer than the surrounding rocks1 and outcrops in a topographic depression1 it is perhaps more likely to show widening below4 ,these features are due to the general facts that1 where the ore body is hard and resistant1 the downward progress of erosion is likely to be arrested where the adjacent rocks occupy the larger part of the surface1 that is1 where the ore body is narrower4 ,this principle is often vaguely recognized in the assumption that an exceptionally large outcrop of an ore vein may be too good to last4 ,again1 such a generalization must be applied to a specific case with much caution4 ,attempts to forecast the depth of veins from their extent at the surface meet with only partial success4 ,in a very general way great persistence horizontally suggests persistence in depth1 on the ground that the section exposed on the surface is as likely to be a section of average dimensions as one along vertical lines4 ,faith is the first article of the prospector's creed1 and it is hard to shake his conviction that every ore outcrop must widen and improve below4 ,as expressed by the ,french-,canadian prospector in the ,cobalt district1 the vein calcite can't go up1 she must go down4 ,while the scientist may have grounds to doubt this reasoning1 he is not often in a position to offer definite negative evidence4 ,,the ,,use ,,of ,,placers ,,in ,,tracing ,,mineral ,,outcrops ,outcrops of ore-bearing rock may occasionally be located by tracing a placer deposit back to its source1 or by following up ore fragments in the wash on mountain sides to the place of origin1 or by noting ore fragments in glacial deposits4 ,the presence of an ore mineral in a placer naturally raises the question as to whence it came4 ,if it is a recent placer1 it may be comparatively easy to follow up the stream channels to the head-water territory which is delivering the main mass of sediment1 and there to locate a vein in place4 ,the problem is complicated by multiplicity of tributaries and by large size of the drainage areas4 ,in such cases careful panning and testing of the gravels at frequent intervals may show which of several tributaries are contributing most of the values1 and thus may further localize the area of search4 ,many important mining districts1 including ,butte1 ,bisbee1 the ,mother ,lode region of southern ,california1 the diamond fields of ,africa1 and others1 have been found by tracing up placers in this manner4 ,in the case of an older placer deposit1 where the topography and drainage have been much altered since its formation1 or where the deposit has been covered by later sediments1 the problem is of course much more difficult4 ,much less than a commercially valuable placer deposit in unconsolidated surface rocks may start a search for the mother lode4 ,a single fragment of ore in the wash naturally directs attention up the slope1 and the repetition of fragments in a certain direction may lead unerringly to the source4 ,the fragments may not even in themselves carry value1 but may consist of detrital material from the leached outcrop--such as iron or manganese oxides1 which1 because of their red or black color1 stand out conspicuously in the rock debris4 ,in the ,lake ,superior region large angular fragments of iron ore or iron formation in the glacial drift immediately raise question as to source4 ,if the fragments are rounded and small1 they usually indicate a very distant source4 ,the general direction of glacial movement is known in most places1 and by tracing up the fragments in this direction the outcrop may be found2 or the chain of fragments may be traced to a point where they stop1 which point may serve to locate the parent bedrock carrying the ore body1 even though it does not outcrop4 ,an interesting suggestion was made some years ago with reference to the diamonds found sporadically in the terminal moraines in ,wisconsin and other mid-west states4 ,the diamonds are of such size and quality as to indicate surely the existence of a real diamond field somewhere to the north4 ,the locations of these diamond finds were platted on a glacial map1 and lines were projected in a general northerly direction along the known lines of the glacial movement4 ,it was found that these lines converged at a point near ,hudson's ,bay4 ,the data were too meager and the base line too short for this long projection1 and the indicated source of the diamonds can be regarded as the merest speculation4 ,however1 with the finding of additional diamonds in the drift1 as seems very likely1 the refinement of this method might conceivably bring results in time4 ,,the ,,use ,,of ,,magnetic ,,surveys ,,in ,,tracing ,,mineral ,,ledges ,magnetic surveys are often useful in tracing iron-bearing rocks beneath the surface1 in the discovery of outcrops of such rocks1 and in working out their lines of connection4 ,this method is in general use for the crystalline iron ores in the ,lake ,superior region1 ,canada1 the ,adirondacks1 and elsewhere in the glaciated portions of the ,united ,states4 ,it is not so useful for the brown ores and the ,clinton ores of the southeastern ,united ,states1 which are only slightly magnetic and can be commonly located by other methods4 ,where the ore is strongly magnetic1 and is associated with other rocks which are non-magnetic1 the nature of the magnetic field determined by a surface survey with vertical and horizontal needles may tell something about the shape and size of the ore body4 ,commonly1 however1 magnetic ores are associated with leaner magnetic rocks1--with the result that the magnetic survey1 unless it happens to lead to an outcrop of ore1 indicates only the general area through which underground exploration might be warranted4 ,in the hematitic iron ores of ,lake ,superior1 magnetism is less pronounced than in the magnetites2 and in the soft hydrous hematites1 like those of the ,mesabi district1 it may cause only slight disturbance of the magnetic needle4 ,this disturbance is usually sufficient to locate the position of the iron-bearing formation1 though not the position of the ore4 ,where the iron formation has been highly metamorphosed1 and rendered resistant to weathering and erosion so that it will not concentrate into ore1 it is likely to have higher magnetic attraction than the richer ores4 ,for this reason an area of strong magnetic attraction is ordinarily regarded as not particularly favorable to the finding of important hematite deposits4 ,however1 this attraction may be very useful in tracing out the formation to a place where it is less metamorphic1 less resistant to erosion1 less likely to outcrop1 and yet more promising for the discovery of iron ore4 ,for instance1 on the east end of the ,mesabi and on the east and west ends of the ,gogebic district1 magnetic surveys trace the iron formation with great ease to points where the attraction is low and the conditions for exploration more favorable4 ,the magnetic needle has also been used in the search for nickel ore in the ,sudbury district of ,ontario1 but without great success1 because of the variety of rocks other than nickel which are more or less magnetic1 and because of the slight magnetic properties of the nickel ore itself4 ,in a large-scale exploration of this type1 conducted some years ago1 a favorable magnetic belt was discovered1 and a pit was sunk to water level but not to bedrock4 ,years later1 the extension of this pit by only a few feet disclosed one of the great ore bodies of the district4 ,experimental work on the use of the magnetic needle on copper deposits has yielded some interesting and suggestive results1 but this investigation is still under way and the results have not been published4 ,,the ,,use ,,of ,,electrical ,,conductivity ,,and ,,other ,,qualities ,,of ,,rocks ,,in ,,exploration ,in addition to magnetism1 rocks and ores have other properties susceptible to observations made at a distance1 such as electrical conductivity1 transparency to ,x-rays1 specific induction1 elasticity1 and density4 ,all these qualities have been of interest to geologists in some connection or another1 but none of them have yet been used effectively in exploration for mineral resources4 ,the only one of these properties that has thus far seemed to promise practical results is electrical conductivity4 ,the results yet obtained are slight1 and this kind of investigation has rested under something of a cloud1 due to extravagant claims of inventors4 ,nevertheless1 there has been a considerable amount of scientific work by physicists1 geologists1 and engineers1 supplemented by special war-time investigations of rock and earth conductivity in connection with ground telephones and the tapping of enemy conversations1 which seems to indicate a distinct possibility of practical results in the future1--perhaps not so much in locating specific ore bodies as in locating general types of formation and structures1--which may serve to supplement other methods of search4#ch ,the transmission and reflection of sound waves in rocks have also been more or less investigated with reference to their possible military use4 ,it seems not impossible that these phenomena may be of some geologic aid in the future1 but experimental work is yet in a very early stage4 ,,the ,,use ,,of ,,structure ,,and ,,metamorphism ,,in ,,exploration ,the necessity for careful use of structural data in exploration scarcely requires discussion4 ,references have been made to structural features in connection with coal1 oil1 iron ore1 and other minerals4 ,this phase of study can scarcely be too intensively followed4 ,the tracing of a folded or faulted vein1 in a particularly complex system of veins1 requires application of all of the methods and principles of structural geology4 ,similarly1 the importance of applying the principles of metamorphism1 embodied in the metamorphic cycle 7pp4 #bg-bh7 is almost self-evident4 ,certain kinds of metamorphism are suggestive of the nature of the mineral deposits with which they are associated4 ,one would not look for minerals known to be caused mainly by surficial processes in rocks which have been altered mainly by deep-seated processes4 ,the presence of metamorphism indicating high temperatures and pressures to some extent limits the kinds of minerals which one may expect to find4 ,on the other hand1 minerals known to be primarily formed at great depths1 providing they are resistant to surface weathering1 may be found in deposits which are the result of surficial alterations or katamorphic processes2 that is1 they may become concentrated as residual materials in weathered zones or as placers4 ,,drilling ,,in ,,exploration ,in the absence of distinctive outcrops1 as well as when outcrops are found1 drilling is a widely used method of underground exploration in advance of the sinking of shafts or the driving of tunnels4 ,drilling is more useful in the locating and proving of mineral deposits of large bulk1 like deposits of coal1 iron1 and oil1 than mineral deposits of small bulk and high value1 like gold and silver deposits4 ,however1 it is not always used in the exploration of the first class of deposits and is not always eliminated in the exploration of the second class4 ,with the development of better mechanical devices1 better methods of controlling and ascertaining the direction of the drill hole1 and more skillful interpretation of drill samples1 the use of drilling is rapidly extending into mineral fields where it was formerly thought not applicable4 ,the geologist takes an active part in drilling operations by locating the drill holes1 by determining the angle of the holes1 by identifying and interpreting the samples1 by studying bedding1 cleavage1 and other structures as shown in the samples1 and determining the attitude of these structures in the ground1 by determining when the horizon is reached which is most promising for mineral1 and by determining when the hole shall be stopped4 ,with a given set of surface conditions1 the problem of locating and directing a drill hole to secure the maximum possible results for the amount expended requires the careful consideration of many geologic factors1--and1 what is more important1 their arrangement in proper perspective and relationship4 ,faulty reasoning from any one of the principal factors1 or over-emphasis on any one of them1 or failure to develop an accurate three-dimensional conception of the underground structural conditions1 may lead to failure or extra expense4 ,success or failure is swiftly and definitely determined4 ,the geologist is usually employed by the company financing the drilling2 but in recognition of the importance of his work1 some of the large contracting drill companies now employ their own geologists4 ,the technique of the geologic interpretation and direction of drilling has become rather complicated and formidable1 and has resulted in the introduction of special college courses in these subjects4 ,the desirability of public registration of drilling records is discussed on another page 7pp4 #cje-cjf74 ,,quantitative ,,aspects ,,of ,,geologic ,,exploration ,in recent years there has been a tendency to reduce the geologic factors in exploration to some kind of a quantitative basis4 ,while these factors may be very variable and very complex1 their net effect frequently may be expressed in terms of quantitative averages4 ,in various mines and mining districts where operations are of wide extent1 local quantitative factors have been worked out which are useful in predicting results from proposed explorations in undeveloped portions4 ,figures of this sort may be useful and practical guides in planning any given exploration1 its cost1 and its probable outcome4 ,quantitative methods are illustrated in the general account of ,lake ,superior iron ore exploration in a later section4 ,curves of production from oil wells and from oil districts have been found to have certain characteristic features in common which are often used in predicting the future output and life of a given well1 property1 or district4 ,where associated with coal1 the percentage of fixed carbon in the coal may be a guide to the presence and nature of the oil 7see ,chapter ,,viii74 ,the geological staff of the ,netherlands ,east ,indies estimated the tin reserves of one of these islands by the use of a factor or coefficient1 based on the experience of another island4 ,in the ,cobalt district of ,canada a factor for future discoveries and output1 based on past experience1 was similarly developed4 ,hoover#ci made a statistical study of several hundred metal mines in various parts of the world1 and found that not #f per cent of the mines that yielded profits ever made them from ore mined below #b1jjj feet2 and that of the mines that paid dividends1 #hj per cent did not yield profit below #a1ejj feet1 and most of them died above #ejj feet4 ,attempt has been made by a ,swedish geologist to estimate the iron ore resources of continents by the use of an iron coefficient4 ,this coefficient was obtained by dividing the known iron ore resources of the comparatively well-investigated portions of the world by the number of square miles in which they occurred1 and was then multiplied into the area of the continents whose resources were to be determined4 ,the application of quantitative methods of this kind has not yet become very general1 nor is it possible to use them in some cases2 where applied many of them have been very crude and others have been partly disproved by experience4 ,with increasing knowledge and experience1 such methods are becoming more accurate and useful1 and are likely to have wider use in the future4 ,,origin ,,of ,,mineral ,,deposits ,,as ,a ,,factor ,,in ,,exploration ,in exploration1 the geologist is keen to ascertain the origin of the mineral deposit4 ,this is often a source of wonder to the layman or practical man1 and the geologist may be charged with having let his fondness for theory run away with him4 ,a widespread fatalistic conception is expressed in the ,cornishman's dictum on ore1 ,where it is1 there it is4 ,yet an understanding of the origin of any particular ore1 the why of it1 is coming to be recognized as the most effective means of reaching sound practical conclusions4 ,by ascertaining the approximate origin of the ore1 it may be possible at once to infer a whole group of practical considerations based on experience with ores of like origin in other localities4 ,the origin of the ore is the geologist's primary interest1 and it is this which gives him his most effective and distinctive tool in exploration4 ,many other phases of exploration work may be picked up empirically by any one familiar with the local conditions2 but when the man without sound geologic training attempts to go into this particular field1 his lack of background and perspective often leads to fantastic hypotheses which may vitiate the inferences on which he plans his exploration4 ,the scientific investigator1 while not accepting the fanciful theories of the local observer1 will make a mistake if he fails to recognize the residuum of solid fact on which they are built4 ,many practical explorers are shrewd observers of empirical facts1 even though their explanations may show a lack of comprehension of the processes involved4 ,any assumption of superiority1 intolerance1 or lack of sympathy1 on the part of the geologist1 toward the inadequate explanations and descriptions given him by the practical man1 is likely to indicate a weakness or limitation in his own mental processes4 ,the geologist's business is to sift out the fact from the inference1 and not to throw over the whole structure because some of the inferences are faulty4 ,,lake ,,superior ,,iron ,,ore ,,exploration ,,as ,,an ,,illustration ,to illustrate the application of some of the methods of exploration of the kinds described in this chapter1 the writer selects an example from his own experience in the ,lake ,superior iron fields4#dj ,in this region1 consideration of the economic aspects of the problem may eliminate from the best explorable field certain ,canadian portions which are far from water transportation1 because the conditions in these sections would prevent the use of anything but an exceptionally large and rich deposit4 ,economic conditions determine in advance also that it is not worth while looking for ores of certain grades1 either because they are not usable on account of deleterious constituents or low content of iron1 or because these particular grades have already been developed in excess of requirements4 ,having determined what ore is desired1 whether ,bessemer or non-,bessemer1 whether open-hearth or foundry1 further elimination of area is possible on the basis of past experience4 ,coming to the geologic phases of the problem1 the first step is to eliminate great areas of rock which are known never to contain iron ore1 like the granite areas and the quartzite and limestone areas4 ,within the remaining areas1 by examination of the surface outcrops and with the aid of magnetic surveys1 iron formations are found which are the mother rock of the ores4 ,in ,michigan1 it has been possible to use certain percentage expectations in the areal location of iron formations within certain series of rocks extending over wide areas4 ,such percentage coefficients have been useful1 not only in exploration1 but also in the valuation of lands which are so covered with drift that no one knows whether they carry an iron formation or not4 ,examination of the iron formations results in elimination of large parts of them1 because their metamorphic condition is not favorable to ore concentration4 ,in the remaining areas more intensive methods are followed4 ,it is scarcely possible to summarize briefly all of the structural and stratigraphic methods used in locating the ore bodies4 ,these have often been described in print4#da ,comparatively recent advances in this phase of exploration work have been in the more detailed application of stratigraphic methods to the iron formation4 ,the group characteristics of the iron formation are fairly uniform and distinctive as compared with all other rocks2 yet within the iron formation there are so many different kinds of layers represented that it is possible to use these variations with great effectiveness1 in correlating favorable horizons for ore deposition1 in interpreting drill records1 and in other ways4 ,another method of approach1 employed chiefly on the ,mesabi ,range1 relates to the slumping of the ore layers which results from the leaching of silica during the concentration of the ore4 ,this slumping can be measured quantitatively1 and has been used to much advantage in exploration1 in correlation of ore horizons1 in preparation of sections and ore estimates1 etc4 ,early geologic explorations in the ,lake ,superior country were based on the assumption that the ores were concentrated by waters working down from the present erosion surface2 but recognition of the fact that the waters which did the work were related to a far older and different erosion surface1 under conditions which allowed of a far deeper penetration1 has modified exploration plans for certain of the districts like the ,marquette and ,gogebic4 ,notwithstanding the complexity of the geologic factors involved1 their net result has been to concentrate iron ores in a surprisingly uniform ratio to the mass of the formation in different parts of the region1--with the result that on an average it may be predicted for any district1 in an exploration of sufficient magnitude1 how much ore is likely to be cut in either vertical or horizontal dimension4 ,thirteen per cent of the productive area of the ,mesabi iron formation is iron ore4 ,for the remainder of the ,lake ,superior region five or six per cent is the factor4 ,these figures mean that1 if a person could explore a broad enough area of iron formation1 any miscellaneous group of drill holes or underground openings would tend to yield these percentage results4 ,such percentages are amply sufficient to pay a large profit on the exploration4 ,the question may be raised why the application of geology is required1 if such average results can be secured from miscellaneous undirected work4 ,the answer is that seldom is it possible to conduct an exploration on a sufficiently large scale to be sure of approximating this average1 and that geologic study has made it possible in many cases to secure a better percentage result4 ,if the geologist is able to raise the percentage ever so little1 the expenditure is amply justified4 ,he is not expected to have #ajj per cent success2 but he is expected to better the average returns1 and in this on the whole he has not failed4 ,applying this method specifically to the ,gogebic ,range1 it appears that up to ,january #a1 #aiah1 exploration and development had covered #c1fej acres of iron formation1 measured along the dip in the plane of the footwall1 within the limits of the area in which the formation is in such condition as to allow concentration of the ore4 ,the total area of the footwall to a depth of #c1jjj feet is approximately #i1fej acres4 ,the range1 therefore1 was #ch per cent developed to this depth4 ,in the developed area1 #afj1jjj1jjj tons of ore had been found1 or approximately one ton per square foot of footwall area1 or #dc1hjj per acre of footwall explored4 ,the total area of ore measured on the footwall was #ghe acres4 ,the ratio of ore area to total explored area1 measured in the plane of the footwall1 was #ba-a_/b per cent4 ,this may be taken in a rough way to indicate the average exploring possibilities in new ground1 where local conditions to the contrary do not exist4 ,this means that over the whole range about one drill hole or cross-cut in five will strike ore on an average4 ,or1 looked at in another way1 about #bjj feet of drifting in every #a1jjj on the footwall will be in ore4 ,applying this factor to the unexplored area1 amounting to #f1jjj acres1 the range had an expectation on ,january #a1 #aiah1 to a depth of #c1jjj feet1 over and above ores already discovered1 of approximately #bfb1hjj1jjj tons4 ,this was sufficient to extend the life of the range by about forty-four years4 ,knowing the average cost of development of ore per foot in the past1 and knowing the annual output and its rate of acceleration1 it is possible to figure with some accuracy how much expenditure should be planned for annually in the future in order to maintain a safe margin of reserves against output4 ,such quantitative considerations in the ,lake ,superior region serve not only to guide the general conduct of the exploration and development work1 but in some cases as a basis for valuation both for commercial and taxation purposes4 ,,development ,,and ,,exploitation ,,of ,,mineral ,,deposits ,the search for new ore bodies is closely related to the development1 extension1 and mining of ore bodies already found4 ,in this field the geologist finds wide application of his science4 ,here he may not be so much concerned with the economic factors or with the broader methods of geologic elimination2 his study is more likely to be based mainly on the local geologic conditions4 ,some of the larger and more successful mining companies1 perhaps the greater number of them these days1 have geologists whose business it is to follow closely the underground operations1 with a view to advising on the conduct of the development work4 ,this requires the most precise and intensive study4 ,for instance1 the ,anaconda ,copper ,mining ,company has a staff of several geologists1 who follow the underground work in the utmost detail and whose approval must be obtained by the operating department in the formulation of any development plan4 ,the complexity and fault relations of the veins in this company's mines are such that the application of these methods has abundantly justified itself on the cost sheet4 ,too often mining companies leave the planning and execution of the underground development work to the local management1 commonly to the underground mining captain1 without geologic consultation4 ,this procedure does not eliminate the economic geologist2 for when the development fails at any point1 or new and unexpected conditions are met1 the geologist is likely to be called in4 ,in such cases the practice of a geologist is like that of the ordinary medical practitioner2 he is called in only when his patients are in trouble4 ,the use of adequate geologic advice in the planning stages is about as little advanced in some localities as the practice of preventive medicine4 ,the work of the economic geologist may not be ended by the finding and development of the ore2 for the moment this is accomplished1 he should again consider the economic phases of the problem--the grade of his ore1 its probable amount1 and other features1 in relation to the general economic setting4 ,in his enthusiasm for physical results1 he may be carried into expenditures not justified by the economic factors in the problem4 ,some one else may and usually does look out for the economic elements1 but the prudent geologist will at least see to it that someone is on the job4 ,,footnotes3 #cg ,smith1 ,george ,otis1 and others1 ,the classification of the public lands3 ,bull4 #ecg1 ,u4,s4 ,geol4 ,survey1 #aiac4 #ch ,schlumberger1 ,c41 ,study of underground electrical prospecting3 ,translated from the ,french by ,sherwin ,f4 ,kelly1 ,paris1 #aibj4 ,bergstrom1 ,gunnar1 and ,bergholm1 ,carl1 ,teknisk ,tidskrift1 ,kemi och ,bergvetenskap1 #aiah1 ,book #ab4 #ci ,hoover1 ,herbert ,c41 ,principles of mining3 ,mc,graw-,hill ,book ,co41 ,new ,york1 #aiji1 p4 #cb4 #dj ,leith1 ,c4 ,k41 ,use of geology in iron ore exploration3 ,econ4 ,geol41 vol4 #g1 #aiab1 pp4 #ffb-fge4 #da ,van ,hise1 ,c4 ,r41 and ,leith1 ,c4 ,k41 ,geology of the ,lake ,superior region3 ,mon4 #eb1 ,u4,s4 ,geol4 ,survey1 #aiaa4 ,,chapter ,,xv ,,valuation ,,and ,,taxation ,,of ,,mineral ,,resources ,,popular ,,conception ,,of ,,mineral ,,valuation ,the total returns from mining may not in the aggregate be far above the expenditure for exploration1 development1 and extraction2 yet the total mineral wealth of the ,united ,states1 on the basis of earning power and aside from the industries based on it1 cannot be far from sixty billions of dollars1 and this wealth has virtually come into existence since the #ahdi gold rush to ,california4 ,the mining industry supports a large population4 ,these facts are the solid basis for the widespread popular interest in mineral investment--and mineral speculation4 ,but there are other reasons for this interest1--the gambler's chance for quick returns1 the lure of gold1 the possibility of getting something for nothing1 the mushroom nature of certain branches of the industry1 the element of mystery related to nature's secrets1 and the conception of minerals as bonanzas with ready-made value1 merely awaiting discovery and requiring no effort to make them valuable4 ,in the ,united ,states a factor contributing to the popular interest is the large freedom allowed by the laws to discover and acquire minerals on the public domain4 ,perhaps no other field of industry comes so near being common ground for all classes of people4 ,the mineral industry is a field in which it is easy to capitalize not only honest and skillful endeavor1 but hopes1 guesses1 and greed4 ,it is not to be wondered at1 therefore1 that in the popular mind the valuation of a mineral resource is little more than a guess1 and sometimes not even an honest one4 ,nevertheless1 the mineral industry has become second only to agriculture in its capital value and in its earning capacity4 ,in this industry it is hardly possible to arrive at valuations as securely based as in many other industries1 but the elements of hazard are not so hopeless of measurement as might be supposed4 ,the great mineral and financial organizations do not depend on mere guesses1 but use well-tried methods4 ,if the general investor were to give more attention to these methods he would doubtless save himself money1 and the mineral industry would be rid of a great incumbrance of parasites who live on the credulity of the public4 ,to anyone familiar with the mineral field1 it is often surprising to see the rashness with which a conservative business man1 who would not think of entering another industrial field without close study of all the factors in the situation1 will invest in minerals without using ordinary methods of analysis of values4 ,in the following account of valuation of minerals in the ground1 and the closely related subject1 taxation of such minerals1 the attempt is made to state some of the principles briefly and simply with a view to making them intelligible to the layman4 ,values beyond the mine are concerned with so many factors of a non-geologic nature that they are not here discussed4 ,,valuation ,,and ,,taxation ,,of ,,mines ,,intrinsic ,,and ,,extrinsic ,,factors ,,in ,,valuation ,it is essential to recognize at the outset that the value of a mineral deposit1 like the value of any other commercial material1 comprises two main elements2 an intrinsic element based on the qualities of the material itself1 and an extrinsic element based on its availability and the nature of the demands for it4 ,the two elements may not be sharply separated1 and neither exists without the other4 ,a mineral deposit in easy reach of a populous community1 which has sufficiently advanced methods and requirements to use it1 may have high value2 an exactly similar deposit1 if far removed from points of consumption1 handicapped by transportation1 or available only to people without developed methods for its use1 may have little or no value4 ,intrinsically the deposits are alike2 but extrinsically they are far different1 and their values are correspondingly unlike4 ,even two adjacent properties1 differently managed and controlled1 and with different relations to markets1 may have somewhat different values depending on the use made of them4 ,the value of a deposit may vary from year to year with changes in demand for its output1 or with changes in metallurgical and other processes which make its use possible4 ,minerals of small bulk and high value1 as for instance gold1 platinum1 and diamonds1 have a nearly standard value related to their intrinsic properties1 because they can be transported so easily to any part of the world4 ,on the other hand1 materials of large bulk and low unit value1 such as coal1 iron ore1 and clay1 may have highly varying values independently of their physical characteristics1 because of their relative immobility4 ,but the values even of gold and precious stones represent a combination of intrinsic qualities and of demand4 ,a diamond is made of carbon but is more valuable than coal or graphite because it appeals to the esthetic taste4 ,it is only because man introduces an element of demand that the diamond takes on value4 ,in short1 man is the multiplier and the mineral substance is the multiplicand in the product known as value4 ,recognition of the two elements of value is vital to a clear understanding of the methods and problems of valuation of minerals4 ,it is too often assumed that the physical properties constitute the sole factor4 ,looked at in a large way1 the returns from the mineral industry are commensurate with the effort put into discovery and development of mineral resources1 even though the returns to lucky individuals have been excessive4 ,in respect to the importance of the human energy element1 the mining of minerals is not unlike the cropping of soils4 ,some interesting economic studies have been made of mining districts to ascertain whether the total return has been equal to the total investments by both successful and unsuccessful participants4 ,the results show that1 even in some of the most successful districts1 there is not a large social surplus1--that is1 a surplus of receipts over total expenditures4 ,it is difficult to generalize from such studies with any degree of accuracy2 but it seems likely that if we could measure the vast amount of fruitless effort which has been expended in non-productive territories1 the result would tend to bear out the general conclusion that the social surplus for the mineral industry as a whole is a modest one1 if it exists at all4 ,of course1 it is to be remembered that the total benefits from mineral resources are not to be measured in terms of gain to the producers1--but that their measurement must take into account the satisfying of all the complex demands of modern civilization4 ,,values ,,of ,,mineral ,,deposits ,,not ,,often ,,established ,,by ,,market ,,transfers ,while minerals as extracted and used may have standard market values1 mineral deposits in the ground are not bought and sold on the open market with sufficient frequency to establish standard market values4 ,a sale may establish a criterion of value for the particular deposit1 but not for the class of deposits1--for no two mineral deposits are exactly alike4 ,stock quotations may establish a certain kind of market value1 but these are often vitiated by extraneous considerations4 ,for these reasons the valuation of a mineral deposit is in each case a special problem4 ,,the ,,ad ,,valorem ,,method ,,of ,,valuation ,the ordinary commercial method of valuing mineral deposits recognizes the two main elements of value above discussed4 ,this method is sometimes called the rational or ad valorem method4 ,the profit per ton 7or per other unit7 of the product is established1 on the basis either of past performance of the property or of experience with other similar properties4 ,this profit is multiplied by the total tonnage estimated in the deposit1 the estimate including known reserves1 probable reserves1 and in some cases possible and prospective reserves4 ,the product of the profit per ton and the total tonnage gives the total net amount which will be received2 it does not1 however1 give the present value1 because the commodity cannot all be taken out and sold at once1 but must be mined and absorbed by the market through a considerable period of years4 ,the returns receivable some years in the future have obviously a lower proportionate present worth than amounts to be received at once4 ,the interest rate comes into play1 making it necessary to discount each annual payment for the number of years which will elapse before it is received4 ,it is evident1 therefore1 that an estimate of the life of the property is necessary1 involving not only knowledge of the reserves1 but also a forecast of the annual extraction or rate of depletion4 ,as a simple case of ad valorem valuation for illustrative purposes1 a deposit containing #a1jjj1jjj tons in reserve has an estimated output of #ajj1jjj tons a year for ten years1 on which the profit per ton has in the past averaged #a and is expected to average #a in the future4 ,ten annual instalments or dividends of #ajj1jjj are to be received4 ,the present value of the total of these instalments is figured by an annuity method4 ,it is the value upon which the series of dividends will pay interest at a predetermined rate1 in addition to paying to a sinking fund annual instalments which1 safely invested each year at a low rate of interest 7usually #d71 will repay the present value at the end of the ten years4 ,in our hypothetical case1 if an interest rate of #h be taken1 the present value of #a1jjj1jjj1 to be received through ten years in ten equal instalments1 is #fab1jjj4 ,in other words1 the sum of #fab1jjj will be replaced by the sinking fund at the end of ten years1 and will pay #h interest during this period1--this requiring total receipts of #a1jjj1jjj in ten equal annual instalments4 ,if the deposit here cited as an illustration were to be worked out in three years1 thus yielding three annual instalments of #ccc1jjj1 its value would be #hcc1jjj4 ,each of the factors entering into this method of valuation covers a wide range of variables1 any one of which may be difficult to determine4 ,the profit per ton for a given deposit may have been extremely variable in the past1 making it difficult to determine whether the highest or lowest figure should be projected into the future or whether some average should be taken2 and if an average1 whether the time covered by the average should be long or short4 ,for a small1 short-lived deposit obviously the most recent conditions would be taken into account in estimating future profits4 ,for a long-lived property there would be more tendency to consider the long-time average vicissitudes1 as reflected in the average profits of the past4 ,for some mineral commodities there are cycles of prices1 costs1 and profits1 of more or less definite length1 established during the long past history of the industry2 and in such cases it is desirable in calculating averages to use a period covering one or more of these cycles1 rather than some shorter or longer period4 ,for many minerals1 however1 these cycles have been too irregular to afford a sound basis for future estimates4 ,if the experience of the property itself is too short to afford a sufficient foundation for forecasting profits1 or if there has been no previous work on the property1 then it is necessary to use averages based on other properties or other districts2 or if there are none strictly comparable1 to build up a hypothetical figure from various estimated costs of labor1 supplies1 and transportation1 selling prices1 etc4 ,in the estimate of the profit factor1 the geologist is not primarily concerned4 ,in estimating the total reserves in a mine1 geological considerations nearly always play a large part4 ,an ore body may in some few cases be completely blocked out by underground work or drilling1 eliminating the necessity for inferring conditions beyond those actually seen2 but in the huge majority of mineral deposits the reserves are not so definitely known1 and it becomes necessary for the geologist1 through knowledge of similar occurrences1 through study of the structural features of the deposit1 its origin1 and its history1 to arrive at some sort of an estimate of reserves4 ,in estimating the life of a mineral deposit it is necessary to start with the figure of total reserves1 and from a study of conditions of mining and of markets to estimate the number of years necessary to exhaust the deposit4 ,this is a more nearly commercial phase of the problem1 in which the geologist takes only part of the responsibility4 ,perhaps more estimates of value have gone wrong because of misjudgment of this factor than for any other cause4 ,if the physical conditions are satisfactory1 it is easy to assume a rate of extraction and life based on hope1 which experience will not substantiate4 ,the choice of the interest rate to be used in discounting future receipts to present worth likewise is a financial and not a geologic matter4 ,again1 however1 the geologist must give consideration to this factor1 in view of the fact that the interest rate must be varied to cover the different degrees of hazard and doubt in the geologic factors4 ,for instance1 to the extent to which the estimate of ore reserves is doubtful1 it is necessary to use a high rate of interest to allow for this hazard4 ,in a large1 well-developed mineral deposit1 with the geological factors all well known and the demand and market well established1 it is reasonable to use a lower rate of interest4 ,in general1 the mineral industry is regarded in financial circles as being more hazardous than many other industrial lines2 and money is put into the industry with the expectation of a high rate of interest1 no matter how safe the investment may be4 ,in actual practice interest rates used in making valuations vary from #f to #ae or #bj per cent4 ,it is clear that1 where a property has long life1 the interest will very materially reduce the present value of the ores to be mined far in the future4 ,reserves to be mined more than thirty years hence have relatively little or no present value4 ,beyond a certain point1 therefore1 the acquirement and holding of reserves for future use by private companies has little commercial justification4 ,this is a matter which is too often not sufficiently well considered4 ,man's natural acquisitiveness often leads him into investments which1 because of the time and interest factor1 have little chance of successful outcome4 ,of course a large corporation1 anticipating an indefinitely long life1 or perhaps aiming at monopoly1 may afford to hold reserves as a matter of general insurance longer than a small company1--even though1 because of the interest rate1 these reserves have no present value on their books4 ,it is likewise true that governments1 looking forward to the future of the nation1 and without the necessity of paying so much attention to interest and taxes1 are not so limited by this consideration4 ,an illustration of the limiting effect of the interest rate on the acquirement of long-lived coal deposits by private interests is discussed in ,chapter ,,xvii on ,conservation4 ,investments made many years ago have so augmented1 even at low interest rates1 as to make it practically impossible to count on a return of capital and interest2 or if the return were to be exacted from the public it would mean excessive charges1 which are not possible in competition with other mines not so burdened4 ,in the commercial valuation of oil wells and pools1 much the same method is used as has been described for mineral resources in the solid form1 but the estimate of reserves or life is based on consideration of curves of production of the sort mentioned on pages #acd-acf4 ,the essence of the ad valorem method of valuation above described is income-producing capacity4 ,this method recognizes the fact that the value of the mineral deposit depends1 not only on its physical constitution1 but also on what performance can be expected from it4 ,stock quotations on mineral properties in the standard markets are based substantially on estimates of income capacity1 more or less on the ad valorem basis4 ,however1 the quotations also reflect the hopes and fears of the public1 often resulting in valuations quite different from those based on studies of the objective conditions4 ,the war introduced new considerations into the problems of ad valorem valuation4 ,under peace conditions there is a tendency toward the establishment of normal costs1 selling prices1 and markets1 which can be taken more or less for granted by anyone attempting to value mineral deposits4 ,under war and post-war conditions1 few of these elements can be taken for granted2 it becomes necessary to consider the entire world situation in regard to a mineral commodity1 the effects of the ,peace ,treaty 7which greatly concerns minerals71 future international relations1 tariffs1 and other matters of a similar sort4 ,if a person were today valuing a manganese deposit according to the method above outlined1 and were to confine himself solely to a narrow consideration of past markets and profits on individual properties1 he would be very likely to go wrong1--for the world manganese situation has an immediate and practical bearing on each local problem 7see pp4 #agc-agf74 ,,other ,,methods ,,of ,,mineral ,,valuation ,,and ,,taxation ,we have discussed the ad valorem method of valuation at some length because it is the one in widest commercial use1 and also because the principles involved underlie practically all other methods of mineral valuation4 ,the ad valorem method is used in appraisals for taxation in some districts and for some commodities1 as1 for instance1 the iron mines of ,michigan and ,wisconsin4 ,its application1 however1 requires skill and judgment if equitable results are to be secured4 ,for taxation purposes1 therefore1 it is not uncommon to adopt purely arbitrary or empirical methods which eliminate the element of judgment1 and which often result in valuations quite different from those used commercially4 ,the state of ,minnesota divides its iron ore deposits into a series of classes1 on each of which a more or less arbitrary flat value per ton is placed1 based on the spread between cost and selling price4 ,the adjustments of flat values on the several classes through a series of years1 however1 as well as the assigning of specific ores to the different classes1 have been based on the same factors as are used in ad valorem valuations4 ,the state of ,wisconsin uses a so-called equated income method of valuation and taxation for the lead and zinc deposits of the southwestern part of the state4 ,under this method the state puts such a tax on the mine incomes for the preceding year as will yield approximately the same total return as under the ad valorem method1--the whole being based on the assumption that each deposit has about the average life figured for the mines of the entire district4 ,so far as individual ore deposits vary from this average life1 the value fixed departs from the true or ad valorem value4 ,several states impose specific taxes based on the operations of the mines for the preceding year or for some combination of preceding years1 as expressed in tonnage output or net profits or net proceeds1 regardless of life or reserves4 ,so far as output or net proceeds for a year are proportional to the real value of the property1 a rough approximation to equitable taxation as between mines is accomplished4 ,often1 however1 the valuation thus obtained has little relation to the true value1 because it does not take into account the great differences between properties in reserves1 in life1 and in capacity for future profit4 ,income taxes1 national and state1 are of course based on the profits of the preceding year2 but in the collection of these taxes from mineral operations1 it is recognized that mineral deposits are wasting assets1 and therefore a considerable part of the income may under the law be regarded as a distribution of capital assets1 and be deducted from taxable income4 ,the amount to be deducted obviously depends on the size of the reserves and the life1--with the result that progressive adjustment of income tax valuations tends to take into consideration exactly the same factors as are used in the ad valorem method4 ,it is obviously unjust1 for instance1 to collect the same proportion of tax from the annual income of a mine which has a life of only two years as from a mine which has a life of fifty years4 ,under the federal income tax a capital value is placed on the mineral deposit as of ,march #a1 #aiac1 which total capital value may be increased with subsequent discoveries4 ,as the ore is taken out of the ground and sold1 income tax is paid only on the difference between the assigned capital value per unit and the selling profit4 ,if1 for instance1 the capital value as of ,march #a1 #aiac1 is placed at #ej;c4 per ton of mineral in the ground1 and ten years later a ton is sold for a profit of #a1 income tax is paid on #ej;c4 ,the figure of #ej;c4 per ton as value in the ground is actually obtained by estimating a profit1 when the ore is ultimately mined and sold1 of #a per ton1 and discounting this dollar to present worth as of ,march #a1 #aiac4 ,therefore the total amounts on which taxes are paid during the life of the mine should represent approximately the total accruals of interest from ,march #a1 #aiac4 ,in this manner the proportion of annual income to be taxed becomes larger with the length of the life period4 ,with a deposit having a life of thirty years the net result is that about half of the aggregate income is taxed1 though this figure of course varies somewhat with the interest rate used4 ,in the collection of income taxes from coal mines in ,england1 and in the collection of certain state income taxes in the ,united ,states1 a considerably smaller allowance is made for the retirement of capital value 7or for depletion1 as this is commonly called74 ,in these cases the deduction allowed is a small fixed percentage of the capital value1 regardless of the actual life of the property4 ,the treatment of mineral resources as wasting assets in the ,united ,states income tax law meets one considerable practical difficulty--namely1 that the law really requires physical or ad valorem valuation of every mineral property by the government1 as a check on the claims for depletion allowance4 ,this immense and expensive task is too much for the tax collection agencies as now organized1 and it may be questionable whether it will ever be desirable to expand these agencies to the extent required for such a purpose4 ,this is the principal argument for the use of arbitrary depletion factors such as those sometimes used abroad4 ,there are many advocates of the straight tonnage tax on mineral deposits1 on the ground that it is simple1 definite1 and easily applied4 ,the present tendency is to extend the application of this form of tax4 ,it is clear1 however1 that to assume the same value per ton for taxing purposes on a property making a large profit1 and on another property which1 because of physical conditions1 is barely able to operate at a profit1 imposes a relative injustice4 ,to meet this difficulty1 it is sometimes proposed that the tonnage tax should be graded in such a manner as to allow for differences in physical conditions and in profit at different mines4 ,when one attempts to apply a graded tonnage tax1 however1 it soon becomes apparent that1 in order to make such a valuation equitable as between properties1 it is necessary to use all of the factors of the ad valorem method for each of the properties4 ,the wide appeal of arguments for a flat tonnage tax is based partly on popular misconception of the complexity of elements entering into mineral valuations4 ,there are many forms of more or less indirect tax which are substituted in different parts of the world for direct taxes4 ,for instance1 certain states in ,south ,america do not tax ores in the ground1 but collect the revenue in the form of mining licenses or export taxes4 ,,general ,,comments ,,on ,,taxation ,,of ,,mineral ,,resources ,there has been a noticeable tendency in recent years to regard mineral resources as a heritage of the people1 to be held in trust1 rather than as property to be acquired and managed solely for private interest4 ,this tendency has been indicated by the adoption in various parts of the world of laws affecting rights to explore and acquire minerals on the public domain2 laws relating to the right of eminent domain over minerals already alienated from the government2 laws regulating the exploitation of minerals in the interests of conservation2 laws relating to tariffs and other restrictions on the export of mineral commodities2 and laws relating to taxation4 ,the feeling that mineral resources really do not belong in private hands has undoubtedly been an underlying factor in the imposition of heavy taxes4 ,contributing to this action also are the popular belief in the intrinsic bonanza values in mineral resources1 the failure to recognize the large element of value which is put into such resources by human efforts1 and the failure to realize that the social surplus in the aggregate is small4 ,to some tax officials an ore is an ore1 more or less regardless of situation1 of conditions of mining1 of the demand for the product1 and of the time when the demand will allow the ore to be mined1--in short1 more or less regardless of what the ore may be made to yield as a going business4 ,in this way heavy taxes are sometimes imposed on mineral reserves1 which are based on unwarrantably high appraisals of future possibilities1 and which cannot be paid out of earnings4 ,ultimately1 a tax must be adjusted to the capacity of the mine to pay out of its earnings1 and this capacity in turn is determined both by the physical characters of the ore and by the success with which it may be made available for consumption4 ,this view of valuation for taxing purposes is sometimes opposed by mining men on the grounds that it taxes brains1 skill1 and initiative1 and that it puts a premium on shiftless management4 ,the same argument might be applied to the valuing of any business or profession4 ,to the writer the argument is not sound1 in that it fails to recognize the element of human energy in resource values4 ,if value were to be confined solely to the intrinsic character of the ore itself1 there would be required an almost impossible degree of discrimination on the part of taxing officials to dissociate this value from other considerations2 and there would be required further the differentiation between efficient and inefficient management1 which involves so many considerations that the conclusion would be worthless4 ,in the application of income taxes to mining operations1 there is sometimes another tendency toward over-taxation in that the income is regarded as more or less permanent1 and insufficient allowance is made for exhaustion of the mineral deposit4 ,under the ,united ,states income tax1 mineral deposits are definitely recognized as wasting assets and this factor is allowed for2 but in state income taxes and in ,england and other parts of the world1 allowances for this purpose are small4 ,there is wide belief that heavy taxation of mineral resources1 particularly on the ad valorem basis1 retards exploration and prevents the development of the reserves which are necessary to stabilize the mineral industry4 ,high taxes have undoubtedly had this effect in some cases1 especially where taxes have been imposed on resources long prior to development2 but1 in the writer's view1 this tendency in general has not yet passed the danger point1 and is not likely to do so until taxes become positively confiscatory of the industry4 ,to argue that increase of taxes may even have certain beneficial results on the mineral industry may lead to suspicion of one's mental soundness2 but it is hard to escape the conclusion that the incidence of high taxes has led to a much more careful study of the question of reserves1 has eliminated in some cases the expenditure of money for development of excessive reserves to be used far in the future1 and has tended to prevent over-production4 ,where mineral reserves are developed too far ahead of demand1 the interest on the investment piles up an economic loss to be charged against the industry4 ,it may be assumed that the urge for exploration will continue as long as there is demand for mineral resources2 and that1 to keep the industry on a sound basis1 a certain amount should be set aside and charged to cost for the purpose of keeping up reserves in a proper ratio to production4 ,much remains to be learned about the most desirable ratio between reserves and production4 ,in many camps1 before the incidence of high taxes1 this ratio was not properly determined2 and there was a tendency1 due to natural acquisitiveness and in the absence of anything to hinder it1 to build up reserves indefinitely4 ,the first effect of high taxes in such camps has frequently been the curtailment of exploration and development4 ,later1 as production has begun to approach the end of the reserves1 exploration has been resumed1 but only on a scale necessary to insure production for a limited period in advance4 ,the argument that high taxes inhibit exploration is good only beyond the point where the industry itself becomes no longer profitable4 ,if there is sufficient demand for the resource1 it is obvious that such a condition cannot long continue2 for1 as production and the development of reserves fall off1 the resulting increase in the price received for the product is likely to offset any effect of taxes1 and to restimulate production and exploration4 ,nevertheless1 in this period of high taxes following the war1 there is much discouragement in the matter of exploration1 suggesting that the danger point is being approached4 ,some relief has been afforded by recent special provisions of the federal income tax law1 recognizing mineral resources as wasting assets1 allowing recent discoveries to be included with total assets for depletion purposes1 and recognizing special and peculiar circumstances with reference to each mine4 ,also a certain amount of exploration goes on through the momentum gained from past conditions1 without sufficiently full recognition of the effect of present high taxes4 ,this is not surprising when it is remembered that the people actively engaged in field exploration often do not think sufficiently fully of the tax situation1 until after a discovery or development has brought them face to face with it4 ,because of the vital importance of the reserve factor in mineral valuation1 geologic aid and advice are extensively sought by both public and private organizations4 ,mining geologists are playing an important part in the application of the national income tax4 ,a larger number are acting for private companies in appraisals required by this tax4 ,many geologists are used in making valuations for state taxes1 and in two cases the state geological surveys have complete charge of appraisals4 ,these appraisals include not only examinations of specific properties1 but general surveys of large regions1 to ascertain possible values of undeveloped lands and to establish broad principles of valuation based on a consideration of all the physical factors in the situation4 ,,chapter ,,xvi ,,laws ,,relating ,,to ,,mineral ,,resources ,this heading is likely to suggest mining law and the vast literature devoted to it4 ,mining law has mainly to do with questions of the ownership and leasing of mineral deposits4 ,in addition1 there are laws relating to the extraction of mineral products1 including those having to do with methods of mining and with safety and welfare measures4 ,there are laws affecting the distribution of mineral products1 such as those relating to tariffs1 duties1 international trade agreements1 and many other matters4 ,there are laws relating to underground water1 to shore lines1 and to various geologic engineering fields4 ,in the formulation of these laws1 as well as in the litigation growing out of their infraction1 basic geologic principles are involved2 and thus it is that the geologist finds much practice in the application of his science to legal questions4 ,it will be convenient to consider some of the laws relating to mineral resources under three headings3 first1 ownership and control2 second1 extraction2 and third1 distribution4 ,i ,,laws ,,relating ,,to ,,ownership ,,and ,,control ,,of ,,mineral ,,resources ,large use of mineral resources is of comparatively recent date4 ,some of the mineral industries are not more than a decade or two old and the greater number of them are scarcely a century old4 ,in the ,united ,states the mineral industry dates mainly from the gold rush to ,california in #ahdi4 ,the formulation of laws relating to the ownership of minerals has on the whole followed rather than preceded the development of the mineral industries2 and hence mining laws relating to ownership are not of great age1 although historical precedent may be traced far back4 ,,on ,,alienated ,,lands ,where lands came into private ownership1 or were alienated from the governments before the formulation of mining laws1 varied procedures have been followed in different countries4 ,in ,england and the ,united ,states1 under the old regime in ,russia1 and to a slight extent in other parts of the world1 mineral titles remain with the owner of the land and the government does not exercise the right of eminent domain4 ,but even in ,england1 where private property rights have been held peculiarly sacred1 the discovery of oil during the later years of the war led to an attempt to expropriate the oil rights for the government4 ,because of the objection of landowners this attempt has not reached the statute books1 but the movement is today an extremely live political question in ,england4 ,a somewhat similar question is involved also in the movement to nationalize the coal resources of ,england1 now being so vigorously urged by the labor party4 ,in the ,united ,states1 no serious attempt has yet been made to take over mineral resources from private ownership4 ,other countries have gone farther in retroactive measures in regard to alienated lands4 ,under the leadership of ,france1 most of the countries of western ,europe have appropriated to their governments the undiscovered mineral resources on private ground1 particularly those beneath the surface1 except where previously they had been specifically conveyed to the private owners1 or with the exception of certain designated areas and minerals which had been conveyed to private ownership prior to certain dates4 ,some minerals occurring at the surface1 variously specified and defined in different countries1 are allowed to remain with the private owners1 although often subject to government regulation in regard to their development and use4 ,in varying degree this treatment of mineral resources on alienated lands is followed in the ,british colonial laws--in ,south ,africa1 ,australia1 ,new ,zealand1 and ,canada--and in the ,latin-,american laws4 ,the laws are usually based on specified classifications of minerals4 ,those occurring at or near the surface1 and called quarries1 placer deposits1 non-mines1 or surface deposits1 usually remain with the surface owners4 ,those beneath the surface1 called sub-surface deposits or mines1 in general belong to the government4 ,in some of the countries of ,south ,america the state exercises eminent domain even over the surface deposits2 and in others even sub-surface minerals remain in private ownership1 where specifically granted1 or where the transfer of property took place prior to certain dates4 ,where the government has acquired mineral ownership of lands previously alienated1 the resources are open for development either by the owners of the surface or by others1 on a rental1 lease1 specific tax1 labor1 or concession basis4 ,the government holds the title1 exacts tribute1 and more or less directs and controls the operation4 ,exceptionally1 as in ,ontario1 ,british ,columbia1 ,quebec1 and ,newfoundland1 the government grants patents1 that is1 it disposes of its rights to purchasers4 ,,on ,,the ,,public ,,domain ,where the development of mineral resources began before the lands had passed from governmental ownership1 special mining laws were enacted4 ,looked at broadly1 these laws may be regarded as based on two partly conflicting considerations4 7#a7 ,the assumption that mineral resources1 which are wasting assets1 accumulated through long geologic periods1 are peculiarly public property1--not to be allowed to go into private ownership1 but to be treated as a heritage for the people as a whole and to be transferred to posterity in the best possible condition4 ,some of the early minerals to be developed were used either for money or for war purposes1 leading naturally to the acceptance of the idea that these belonged to the government or to the sovereign4 7#b7 ,the assumption that the discovery and development of mineral resources requires a free field for individual initiative1 and that the fewest possible obstacles are to be put in the way of private ownership4 ,governments have not as a rule been greatly interested nor particularly successful in exploration4 ,therefore1 in framing laws of ownership1 concessions have been made to encourage private initiative in exploration and development4 ,in the case of the ,united ,states this idea was coupled with the broad doctrine that the government held public lands only in the interest of the people1 and that its people were entitled to secure these lands for private ownership with the least possible restriction4 ,a survey of the mining laws affecting the public domain or non-alienated lands of different parts of the world1 as well as the history of changes in the mining laws1 indicates a wide range of relative emphasis on these two underlying considerations4 ,in the ,united ,states1 at one extreme1 the laws have been such as to give the maximum possible freedom to private initiative1 and to allow easy acquirement of mineral resources from the government4 ,at the other extreme1 in ,south ,africa1 ,australia1 and ,south ,america1 it is impossible for the individual to secure title in fee simple from the government2 he must develop the mineral resources on what amounts to a lease or rental basis1 the ownership remaining in the government4 ,the trend of events in mineral laws is toward the latter procedure4 ,this is evidenced in the ,united ,states by the withdrawal of large areas of public lands from entry1 and by the recent enactment substituting leasing privileges for specified minerals for the outright ownership which was allowed under the federal law before the lands were withdrawn from entry4 ,the withdrawal of oil lands from public entry in other parts of the world is another illustration 7see pp4 #aca-acb74 ,,nationalization ,,of ,,mineral ,,resources ,nationalization1 as this term is popularly understood1 means financial control and management of mineral resources by the government1 either through actual ownership or through measures of public control designed to eliminate private interest from the active direction of the resources4 ,in a broader sense1 it may be used to include a considerable variety of restrictive and coercive measures adopted by the government in the proposed interests of public welfare1--as illustrated by the war-time measures instituted by the ,united ,states and other governments relating to the mining and distribution of coal1 and to coal prices4 ,in this broader sense various aspects of nationalization are indicated under other headings in this and other chapters4 ,it is clear that other countries of the world have gone farther in the direction of nationalization of mineral resources than the ,united ,states4 ,the tendency was manifest before the war1 and has been strongly emphasized during and since the war4 ,in the ,united ,states1 notwithstanding war-time measures1 the subject has not yet come prominently forward1 at least by name4 ,on the other hand1 there has been growing recognition of the dependence of public welfare on the proper handling of mineral resources--particularly of the energy resources1 coal and oil1--as evidenced by a variety of proposals and measures under consideration in legislative and administrative branches of our national and state governments4 ,even taxation1 both local and national1 has in effect reached a stage where private interest has become considerably minimized by the increasing burdens laid on the industry by government requirements4 ,the immediate purpose of taxation is to raise money for the needs of the government2 but in the formulation of tax measures there is clearly to be discerned a growth of underlying sentiment that natural resources belong in some fashion to the public1 and that private control is to be regarded not as a sacred property right but as a trust held on sufferance of the public4 ,in view of the obvious trend toward nationalization in other parts of the world and the significant tendencies in the ,united ,states1 it seems likely that the subject of nationalization of mineral resources will come prominently to the front in this country in the comparatively near future4 ,if so1 it is time that students of mineral resources should recognize the comprehensiveness of this problem1 and should attempt to develop basic principles to serve as a guide in the direction and formulation of the numerous and complex measures which are sure to be proposed4 ,at present there is no government or technical organization related to the industry which is studying the problem in its broader aspects and is in a position to advise wisely with public officials interested in this problem4 ,it is beyond the scope of this book to discuss the pro and con of an economic question of this magnitude4 ,the writer would1 however1 record his belief1 which is implied also in discussions in other chapters1 that the discovery and intelligent management of mineral resources by their very nature and infinite variety require private initiative1 and that the history of government efforts in this field in this and other countries does not promise that nationalization can supply sufficient advantages to counterbalance the loss of this element4 ,with this view the problem of nationalization becomes one of determining what steps1 if any1 can be taken by a government to the advantage of public welfare1 which will at the same time preserve and foster private initiative1 exercised with the hope of reward1 which seems alone to be capable of meeting the variable1 elastic1 and complex problems inherent in the development of a natural resource4 ,a first step toward a broad scientific attack on this problem would be the recognition of the fact that tariffs1 taxes1 conservation1 international mineral questions1 leasing laws1 and various technical investigations of minerals are but parts of a great unit problem4 ,with this recognition there should follow naturally an attempt to correlate and direct the many government agencies1 legislative and administrative1 now concerned with different aspects of the problem4 ,under present conditions1 the various elements of the problem are considered by different groups of persons1 without sufficient contacts or correlation to promise the development of a broad1 underlying policy4 ,,effect ,,of ,,ownership ,,laws ,,on ,,exploration ,the nature and the progress of exploration 7and development7 in different countries have been more or less related to the character of the mining laws4 ,where the mineral resource has passed from government control into private ownership1 exploration is a matter of commercial arrangement between the explorer and the owner4 ,there is often some lag in exploration1 especially where the lands are held in considerable blocks4 ,the owner is often not inclined1 or unable1 to institute effective exploration himself2 and even though he is willing to offer favorable exploration terms to others1 the inducement is often less attractive than on government lands4 ,for instance1 it is stated that in ,england1 due to the many requirements of law and custom1 it takes on an average eight years1 and in some cases even longer1 to close a coal lease after the terms have been agreed upon4 ,the slowness of exploration and development on the great land grants in the ,united ,states1 and on the tracts of the large timber companies1 also illustrates the retarding effect of private ownership4 ,it is partly this situation that is making governments increasingly careful about parting with mineral ownership1 and that is leading to the introduction of more or less coercive measures1 either to regain control or to make it easier for the public to explore and develop minerals on privately owned lands4 ,under the great land grants to railroads in the ,united ,states it is becoming increasingly difficult to secure mineral patents from the government2 and there has been litigation between government and grantees1 as in the case of certain oil lands of the ,southern ,pacific ,railway4 ,the taxation in some states of mineral rights which have been reserved by large owners is indirectly resulting in appraisal of these rights by the owners and in efforts to utilize them4 ,as long as mineral rights were not taxed independently of surface rights1 they were often reserved in selling surface rights on the mere chance that mineral might be found in the future1 and thereby general exploration and development were held back4 ,in the ,united ,states1 minerals on the public domain have been open to exploration and acquirement with minimum restrictions1 except for the considerable areas later withdrawn from entry4 ,after long delay a part of these withdrawn lands are again open to private exploration1 but not to fee ownership4 ,specified minerals--coal1 oil1 phosphates1 and potash--may be explored for1 and may be leased under certain restrictions as to amount and time of development4 ,the effect of this act on exploration is yet to be proved2 but since many of the lands have now been shown to be favorable for minerals which are in great demand1 there is little doubt that exploration will be resumed on a large scale4 ,on the whole1 under the federal mining laws of the ,united ,states the individual prospector has maximum leeway1--and from the standpoint of development of resources this procedure probably has been justified4 ,in other countries where the mineral resources are owned by the government1 there is in most cases considerable restriction1 through licenses and other regulative measures1 upon the activities of prospectors4 ,this restriction1 together with the fact that it is usually not possible to secure title to the land1 but only to secure rights through rental or leasing1 is to some extent a deterring influence on the penniless prospector4 ,it does not follow that under these conditions exploration and development are absent4 ,the charges imposed are light1 and in the early stages require comparatively small contributions as evidence of good faith4 ,it is to be remembered that exploration has become concentrated more and more into the hands of persons financially able to meet such conditions4 ,exploration is passing from the highly hazardous stage of individual effort into a systematic business with calculable returns4 ,,use ,,of ,,geology ,,in ,,relation ,,to ,,ownership ,,laws ,the contacts between geology and laws relating to mineral ownership are many and varied2 a few illustrative examples are offered4 ,many difficulties arise from the loose use of mineral names in these laws4 ,the laws governing location of mineral deposits in ,cuba are so framed that iron ores may be located and claimed from the government either as iron ores or as bog ores and yellow ochers4 ,some of the important ores of eastern ,cuba1 now being extensively used in the ,united ,states1 came into litigation because rival claimants had overlapping claims under the two classifications4 ,the wording of the law is of course ambiguous1 and suggests that geologists did not have a hand in its framing4 ,to establish title to these claims it was necessary to show whether these ores had been rightfully located as iron ores1 or whether they should have been located as bog ores and yellow ochers4 ,this involved an analysis of the geological conditions1 to show that the ores are the result of normal weathering and concentration in place of the underlying rocks--an origin common to many iron ore deposits1--and that they do not have the characteristic origin of bog ores4 ,in short1 the question was settled on the scientific principles of origin of ores and of metamorphic geology4 ,the efforts of our federal government to frame and apply mining laws to public lands have involved extensive geological and mining surveys by the ,united ,states ,geological ,survey and the ,bureau of ,mines4 ,the land classification work for this purpose by the ,geological ,survey has been of wide scope4 ,the recently enacted leasing law1 which opens up government lands for exploration of coal1 oil1 potash1 and phosphate1 requires carefully prepared geologic data for its proper administration4 ,state governments also have initiated surveys of an exploring nature for taxing and other public purposes 7see pp4 #cjf1 #caa74 ,in the ,united ,states there is a wide use of geologists as witnesses in litigation affecting extralateral rights4 ,the federal mining law gives the owner of the claim containing the apex or top of a mineral vein or lode the right to follow the vein down the dip1 with certain limitations1 even though this takes him on to adjacent properties under other ownership4 ,where two branches of a vein are followed down from separate claims1 the owner of the oldest claim is entitled to the vein below the point of junction4 ,the law was framed to validate a procedure more or less established by mining custom4 ,it was obviously framed with a very simple and precise conception in mind--namely1 a simple vein definitely and easily followed1 without much interruption or contortion4 ,in nature1 however1 veins or lodes have a most astonishing variety of form and occurrence1 making it difficult to frame a definition that is comprehensive and at the same time sufficiently precise for all cases4 ,a commonly used definition of a vein or lode is a mineralized mass of rock which is followed for purposes of finding ore4 ,the mineral matter may be continuous or discontinuous4 ,there may be one definite wall1 or two walls1 or none at all4 ,there may be associated gouges and altered or mineralized rock4 ,the vein may consist of almost any combination of the elements of mineral matter1 walls1 gouges1 and mineralized rock4 ,instead of being a simple tabular sheet1 a vein may have almost any conceivable shape2 it may consist of multiple strands of most complex relations2 it may have branches and cross-over connections4 ,it may be a more or less mineralized sedimentary formation with limits determined by original deposition4 ,it is very often bent or folded1 and even more often faulted2 the faulting may be of great complexity1 making it extremely difficult to follow the vein4 ,the vein may be cut by other veins of different ages1 which in places may be hard to distinguish one from another4 ,erosion working down on a complex vein displaced by faulting and folding may bring several parts of the same vein to the surface1 developing what seem to be separate vein apices4 ,where there are many veins close together1 it may be difficult to determine whether the entire mass should be considered a unit vein or lode 7a broad lode71 or whether each vein should be considered independently under the law4 ,the geologic aspects of these problems are obvious4 ,there are few mining districts where the vein conditions are so simple that no geological problems are left to be solved with relation to extralateral rights4 ,in the early stages of the mining1 separate operations may be carried on for a considerable time in a district without mutual interference2 but as mining is carried down the dip1 what seemed to be separate veins may be found to be parts of the same vein or parts of a complex vein system1 and separate mining organizations are thus brought into conflict4 ,it then becomes necessary either to consolidate the ownerships or to go to the courts to see which claim has the extralateral rights4 ,in either case1 the geologist is called on to play a large part1--in the valuation of rights for the purpose of combination1 or in litigation to settle apex rights4 ,a geologic survey of the conditions is a prerequisite4 ,in order to get the needed information for the courtroom1 it may be necessary to go further1 and to conduct extensive underground exploration under geologic direction4 ,some of the most intensive and complete geological surveys of mineral resources in existence have been done for litigation purposes4 ,the study in these cases is not empirical1 but goes into every conceivable scientific aspect of the situation which may throw any light on the underground conditions--the source of the ores1 the nature and source of the solutions which deposited them1 their paths of travel1 the structural and metamorphic conditions1 the mineralogical and chemical character of the ores and rocks1 and even broader questions of geologic age4 ,the many volumes of testimony which have accumulated during famous apex trials cover almost every phase of geology1 and are important primary sources for the student of economic geology4 ,it is often argued that strictly scientific1 impartial geologic work is impossible in connection with one of these trials1 because the viewpoint is warped by the desire to win4 ,the sharp contrast in the views of experts on the two sides is cited in evidence4 ,there is no denying the fact that the conditions of a trial tend toward a certain warp in scientific perspective4 ,on the other hand1 the very existence of competitive and opposing interests leads to the most intensive detailed study1 and to complete disclosure of the facts4 ,in most cases there are no substantial differences in the statements of scientific fact by reputable experts on the two sides1 although there may be wide differences in the inferences drawn from these facts4 ,the failure to note a fact1 or any distortion or misstatement of a fact1 is followed so quickly by correction or criticism from the other side1 that the professional witness usually takes the utmost pains to make his statement of fact scientific and precise as far as his ability goes4 ,few scientific treatises in geology contain any more accurate accounts of mineral deposits than testimony in cases of this sort4 ,if every student of geology1 early in his career1 could have a day on the witness stand on a geologic problem1 under both direct and cross examination1 he would learn once and for all the necessity for close and accurate thinking1 the difference between a fact and an inference1 and the difference between inductive study of facts and the subjective approach to a problem4 ,it is a common assumption that a witness called to testify on scientific matters is on a somewhat different basis from the eye-witness to an event or transaction4 ,we are not sure that this assumption is justified4 ,seldom is it possible in mining operations to disclose the facts in three dimensions so completely that they may be empirically observed and platted by the layman4 ,the grouping and presentation of the facts in adequate perspective require an analysis of the origin of the ores and rocks1 the rock alterations1 the structural systems1 and other facts4 ,no one ever saw the vein or lode in the process of formation4 ,the true nature of the event and of its physical results must be inferred inductively from circumstantial evidence4 ,if it be conceded that it is necessary and right to call an eye-witness to an event involved in litigation1 it is equally necessary where there are no eye-witnesses to call the persons best qualified to interpret the circumstantial evidence4 ,it is to be remembered that apex cases are only one kind of a vast variety of cases affecting mineral resources4 ,at one time or another1 and in some connection or another1 practically every geologist of considerable experience has found it necessary to testify on geologic matters in court4 ,the wide interest attaching to certain spectacular apex cases has led in some quarters to hasty criticism of the participation of geologists therein1 without apparent recognition of the fact that the criticism applies in principle to many other kinds of litigation and to practically all economic geologists4 ,this criticism also fails to take cognizance of the fact that1 for every case tried1 there are many settled out of court through the advice and cooperation of geologists4 ,while there may be in the geologic profession1 as in others1 a very few men whose testimony can be bought outright1 in general it must be assumed that geologists will appear on the witness stand only when1 after careful examination1 they are satisfied that there is a legitimate point of view to be presented4 ,geologists and engineers understand more clearly than almost any other group the extent to which the complexities of nature vary from the conditions indicated in the simple wording of the law of extralateral rights4 ,almost to a man1 they favor either modification or repeal of the law4 ,on the other hand1 the law has been in force since #ahgb1 it has been repeatedly interpreted and confirmed by the courts1 and a vast body of property rights has been established under it4 ,lawyers see great legal difficulties in the way of its repeal or serious modification4 ,mining men for the most part are not primarily interested one way or another1 unless there is potential application of the extralateral-rights provision to their particular properties4 ,of those who are thus interested1 some hope to gain and some fear they may lose in the application of the law4 ,the general public naturally has little direct interest in the problem4 ,there is thus no effective public sentiment favoring the repeal or modification of the law4 ,it seems likely that for some time to come the law1 in spite of its recognized defects1 must be applied1 and the best geological effort must be directed toward reaching interpretations which come most near to meeting its intent4 ,to refuse to lend geologic science to the aid of justice because the law was improperly framed is hardly a defensible position4 ,presumably it will never be possible to frame laws with such full knowledge of nature's facts as to eliminate the necessity for scientific advice in their interpretation4 ,it has been suggested that the courts1 and not the litigants1 should employ the geologists4 ,the practical objection to this proposition lies in the difficulty encountered by the judge in the proper selection of geologists4 ,on the assumption that the judge would select only men in whom he had confidence1 it is not likely that he would override their conclusions4 ,the outcome of the case1 therefore1 would be largely predetermined at the moment the selection of experts was made4 ,it is to be doubted whether courts can have the knowledge of the scientific field and of the requirements of the situation necessary to make the wisest selection of men to interpret the given condition4 ,the competitive element would be eliminated4 ,from a judicial standpoint1 there seems to be an equally good chance of getting at the best interpretation of the facts by listening to presentations from different standpoints1 with the accompanying interplay of criticism and questioning4 ,another practical objection to appointment of experts by the court is the limitation of court costs1 which would make it impossible to secure the highest grade men4 ,so far as these men are public employees1 such as members of the federal or state geological surveys1 this might be arranged4 ,for others1 it might be suggested that they should be willing to sacrifice their energy and time in the interests of justice2 but as long as human nature and conditions are what they are1 it is perhaps futile to argue this question4 ,if it is right to apply science to practical affairs1 in other words1 if the profession of economic geology is a legitimate one1 it seems inevitable that the application must be in some part directed by the geologist himself1 in order to avoid mistakes and confusion4 ,the contention that the scientist must isolate himself in a rarified atmosphere to avoid contamination from a non-scientific1 commercial1 or legal atmosphere1 seems to the writer practically untenable1 if we recognize any obligation on the part of science to the practical conduct of human affairs4 ,the fact that the geologist in making these applications may occasionally find himself in a non-scientific atmosphere may be deplored from the standpoint of maximum creativeness in science1 and from this standpoint there may be reason for limitation of time given to this kind of work1--but to stay out entirely on this ground is to deny his obligation to make his science helpful to his fellows4 ,the problem cannot be solved by staying out4 ,it calls rather for an especial effort on the part of the scientist to establish and maintain his standards of science and ethics in the applied fields4 ,some doubtless fail in this effort4 ,others are strengthened scientifically and ethically1 and contribute important aid in raising general standards4 ,the principle of non-participation in such activities for fear of lowering scientific standards may make the geologist's problem easier1 but at the expense of non-fulfillment of duties4 ,such a course has for its logical consequence an abandonment of the application of his science to untrained men without the ethical anchorage of scientific achievement4 ,in short1 there may be legitimate criticism of individual geologists for their methods and ethics in the applied field1 and this is desirable as an aid to maintaining and improving standards2 but it is not a logical step from this to the conclusion that1 to avoid unfortunate incidents1 economic geologists must cloister themselves and thus deny the very implication of their title4 ,,ii ,,laws ,,relating ,,to ,,extraction ,,of ,,mineral ,,resources ,under this heading come a wide variety of laws and regulations1--national1 state1 and local1--affecting the manner in which mineral resources shall be mined or quarried4 ,such laws may specify the number of shafts or outlets1 the use of safety and prevention devices1 miners' compensation and insurance1 and many other features4 ,most of these laws are framed for the purpose of conserving human life and energy1 but they directly affect the mining or extraction of the mineral resources themselves4 ,geology plays but little part in relation to such laws4 ,where the government retains ownership and leases or rents the resources1 there are often provisions regarding the manner of mining and the quality and quantity of the material to be mined1 in the interests of efficient operation and conservation4 ,the geologist is often called into consultation both in framing and in dealing with the infraction of such provisions4 ,it may be noted that the control thus exercised on the operator by government ownership is very much the same as that often exercised by the private fee owner4 ,it is not unusual for fee owners of mineral rights to maintain a geological staff in order to follow intelligently underground developments1 to see that the best methods of exploration and mining are followed1 and that ores are either extracted or left in accordance with the best conservational practice4 ,,iii ,,laws ,,relating ,,to ,,distribution ,,and ,,transportation ,,of ,,mineral ,,resources ,under this heading come governmental regulations affecting directly or indirectly the transportation and the destination of mineral products4 ,transportation rates1 tariffs1 zoning1 duties1 and international trade agreements of all sorts have vital effects on distribution4 ,in framing any of these measures for a mineral resource1 it is desirable to know all about the character of the raw material1 its physical occurrence and distribution1 and the possibilities for future development4 ,in adjusting the scientific naming and classification of mineral materials with the crude names and classifications used commercially--as in tariffs1 in import and export laws1 in reports of revenue collectors1 in railway and ship rates1 etc4--the geologic information is likewise necessary4 ,heretofore1 the formulation of measures concerning mineral distribution has often not been done on a scientific and impartial basis2 but in recent years geologists have been called on more frequently for aid and advice1 as a means of checking or verifying the special pleadings of the different industries4 ,the rude disturbance of trade routes during the war brought home the necessity of basing control of distribution of mineral products on fundamental facts of geology and geography2 thus it was that geologists had a considerable voice in the vast number of special measures taken for war purposes by such organizations as the ,shipping ,board1 the ,war ,trade ,board1 the ,war ,industries ,board1 and other public organizations4 ,the same was true in relation to the mineral resource questions at the ,peace ,conference4 ,in the reconstructive measures of the future1 a still larger use of scientific considerations may be looked for4 ,further suggestions as to the relation of geology to laws affecting distribution appear in the chapter on ,international ,aspects 7,chapter ,,xviii74 ,,iv ,,other ,,relations ,,of ,,geology ,,to ,,law ,it is often assumed that the economic geologist is exclusively interested in mineral resources4 ,however1 there are varied applications of geology outside of the mineral resource field1--to many kinds of engineering and construction operations1 to soils1 to water resources1 and to transportation1--any of which may develop legal problems requiring geologic service4 ,a few illustrative cases follow4 ,the classification of mineral materials in contracts presents many difficulties4 ,a contract for a railway cut1 for a canal1 or for any other kind of excavation may specify different prices for removing different mineral materials4 ,too often these are stated in extremely crude and arbitrary terms1 such as rock1 hard rock1 hardpan1 earth1 dirt1 etc41 without regard to the actual variety of materials to be dealt with4 ,when1 therefore1 in the case of the ,chicago drainage canal1 the contractor encountered a soft shale and claimed compensation for rock excavation1 geologists played a considerable part in the extensive litigation that followed in the attempt to define the facts of nature in terms of a contract which did not recognize them4 ,in a railway cut through glacial drift or till1 a contractor came suddenly upon a mass of till which had been so thoroughly cemented in place as to have all the resistance of rock4 ,litigation was then necessary to decide whether this should be classified as dirt or rock4 ,rock and dirt slides of all kinds1 met with in open-pit mining1 canals1 and other excavations1 present engineering problems with a geologic basis4 ,the kinds of rocks1 their strength1 porosity1 and moisture content1 the effects of weathering1 and the structural conditions must be determined in order to ascertain the cause of the slides1 and are features which figure largely in litigation arising from troubles of this sort4 ,both federal and state laws give the right to lateral and vertical support4 ,when1 therefore1 adjacent or underlying excavations cause earth movements in a neighbor's property1 litigation is likely to ensue and the geologist is likely to be called in4 ,the long-wall method of coal mining1 extensively practiced in certain parts of the ,united ,states1 is slowly withdrawing support from the ground overlying the coal seams1 resulting in damages to surface structures and in some cases to overlying mineral deposits4 ,extensive litigation has been the result1 and the future seems to promise more of it4 ,in certain metal-mining camps1 where considerable amounts of materials have been mined to great depths1 caves and cracking in the surface are reaching over unexpectedly wide areas1 again threatening litigation4 ,the laws relating to the use of surface and underground waters touch the geologic conditions in many ways4 ,the permanent lowering or raising of a water level through mining or damming may require a careful geological analysis of the underground conditions affecting the movements of ground-water4 ,the use of streams for placer mining1 as in ,california1 has resulted in formulation of laws and in extensive litigation1 again requiring analysis of geologic conditions4 ,in fact geologists1 perhaps more than any other group1 have come to realize how many and how varied are the ways in which people get into conflict in using the earth on which they live4 ,,chapter ,,xvii ,,conservation ,,of ,,mineral ,,resources ,,the ,,problem ,conservation of mineral resources may be defined as an effort to strike a proper balance between the present and the future in the use of mineral raw materials4 ,mineral resources have been used to some extent as far back as evidences of man go1 but great drafts on our resources have come in comparatively recent years4 ,the use of many minerals has started within only a few years1 and for others the acceleration of production within the past two or three decades has been rapid 7see pp4 #fc-fd74 ,in general1 the use of mineral resources on a large scale may be said to have started within the lifetime of men still active in business4 ,the wide use of power necessary to an industrial age1 the development of metallurgy1 the increasing size and complexity of demands for raw material1 mean that the intensive development and use of our mineral resources is in its infancy1 and is in many respects in an experimental stage4 ,as nations have awakened to their need of mineral raw materials and to the recent rapid depletion of these materials1 they have been naturally led to inquire how long the reserves may last1 and to consider prevention of waste and the more efficient use of materials1 with a view to planning more prudently for future national supplies4 ,the first inquiries seemed to reveal such shortage of mineral supplies as to call for immediate and almost drastic steps to prevent waste1 and possibly even to limit the use of certain minerals in the interests of posterity4 ,more careful study of the problem1 as might be expected1 revealed new factors and greater complexity4 ,the conservational idea has a wide sentimental appeal1 but the formulation and application of specific plans meet many difficulties4 ,in its practical aspects the problem is now a live one1 the solution of which is requiring the attention of mining men1 engineers1 geologists1 economists1 and public officials4 ,it is a question which is coming more and more into the field of actual professional practice of the economic geologist4 ,it is our purpose to indicate the general nature of the conservation problem4 ,we may assume agreement to the desirability of preventing waste1 of making a wise present use of mineral products1 and of striking a proper balance between the present and future in their use4 ,nature has taken many long geologic periods to build up these reserves4 ,we1 of the present generation1 in a sense hold them in trust2 they are entailed to our successors4 ,with this general thought in mind1 how shall we proceed to formulate definite plans for conservation8 ,an initial step is obviously a careful taking of stock4 ,with increasing knowledge of mineral resources1 it is becoming apparent that early estimates of supplies were too low4 ,many of these estimates failed to take into account mining to great depths1 and wide use of low-grade ores1 rendered possible by improved methods2 and especially they failed to put sufficient emphasis on the probabilities of new discoveries to replace exhausted supplies4 ,early predictions have already been upset in regard to a number of mineral resources4 ,the recognition of the general fact that the world is far from explored in two dimensions1 to say nothing of three1 of the fact that known geologic conditions do not yet indicate definite limits to the possibilities of exploration for most mineral resources1 and of the consequent fact that for a long time in the future1 as in the past1 discoveries of new mineral deposits will be roughly proportional to the effort and money spent in finding them1--which means1 also1 proportional to the demand1--makes it impossible1 for most of the mineral resources1 to set any definite limits on reserves4 ,it is comparatively easy to measure known reserves2 but a quantitative appraisal of the probable and possible reserves for the future is extremely difficult4 ,successive revisions of estimates have1 with but few exceptions1 progressively increased the total mineral supplies available4 ,the result is that the time of exhaustion has been pushed far into the future for most of the important minerals1 thus minimizing the urge for immediate and drastic conservational action1 which followed naturally from early estimates of very limited supplies4 ,for both coal and iron1 supplies are now known for hundreds or even thousands of years4 ,for oil and lead1 on the other hand1 the reserves now known have a life of comparatively few years1 but the possibilities for successful exploration make it probable that their life will be greatly extended4 ,notwithstanding this tendency to lengthen the exhaustion period1 the limits of mineral resource life are still small as compared with the life of the nation or of civilization1--and the fundamental desirability of conservation is not materially affected4 ,it is not easy to predict the rate of production for the future4 ,at the present rate of coal production in the ,united ,states1 the supplies to a depth of #f1jjj feet might last #f1jjj years2 but if it be assumed that the recent acceleration of production will be continued indefinitely into the future1 the result would be exhaustion of these supplies in less than #bjj years4 ,it is generally agreed that exhaustion will come sooner than #f1jjj years1 but will require more time than #bjj years4 ,the range between these figures offers wide opportunity for guessing4 ,it is supposed that per capita consumption may not increase as fast in the future as in the past1 that possibly an absorption point will be reached1 and that there will be limits to transportation and distribution2 but how to evaluate these factors no one knows4 ,in the case of some of the metallic resources1 such as iron1 the fact that the world's stock on hand is constantly increasing--losses due to rusting1 ship-wrecks1 etc41 being only a small fraction of the annual output--suggests that a point will be reached where new production will cease to accelerate at the present rate and may even decline4 ,but again1 the factors are so complex and many of them so little known1 that no one can say how soon this point will be reached4 ,for the immediate future1 there is little to be feared from shortage of mineral supplies in the ground4 ,the difficulties are more likely to arise from the failure of means to extract and distribute these supplies fast enough to keep up with the startling acceleration in future demand indicated by the figures of recent years4 ,the speed and magnitude of recent material developments in many lines cannot but raise question as to whether we have the ability to understand and coodinate the many huge1 variable1 and accelerating factors we have to deal with1 or whether some of the lines of development may not get so far ahead of others as to cause serious disturbance of the whole material structure of civilization4 ,coal alone1 which now constitutes a third of our railway tonnage1 may with increased rate of production require two-thirds of present railway capacity4 ,will railway development keep up8 ,it may be noted that national crises and failures in the past history of the world have seldom1 if ever1 been due to shortage of raw materials1 or in fact to any failure of the material environment4 ,in its early stages the conservation movement in this country concerned itself principally with the raw material4 ,later there came the recognition of the fact that conservation of raw materials is closely bound up with the question of conservation of human energy4 ,the two elements in the problem are much like the two major elements in mineral resource valuation 7see pages #cbi-ccj74 ,if in saving a dollar's worth of raw material1 we spend two dollars worth of energy1 it naturally raises question as to the wisdom of our procedure4 ,it might be wiser in some cases to waste a certain amount of raw material because of the saving of time and effort4 ,it might be better for posterity to have the product of our energy multiplied into raw material than to have the raw material itself4 ,the valuation of these two major elements of conservation is again almost impossible of quantitative solution4 ,we do not know what is the best result to be aimed for4 ,we cannot foresee the requirements of the future nor the end toward which civilization is moving--or should move4 ,the extravagance of the ,united ,states is often contrasted unfavorably with the thriftiness of ,europe4 ,when considered in relation to raw materials alone1 there seems to be basis for this charge4 ,when considered in relation to the product of human energy into raw materials1 the conclusion may be far different2 for the output per man in the industries related to mineral resources is far greater in the ,united ,states than in ,europe4 ,in the case of iron1 it has been estimated that the output per man in the ,united ,states is two and one-half times as great as in the rest of the world4 ,which is best in the true interests of conservation1 we are not yet able to see4 ,our view of what is desirable in the way of conservation depends somewhat on the limitations imposed by self-interest or location4 ,by devoting ourselves exclusively to one mineral resource1 we might work out a conservation program very disadvantageous to the best use of some other mineral commodity4 ,we might take steps to conserve chromite in the ,united ,states which would have a disastrous effect on the iron and steel industry4 ,we might conserve coal by the substitution of oil1 when the procedure is hardly warranted by the supplies of oil available4 ,we might work out a program for the ,united ,states which would not be the best conservational plan for the world as a whole1 and which would ultimately react to the disadvantage of the ,united ,states4 ,the wisest and most intelligent use of mineral resources seems to call unquestionably for their consideration in their world relations1 rather than for a narrow interpretation of local requirements4 ,,differences ,,between ,,private ,,and ,,public ,,efforts ,,in ,,conservation ,it appears that a wide range of effective conservational practices has resulted solely from the effort to make more money through more efficient operations1 and this is likely to be true in the future4 ,many improvements in mining1 grading1 sorting1 concentration1 and metallurgy of minerals1 to yield larger financial returns1 are coming naturally through private initiative1 under the driving power of self-interest4 ,another considerable group of conservational practices is possible only to governments or other public agencies4 ,this group of practices on the whole requires some sacrifice of the immediate financial interest of the individual1 in the interests of the community as a whole1 or in the interests of posterity4 ,in this group may be mentioned the compulsory use of methods of mining1 sorting1 and metallurgy which tend to conserve supplies but result in higher prices2 the control of prices2 the elimination or lowering of the so-called resource or royalty value 7p4 #cge72 and the removal of restrictions on private combination or cooperation1 leading to more efficient methods1 lessening of cost1 and better distribution of the product2 or1 what might amount to the same thing1 the acquirement by the government of the resources to be operated on this larger scale4 ,the most effective conservation measures yet in effect are the ones dictated by self-interest and instituted by private initiative4 ,governmental measures are not yet in effective operation4 ,illustrations of these two types of conservational effort are cited in relation to coal on later pages4 ,,the ,,interest ,,rate ,,as ,a ,,guide ,,in ,,conservation ,in striking a balance between the present and the future1 economists have emphasized the importance of recognizing the interest rate as a guiding1 if not a controlling consideration4 ,it is obviously difficult for private capital to make investments of effort and money for the purpose of conservation which will not be returned with interest some time in the future4 ,for the present1 at least1 this consideration furnishes the best guide to procedure in the field of private endeavor4 ,so far as conservational measures1 such as investment in an improved process of concentrating low-grade ores1 promise return of capital and an adequate interest rate in the future1 they are likely to be undertaken4 ,it is clear that governments are not so closely bound by this economic limitation4 ,they can afford to carry their investments in raw materials and processes at a lower interest rate than the private investor4 ,their credit is better4 ,taxes do not figure so directly4 ,they can balance losses in one field against gains in another4 ,as a matter of insurance for the future of the nation1 a government may feel justified in inaugurating conservational measures for a particular resource without hope of the interest return which would be necessary to the private investor4 ,in appraising the iron ores of ,lorraine taken over by ,france from ,germany at the close of the war1 the actual commercial value of these ores1 as figured by the ordinary ad valorem method1 was only ninety millions of dollars4 ,it is clear1 however1 that to ,france as a nation the reserves were worth more4 ,they could afford to pay more for them1 and could afford to spend more money on conservational practice than under ordinary commercial limitations1 because of the larger intangible and more or less sentimental interest4 ,the valuation of this larger interest1 as a means of determining the limit to which conservational investments may be made1 lies in the political field4 ,it may be suggested1 however1 that a desirable first step in any governmental program of conservation is to ascertain the cost and the possibility of an adequate return of capital and interest4 ,these determinations at least afford a definite point of departure1 and a means for measuring the cost to the people of measures which are not directly self-supporting4 ,,anti-,,conservational ,,effects ,,of ,,war ,experience during the recent past indicates that the exploitation of mineral resources for war purposes is on the whole anti-conservational4 ,it is true that the vast amount of war-time exploration and development1 as well as the thoroughgoing investigations of the utilization of various minerals1 have led to better knowledge of the mineral resources and their possibilities4 ,it is also true that the war required a much more exhaustive census of mineral possibilities than ever before attempted4 ,the immediate and direct effect of the war1 however1 was the intensive use of mineral resources without careful regard to cost1 grade1 or many other factors which determine their use in peace times4 ,for instance1 in ordinary times considerable quantities of high-phosphorus iron ores are mined2 but1 because of the fact that such ores require more time for conversion into steel1 war-time practice concentrated on the higher-grade1 low-phosphorus ores1 resulting in an unbalanced production which in some cases amounted almost to robbing of ore deposits4 ,in the case of coal1 quantity was almost the only consideration2 it was impossible to grade and distribute the coal to meet the specialized demands of industry4 ,the results were a general lowering of the standards of metallurgical and other industrial practices1 and increased cost4 ,high-grade coals were used where lower-grade coals were desirable for the best results4 ,in the making of steel1 it is the custom to select the coal and coke with great care in regard to their content of phosphorus1 sulphur1 ash1 and other constituents which affect the composition of the steel product2 but during the war it became necessary to accept almost any kind of coal1 with a resulting net loss in quantity and in grade of output4 ,for a considerable number of mineral resources1 such as the ferro-alloys1 foreign sources of supply were cut off during the war1 requiring the development and use1 at high cost1 of low-grade scattered supplies in the ,united ,states4 ,it was found possible to produce enough chromite in the ,united ,states for domestic requirements1 but at two or three times the normal price of imported chromite4 ,the grade was low and the loss in efficiency to the consuming interests was a high one4 ,the extremely limited natural supplies were raided almost to the point of exhaustion4 ,with the post-war resumption of importation of minerals of this kind1 producers naturally began a fight for a protective tariff1 and the question is yet unsettled4 ,the tariff1 if enacted1 would in most cases have to be a high one in order to permit the use of domestic supplies4 ,the results would be a large increase in cost to other industries1 decreased efficiency1 and the early exhaustion of limited supplies in this country4 ,most of the mineral resources have been concentrated by nature in a comparatively few places in the world2 and when the two elements of conservation are considered--the materials themselves and the human energy expended in obtaining and using them--it is clear that any measure which interferes with the natural distribution of the favored ores is anti-conservational from the world standpoint4 ,,conservation ,,of ,,coal ,in the sections on mineral resources1 there are many casual references to conservation of specific minerals4 ,here we shall not go further than to introduce a brief discussion of the conservation of coal as illustrative of the general problem of conservation of mineral resources4 ,it has been estimated that the ,united ,states possesses1 to a depth of #c1jjj feet1 in beds #ad inches or over1 #c1ech1eed1jjj1jjj tons of coal1 and an additional reserve between #c1jjj and #f1jjj feet of #fff1fjj1jjj1jjj tons4#db ,if all the unmined coal to a depth of #c1jjj feet could be placed in one great cubic pile1 the pile would be #ah miles long1 #ah miles wide1 and #ah miles high4 ,of the original amount of coal to this depth only about #j4d of #a per cent has been mined or wasted in mining4 ,the wastage is estimated at about #ej per cent4 ,if the annual production of coal were to remain the same as in recent years1 the total life of the coal reserves 7to a depth of #c1jjj feet7 would be between #d1jjj and #f1jjj years2 but if the acceleration of production of recent years were to be maintained in the future1 the life would be but little over #ajj years1 and the life of the highest-grade coal now being mined might not be over #ej years4 ,all agree that the acceleration of production is not likely to continue indefinitely1 which will mean that the life of coal reserves to #c1jjj feet will be somewhere between the two extremes named4 ,it seems clear that actual shortage of coal will not be felt for some hundreds of years2 but this period of years is short as compared with the probable life of the race4 ,,measures ,,introduced ,,or ,,proposed ,,to ,,conserve ,,coal ,the following list of measures for conservation of coal is taken from several sources4 ,the exhaustive report of the ,british ,coal ,commission1#dc published in #aije1 contains a considerable number of specific recommendations for conservation of the coal of ,great ,britain4 ,the reports of the ,national ,conservation ,commission#dd of the ,united ,states1 published in #aiji1 treat of the conservation of the coal of the ,united ,states and naturally follow some of the recommendations of the ,british report4 ,the coal section of the ,national ,conservation report was prepared by ,m4 ,r4 ,campbell and ,e4 ,w4 ,parker of the ,u4 ,s4 ,geological ,survey1 and is contained in ,u4 ,s4 ,geological ,survey ,bulletin #cid4 ,the recommendations there given are amplified and developed by ,van ,hise#de in his book on ,conservation1 published in #aiaj4 ,since that time the subject has been discussed by ,smith1 ,chance1 ,burrows1 ,haas1#df and others1 and certain additional conservational methods have been proposed4 ,a considerable number of men have also discussed the sociologic and economic aspects of the question4 ,the report of the ,conservation ,commission of ,canada1#dg published in #aiae1 treats rather fully of the conservation of mineral resources4 ,it will suit our purpose1 and avoid some repetition1 if we group most of these recommendations without regard to authorship4 ,in general1 these recommendations can be grouped under the heads3 7,a7 ,methods of mining and preparation of coal2 7,b7 ,improvement of labor and living conditions at the mines2 7,c7 ,introduction or modification of laws to regulate or to remove certain restrictions on the coal industry2 7,d7 ,distribution and transportation of coal2 7,e7 ,utilization of coal2 7,f7 ,substitutes for coal as a source of power4 7,a7 ,mining and preparation of coal4 ,under this heading may be included a large number of proposals which concern primarily the engineering treatment of the coal underground and in the mine plants4 ,some of the more important measures are3 #a4 ,introduction of the long-wall system of mining in places where the conditions allow it1 in order to minimize the waste underground4 #b4 ,modification of the room-and-pillar system of mining1 by which larger pillars are left while the mine advances1 and are recovered in the retreat1--thereby recovering a larger percentage of coal than under the old system1 where small1 thin pillars were left1 which failed and were permanently lost4 ,it has been argued that the great loss of coal by leaving it in pillars could be saved by using other material to support the roof2 but an elementary calculation of the cost of this procedure shows that it is cheaper to use the coal4 ,chance#dh says3 ,the coal left as pillars to support the roof is thus utilized and performs a necessary and useful function1 yet the principal part 7perhaps two-thirds7 of the #bjj1jjj1jjj tons our friends the conservationists claim is wilfully and avoidably wasted every year is this coal that is left in pillars to support the roof4 ,i think we can safely claim that this is not waste1 but1 on the contrary1 is engineering efficiency of the highest type1 in that it utilizes the cheapest and least valuable material available to support the roof and saves the whole labor cost of building supports of other materials4 ,investigation as to what becomes of that part of the #bjj1jjj1jjj tons claimed as wasted1 which is not utilized as pillars to support the roof1 will disclose the fact that a very large portion is coal that is left in mine workings that are abandoned because the roof is unsafe and because a continuance of operation would result in injuries or loss of life4 ,coal left in the mines in order to conserve human lives cannot be classed as avoidable waste4 ,a small part of the #bjj1jjj1jjj tons is lost because it is intimately mixed with refuse and because the labor cost of recovering it and separating it from the refuse would be greater than its value4 #c4 ,mining of shallow bituminous beds by means of the steam shovel4 ,progress has been made along this line in the last few years1 and valuable deposits are thus mined which can be mined profitably by no other method4 #d4 ,new methods of filling mined-out spaces with sand1 and new methods of mine survey and design4 ,according to ,haas#di the greatest advance in the question of method was the system of mine survey and design perfected in both the anthracite and bituminous fields4 ,the relatively new method of filling old spaces with sand1 etc41 has also achieved success4 #e4 ,use of methods by which coal is not left in the roof for the support where the roof is weak1 and by which coal of inferior quality is not left in the roof4 #f4 ,wider use of coal-cutting machines by which the wasting of thinner beds may be avoided4 #g4 ,where conditions allow it1 the working of the upper beds before the lower1 in order not to destroy the upper ones by caving4 ,the mining of a lower coal seam has often so broken up the overlying strata as to render it impossible to recover the upper coal seams contained therein4 ,there are certain difficulties1 however1 in the way of this conservational measure4 ,in some localities the seams are under separate ownership1 and there is a resulting conflict of interests4 ,also1 if the better coal seam happens to be below and the poorer seams above1 market conditions may require that the lower seam be mined regardless of the destruction of the upper ones4 #h4 ,elimination of coal barriers to mark the limits between properties4 ,this involves more cooperation4 #i4 ,improvement of mining machinery1 power drills1 etc4 #aj4 ,centralization of power stations1 rather than the use of many small units4 #aa4 ,elimination of the wasting of slack or fine coal1 through more careful methods of mining1 through limitations on the excessive use of powder and larger use of wedges1 through the abolition of laws for the payment of miners on a run-of-mine basis1 and in the case of anthracite through recovery of the silt or dust caused by mining and sorting4 ,it has been argued that the excessive use of powder 7shooting from the solid7 means loss of coal1 owing to the fact that it shatters the coal and makes a relatively large amount of slack1 besides being accompanied by increased danger from fire and explosion and from weakening of the roof4 ,although the excessive use of powder makes a large amount of slack1 it does not necessarily result in waste1 for this fine coal is carefully saved and for certain purposes is as valuable as the lump coal4 ,so far as the procedure endangers life1 it is of course objectionable4 #ab4 ,better use of fine coal4 ,it has been recommended that infirm and finely broken coal be washed and compressed1 thus avoiding the wasting of slack coal1 which was formerly thrown away or burned4 ,however1 in recent years there has been comparatively little waste of this kind1 for slack coal in general finds nearly as ready a market as lump coal and the use of slack is increasing4 ,there has been much discussion also of the possibilities of using the coal waste on the ground to make power for electric transmission4 #ac4 ,more careful attention to sorting and sizing of all grades of coal coming from the mine and to preparation of coals for special uses4 ,on the other hand1 some operators say that the ends of conservation will be best met by limiting the sorting and sizing now practiced4 ,the large number of sizes now put on the market greatly increases the cost of production4 #ad4 ,wider use of the lower-grade fuels of the west1 particularly with the aid of briquetting4 ,progress in above methods4 ,methods of mining and preparation of coal have been improved4 ,campbell and ,parker state3#ej ,a much greater proportion of the product hoisted is now being sent to market in merchantable condition4 ,part of this is due to better and more systematic methods of handling1 and part to the saving of small sizes which formerly went to the culm banks4 ,the higher prices of coal and the development of methods for using these small sizes have also made it possible1 through washing processes1 to rework the small coal formerly thrown on the culm banks1 and these are now furnishing several millions of tons of marketable coal annually4 ,in general there is increase in the percentage of recovery of coal4 ,whereas in the past the loss in mining was said by ,campbell and ,parker#ea to average #ej per cent1 now an extraction of #gj to #ij per cent may be looked for4 ,quoting from ,smith and ,lesher3#eb ,observation of the advances made in mining methods in the last decade or two affords slight warrant for belief in any charge of wasteful operation4 ,as consumers of coal we might do well to imitate the economy now enforced by the producers in their engineering practice4 ,in the northern anthracite field machine mining in extracting coal from #bb- and #bd-;inch beds1 and throughout the anthracite region the average recovery of coal in mining is #fe per cent41 as against #dj per cent4 only twenty years ago4 ,nor are the bituminous operators any less progressive in their conservation of the coal they mine4 ,in anthracite mining1 powdered coal or silt has accumulated in stockpiles and in stream channels to many tens of millions of tons4 ,it is estimated that this constitutes nearly #f per cent of the coal mined4 ,significant progress has been made recently in the recovery and use of this silt as powdered fuel for local power purposes4 ,however1 physical and commercial conditions do not in all cases allow of the full application of these new methods4 ,once a mine has been opened up on a certain plan1 it is difficult to change it4 ,as a whole the longer and better organized companies are better able to change than the smaller companies4 ,conservation measures of the above kinds1 as so far applied1 have come mainly from private initiative based on self-interest1--though the cooperation of the government has been effective1 particularly along educational and publicity lines4 7,b7 ,improvement of labor and living conditions at the mines4 ,under this heading should be mentioned the improvement of housing1 sanitation1 and living conditions2 improvements in the efficiency of labor1 through making living conditions such as to attract a higher-grade labor supply and through educational means2 the introduction of safety methods2 the introduction of workmen's compensation and insurance2 and other measures of a similar nature4 ,all these measures as a class are sometimes grouped under the name of welfare work4 ,much thought and discussion have been devoted to the possibilities of improvement of labor and living conditions from the standpoint of conservation of human energy4 ,in some quarters this subject has been treated as being independent of the physical conservation of mineral resources1 and it has been the tendency to assume that conservation of human energy might be more or less inimical to conservation of mineral resources4 ,certain of the changes already introduced have undoubtedly increased the cost of mining2 and1 until there was a general increase in selling price1 this increased cost may have had the effect of eliminating certain practices of mineral conservation which might otherwise have been possible4 ,for instance1 according to ,smith and ,lesher3#ec ,the increased safety in the coal mines that has come through the combined efforts of the coal companies1 the state inspectors1 and the ,federal ,bureau of ,mines necessarily involves some increase in cost of operation1 but the few cents per ton thus added to the cost is a small price to pay for the satisfaction of having the stain of blood removed from the coal we buy4 ,that form of social insurance which is now enforced through the workmen's compensation laws alone adds from #b to #e cents a ton to the cost of coal4 ,on the other hand1 there can be no doubt that large advances have been made in welfare movements which were introduced for the purpose of insuring a steadier1 better1 and larger supply of labor1 and that the general gain in efficiency of operation thereby obtained has absorbed a large part of the increased cost4 ,in general1 conservation measures of this class have been developed cooperatively by private and public efforts1 without important sacrifice of private interest4 ,there is obviously room for much wider application of such measures1 especially in some of the bituminous fields where conditions are still far from satisfactory4 7,c7 ,introduction or modification of laws to regulate or to remove certain restrictions on the coal industry4 ,it has been proposed3 #a4 ,to modify the laws so as to take care of situations where vertically superposed beds are owned by different parties1 preventing the proper mining of the coal by either party4 #b4 ,to modify the laws so as to eliminate conflict in mining practice in cases where the coal is associated with oil and gas pools4 #c4 ,to allow larger ownership by companies utilizing the coal 7now only #c per cent owned by such companies74 #d4 ,to place restrictions on over-capitalization1 which leads to wasteful mining in order to secure quick and large returns on large capital4 #e4 ,to remove restrictions on concentration of control4 ,this means1 as a corollary proposition1 virtual restriction of competition4 ,concentration of control into comparatively few hands has undoubtedly favored conservation4 ,it is easy to see that the stronger financial condition of the large companies makes it possible for them to take fuller advantage of modern methods of extraction1 distribution1 and marketing4 ,this proposal was especially urged for the bituminous coal industry before the war in order to avoid over-production and over-development4 ,the very wide distribution of the bituminous coals1 their enormous quantity1 and their exceedingly diversified ownership had led to over-development of coal properties4 ,quoting from ,smith and ,lesher3#ed ,in estimating the aggregate losses incurred by society by reason of the large number of mines not working at full capacity1 the facts to be considered are that the capital invested in mine equipment asks a wage based on a year of #cfe days of #bd hours1 while labor's year averaged last year only #bcj days in the anthracite mines and only #bjc days in the bituminous mines1 with only five to eight hours to the day4 ,these conditions prevented in some cases even the most modest introduction of better methods1 or of changes that would enhance the average profits through a relatively short period of ten or fifteen years at the expense of the present year4 ,it was necessary to get at the best of the coal available in the cheapest possible way1 regardless of the losses of coal left in the ground4 ,to some extent the force of this argument was minimized by war and post-war conditions1 but even yet development of coal mines is ahead of transportation and distribution4 #f4 ,to allow cooperation in the limitation of output1 in the avoidance of cross freights1 in gauging the market in advance1 and in division of territory1 all of which would allow cheaper mining and thus give larger leeway to conservational measures4 ,this necessarily would be accompanied by government regulation4 ,according to ,van ,hise1#ee who was active before the war in advocating this conservational measure1 such a procedure is neither regulated competition1 nor regulated monopoly2 but the retention of competition1 the prohibition of monopoly1 permission for cooperation and regulation of the latter4 ,in ,chicago there cannot be one selling agency for the different coal companies which operate in ,illinois1 but there must be many selling agencies1 and the coal of ,pittsburgh must come into ,illinois and the ,illinois coal go toward ,pittsburgh2 every one of which things makes unnecessary costs1 but all of which are inevitable under the extreme competitive system4 ,because of these facts it is necessary to waste the coal4 ,if at the very same prices the different mines could cooperate in the limitation of the output1 avoidance of cross freights1 gauging the market in advance1 and division of territory1 they could mine their coal more cheaply1 have a greater profit for themselves and conserve our resources4 ,to some extent the plan here advocated was put into effect during the war by the ,united ,states ,coal ,administration2 but the conditions of this trial were so complicated by special war requirements1 that the conservational advantages of unified control were not demonstrated4 #g4 ,to reduce the excessive royalties paid to fee owners4 ,smith and ,lesher#ef have recently called attention to the relatively high resource cost in some of the coal fields1 represented by the payment of royalties to fee owners4 ,in the case of anthracite the payment averages #cb to #ce cents per ton1 and exceptionally runs as high as a dollar per ton4 ,for the bituminous coal the average resource cost is probably not much over five cents a ton4 ,they suggest the possibility of lowering this cost by governmental regulation2 and make an especially strong argument for not allowing the government-owned coal lands to go to private owners1 who in the future1 with the accumulation of interest on the investment1 will feel justified in asking for a large resource return in the way of royalty4 ,if the resource cost could be lowered1 further introduction of conservational methods by the operators would be possible without greatly increasing the cost to the public4 #h4 ,to require or allow1 by government regulation1 a raising of the price of coal to the consumer1 thereby allowing wider application of conservational practices4 ,some of the increased recoveries of coal above noted have been made possible only by increase in the market price4 ,if cooperation were permitted in the manner described in paragraph #f1 the same results might be accomplished without increasing the price4 ,recent high prices caused by the war situation are reflected in the introduction of many conservational changes which were not before possible4 ,however1 in some cases the demand for quick results under present conditions has an opposite effect1 because of the desire to realize quick profits regardless of conservation4 #i4 ,the local conservation of coal at the expense of heavier drafts on coal of other parts of the world1 by imposition of export taxes and preferential duties1 has been discussed4 ,while the effect of such a measure would doubtless be conservational from the standpoint of the ,united ,states1 it is doubtful if it could be so regarded from the broader standpoint of world civilization4 ,under present world conditions such a step would be disastrous4 #aj4 ,government ownership has been proposed as a means of facilitating the introduction of conservation measures4 ,in the ,united ,states there is yet no major movement in this direction4 ,in ,england the question of nationalization of coal mines is an extremely live political problem 7see pp4 #cdc1 #cde-cdg74 ,little progress has been made in conservation measures which involve legal enactments of the kinds above listed4 7,d7 ,distribution1 and transportation of coal4 ,it has been argued that conservational results would ensue from3 #a4 ,cheaper transportation4 #b4 ,larger use of waterways4 #c4 ,improvement in distribution of the product by partition of the market and by larger use of local coals4 ,for effectiveness this proposition would have to include control of the agencies of distribution1 in order to minimize excessive profits of middlemen4 #d4 ,purchasing and storage of coal by consumers during the spring and summer months in anticipation of the winter requirements1 in order to equalize the present highly fluctuating seasonal demands on the mines and railroads1 and to eliminate the recurring shortages of coal in the winter months4 ,this was particularly recommended by the ,united ,states ,bituminous ,coal ,commission in a recent report4#eg #e4 ,where conditions allow it1 conversion of coal into power at the mine and delivery of power rather than coal to consuming centers4 ,this type of conservation is being put into practice on a large scale above ,wheeling1 on the ,ohio ,river1 where there has recently been built a two hundred thousand kilowatt installation for steam-generated electric power4 ,some of the power will be delivered to ,canton1 ,ohio1 over fifty miles away4 ,this plant uses local coal and the cost of coal is figured at two mills per kilowatt-hour4 ,under this heading of distribution and transportation of coal1 might be considered certain international relations4 ,the international movements of coal are summarized in another place 7pp4 #aae-aag74 ,anything in the way of tariffs or trade agreements which would tend to interfere with or to limit the great natural international movements of coal--which in a free field are based on suitability of grade1 cost1 location1 transportation1 etc4--would be anti-conservational from the world's standpoint1 although they might be of local and temporary advantage4 ,for instance1 the coal exported from ,england1 which has heretofore dominated the international trade of the world1 is of a high grade4 ,american coal available for export is on the whole of considerably lower grade1 being higher in volatile matter4 ,unless this coal is beneficiated at home1 it can replace the ,english coal in the export field only at increased cost of transportation and lower efficiency in use4 ,the time may come when it will be desirable to ship lower-grade coals long distances2 but when the two factors of conservation are considered--the intrinsic qualities of the coal1 and the efforts necessary to utilize it--it would seem to be conservational at this stage to ship to long distances only the coal which nature seems specially to have prepared for this purpose4 7,e7 ,utilization of coal4 ,conservational proposals of this kind are3 #a4 ,substitution of retort coke-ovens for beehive ovens1 to save not only a larger quantity of coke but also valuable by-products 7see pp4 #aah-aai74 ,additional improvements in coking ovens may make possible the manufacture of some sort of coke from a much wider range of bituminous coals than can be used at present4 #b4 ,larger use of smoke consumers and mechanical stokers4 #c4 ,larger use of central heating plants1 with higher efficiency than many local plants4 #d4 ,substitution of gas engines for steam engines1 and improvement of the steam engine4 #e4 ,improvement in methods of smelting1 leading to larger output of metal per ton of coke used4 ,also the development of electric smelting for certain metals4 #f4 ,more careful study and classification of the qualities of coals1 in order to avoid use of higher-grade coals where inferior coals would serve the purpose4 #g4 ,more consumption at the collieries4 #h4 ,larger use of powdered coal as fuel4 #i4 ,improvement of force-draft furnaces4 #aj4 ,larger use of gas1 a by-product of coal mining1 and extraction of other by-products4 #aa4 ,more efficient transformation of peat and coal into power and light4 #ab4 ,the possible use of oil flotation to eliminate foreign mineral matter4 ,most of the conservation measures above proposed have already been applied with good results1 and with promise of large results for the future4 ,the stimulus has come largely from self-interest4 ,war conditions in some ways aided and in others hindered these developments4 ,one of the conspicuous gains was the building of many by-product coke plants1 under the necessity of securing the nitrates and hydrocarbons for munition and other purposes4 7,f7 ,substitutes for coal as a source of power4 ,some of the more prominent measures along this line which have been discussed are3 #a4 ,larger use of water power4 ,this has sometimes been popularly assumed to be1 at least potentially1 a complete solution of the problem2 but nevertheless it has its distinct limitations4 ,water power has the advantages that its sources are not exhausted by use1 and that the relatively greater initial cost of a hydro-electric plant is frequently more than compensated for by the saving in man power required and by the lower operating expense4 ,however1 the total amount of water power which can be developed on a commercial basis is rather closely limited1 and much of the available power is so distributed geographically that it cannot be economically supplied to the industries which need it4 ,of the total water-power resources of the ,united ,states which have been estimated by the ,geological ,survey to be available for ultimate development1 over #gj per cent is west of the ,mississippi1--whereas over #gj per cent of the horse-power now installed in prime movers is east of the ,mississippi4 ,electric power cannot at present be economically transmitted more than a few hundred miles4 ,furthermore1 for many uses of coal1 as in metallurgical and chemical processes which require the heat or reducing action of burning coal1 and in its use as fuel for ships1 hydro-electric power cannot be substituted4 ,it seems clear that while the use of water power will increase1 particularly as rising prices of coal make possible the development of new sites1 it can never take the place of the mineral fuels in any large proportion4 ,for the immediate future1 measures which have been suggested to extend the use of water power include3 the more complete utilization of water powers already in use through more efficient machinery and methods2 a certain degree of redistribution of industries1 so that those requiring large amounts of power may be located in areas where water power is cheap and abundant2 and the interconnection of hydro-electric plants so that their full capacity may be used4 ,some water powers which have been developed are not being fully utilized because the plants are not connected with distribution systems large enough to use all the power4 ,during the war the ,united ,states ,geological ,survey1 in cooperation with the ,fuel ,administration and the ,war ,industries ,board1 collected the information required to prepare maps showing the locations and relations of power stations and transmission lines throughout the country4 ,this survey of the situation showed many possibilities1 which had before been but vaguely realized1 of interconnections which would increase the efficiency of the plants4 #b4 ,substitution of lower-grade coals--of bituminous for anthracite1 and of low-grade bituminous for high-grade bituminous coals4 ,larger use of low-grade western coals4 ,war and post-war conditions have shown ,germany the way to a wide and effective use of its lignites4 ,this has been accomplished by cooperation of the government and private interests4 ,this vast improvement in methods of treatment and recovery of heating elements and by-products will doubtless have a widespread effect on utilization of lignites in other parts of the world4 #c4 ,substitution of alcohol and natural gas1 oil1 oil shales1 peats1 etc41 as a source of power4 ,this merely concentrates the conservation problem more largely on these minerals1 in some of which1 at least1 it is already considerably more acute than in the case of coal2 it is not a solution of the problem1 but merely a shifting of emphasis4 ,business conditions have limited private enterprise in this class of measures1 but some progress has been made4 ,more rapid introduction of these measures would require sacrifice of private interest and probably may be accomplished only by application of public power4 ,,division ,,of ,,responsibility ,,between ,,government ,,and ,,private ,,interests ,,in ,,the ,,conservation ,,of ,,coal ,a review of the conservation measures above listed indicates that many of them are already in operation1 and that the initiative for such measures has been largely supplied by private ownership endeavoring to advance its own interest4 ,in this category are to be included most of the improvements in physical methods of mining1 preparation1 and utilization of coal1 the use of substitutes for coal1 the concentration of control into larger groups better able to introduce new methods1 and the improvement of labor and living conditions2 also1 under recent conditions1 the increase in selling price1 allowing for a wider application of these measures4 ,another group of conservation proposals1 which have not yet been put into substantial effect1 are obviously beyond the power of private interests2 and must be introduced1 if at all1 by the application of government power4 ,these include the elimination of resource or royalty costs1 the control of over-capitalization1 the removal of restrictions on concentration of control1 the granting of permission for cooperation among competitive units1 the regulation of selling price minimums in order to insure during normal times the use of better physical practices1 and the control of distribution4 ,in short1 it appears that there are two great spheres of conservational activity--one within the field of private endeavor1 and the other possible only by collective action through the government4 ,the principal advances thus far made have been in the field of private endeavor4 ,the government has aided greatly in the advancement of conservation measures arising within the field of private endeavor4 ,one need only refer to many governmental investigations1 to the spreading of information as to best methods1 and to local compulsory requirements that the best practices be made uniform and that backward interests thereby be brought into line4 ,recognition of the fact that there is a large body of sound conservational practice in the coal industry which falls within the range of self-interest seems essential in planning further changes in the direction of conservation4 ,conservational measures do not all require sacrifice of the individual to the public1 nor of the present to the future generations4 ,an exercise of public power is not in all cases essential to the advancement of conservation4 ,the respective limits of the fields of public and private endeavor are not sharply defined1 and vary from place to place and time to time1 depending upon local conditions and special requirements4 ,in general1 the sphere of private interest includes measures which will bring adequate commercial return4 ,the interest rate is the limiting and controlling factor4 ,when it is possible--by improvement of methods of mining1 better planning1 better preparation of coal1 better transportation and distribution1 or better utilization--to secure a larger average return on the investment1 or to insure return through a longer period of years1 self-interest naturally requires the introduction of such methods as rapidly as financial conditions allow4 ,even some of the improvements in labor and welfare conditions have been introduced in this way1 with a view to securing a more permanent and more efficient labor supply1 and thereby aiding the enterprise from the commercial standpoint4 ,within the sphere of government activity lie the removal of unnecessary restrictions on private initiative1 and such conservation measures as involve some sacrifice of individual returns--in other words1 a reduction of the normal interest rate4 ,exercise of government power may be directly helpful within the field of private endeavor without materially sacrificing private interests2 but beyond this point there are additional large possibilities of conservational activity which are clearly beyond the control of private interests4 ,the introduction of any of these latter changes would evidently be so far-reaching in effect1 and would require such broad readjustments not only within but without the mineral industry1 that the necessity or desirability is not in all cases so clear as in the case of measures already introduced for private interest4 ,the most obviously helpful step possible to the government in the immediate future is to permit cooperative arrangements under private ownership1--which would make it possible to use common selling agencies1 thereby reducing the cost of selling2 to divide the territory to be served1 thereby avoiding excessive cross freights2 and to allot the output in proportion to the demand from various territories1 thus eliminating excessive competition and over-production4 ,all of these measures could be accomplished without detriment to the public if properly regulated by the government4 ,the very large saving possible by this means would allow the introduction of conservational methods at the mines without raising the cost to the public4 ,war conditions required even more immediate and sweeping application of government power than above indicated1 but conservational purposes were quite overshadowed by other considerations4 ,where the mineral resources are already owned by the government1 or can be acquired by the government1 some of the troublesome factors in the problem are removed4 ,in such cases it is possible to work out an intelligent plan for government control without the difficulties which arise in dealing with private ownership1--although1 of course1 new difficulties are introduced 7see also pp4 #cde-cdg47 ,the fact that there are conservational measures possible only to governments has been widely used as an argument for introducing government ownership or control4 ,recent vigorous demands for the nationalization of natural resources in ,europe1 and the increasing discussion of the subject in this country1 may be regarded as phases of the conservation problem4 ,it is not the purpose here to argue either for or against the drastic exercise of government power in the conservation of natural resources1 but merely to call attention to the measures which are being discussed4 ,,conservation ,,of ,,minerals ,,other ,,than ,,coal ,the discussion of conservation as applied to specific minerals might be extended almost indefinitely2 but perhaps enough has been said to indicate the general nature of the field4 ,before the war careful estimates of world supplies had been made for comparatively few minerals1 although these included some of the most important1 such as coal1 oil1 and iron4 ,war conditions required a hasty estimate of world reserves of most of the mineral products4 ,the reader interested in the problem will find an extremely interesting body of literature issued by the various governments on this subject4 ,of especial interest to the ,american reader will be the reports of the ,u4 ,s4 ,geological ,survey and of the ,bureau of ,mines4 ,in recent years there has been increasing recognition of the possibilities of conservational saving by concentration1 refinement1 and even manufacture of mineral commodities at or near the point of origin1--thus lessening the tonnage involved in transportation of the crude products4 ,limitations of fuel and other conditions often make this procedure difficult2 but considerable progress is being made both through private initiative and1 especially in international trade1 through governmental regulations of great variety4 ,,footnotes3 #db ,campbell1 ,m4 ,r41 ,the coal fields of the ,united ,states3 ,prof4 ,paper #ajj-;,a1 ,u4 ,s4 ,geol4 ,survey1 #aiag1 p4 #bd4 #dc ,final report of the ,royal ,commission on coal supplies3 ,house of ,commons1 ,london1 vol4 #af1 #aije4 #dd ,report of the ,national ,conservation ,commission3 ,senate ,document ,no4 #fgf1 #fjth ,congress1 #b;d session1 ,govt4 ,printing ,office1 ,washington1 #aiji4 #de ,van ,hise1 ,c4 ,r41 ,the conservation of natural resources in the ,united ,states3 ,macmillan ,co41 ,new ,york1 #aiaj4 #df ,haas1 ,frank1 ,the conservation of coal through the employment of better methods of mining3 ,abstract of paper presented to ,pan-,american ,scientific ,congress1 ,washington1 ,dec41 #aiae-;,jan41 #aiaf4 #dg ,adams1 ,frank ,d41 ,our mineral resources and the problem of their proper conservation3 #fth ,ann4 ,rept41 ,commission of ,conservation1 ,canada1 #aiae1 pp4 #eb-fi4 #dh ,chance1 ,h4 ,m41 ,address before the mine engineering class of the ,pennsylvania ,state ,college1 ,quoted by ,f4 ,w4 ,gray1 ,the conservation of coal3 ,bull4 #dg1 ,can4 ,mining ,inst41 #aiaf1 p4 #bja4 #di ,loc4 cit4 #ej ,campbell1 ,m4 ,r41 and ,parker1 ,e4 ,w41 ,coal fields of the ,united ,states1 ,papers on the conservation of mineral resources3 ,bull4 #cid1 ,u4 ,s4 ,geol4 ,survey1 #aiji1 p4 #ab4 #ea ,loc4 cit4 p4 #ab4 #eb ,smith1 ,george ,otis1 and ,lesher1 ,c4 ,e41 ,the cost of coal3 ,science1 vol4 #dd1 #aiaf1 p4 #gfh4 #ec ,loc cit41 pp4 #gfh-gfi4 #ed ,loc4 cit41 p4 #gga4 #ee ,van ,hise1 ,charles ,r41 ,cooperation in industry1 pp4 #g-h1 ,address given before annual meeting of the ,national ,lumber ,manufacturers' ,association1 ,chicago1 ,illinois1 ,may #ca1 #aiaf4 #ef ,loc4 cit41 p4 #gfg4 #eg ,stabilization of the bituminous coal industry1 ,extracts from the award and recommendations of the ,united ,states ,bituminous ,coal ,commission1 ,government ,printing ,office1 ,washington1 #aibj4 ,,chapter ,,xviii ,,international ,,aspects ,,of ,,mineral ,,resources ,,world ,,movement ,,of ,,minerals ,of the annual world production of minerals about two-thirds are used within the countries where the minerals are produced and one-third is shipped to other countries4 ,in this chapter we are concerned primarily with the part which moves between countries4 ,it may be assumed that the consumption within the countries of origin is a matter of national rather than international concern4 ,in pre-war times minerals constituted about #cc per cent#eh of the value of the total foreign trade of the ,united ,states1 and #bh per cent of the foreign trade of ,germany4 ,figures are not available to show the proportion of mineral tonnage to that of other commodities4 ,one of the several interesting facts in this world movement of minerals is that the movement of most of them shows a rather remarkable concentration4 ,for instance1 manganese moves from three principal sources to four or five consuming centers4 ,chromite moves from two principal sources2 tungsten also from two4 ,even for certain commodities which are widely distributed and move in large amounts1 the concentration of movement is rather marked2 for instance1 the world movement of coal is controlled by ,england1 the ,united ,states1 and ,germany4 ,in other words1 although the world movement of mineral commodities is widespread and exhibits many complex features1 most of the individual minerals follow two or three salient lines of movement4 ,this means in general that for each mineral there are certain sources of limited geographic extent1 which1 because of location1 grade1 relation to transportation1 cost--in short1 all the factors that enter into availability--are drawn upon heavily for the world's chief demands4 ,the convergence of these materials toward a few consuming centers indicates generally concentration of coal production necessary to smelting1 high development of manufacturing1 large per capita use1 concentration of facilities1 strong financial control1 and1 not least1 a large element of enterprise which has taken advantage of more or less favorable conditions4 ,if a nation were fully supplied with mineral resources1 without excess1 the mineral problem might be almost exclusively domestic in its nature4 ,but no country is so situated4 ,for most of the mineral products the dominant supply is likely to be controlled by one or two nations1 the other nations being correspondingly deficient and dependent4 ,even the ,united ,states1 which is more nearly self-sustaining in mineral resources than any other country1 is almost wholly dependent on other countries for certain mineral supplies2 and in the case of minerals of which it has an excess it is dependent on other countries for markets4 ,the view that the mineral resource problem is solely a local and national one1 of no concern to outsiders1 ignores this fundamental fact of distribution of raw materials4 ,control of smelting facilities makes it possible for certain countries to exercise considerable influence over the production and distribution of minerals in other countries1 and thus presents many difficult international questions4 ,even more difficult are the international problems created by the commercial ownership and control of minerals in the ground by nationals of other countries4 ,the national and international aspects of mineral resources are difficult to separate1 so intimately do they react on each other4 ,to some extent there may be conflict of interest between the two1 but in the main the international questions may be logically approached from the standpoint of national self-interest2 for1 in the conduct of the national industry along broad and enlightened lines1 world conditions must necessarily be considered4 ,a clearer comprehension of the world mineral relations1 and an understanding of our own opportunities and limitations in comparison with those of our neighbors1 cannot but eliminate some of the unnecessary handicaps to the best use of the world mineral resources1 and result in a lessening of causes of international discord4 ,a brief survey of the mineral conditions preceding1 during1 and following the war may serve as a convenient means of approach to a study of the present international aspects of the mineral problem4 ,,movement ,,of ,,minerals ,,under ,,pre-,,war ,,conditions ,,of ,,international ,,trade ,if the world pre-war movement of minerals is considered broadly1 it may be regarded as conforming essentially to normal trade conditions of supply and demand4 ,there have been barriers to overcome1 such as tariffs and trade controls and monopolies of various kinds1 but these barriers have not prevented the major movements between the best sources of supply and the principal consuming centers4 ,these movements may be regarded as a more or less spontaneous internationalization of mineral resources by private enterprise4 ,the aim of free trade or unrestricted commerce was equality of trade opportunities2 but such conditions of unrestricted competition tended to concentrate trade in the hands of the strongest interests and to prevent equality of opportunity4 ,the efforts made to promote or hinder international mineral movements by tariffs1 bonuses1 embargoes1 subsidies1 transport control1 patents1 government management1 financial pressure1 and other means have been incited mainly by national or imperial self-interest1 and have thus been to some extent inimical to an internationalization based on the principle of the greatest good to the greatest number4 ,it may be supposed that1 in any effort to attain supernational or international control1 motives and measures based on national self-interest of the sort here mentioned will continue to play an important part4 ,,changes ,,during ,,the ,,war ,the war wrought fundamental changes in the world movement of minerals4 ,the character and distribution of the demands changed4 ,customary sources of supply were cut off4 ,financial disturbances and ship shortage profoundly modified the nature1 distribution1 and extent of the world movement4 ,our domestic mineral industry was abruptly brought to a realization of its vital relations with international trade4 ,to illustrate1 the large movement of manganese from ,india and ,russia to the ,united ,states was abruptly stopped1 and we had to develop a source of supply in ,brazil4 ,the stoppage of pyrite importations from ,spain as a means of saving ships required the development of pyrite and sulphur supplies in the ,united ,states4 ,the export of oil from the ,united ,states to ,european countries was greatly stimulated1 and the export to other countries was correspondingly decreased4 ,the world movements of coal were vitally affected1 principally by the limitation of the coal shipments from ,england and the ,united ,states to ,south ,america and the concentration of shipments to ,european countries4 ,the closing of ,german coal supplies to nearby countries also had far-reaching consequences4 ,the cutting off of the ,german potash left the world for the time being almost unsupplied with this vital fertilizing ingredient4 ,the ,chilean nitrates1 on which the world had relied for fertilizer purposes1 were diverted almost exclusively to the manufacture of powder4 ,the total annual imports of mineral commodities into the ,united ,states were reduced by #a1bjj1jjj tons4 ,our exports1 though they continued in large volume1 were mainly concentrated in ,europe4 ,the story of these disturbances in the world movement of minerals1 though highly interesting1 is too long to be told here4 ,out of these sweeping and rapid changes in the world movement of mineral commodities there arose1 partly as cause and partly as effect1 international agreements for the allocation of minerals1 as a means of insuring the proper proportions of supplies to the different countries for the most effective prosecution of the war4 ,inter-,allied purchasing committees in ,london and in ,paris found it necessary to make an inter-,allied allocation of the output of ,chilean nitrate1 because the sum of the demands exceeded the total supply by a considerable fraction1 and to agree on the distribution and prices of the world's supplies of tin1 tungsten1 and platinum4 ,for many other commodities agreements of various sorts were made4 ,for instance1 the ,united ,states entered into an agreement with ,england and ,france for the purchase of iron ore and molybdenum from ,scandinavia to keep it out of ,germany4 ,the ,united ,states and ,england agreed as to supplying ,canada with ferromanganese4 ,new problems of world allocation came up almost daily4 ,another war change in mineral conditions1 of a more permanent nature1 was the liquidation of ,german ownership and control of minerals in allied countries1 and in some cases even in neutral countries4 ,,post-,,war ,,condition ,,of ,,the ,,mineral ,,trade ,the mineral industry has by no means reverted to its pre-war condition4 ,the old movements have been only partially resumed1 and new elements have entered4 ,shipping is still disturbed4 ,governments have been cooperating in various ways in the liquidation of government stocks of minerals4 ,the ,german commercial control of minerals outside of its boundaries1 as noted above1 has been much weakened4 ,the ,reparations ,committee created by the ,peace ,treaty has enormous powers over the use and distribution of the mineral resources of ,germany1 which directly and indirectly affect the mineral supplies of ,europe and all the world4 ,the terms of the ,peace ,treaty changed in fundamental ways the international channels of mineral movement4 ,the mineral situation of ,europe is in such a state of chaos that the combined efforts of governments will be necessary for many years to bring order4 ,this will be accomplished partly through the ,reparations ,committee1 but may require other forms of cooperation4 ,an international coal commission has already been formed to look after the distribution of coal through ,europe4 ,international cooperation in mineral distribution is not merely a theoretical possibility for the future1--it is now the outstanding fact with reference to the ,european situation4 ,the recognition of their dependence on neighbors for important mineral resources has led to earnest efforts on the part of nations to supply deficiencies4 ,the great activity of the ,british government in acquiring oil is one example4 ,the falling off of gold production the world over1 together with the increased disparity between gold reserves and the currency issued against them1 is causing serious consideration of government action to encourage the gold industry by financial measures tending to increase the profit of the miners 7see pp4 #bbd-bbe74 ,before and since the war most countries of the globe1 outside of ,england and the ,united ,states1 have gone far in the exercise of the right of eminent domain over mineral resources within their own boundaries4 ,even in ,england the recent movement to nationalize the coal and oil resources is an indication of the general tendency4 ,in the ,united ,states the movement has manifested itself thus far only in the increasing reluctance on the part of the government to part with mineral resources on the public domain1--as is clear from the terms of its new leasing law to cover oil1 coal1 gas1 potash1 and phosphates on public lands4 ,before the war only the ,german government was clearly identified with private interests in international trade and in the acquirement of mineral reserves4 ,since the war all governments except that of the ,united ,states are taking an active part in these fields1 both directly and in cooperation with private capital4 ,the ,british government has taken a direct financial interest in certain companies1 such for instance as the ,anglo-,persian and ,shell ,oil ,companies1 and in some cases is actively interested in the acquirement of selling contracts4 ,in ,england there is a wider use of voting trusts in controlling private companies1 with the purpose of preventing the control from falling into alien hands4 ,government control of shipping in certain countries is involving various degrees of control of mineral movements4 ,also1 through loans and bonds1 mineral resources in certain countries have been tied up by the loaning governments4 ,there has been wide extension of government control of minerals in mandatory territories and elsewhere through many new loans and regulations4 ,these steps are in effect closing important parts of the world to private initiative1 and particularly to nationals of other countries4 ,whether these activities of governments are economically desirable or not1 they are the actual conditions1 not theories4 ,if this situation continues1 it raises the question whether our government will not be forced1 in protection of its own mineral industries1 also to take a direct part2 for under present conditions1 our importers and exporters find themselves dealing single-handed with governments or with private groups so closely identified with governments as to have much the same power4 ,in matters of shipping1 credits1 exchange1 tariffs1 embargoes1 and opportunity to acquire foreign reserves1 the actual and potential disadvantage to ,american interests is obvious4 ,,tendencies ,,toward ,,international ,,cooperation ,,and ,,possibility ,,of ,,international ,,control#ei ,,of ,,minerals ,under the pre-war conditions1 unrestricted competition in world trade by private enterprise had led to a certain kind of internationalization of mineral deposits based on natural conditions of availability4 ,there is a natural tendency to work back as quickly as possible to this condition1 but new elements have entered which seem to make it difficult for governments to keep their hands off4 ,the participation of governments in world mineral trade1 when not modified by international cooperation or some other higher form of control1 seems to be having a tendency in the opposite direction--to be closing the doors of equal opportunity and preventing the natural world use of the world's resources4 ,these new conditions1 together with others outlined in the preceding section1 have made it necessary to pay more attention to the possibilities of international cooperation than ever before1--not as a restrictive measure1 except temporarily in regard to the ,central ,european powers1--but as a means of insuring open channels of movement for raw materials1 and of insuring equal economic opportunities to all4 ,many of our mineral industries have already appealed to our government for cooperation and aid in their international dealings4 ,further1 mineral industries in private hands in the various ,allied countries have attempted to get together to arrange for private cooperation1 and appealed to the ,peace ,conference for authority to do so4 ,in certain cases the necessity for cooperative action became so apparent that pressure was brought to bear on the ,peace ,conference for the forming of some sort of international economic body which would make possible some of these steps4 ,these movements were all dictated by considerations of self-interest1 but self-interest broadened and educated by a knowledge of the world's situation4 ,just as the increasing size of the units engaged in the mineral trade within national boundaries has led to discussion of the possibilities of government control in the interest of the public1 so the increasing size of the units in the international mineral trade1 the units in many cases being governments1 is leading to discussion of the possibility of some international or supernational control in the interest of the world good4 ,just as national interest is the lengthened shadow of individual interest1 so international interest may be regarded in some aspects as the lengthened shadow of national interest4 ,the general purpose of the suggested control is to minimize international friction2 but more specifically it has been suggested that some sort of international cooperation is necessary in order to insure equality of opportunity among nations1 both in supplies and in markets1 and thereby to prevent the crowding of the weaker by the stronger nations4 ,this is the gist of one of the famous fourteen points4 ,the purpose might be accomplished by direct allocation of supplies or by control of tariffs and exchange4 ,one of the conditions which seems to require international cooperation is the exploitation of mineral deposits in backward countries4 ,unrestricted competition among nations in such exploitation has been an important cause of international controversy4 ,it was planned at ,peace ,conference that the mineral resources in countries taken over by the great powers under mandatories should be developed and used in the interest of the group of nations1 rather than for the special interest of the nation taking the mandatory4 ,one of the natural functions of any international or supernational organization would be the adjustment and settlement of difficulties arising from this provision4 ,this topic brings up the question as to the right of any nation or group of nations to exert any force on weaker nations in the exploitation of mineral resources4 ,on the principal of self-determination and of the complete freedom of action of nations1 this procedure seems unjustified4 ,on the other hand1 whether rightly or wrongly1 civilization has created great material demands which must be satisfied4 ,the individuals1 companies1 and governments which use force to exploit resources in weaker countries are merely the agents in supplying the demand created by all of us4 ,while their methods are often indefensible1 the exploiters cannot be regarded merely as irresponsible buccaneers who are projecting themselves unnecessarily into somebody else's business4 ,whatever the sentimental and ethical aspects of the question1 it seems almost inevitable that the demands of civilization will continue to require the exploitation of weaker countries2 and in proportion as these countries are backward in cooperating1 they must feel the world pressure4 ,an agreement for international cooperation in such matters1 therefore1 is not to be regarded as merely a cold-blooded attempt to rob weaker nations1--but rather as a means of improving methods in satisfying the actually existing material demands of civilization4 ,for illustration1 the criticism of ,england's attempt to develop the oil industry of ,mesopotamia and ,persia has to a large extent confused the methods with the aim sought for4 ,it is the writer's view that development of these resources is inevitable1 and that criticism should not be directed toward nations and groups attempting to attain these results1 but rather to the methods applied4 ,for the purposes of this discussion1 it is not necessary to go beyond the acceptance of the fact of demand1 nor to argue the question as to whether the material demands of civilization should be curbed and progress restricted to matters of mind and human happiness4 ,,methods ,,of ,,international ,,cooperation ,the first step in international consideration of minerals is obviously one of fact-finding4 ,this became painfully evident during the great war1 when the sudden cutting off of outside supplies and markets brought home the fact that the mineral question is only in part a domestic one4 ,the average mining man had come to take the established marketing and commercial conditions more or less for granted1 and had not looked into the underlying factors4 ,there had been a tendency to assume that a kind ,providence was in some manner looking after these elements in the situation4 ,the nearest approach to ,providence1 as a matter of fact1 was a small group of importers and exporters1 possessing special knowledge of the international movements of certain commodities1--which knowledge was of unsuspected importance to the mineral industry4 ,war conditions showed that neither the general public nor the mineral industry as a whole1 much less the government1 had even an elementary grasp of the important elements of the world mineral situation4 ,the mobilizing of this information under high pressure1 through the cooperation of government and private agencies1 was an interesting and important feature in the complex activities back of the firing line4 ,it is vastly to the credit of the men interested in the mineral industry in this country1 and presumably also in other countries1 that almost without exception they contributed their bits of knowledge to the common pool1 even though these bits had been in a sense their private capital4 ,certain importers1 who by their knowledge of international phases of the mineral situation had been able to exercise a profound influence on domestic markets1 voluntarily sacrificed their own interest for the common cause and pointed out ways in which reductions of imports could be made4 ,the problems of the ,peace ,conference1 and of other international agreements now pending1 have required a still further systematizing of international information4 ,one of the results has been the establishment of organizations of an international fact-finding character in our own and in certain other governments4 ,in the chapters on the several minerals in this book1 are summarized some of the salient features of the international situation developed by study of the kind indicated4 ,knowledge of the physical facts of the world mineral situation is only a first step4 ,their interpretation and correlation1 the study of the underlying principles1 the formulation of the necessary international agreements and regulations1 constitute even more difficult problems1 which are far from solved4 ,there always has been some cooperation of governments in the mineral trade through the ordinary diplomatic channels4 ,the question is now prominent whether1 in view of the new conditions1 it may not be necessary to develop better machinery--in the form of some international or supernational organization1 possibly patterned on war procedure--in order to expedite the negotiations and to minimize possibilities of friction4 ,during the war1 when the world demand exceeded the total world supply of certain commodities1 such as nitrate and tin1 international commissions were formed in order to make an equitable distribution of these minerals and prevent favored strong nations from taking too large a proportion of the total4 ,this procedure presented no insurmountable difficulties4 ,a canvass of the total supplies available and of the demands of the various countries ordinarily led to voluntary compromise in the allocation of supplies4 ,most of the regulations of these commissions were applied to mineral industries which were unable to meet the total demand4 ,they were not tried out in cases where there were excess supplies2 this process obviously would have been much more difficult1 though perhaps not impossible4 ,the general success of international attempts to allocate mineral supplies during the war suggests the lines along which results might be accomplished during peace4 ,the process is essentially a matter of getting at the facts1 and then discussing the situation around a table1--thus eliminating the long delays and misunderstandings arising from the procedure through the older established diplomatic channels4 ,how far such a procedure might be possible without the compelling common interest of war is debatable4 ,the great powers of the ,reparations ,committee1 previously noted1 and of the recently formed ,european coal commission1 already indicate the general nature of the machinery for international control which might be exercised through a league of nations4 ,it is not our purpose to argue for international control or for any specific plan of control1 but rather to outline the problem4 ,the question is not an academic one4 ,various kinds of international control are present facts1 and the problem relates to the possibilities of more effective organization of existing agencies4 ,,conservation ,,in ,,its ,,international ,,relations ,the interests of conservation1 considering both its physical and its human energy phases 7p4 #cfb71 seem to call for an international understanding in the use of mineral resources which will result in the minimum hindrance to their free movements along natural channels of trade4 ,the essential fact of the concentration of mineral supplies in comparatively few world localities1 and the fact that no nation is supplied with enough of all varieties of minerals1 mean that artificial barriers to their distribution cannot but impose unnecessary handicaps on certain localities1 which may be anti-conservational from a world standpoint4 ,if the few countries possessing adequate supplies of high-grade ferro-alloy minerals1 for instance1 were to restrict their distribution by tariffs or other measures1 the resulting cost to civilization through the handicapping of the steel industry would be a large one4 ,or if1 for the general purpose of making the ,united ,states entirely self-supporting in regard to mineral supplies1 sufficiently high import tariffs were imposed on these minerals to permit the use of the low-grade deposits in the ,united ,states1 earlier exhaustion of the limited domestic supplies would follow1 and in the meantime the cost to the domestic steel industry would be serious4 ,cost may be taken to represent the net result of human energy multiplied into raw material4 ,the movement would therefore be anti-conservational4 ,if each state in the ,united ,states were to start out to become entirely self-sustaining in regard to minerals1 and by various regulations were able to prohibit the use of minerals brought in from without1 or the export of its excess of minerals1 the waste in effort and materials would be obvious4 ,nature has clearly marked out fields of specialization for different localities1 and the effective use of mineral supplies is just as much a matter of specialization as the effective use of man's talents4 ,if the ,united ,states1 because of its vast copper deposits1 is in a position to specialize in this line and to aid the world thereby1 this should involve recognition of the fact that other countries are better able to specialize in other commodities1--thereby forming a basis for mutual exchange1 which is desirable and necessary for world development4 ,this conservational argument against artificial barriers does not necessarily imply complete elimination of tariffs or other restricting or fostering measures4 ,within limits these may be necessary or desirable in order to maintain differences in the standard of living1 or in order to permit the growth of infant industries2 but to carry these measures to a point where they interfere with essential mineral movements determined by nature is obviously anti-conservational4 ,for some mineral commodities1 international cooperation may prevent duplication in efforts and the development of excessive supplies in advance of the capacity of the world to use them4 ,partly because of lack of such cooperation1 certain mineral commodities have been developed in such large quantities in various parts of the world that it may be many years before demand catches up with development4 ,in the meantime1 large and unnecessary interest charges are piling up4 ,this financial loss measures the loss in effectiveness of collective human effort4 ,in the above discussion1 little reference has been made to shortage of total world supplies as an argument for international cooperation4 ,this is an argument often cited1 and with some effectiveness during the war4 ,it is the writer's view that this phase of the problem has been much exaggerated4 ,except for certain periods during the war1 in considering the world as a whole adequate supplies of all mineral commodities have been available at all times4 ,they have been developed as rapidly as needed1 in some cases more rapidly2 and geological conditions seem to indicate that this condition will continue for some time in the future1 through national and individual effort4 ,combined efforts of governments seem hardly necessary as yet to accomplish this purpose4 ,in fact1 there is rather more danger of over-development1 without due regard to the working of the interest rate1 which might be prevented by international cooperation4 ,the main problem now is not one of total supplies1 but of their effective and equitable distribution4 ,,exploration ,,in ,,its ,,international ,,relations ,when an explorer or prospector leaves his own country to discover and acquire minerals in other countries1 with a view to exportation1 it is reasonably obvious that he must first acquire a sound knowledge of at least some of the elements of international trade in minerals1--such as shipping facilities1 rates1 tariffs1 attitude of the government toward ownership1 toward export1 etc4 ,for example1 the prospector for oil in foreign countries will not get very far without considering the recent steps taken by foreign governments1 and mentioned on pp4 #aca-acb4 ,the necessity of study of the international situation in conducting domestic exploration is not so generally recognized2 and yet anyone today who confines his attention solely to the local physical facts of the situation1 and who ignores international considerations1 may find himself in difficulties4 ,the investigation of international questions is not merely desirable from the standpoint of general information1 but may be vital to the business or professional success of the explorer4 ,for instance1 he might take up the exploration and development in the ,united ,states of fertilizers and ferro-alloy minerals which are ordinarily imported2 and without understanding the severe limitations imposed by the foreign situation1 he might find himself with a property1 sound from a physical standpoint1 but financially a failure4 ,it is comparatively easy1 by running over the long list of mineral commodities used in the ,united ,states1 to eliminate1 on international grounds1 a considerable number from the field inviting financial success1 and to concentrate on others whose economic relations are sound4 ,in the rapid changes during and since the war1 the necessity for consideration of world conditions has been brought home at heavy expense to many business and professional men engaged in the mineral industry4 ,,valuation ,,in ,,its ,,international ,,relations ,for mineral commodities of limited supply and steady demand1 market conditions may be more or less taken for granted1 and valuation may be based on local considerations4 ,for a large number of mineral resources1 however1 the competitive market conditions are anything but stable1 because of foreign competition4 ,it is necessary not only to know the basis for this competition1 but also to be able to follow intelligently its various changes4 ,the value of many of our mineral deposits in recent years has varied widely with changes in the foreign situation4 ,,relative ,,position ,,of ,,the ,,united ,,states ,,in ,,regard ,,to ,,supplies ,,of ,,minerals ,the ,united ,states is more nearly self-sustaining in regard to mineral commodities as a whole than any other country on the globe4 ,the following statement summarizes qualitatively our position3 #a4 ,minerals of which our exportable surplus dominates the world situation3 ,copper4 ,petroleum has belonged in this class until recently4 ,in the future imports will be required 7see #e following74 #b4 ,minerals of which our exportable surplus constitutes an important but not a dominant factor in the world trade3 ,cement4 ,coal4 ,iron and steel4 ,phosphates4 ,silver4 ,sulphur4 ,uranium and radium4 #c4 ,minerals of which our exportable surplus is not an important factor in world trade4 ,small amounts of most of these minerals have been and will doubtless continue to be imported because of special grades1 back-haul1 or cheaper sources of foreign supply1 but these imports are for the most part not essential as a source of supply3 ,aluminum and bauxite4 ,arsenic4 ,artificial abrasives and emery 7except ,naxos emery74 ,asphalt and bitumen4 ,barite4 ,bismuth4 ,borax4 ,bromine4 ,building stone 7except ,italian marble74 ,cadmium4 ,feldspar4 ,fluorspar4 ,fuller's earth4 ,gold4 ,gypsum4 ,lead4 ,lime4 ,magnesite4 ,mineral paints 7except umber1 sienna1 and ocher from ,france and ,spain74 ,molybdenum4 ,pyrite4 ,salt 7except special classes74 ,talc4 ,titanium4 ,tripoli and diatomaceous earth4 ,zinc4 #d4 ,minerals for which the ,united ,states must depend almost entirely on other countries3 ,cobalt4 ,nickel4 ,platinum and metals of the platinum group4 ,tin4 #e4 ,minerals for which the ,united ,states will depend on foreign sources for a considerable fraction of the supply3 ,antimony4 ,asbestos4 ,ball clay and kaolin4 ,chalk4 ,chromite4 ,corundum4 ,diamond dust and bort4 ,garnet4 ,graphite4 ,grinding pebbles4 ,manganese4 ,mercury4 ,mica4 ,monazite4 ,naxos emery4 ,nitrates4 ,petroleum 7see below74 ,potash4 ,precious stones4 ,pumice4 ,tungsten4 ,vanadium4 ,zirconium4 ,in the past the production of petroleum in the ,united ,states has dominated the world petroleum situation2 but domestic consumption has now overtaken production1 and unless discoveries of oil come along at a rapid rate the domestic deficiency seems likely to increase1 with corresponding increase in our dependence on foreign sources 7see pp4 #abh-acb74 ,some of the minerals of this last class1 such as potash1 manganese1 and chromite were developed under war conditions in the ,united ,states to such an extent as to materially lessen the demand for importation2 but in normal times domestic sources can supply a considerable fraction of the demand only at high cost and with the aid of a protective tariff4 ,no attempt will be made here to present the detailed figures on which the above generalizations are based4 ,in view of the present disturbed conditions of production and consumption1 any judgment as to future demands or available surplus must take into account several factors which cannot be accurately measured1--such as financial control in foreign countries1 possible tariffs1 and foreign competition4 ,for this reason the above statement should be regarded as only tentative1 though it is the result of a rather exhaustive study of conditions in relation to the world control of shipping4 ,the classes named overlap to some extent1 and it is to be expected that some of the commodities placed in one class may in the near future be transferred to another4 ,in terms of value1 the ,united ,states has a potential export surplus of minerals about twice as large as that of all the rest of the world put together4 ,countries which were neutral during the war have the remaining export surplus4 ,great ,britain1 ,france1 and ,italy have net import requirements considerably in excess of their exports4 ,germany has almost as large a deficit of minerals as the ,united ,states has a surplus4 ,from the above facts it is clear that1 in any scheme of international control or cooperation1 the ,united ,states would have by far the heaviest stake1 and perhaps the most to lose by restriction4 ,it seems equally clear that the preponderance of exportable surplus of minerals over necessary imports justifies the ,united ,states in taking a broad and liberal view of the importation of needed minerals4 ,the war-time necessity of making our country as nearly self-sustaining as possible does not seem to obtain in peace times4 ,to carry that principle to an extreme means not only the expensive use of low-grade domestic supplies1 but the elimination of the imports which are so necessary to balance our export trade4 ,these facts also raise the question as to how far the ,united ,states is justified in exploiting the rest of the world to add to its already great preponderance of control1--as1 for instance1 in copper4 ,any further aggrandizement of our position in regard to such minerals may be directly at the expense of neighbors who are already far less well supplied than ourselves1 and is to be justified only on the basis of adding to the world's supply for common use1 and of lending our expert assistance to neighbors to make them more nearly self-supporting4 ,to carry out our campaign in these cases without regard to the needs of other countries will obviously not hasten the ideal of a democratic world with equal opportunity for all4 ,on the other hand1 the great freedom allowed by our laws in regard to foreign commercial control of our minerals1 as compared to the restriction on such control in other countries1 suggests the desirability of exerting our pressure for the open door policy in all parts of the world1 in the interest of desirable reciprocal relations4 ,in this connection there has been a tendency to criticise ,england's post-war activity in securing oil reserves for the future4 ,self-interest has clearly dictated the necessity for improving ,england's weak position in regard to this vital energy resource4 ,the success of this movement obviously means a lessening of the future preponderance of the ,united ,states in the oil industry1 and calls for increased activity on the part of the ,united ,states in maintaining the desirable leading position it has long held4 ,from the writer's viewpoint1 however1 the fair success of a rival does not call for criticism of motives4 ,if there is any just criticism1 it applies to methods 7see pp4 #cij-cia74 ,whatever action may be taken by the ,united ,states in regard to international mineral questions1 it is clear that the war has brought this country into such world relations that it has become imperative for us to study and understand the world mineral situation much more comprehensively than before1--in the interest not only of intelligent management of our own industries1 but of far-sighted handling of international relations4 ,under the stress of war the government1 especially through the ,geological ,survey1 the ,bureau of ,mines1 and the several war boards1 found it necessary to use extraordinary efforts to obtain even elementary information on the international features of mineral trade4 ,much progress has been made1 but only a start4 ,the geologist or engineer who fails to follow these investigations may be caught napping in the economic phases of his work4 ,,the ,,coal ,,and ,,iron ,,situation ,,of ,,western ,,europe ,,under ,,the ,,terms ,,of ,,the ,,peace ,,treaty ,a mineral problem of special international importance at the present time relates to the disposition of the coal and iron resources of ,germany4 ,germany's coal and iron have been the basis for its commanding position in industry and commerce4 ,in fact1 its development of these resources has been probably the most vital element in the ,european economic situation4 ,the terms of the ,peace ,treaty in regard to these commodities have far-reaching consequences1 not only for ,germany but for all ,europe1 and indirectly1 for the world4 ,germany 7,westphalia7 outclasses all other ,european sources in grades of metallurgical coal1 in quantities produced1 and in cheapness of production4 ,both ,france and ,belgium must continue to be dependent on this source for important parts of the coking coal for metallurgical purposes1 notwithstanding ,france's acquisition of the ,saar ,basin1 which produces mainly non-coking coal1 and the development of new reserves in ,belgium4 ,germany's command of coal is wrecked in several ways4 ,the ,french take over full and absolute possession of the coal of the ,saar ,basin1 though ,germany has the right to repurchase it at the end of fifteen years1 in case this territory then elects for union with ,germany4 ,the coal of ,upper ,silesia1 with a production of about #bc per cent of the total of all ,german hard coal1 is to be ceded to ,poland1 subject1 however1 to plebiscite4 ,germany undertakes to deliver to ,france each year1 for not to exceed ten years1 an amount of coal equal to the difference between the annual pre-war production of the ,french coal mines destroyed as a result of the war1 and the production of the mines of the same area during the years in question1--such delivery not to exceed #bj1jjj1jjj tons in any one year of the first five1 nor #h1jjj1jjj in any one year of the succeeding five years4 ,in addition1 ,germany agrees to deliver coal1 or its equivalent in coke1 as follows3 to ,france #g1jjj1jjj tons annually for ten years2 to ,belgium #h1jjj1jjj tons annually for ten years2 to ,italy an annual quantity rising by annual increments from #d1ejj1jjj tons in #aiai-bj to #h1ejj1jjj tons in each of the six years #aibc-bd to #aibh-bi2 and to ,luxemburg1 if required1 a quantity of coal equal to the pre-war annual consumption of ,german coal in ,luxemburg4 ,the total pre-war coal production of ,germany in #aiac was #aia1ejj1jjj tons4 ,the diminution of production due to loss of territory in ,alsace-,lorraine1 in the ,saar ,basin1 and in ,upper ,silesia amounts to about #fa1jjj1jjj tons4 ,the further required annual distribution of coal to ,france1 ,italy1 ,belgium1 and ,luxemburg amounts to about #dj1jjj1jjj tons4 ,this leaves about #ij1jjj1jjj tons for ,germany's domestic use1 as compared with a pre-war domestic use of #aci1jjj1jjj tons4 ,even then1 these calculations make no allowance for coal to be used in export trade to neutrals or other countries1 some part of which seems vital to ,germany's trade4 ,they make no allowance for the deterioration of plant and machinery in the mines1 which will delay resumption of coal production4 ,they make no allowance for the diminution in working hours and the lack of transportation4 ,in short1 unless there is a miraculous recovery and development of ,germany's coal industry1 impossible conditions have been imposed4 ,some recognition of this fact appears in the great powers to adjust terms which have been vested in the ,reparations ,committee4 ,successive revisions of requirements by the ,reparations ,committee have already reduced the direct contributions of coal from ,germany nearly fifty per cent4 ,the entire ,european coal situation is in a state of chaos4 ,it was found necessary in #aiah to appoint a ,coal ,commission under international control1 to attempt to allocate and distribute supplies4 ,it seems inevitable that the physical facts of the situation will prevail1 and that the control of the ,allies will resolve itself into efforts to distribute and coordinate supplies so as to keep the ,european machinery going1 more or less regardless of the terms of the ,peace ,treaty4 ,one of the important outcomes of this situation has been the recent rapid development of ,german lignite production1 based on newly worked-out methods of treatment and utilization4 ,by taking over ,alsace-,lorraine1 ,france acquires about #gj per cent of the iron ore reserves and annual production of ,germany4 ,this production was in minor part smelted locally1--the larger part moving down the ,rhine to the vicinity of the ,ruhr coal fields1 and ,ruhr coal coming back for the smelting in ,lorraine4 ,this great channel of balanced exchange of commodities has been determined by nature1 and is not likely to be permanently affected by political changes4 ,for the time being1 however1 the drawing of a political boundary across this trade route hinders the full resumption of the trade4 ,self-interest will require both ,germany and ,france to keep these routes open4 ,france requires ,german coal to supply the local smelters near the iron fields1 and ,german markets for the excess production of iron ore4 ,on the other hand1 ,germany's great smelting district in the ,ruhr ,basin is largely dependent on the ,lorraine iron ore1 and the movement of this iron ore requires coal from down the ,rhine as a balance4 ,the intelligent handling of this great coal and iron problem is of far-reaching consequence to the mineral industries of the world4 ,,conclusion ,in the foregoing discussion it is not our purpose to argue for any specific national or international plan or procedure1 but rather to show something of the nature of the problem1--and particularly to show that intelligent and broadened self-interest requires a definite national policy in regard to world mineral questions4 ,realization of this fact is a long step toward the solution of the international problems4 ,no geologist1 engineer1 or business man is safe1 in the normal conduct of his affairs1 without some attention to these matters4 ,it is our purpose further to bring home the fact that international cooperation in the mineral field is not merely an academic possibility1 but that in many important ways it is actually in existence4 ,the terms of the ,peace ,treaty alone have far-reaching consequences to the explorer or mining man in all parts of the world4 ,the modifications of these terms1 which are inevitable in the future1 will not be of less consequence4 ,it is necessary not only to know what these are1 but to aid in their intelligent formulation4 ,,literature ,a vast new literature on the subject of international mineral relations has sprung into existence during and following the war1 and anyone may easily familiarize himself with the essentials of the situation4 ,some of the international features are noted in the discussion of mineral resources in this book4 ,for fuller discussion1 the reader is especially referred to the following sources3 ,the reports of the ,united ,states ,geological ,survey4 ,note especially ,world ,atlas of ,commercial ,geology1 #aiba4 ,the reports of the ,united ,states ,bureau of ,mines4 ,political and commercial geology1 edited by ,j4 ,e4 ,spurr1 ,mc,graw-,hill ,book ,co41 ,new ,york1 #aibj4 ,strategy of minerals1 edited by ,george ,otis ,smith1 ,d4 ,appleton and ,co41 ,new ,york1 #aiai4 ,coal1 iron and war1 by ,e4 ,c4 ,eckel1 ,henry ,holt and ,company1 ,new ,york1 #aibj4 ,the iron and associated industries of ,lorraine1 the ,sarre district1 ,luxemburg1 and ,belgium1 by ,alfred ,h4 ,brooks and ,morris ,f4 ,la,croix1 ,bull4 #gjc ,u4 ,s4 ,geological ,survey1 #aibj4 ,the ,lorraine iron field and the war1 by ,alfred ,h4 ,brooks1 ,eng4 and ,min4 ,journ41 vol4 #aji1 #aibj1 pp4 #ajfe-ajfi4 ,munitions ,resources ,commission of ,canada1 final report1 #aibj4 ,,footnotes3 #eh ,umpleby1 ,joseph ,b41 ,strategy of minerals--,the position of the ,united ,states among the nations3 ,d4 ,appleton and ,co41 ,new ,york1 #aiai1 p4 #bhf4 #ei ,control is here used in a very general sense to cover activities ranging from regulation to management and ownership4 ,the context will indicate in most cases that the word is used in the sense of regulation when referring to governmental relationships4 ,,chapter ,,xix ,,geology ,,and ,,war ,,geology ,,behind ,,the ,,front ,the experience of the great war disclosed many military applications of geology4 ,the acquirement and mobilization of mineral resources for military purposes was a vital necessity4 ,in view of the many references to this application of geology in other parts of this volume1 we shall go into the subject in this chapter no further than to summarize some of the larger results4 ,as a consequence of the war-time breakdown in international commercial exchange1 the actual and potential mineral reserves of nations were more intensively studied and appraised than ever before1 with the view of making nations and belligerent groups self-sustaining4 ,this work involved a comprehensive investigation of the requirements and uses for minerals1 and thus led to a clearer understanding of the human relations of mineral resources4 ,it required also1 almost for the first time1 a recognition of the nature and magnitude of international movements of minerals1 of the underlying reasons for such movements1 and of the vital inter-relation between domestic and foreign mineral production4 ,the domestic mineral industries learned that market requirements are based on ascertainable factors and that they do not just happen4 ,large new mineral reserves were developed4 ,metallurgical practices were adapted to domestic supplies1 thus adding to available resources4 ,better ways were found to use the products4 ,some of these developments ceased at the end of the war1 but important advances had been made which were not lost4 ,one of the advances of permanent value was the increased attention to better sampling and standardization of mineral products1 as a means of competition with standardized foreign products4 ,for instance1 the organization of the ,southern ,graphite ,association made it possible to guarantee much more uniform supplies from this field1 and thereby to insure a broader and more stable market4 ,such movements allow the use of heterogeneous mineral supplies in a manner which is distinctly conservational1 both in regard to mineral reserves and to the human energy factors involved4 ,in another war the possibilities and methods of meeting requirements for war minerals will be better understood4 ,in these activities1 geologists had a not inconsiderable part4 ,the ,u4 ,s4 ,bureau of ,mines1 the ,u4 ,s4 ,geological ,survey1 state geological surveys1 and many other technical organizations1 public and private1 turned their attention to these questions4 ,one of the special developments was the organization by the ,shipping ,board of a geologic and engineering committee whose duty it was to study and recommend changes in the imports and exports of mineral commodities1 with a view to releasing much-needed ship tonnage4 ,this committee was also officially connected with the ,war ,industries ,board and the ,war ,trade ,board4 ,it utilized the existing government and state mineral organizations in collecting its information4 ,over a million tons of mineral shipping not necessary for war purposes were eliminated4 ,this work involved also a close study of the possibilities of domestic production to supply the deficiencies caused by reduction of foreign imports4 ,other special geological committees were created for a variety of war purposes4 ,in the early stages of the war a ,war ,minerals ,committee1 made up of representatives of government and state organizations and of the ,american ,institute of ,mining ,engineers1 made an excellent preliminary survey of mineral conditions4 ,a ,joint ,mineral ,information ,board#fj was created at ,washington1 composed of representatives of more than twenty government departments which were in one way or another concerned with minerals4 ,it was surprising1 even to those more or less familiar with the situation1 to find how widely mineral questions ramified through government departments4 ,for instance1 the ,department of ,agriculture had men specially engaged in relation to mineral fertilizers and arsenic4 ,sulphur and other mineral supplies were occupying the attention of the ,war ,department4 ,mica and other minerals received special attention from the ,navy ,department4 ,the ,tariff ,board1 the ,federal ,trade ,commission1 the ,commerce ,department1 even the ,department of ,state1 had men who were specializing on certain mineral questions4 ,all these departments had delegates on the ,joint ,mineral ,information ,board1 in which connection they met weekly to exchange information for the purpose of getting better coordination and less duplication4 ,the ,national ,academy of ,sciences established a geologic committee1 with representatives from the ,u4 ,s4 ,geological ,survey1 the state geological surveys1 the ,geological ,society of ,america1 and other organizations4 ,this committee did useful work in correlating geological activities1 mainly outside of ,washington1 and in cooperation with the ,war ,department kept in touch with the geologic work being done at the front4 ,while the activities of geologists for government1 state1 and private organizations were for the most part in relation to mineral resource questions1 this was by no means the total contribution4 ,the ,u4 ,s4 ,geological ,survey and other organizations1 in cooperation with the ,war ,department1 did a large amount of topographic and geologic mapping of the eastern areas for coast-defense purposes4 ,this work involved consideration of the topography for strategic purposes1 as well as the stock-taking of mineral resources--including road materials and water supplies4 ,the revision of ,geological ,survey folios1 with these requirements in mind1 brought results which should be of practical use in peace time4 ,studies were likewise made of cantonment areas1 with reference to water supplies and to surface and sub-surface conditions4 ,many geologists were engaged in the military camps at home and abroad1 and in connection with the ,student ,army ,training ,corps at the universities1 in teaching the elements of map making1 map interpretation1 water supply1 rock and soil conditions in relation to trenching1 and other phases of geology in their relation to military operations4 ,the textbook on ,military ,geology1#fa prepared in cooperation by a dozen or more geologists for use in the courses of the ,student ,army ,training ,corps1 is an admirable text on several phases of applied geology4 ,the name of the book is perhaps now unfortunate1 because most of it is quite as well adapted to peace conditions as to those of war4 ,there is no textbook of applied geology which covers certain phases of the work in a more effective and modern way4 ,the topics treated in this book are rocks1 rock weathering1 streams1 lakes and swamps1 water supply1 land forms1 map reading and map interpretation1 and economic relations and economic uses of minerals4 ,another book1#fb on land forms in ,france1 prepared from a physiographic standpoint1 was a highly useful general survey of topographic features and was widely used by officers and others4 ,,geology ,,at ,,the ,,front#fc ,perhaps the most spectacular and the best known use of geology in the war was at and near the front4 ,this use reached its earliest and highest development in the ,german army1 but later was applied effectively by the ,british and ,british ,colonial armies1 and by the ,american ,expeditionary ,force4 ,one of the first intimations to the ,american public of the use of geology at the front appeared in the publication of ,german censorship rules in #aiah1--when1 among the prohibitions1 there was one forbidding public reference to the use of earth sciences in military operations4 ,a leading ,american paper noted this item and speculated at some length editorially as to what it meant4 ,it was discovered that geologists to the number of perhaps a hundred and fifty were used by the ,germans to prepare and interpret maps of the front for the use of officers4 ,features represented on these maps included topography2 the kinds of rocks and their distribution2 their usefulness as road and cement materials2 their adaptability for trench digging1 and the kinds and shapes of trenches possible in the different rocks2 the manner in which material thrown out in trenching would lie under weathering2 the ground-water conditions1 and particularly the depth below the surface of the water table at different times of the year and in different rocks and soils2 the relation of the ground-water to possibilities of trench digging2 water supplies for drinking purposes2 the behavior of the rocks under explosives1 and the resistance of the ground to shell-penetration2 the underground geological conditions bearing on tunnelling and underground mines2 and the electrical conductivity of rocks of different types1 presumably in connection with sound-detection devices and groundings of electric circuits4 ,some of the captured ,german maps were models of applied geology4 ,they contained condensed summaries of most of the features above named1 together with appropriate sketches and sections4 ,during the ,argonne offensive by the ,american army the captured ,german lines disclosed geologic stations at frequent intervals1 each with a full equipment of maps relating to that part of the front4 ,from these stations schools of instruction had been conducted for the officers in the adjacent parts of the front4 ,the ,british efforts were along similar lines1 although they came late in the war1 under the leadership of an ,australian geologist4 ,their efforts were especially useful in connection with the large amount of tunnelling and mining done on the ,british front4 ,among the many unexpected and special uses of geology might be cited the microscopical identification of raw materials used in the ,german cement4 ,it became necessary for certain purposes to know where these came from4 ,the microscope disclosed a certain volcanic rock known to be found in only one locality4 ,in the ,palestine campaign1 the knowledge of sources of road material and water supply based on geologic data was an important element in the advance over this arid region4 ,wells were drilled and water pipes laid in accordance with prearranged plans4 ,in spite of the fact that the usefulness of geology had been clearly indicated by the experience of the ,german and ,british armies1 the ,american ,expeditionary ,force was slow to avail itself in large measure of this tool2 but after some delay a geologic service was started on somewhat similar lines under the efficient leadership of ,lieutenant-,colonel ,alfred ,h4 ,brooks1 ,director of the ,division of ,alaskan ,resources in the ,u4 ,s4 ,geological ,survey4 ,the work was organized in ,september1 #aiag1 and during the succeeding ten months included only two officers and one clerk4 ,for the last two months preceding the armistice there was an average of four geologic officers on the ,general ,staff1 in addition to geologists attached to engineering units engaged in road building and cement making1 and plans had been approved for a considerable enlargement of the geologic force4 ,the work was devoted to the collection and presentation of geologic data relating to 7#a7 field works2 7#b7 water supply2 and 7#c7 road material4 ,of these the first two received the most attention4 ,maps were prepared1 based somewhat on the ,german model1 for the ,french defenses of the ,vosges and ,lorraine sectors1 and for the ,german defenses of the ,st4 ,mihiel1 ,pont-a-,mousson1 and ,vosges sectors4 ,water supply reports covered nearly #ae1jjj square kilometers4 ,the following description of the formations1 taken from the legend of one of the geologic maps1 shows the nature of the data collected3 ,silt1 clay and mud1 with some limestone gravel1 usually more or less saturated1 except during dry season 7,june to ,september71 in many places subject to flooding4 ,surface usually soft except during ,summer4 ,these deposits are #a_/b to #b meters thick in the small valleys1 and #b to #c meters in the ---- ,valleys4 ,unfavorable to all field works on account of ground-water and floods1 and not thick enough for cave shelters4 ,silts with some clay and fine sands and locally some fine gravel and rock debris4 ,these deposits occur principally on summits and slopes1 and are probably from #a to #b meters thick4 ,even during dry season 7,june to ,september7 they retain moisture and afford rather soft ground4 ,in wet season the formation is very soft and often muddy4 ,in many places water occurs along bottom of these deposits4 ,favorable for trenches1 but which require complete revetment1 and ample provision for drainage1 not thick enough for cave shelters2 cut and cover most practical type of shelter4 ,clay at surface with clay shales below4 ,this deposit occurs in flats and is usually saturated for a depth of #a to #b-a_/b meters1 during wet season1 for most of the year the surface is soft1 but in part dries out in ,summer4 ,deep trenches usually impossible1 and even shallow trenches likely to be filled with water2 defensive works will be principally parapets revetted on both sides4 ,cave shelter construction usually impracticable1 unless means be provided for sinking through saturated surface zone into the dry ground underneath4 ,cut and cover usually the most practical type of shelter in this formation4 ,clay at surface with calcareous clay shale and some thin limestone layers below4 ,this formation occurs in low rounded hills2 surface saturated during wet weather1 but terrain permits of natural drainage1 and dries out during ,summer2 during wet season 7,october to ,may7 the surface zone is more or less saturated1 and ground may be muddy to a depth of a meter or more1 ground-water level usually within two or three meters of surface4 ,trench construction easy1 but requires complete revetment1 and ample provision for surface drainage4 ,cave shelters can be constructed in this formation where the slope is sufficient to permit of drainage tunnels4 ,the depth to ground-water level should always be determined by test shafts or bore holes in advance of dugout construction4 ,surface formation usually clay #a to #b meters in depth2 below this is soft clay shales or soft limestone4 ,surface usually fairly well drained1 and fairly hard ground4 ,in general1 favorable for trenches and locally favorable for cave shelters4 ,in some localities underground water prevents cave shelter construction4 ,the presence or absence of underground water should always be determined by test shafts or bore holes in advance of dugout construction4 ,surface formation consisting of weathered zone #a_/b to #a-a_/b meters thick1 made up of clay with limestone fragments and broken rock4 ,below is compact limestone formation4 ,the surface of this formation is usually fairly hard1 and well drained except in wettest season4 ,trenches built in it require little revetting2 very favorable for cave shelters1 but requires hard rock excavation4 ,some thin beds of clay occur in some of the limestone1 and at these a water bearing horizon will be found4 ,where a limestone formation rests on clay as near ---- a line of springs or seepages is usually found4 ,such localities should be avoided1 or the field works placed above the line of springs or seepages4 ,this formation is best developed in the plateau west of ----4 ,here it is covered by only a thin layer of soil1 hard rock being close to the surface4 ,the limestones afford the only rock within the quadrangle which can be used for road metal4 ,quarries 7in part abandoned74 ,limestone gravel pits4 ,locus of springs and seepages4 ,these should be avoided as far as possible in the location of field works1 especially of dugouts4 ,field works should be placed above the lines of springs4 ,the water supply maps with accompanying engineer field notes are models of concise description of water supply conditions1 with specific directions for procedure under different conditions4 ,a few paragraphs taken from these notes are as follows3 ,ground overlying rock1 such as limestone1 compact sandstone1 granites1 etc41 which are usually fractured1 is from the standpoint of underground water1 most favorable for siting of field works4 ,clay shales and clay hold both surface and underground water1 and are1 therefore1 unfavorable for field works4 ,the contact between hard rocks resting on clay or clay shales is almost invariably water bearing1 and should be avoided in locating field works4 ,at localities where impervious formations 7clay1 etc47 occur at or near the surface1 they hold the water and form a superficial zone of saturation4 ,this condition makes trench construction and maintenance difficult1 and cave shelters can usually only be made by providing means of sinking through the saturated zone4 ,the surface saturated zone often dries out in summer4 ,in pervious1 or almost pervious rocks1 the zone of saturation1 or ground-water level1 lies at much lower depth1 and may permit of the construction of field works as well as cave shelters above it4 ,underground water bearing horizons and water bearing faults should be avoided in locating field works4 ,wherever there is any uncertainty about the underground water conditions1 test shafts or bore holes should always be made in advance of the construction of extensive deep works4 ,,effect ,,of ,,the ,,war ,,on ,,the ,,science ,,of ,,economic ,,geology ,in general1 the war required an intensive application of geology along lines already pretty well established under peace conditions4 ,much was done to make the application more direct and effective1 and a vast amount of geologic information was mobilized4 ,the general result was a quickened appreciation of the possibilities of the use of geology for practical purposes4 ,perhaps the most important single result was a wider recognition of the real relations of mineral resources to human activities1 and of the international phases of the problem4 ,more specifically1 there was a most careful stock-taking of mineral resources and a consideration of the why of their commercial use4 ,many new resources were found1 as well as new ways to utilize them4 ,,footnotes3 #fj ,now known as ,economic ,liaison ,committee4 #fa ,military geology and topography1 ,herbert ,e4 ,gregory1 ,editor4 ,prepared and issued under the auspices of ,division of ,geology and ,geography1 ,national ,research ,council1 ,yale ,univ4 ,press1 ,new ,haven1 #aiah4 #fb ,davis1 ,w4 ,m41 ,handbook of ,northern ,france1 ,harvard ,univ4 ,press1 ,cambridge1 #aiah4 #fc ,for more detailed description of this subject the reader is referred to ,the use of geology on the ,western ,front1 by ,alfred ,h4 ,brooks1 ,prof4 ,paper #abh-;,d1 ,u4 ,s4 ,geol4 ,survey1 #aibj4 ,,chapter ,,xx ,,geology ,,and ,,engineering ,,construction ,economic applications of geology are by no means confined to mineral resources 7including water and soils74 ,the earth is used by the human race in many other ways4 ,human habitations and constructions rest on it and penetrate it4 ,it is the basis for transportation1 both by land and water4 ,its water powers are used4 ,in these various relations the applications of geology are too numerous to classify1 much less to describe4 ,while only a few of these activities have in the past required the participation of geologists1 the growing size of the operations and increasing efficiency in their planning and execution are multiplying the calls for geologic advice4 ,the nature of such applications of geology may be briefly indicated4#fd ,,foundations ,the foundations of modern structures such as heavy buildings1 especially in untried localities1 require much more careful consideration of the substrata than was necessary for lighter structures4 ,in planning such foundations1 it is necessary to know the kinds of rocks to be excavated1 their supporting strength1 their structures1 the difficulties which are likely to be caused by water1 and other geologic features4 ,failure to give proper attention to these factors has led to some disastrous results4 ,the planning of foundations and abutments of bridges requires similar geologic knowledge4 ,in addition1 there must be considered certain physiographic factors affecting the nature and variation of stream flow and the migration of shore lines4 ,,surface ,,waters ,construction of great modern dams is preceded by a careful analysis of sub-surface conditions1 in regard to both the rocks and the water4 ,it is necessary to know the supporting strength of the rocks in relation to the weight of the dam2 to know whether the rocks will allow leakage around or beneath the dam2 and to know whether there are any zones of weakness in the rocks which will allow shearing of foundations under the weight of the dam in combination with the pressure of the ponded water4 ,it is necessary to know whether the valley is a rock valley or whether it is partially filled with rock debris2 if the latter1 how deep this debris is1 and its behavior under load and in a saturated condition4 ,here again physiographic factors are of vital importance1 both in relation to the history of development of the valley1 and to questions of stream flow and reservoir storage4#fe ,construction of dams is only an item in the long list of engineering activities related to surface waters4 ,river and harbor improvements of a vast range likewise involve geologic factors4 ,problems of wave action1 shore currents1 shifting of shores1 erosion1 and sedimentation1 which are of great importance in such operations1 have long occupied the attention of the geologist4 ,they belong especially in the branch of the science known as physiography4 ,geology in relation to underground water supplies is discussed in ,chapter ,v4 ,,tunnels ,the digging of tunnels for transportation purposes1 for aqueducts1 and for sewage disposal requires careful analysis of geologic conditions in regard to both the rocks and the underground water4 ,knowledge of these conditions is necessary in planning the work1 in inviting bids1 and in making bids4 ,it is necessary during the progress of the work4 ,too often in the past disastrous consequences1 both physical and financial1 have resulted from lack of consideration of elemental geologic conditions4 ,the building of the great ,new ,york aqueducts and subways through highly complex crystalline rocks has been under the closest geological advice and supervision4 ,the detailed study of the geology of ,manhattan ,island through a long series of years has resulted in an understanding of the rocks and their structures which has been of great practical use4 ,in the aqueduct construction the kinds of rock to be encountered in the different sections1 their water content1 their hardness1 their joints and faults1 were all platted and planned for1 and actual excavation proved the accuracy of the forecasts4 ,an interesting phase of this work was the tunneling under the ,hudson at points where the pre-glacial rock channel was buried to a depth of nearly a thousand feet by glacial and river deposits1--this work requiring a close study of the physiographic history of the river4 ,,slides ,slides of earth and rock materials1 both of the creeping and sudden types1 have often been regarded as acts of ,providence1--but studies of the geologic factors have in many cases disclosed preventable causes4 ,a considerable geologic literature has sprung up with reference to rock slides1 which is of practical use in excavation work of many kinds4 ,the cause of such movements is gravity4 ,the softer1 unconsolidated rock materials yield of course more readily than the harder ones1 but even strong rocks are often unable to withstand the pull of gravity4 ,the relative weakness of rock masses on a large scale was graphically shown by ,chamberlin and ,salisbury1#ff in a calculation indicating that a mass of average hard rock a mile thick1 domed to the curvature of the earth1 can support a layer of only about ten feet of its own material4 ,the structural geologist1 through his study of folds1 faults1 and rock flowage1 comes to regard rocks essentially as failing structures4 ,disturbances of equilibrium1 resulting in rock movements under gravity1 may be caused by local loading1 either natural or artificial4 ,natural loading may be due to unusual rainfall1 or raising of water level1 or increased barometric pressure4 ,artificial loading may come from construction of heavy buildings or dams4 ,movement may also result from excavation1 which takes away lateral support--and such excavation again may be caused by natural processes of erosion or by artificial processes involved in construction4 ,movement may be caused by mere change in the moisture content of rocks1 or by alterations of their mineral and chemical character1 affecting their resistance to gravity4 ,in still other cases1 earthquakes are the initiating cause of movement4 ,in unconsolidated rocks1 a frequent cause of movement is the presence of wet and slippery clay layers4 ,the identification and draining of these clay layers may eliminate this cause4 ,in certain sands1 on the other hand1 water may actually act as a cement and tend to increase the strength of the rock4 ,planes of weakness in the rock1 such as bedding1 joints1 and cleavage1 are also likely to localize movement4 ,earth materials1 and even fairly hard rocks1 may creep under gravity at an astonishingly low angle4 ,the angle from the horizontal at which loose material will stand on a horizontal base without sliding is called the angle of rest or repose4 ,it is often between #cj deg4 and #ce deg41 but there is wide variation from this figure1 depending on the shapes and sizes of the particles and on other conditions4 ,it has been suggested that even the slight differences in elevation of continents and sea bottoms may1 during long geologic eras1 have caused a creep of continental masses in a seaward direction4 ,in problems relating to slides1 the geologist is concerned in determining the kinds of rocks1 their space relations1 their structures and textures1 their metamorphic changes1 their water content and the nature of the water movement1 their strength1 both under tension and compression1 and other factors4 ,in the digging of the ,panama ,canal1 a geological staff was employed in the study of the rock and earth formations to be met4 ,however1 had more attention been paid to geologic questions in the planning stages1 this great undertaking1 so thoroughly worked out from a purely engineering standpoint1 would have avoided certain mistakes due to lack of understanding of the geological conditions4 ,it is a curious fact that in these early stages no strength tests of rocks were made1 and that no thorough detailed study was made of the geologic factors affecting slides and their prevention4 ,it was only after the slides had become serious that the geological aspects of the subject were intensively considered4 ,the results of the geologic study1 therefore1 are useful only for preventive measures for the future and for other undertakings4 ,one of the interesting features of this investigation was the discovery that certain soft rock formations were rendered weaker rather than stronger by the draining off of the water4 ,it had been more or less assumed that the water had acted as a lubricant rather than as a cement4 ,,subsidence ,not the least important application of geology to slides is in relation to deep mining operations4 ,while the mining geologist has been principally engaged in exploration and development of ores1 he is now beginning to be called in to interpret the great earth movements caused by the sinking of the ground over mining openings4 ,for instance1 the long-wall method of coal mining has resulted in a slow progressive subsidence of the overlying rock1 affecting overlying mineral beds and surface structures over great areas4 ,detailed studies have been made of this movement1 in order to ascertain its relation to the strength and structure of the rocks1 its relation to the nature of the excavation1 its speed of transmission1 and the possible methods of prevention4 ,german scientists have perhaps gone further with this kind of study than anyone else4 ,in an elaborate investigation of subsidence over a coal mine in ,illinois1#fg unusually complete data were obtained as to the nature1 direction1 and speed of the transmission of strains through large rock masses1 and as to their effect in producing secondary rock structures4 ,,railway ,,building ,in railway building1 the planning and estimation of cuts and fills is now receiving geologic consideration1 in order to make sure that no geologic condition has been overlooked which will affect costs1 the stability of the road1 or the accurate formulation of contracts4 ,the location of best sources of supply for ballast is also a geologic problem 7see pp4 #ij-ia74 ,the physiographic phases of geology also are finding important applications to railroad building4 ,the physiographer studies the surface forms with a trained eye1 which sees them not as lawless or heterogeneous units but as parts of a topographic system1 and he is able to eliminate much unnecessary work in the location of trial routes4 ,further study of some of the older railroads from this standpoint has led to considerable improvements4 ,physiographic study has also been applied to railway bridge construction1 in the appraisal of the difficulties in surmounting stream barriers4 ,a still broader use of physiography or geography1 not popularly understood1 is illustrated in the case of certain transcontinental railroads1 in the study of the probable future development of the territory to be served--many features of which can be predicted with some accuracy from a study of the rocks1 soils1 topography1 conditions of transportation1 and natural conditions favoring localization of cities4 ,the location of new towns in some cases has been based on this kind of preliminary study4 ,in locating an ,alaskan railway close to the end of a momentarily quiescent glacier1 troubles were not long in appearing1 due to the fact that the glacier was really not as stable as it seemed to the layman4 ,a specialist on glaciers1 knowing their behavior1 their relations to precipitation1 their relations to earthquakes1 the speed of their movement1 and the periodicity of their movement1 was ultimately called into consultation on the location of the railroad4 ,,road ,,building ,road building in recent years has become a stupendous engineering undertaking1 which is requiring geologic aid to locate nearby sources of supply for road materials4 ,a considerable number of geologists are now devoting their attention to this work4 ,it relates not only to the hard-rock geology but to the gravel and surface geology4 ,certain northern states are using specialists in glacial geology to aid in locating proper supplies of sand and gravel4 ,,geology ,,in ,,engineering ,,courses ,many engineering courses include elementary geologic studies1 in recognition of the close relationship between geology and engineering4 ,men so trained1 though not geologists1 have been responsible for many applications of geology to engineering4 ,with the increasing size and importance of operations1 calling for more specialization1 the professional geologist is now being called in to a larger extent than formerly4 ,a logical trend also is the acquirement of more engineering training on the part of the geologist1 for the purpose of pursuing these applications of his science4 ,,footnotes3 #fd ,excellent texts on this subject may be found in ,military ,geology and ,topography1 ,herbert ,e4 ,gregory1 ,editor1 prepared and issued under the auspices of ,division of ,geology and ,geography1 ,national ,research ,council1 ,yale ,univ4 ,press1 ,new ,haven1 #aiah1 and ,engineering ,geology1 by ,h4 ,ries and ,t4 ,l4 ,watson1 ,wiley and ,sons1 ,new ,york1 #b;d ed41 #aiae4 #fe ,atwood1 ,w4 ,w41 ,relation of landslides and glacial deposits to reservoir sites in the ,san ,juan mountains1 ,colorado3 ,bull4 #fhe1 ,u4 ,s4 ,geol4 ,survey1 #aiah4 #ff ,chamberlin1 ,t4 ,c41 and ,salisbury1 ,r4 ,d41 ,geology1 vol4 #a1 #aijd1 pp4 #eee-eef4 #fg ,schultz1 ,robert ,s41 ,jr41 ,bull4 ,am4 ,inst4 ,mining and ,metallurgical ,engrs4 ,in preparation4 ,,chapter ,,xxi ,,the ,,training1 ,,opportunities1 ,,and ,,ethics ,,of ,,the ,,economic ,,geologist ,economic geology is now an established and well-recognized profession1 but there is yet nothing approaching a standardized course of study leading to a degree in economic geology4 ,there are as many different kinds of training as there are institutions in which geology is taught4 ,within an institution1 also1 it is seldom that any two persons take exactly the same groups of geologic studies4 ,this situation allows wide latitude of training to meet ever changing requirements1 but in other respects it is not so desirable4 ,,pure ,,versus ,,applied ,,science ,in no institution are all the applied branches of geology taught4 ,there is constant pressure for the introduction of more applied courses2 this seems to be the tendency of the times4 ,the economic geologist1 fresh from vivid experiences in his special field1 is often insistent that a new course be introduced to cover his particular specialty4 ,any attempt1 however1 to put into a college course a considerable fraction of the applied phases of geology would mean the crowding out of more essential basic studies4 ,to yield wholly to such pressure would in fact soon develop an impossible situation2 for1 on the basis of time alone1 it would be quite impossible to give courses on all of the applied subjects in a training period of reasonable length4 ,on the other hand1 the failure to introduce a fair proportion of applied geology1 on the ground that the function of the college is to teach pure science and that in some way economic applications are non-scientific1 seems to the writer an equally objectionable procedure1--because it does not take into account the unavoidable human relations of the science1 which vivify and give point and direction to scientific work4 ,the development of science in economic directions does not necessarily mean incursion into less scientific or non-scientific fields4 ,it is true that many of the economic applications of geology are so new and so constantly changing that they are not yet fully organized on a scientific basis2 but this fact is merely an indication of the lag of science1 and not of the absence of possibilities of developing science in such directions4 ,there is today a considerable tendency among geologists of an academic type1 whose lives have been spent in purely scientific investigation and teaching1 to assume that anything different from the field of their activities is in some manner non-scientific1 and therefore less worthy4 ,many economic geologists have been made to feel this criticism1 even though seldom expressed openly4 ,for the good of geologic science1 this tendency seems to the writer extremely unfortunate4 ,the young man entering the field of economic geology should be made to understand that his is the highest scientific opportunity2 and that if parts of his field are not yet fully organized1 the greater is his own opportunity to participate in the constructive work to be done4 ,under war requirements many geologists were called upon to extend their efforts to bordering fields of endeavor4 ,in some quarters these activities were regarded as non-scientific1 and as subtracting from efficiency in purely geological work1--and yet out of this combined effort came a wider comprehension of new scientific fields1 between the established sciences and between sciences and human needs4 ,it is inevitable that in the future these fields1 now imperfectly charted1 will be occupied and developed1 perhaps not by the men who are already well established in their particular fields of endeavor1 but by coming scientists4 ,in this light1 it was a privilege for geologists to participate in the discovery and charting activities of the war4 ,still another attempt to discriminate between scientific and non-scientific phases of geologic effort has been the assumption by certain scientific organizations with reference to standards of admission1--that work done for practical purposes may be regarded as scientific only if it leads to advancement of the science through the publication of the results4 ,there is by no means any general agreement as to the validity of this distinction4 ,on this basis1 some of the most effective scientific work which is translated directly into use for the benefit of civilization is ruled out as science1 because it is expressed on a typewritten rather than on a printed page4 ,while applied phases of the geologist's work may be truly scientific in the broader sense1 it is undoubtedly easy in this field to drift into empirical methods1 and to emphasize facility and skill at the expense of original scientific thought4 ,the practice of geology then becomes an art rather than a science4 ,this remark is pertinent also to much of non-applied geologic work in recent years4 ,a considerable proportion of this empirical facility is desirable and necessary in the routine collection of data and in their description2 but where1 as is often the case1 the geologist's absorption in such work minimizes the use of his constructive faculties1 it does not aid greatly in the advancement of science4 ,geology is by no means the only science in which there has been controversy as to the relative merits of the so-called pure and applied phases2 but as one of the youngest sciences1 which heretofore has been pursued mainly from the standpoint of pure science1 it is now1 perhaps more than any other science1 in the transition stage to a wider viewpoint4 ,in the past there was doubt about the extension of chemistry toward the fields of physics and engineering1 and of physics toward the fields of chemistry and engineering1 and of both physics and chemistry toward purely economic applications2 but out of these fields have grown the great sciences of physical chemistry1 chemical engineering1 and others1--and few would be rash enough to attempt to draw a line between the pure and applied science1 or between the scientific and non-scientific phases of this work4 ,this general tendency means a broadening of science and not its deterioration4 ,,course ,,of ,,study ,,suggested ,there are almost as many opinions on desirable training for economic geology as there are geologists1 and the writer's view cannot be taken as representing any widely accepted standard4 ,on the basis of his own experience1 however1 both in teaching and in field practice1 he would lay emphasis on the fundamental branches both of geology and of the allied sciences1--general geology1 stratigraphy1 paleontology1 physiography1 sedimentation1 mineralogy1 petrology1 structural and metamorphic geology1 physics1 chemistry1 mathematics1 and biology4 ,after these are covered1 as much attention should be given to economic applications as time permits4 ,the time allowance for training1 at a maximum1 is not sufficient to cover both pure and applied science4 ,subsequent experience will supply the deficiencies in applied knowledge1 but will not make up for lack of study of basic principles4 ,it is safe advice to a student wishing to prepare for economic geology that there is no royal road to success2 that his best chance lies in the effort to make himself a scientist1 even though he cover only a narrow field2 that if he is successful in this1 opportunities for economic applications will almost inevitably follow4 ,to devote attention from the start merely to practical and commercial features1 rather than to scientific principles1 brings the student at once into competition with mining engineers1 business men1 accountants1 and others1 who are often able to handle the purely empirical features of an economic or practical kind better than the geologist4 ,in the long run the economic geologist succeeds because he knows the fundamentals of his science1 and not because he has mere facility in the empirical economic phases of his work4 ,of course there are exceptions to this statement1--there are men with a highly developed business sense who are successful in spite of inadequate scientific training1 but such success should be regarded as a business and not a professional success4 ,geology is sometimes described as the application of other sciences to the earth4 ,this statement might be made even broader1 and geology described as the application of all knowledge to the earth4 ,in the writer's experience1 the best results on the whole have been obtained from students who1 before entering geology1 have had a broad general education or have followed intensively some other line of study4 ,whether this study has been the ancient languages1 law1 engineering1 economics1 or other sciences1 the results have usually been good if the early training has been sound4 ,to start in geology without some such background1 and without the resulting power of a well-trained mind1 is to start with a handicap in the long race to the highest professional success4 ,it follows1 then1 that intensive study of geology should in most cases not begin until late in the undergraduate course1 and preferably not until the graduate years4 ,two or three years of graduate work may then suffice to launch the geologist on his career1 but so great is the field1 and so rapid the growth of knowledge within it1 that there is no termination to his study4 ,it is not enough to settle back comfortably on empirical practice based solely on previously acquired knowledge4 ,each problem develops new scientific aspects4 ,it is this ever renewing interest which is one of the great charms of the science4 ,however1 whether the student has a general training in geology1 a specialized knowledge of certain branches1 or takes it up incidentally in connection with engineering and other sciences1 he will find opportunities for economic applications4 ,the frequent success of the mining engineer in the geological phases of his work is an indication that even a comparatively small amount of geological knowledge is useful4 ,the writer is inclined to emphasize also the desirability of what might be called the quantitative approach to the subject1--that is1 of training in mathematics and laboratory practice1 which gives the student facility in treating geologic problems concretely and in quantitative terms4 ,geology is passing from the descriptive and qualitative stages to a more precise basis4 ,for this reason the combination of geology with engineering often proves a desirable one4 ,it is not uncommon for the student trained solely in the humanities and other non-quantitative subjects to have difficulty in acquiring habits of mind which lead to sufficient precision in the application of his science4 ,he may have a good grasp of general principles and be able to express himself well1 but he is handicapped in securing definite results4 ,this does not necessarily mean that a large amount of time should be given to study of quantitative methods2 exact habit of mind is more important in the early stages than expert facility with methods4 ,the teacher of economic geology finds his data so voluminous that it is difficult to present all the essential facts and yet leave sufficient time for discussion of general principles or for drill in their constructive application4 ,it is difficult to lay down any rule as a guide to the proper division of effort2 but from the writer's point of view1 it is a mistake to attempt to crowd into a course too many facts4 ,at best they cannot all be given2 and in the attempt to do so1 the student is brought into a passive and receptive attitude1 requiring maximum use of his memory and minimum use of his reasoning power4 ,presentation of a few fundamental facts1 combined with vigorous discussion tending to develop the student's ability to use these facts1 and particularly tending to develop a constructive habit of investigation1 seems to be the most profitable use of time during the course of training4 ,the acquirement of facts and details will come fast enough in actual practice4 ,the variety1 amount1 and complexity of the data available in geology tend in themselves toward generalizations in teaching--toward the deductive rather than the inductive method4 ,a certain amount of generalization is desirable1 but its over-emphasis develops bad habits of mind on the part of the student1 and requires radical readjustment of his ideas in subsequent field investigations4 ,to retain a proper emphasis on inductive methods1 it is necessary to limit the amount of data presented4 ,good results have been obtained by using the case system1 now common in the teaching of law--that is1 by starting with a specific fact or situation as a basis for developing principles4 ,another advantage in the restriction of data is the opportunity thus afforded for spending more time in the study of original reports rather than of the short textbook summaries4 ,the student thus learns where the best primary sources of information are1 how to find them1 and how to extract essentials from them4 ,,field ,,work ,field work is an essential part of any course of geologic training4 ,not only should it be taken at every opportunity during the regular school year1 but no summer should be allowed to pass without geologic practice in the field4 ,opportunities for such work are offered in the summer field courses given by various institutions4 ,in recent years it has usually been possible1 also1 for the student with elementary training to take part in summer geological survey work for state1 national1 or private organizations4 ,in fact1 after two or three years of geologic training1 it is comparatively easy for the student to earn at such intervals during the year a fair fraction of his year's expenses4 ,the ideal arrangement1 from the writer's viewpoint1 would be about an equal division of time between indoor and outdoor study4 ,the alternation from one to the other supplies a much needed corrective to clear thinking4 ,it is impossible to bring all the subject materials into the classroom and laboratory2 such study must inevitably be more or less deductive and generalized4 ,if the student at frequent intervals is not able to acquire and renew a mental picture of field conditions1 there is likely to be a faulty perspective even in regard to principles1 and a considerable gap between the theoretical and applied phases of his knowledge4 ,it may be possible in the classroom1 for instance1 to discuss faults in great detail with the aid of maps1 diagrams1 and pictures2 and yet it is extremely difficult to get a real three-dimensional conception of the problems without actually standing on the ground4 ,,specialization ,,in ,,studies ,with the increasing size and efficiency of human operations has come an inevitable tendency to specialization4 ,where1 in the past1 the necessary geologic work might be passably done by the mining engineer1 the local superintendent or operator1 it is now being intrusted to specialists4 ,even within the more strictly engineering phases of the mining engineer's work1 there is the same tendency toward specialization2 his work is being divided up among the electrical engineers1 the mechanical engineers1 the hydraulic engineers1 and others4 ,the opportunities for geologic work1 therefore1 are distinctly in the direction of specialization4 ,the student in determining the field he shall enter needs to take this fact into account and to prepare accordingly1 but not at the sacrifice of the broad basal training4 ,only a small part of the specialization can be accomplished in college4 ,the remainder will come with experience4 ,in the future there is likely to be increasing specialization among the different educational institutions in the phases of applied geology which are taught4 ,geographic location has a good deal to do with this tendency4 ,where an institution is located near a coal or oil field1 it is likely1 as a matter of course1 to specialize to some extent in the application of geology to these resources4 ,or1 the specialization may arise from the fact that the teachers have had special training in certain phases of applied geology1 and such training naturally and properly determines the emphasis to be placed4 ,courses in engineering geology are finding a natural development in the leading engineering colleges4 ,in view of the fact that it is impossible for any one institution to cover all phases of applied geology1 because of lack of time1 and in view of the fact that even if this were attempted the results would be very unequal1 because of the varied experience of teachers or because of geographic location1 it would seem wise definitely to recognize these limitations and for each institution to play up the work it can do best4 ,with freedom of migration among universities1 a student by moving from place to place can thus secure any combination of specialized courses which best fits his requirements4 ,a ,,degree ,,of ,,economic ,,geology ,there has been some agitation in recent years for standardization of courses in economic geology1 and for the granting of a special degree in evidence of the completion of such a course4 ,the principal argument for this procedure is that it would tend to insure a better average of training and would draw a line between worthy geologists and a host of ill-trained pseudo-geologists4 ,the earth is so accessible1 and its use so varied1 that geology is handicapped perhaps more than any other science by persons who really have no valid claim to a scientific title4 ,the writer doubts whether a special degree in economic geology would go far toward improving this situation4 ,even if the courses were the same in different institutions1 the manner of treatment and the ability of the teachers would be so varied that in the future1 as in the past1 anyone inquiring into the real standing of a geologist would be likely to consider his individual training rather than the degree attached to his name4 ,there would be no guarantee that institutions not qualified to give the degree might not do so4 ,however1 the principal objection in the writer's mind to a degree of economic geology is the assumption that it is possible for anybody1 in the present stage of knowledge1 to formulate a standardized course adequate or best to meet the varied requirements4 ,considering the breadth and the variety of the field1 any such attempt at standardization would have to be highly arbitrary4 ,once established1 it would be a hindrance to the natural development of new courses to meet the ever changing requirements4 ,when1 if ever1 the science of economic geology becomes fully organized1 a standardized course may be possible4 ,in the present stage of the science1 more elasticity is required than seems to be possible in any of the courses proposed4 ,one of the purposes of the introduction of a degree of economic geology1 to separate the sheep from the goats1 may be accomplished in another way1--namely1 by the establishment and maintenance of high standards of admission and high aims on the part of the various professional societies having to do with geology and mining4 ,if this is done1 membership in such societies may be regarded as evidence of sound training and achievement4 ,to some extent this procedure may relieve the pressure on universities for uniformity of courses and degrees1 leaving them free to develop in such manner as seems best4 ,scientific organizations1 overlooking the entire field1 are in a position to take into account the greatest variety of factors of training and experience in selecting their members4 ,failure of any university course to make men eligible for such recognition will obviously react on the course in a desirable way4 ,,the ,,opportunities ,,of ,,the ,,economic ,,geologist ,it has been the aim in this book to present a general view of the fields of activity of the economic geologist2 and the list of chapter headings in itself summarizes the variety of his opportunities4 ,the rapidly increasing use of earth materials promises far greater calls for geologic aid in the future than in the past4 ,the profession is in its infancy4 ,opportunities for employment are ordinarily found in three main directions--in educational institutions1 in the federal and state geological surveys1 and in private organizations4 ,connection with the ,united ,states ,geological ,survey excludes participation in private work1 and in recent years even in teaching4 ,in the state surveys there is ordinarily more latitude in this regard4 ,in the educational institutions1 it is rather the common procedure for the instructor to secure his field practice and experience through private agencies1 or through part time connection with state surveys1--an arrangement with advantages to all concerned4 ,the educational institution secures the benefit of the field experience which it cannot afford to provide1 and is enabled to hold geologists at salaries far below their earning capacity4 ,the geologist gains by the opportunity to alternate between office and field study1 and to correct his perspective by the constant checking of theory with field conditions4 ,the combination tends to keep the clearly scientific and the applied phases in a proper relative proportion2 it minimizes the danger of drifting into purely empirical field methods on the one hand1 and of losing touch with actualities on the other4 ,geologists devoting their attention solely to field work often complain that they do not have time to digest and correlate their results1 nor to keep up with what others are doing4 ,on the other hand1 geologists without current field practice are likely to develop too strongly along subjective1 deductive1 and theoretical lines4 ,the teacher gains in freshness and force in the presentation of his subject in the classroom1 and the very effort necessary for presentation requires better analysis and coordination of his field observations4 ,the private or state organization gains in this combination by drawing on the general and varied knowledge which has necessarily been accumulated for teaching and investigative purposes4 ,temperament and circumstances will determine in which of these directions the student will turn4 ,however1 in view of the present natural tendency to be attracted by the large financial rewards in the commercial field1 it may not be out of place to emphasize the fact that these rewards are perhaps more likely to be gained through perfected training and experience in state and national surveys and in educational institutions1 than through early concentration in the commercial field4 ,in any case1 the financial side will take care of itself when sufficient knowledge and proficiency have been attained in any branch of the science4 ,the world is the geologist's laboratory2 it is the only limit to his activities4 ,the frontiers are near at hand1 both physically and intellectually4 ,there are few fields so attractive from the scientific standpoint4 ,there are few in which the successful prosecution of the science can be of so much direct benefit to civilization and can yield such large financial rewards4 ,if1 in addition1 the opportunities for travel and adventure are taken into account1 what profession promises a more interesting and useful life8 ,so far we have discussed geology as a profession4 ,it has proved its value also as a training for administrative and other public careers4 ,the profession contributes its full share of men to these activities4 ,the practice of geology deals with a wide variety of factors1 and requires the constant exercise of judgment in balancing1 correlating1 and integrating these factors in order to reach sound conclusions4 ,this objective treatment of complex situations is valuable training for the handling of human affairs4 ,,ethics ,,of ,,the ,,economic ,,geologist ,ethical questions involved in the practice of economic geology have called out much discussion1 and1 in some cases1 marked differences of opinion among men equally desirous of doing the right thing4 ,in the plain choice between right and wrong1 there is of course no difference of opinion4 ,unfortunately in many of the questions which arise the alternatives are not so clearly labeled4 ,the lure of discovery and quick returns always has1 and doubtless always will1 draw into the field large numbers of persons without sound ethical anchorage or standards4 ,fortunately1 these are not the persons in control of the mineral industries2 they are mere incidents in the great and stable business built up by legitimate demands for raw materials4 ,the view is sometimes expressed that the geologist should hold himself aloof from the business or applied phases of his profession1 because of the danger of being tainted with commercialism4 ,this argument would apply to the engineer as well as to the geologist4 ,to carry such a procedure through to its logical conclusion would mean substantially the withdrawal of scientific aid from industry1--which1 to the writer1 is hardly a debatable question4 ,circumstances are trending inevitably to the larger use of geologic science in the commercial field4 ,the problems of ethics cannot be solved by staying out4 ,the economic geologist is rather called upon to do his part in raising the standards of ethics in that part of the field in which he has influence4 ,this he can do by careful appraisal of all the conditions relating to a problem which he is asked to take up1 and by refusing to act where questionable ethical standards are apparent or suspected4 ,he must understand fully the purposes for which his report is to be used2 merely as a matter of professional self-interest1 there is no other course open to him4 ,in a field in which there is so much danger from loose ethical conceptions1 the premium on rigid honesty and nice appreciation of professional ethics is proportionately higher4 ,the extreme care taken in this matter by acknowledged leaders in the profession of economic geology should be carefully considered by the young man entering the profession4 ,there is a reason4 ,in other chapters reference is made to certain special ethical questions1 such as the use of geology in mining litigation 7pp4 #cdi-cee71 and the necessity of the geologist's recognizing his own limitations 7pp4 #ib-id71 but no attempt has been made to cover the variety of such questions that may come up4 ,it is safe to assume that no special ethical code can be made sufficiently comprehensive1 detailed1 and elastic to cover all the contingencies which are likely to be met in the practice of economic geology2 nor is it likely that any such code1 if attempted1 would be any improvement on the spirit of the ,golden ,rule4 ,simple decency and common sense in their broader implications are essential to the practice of the profession4 ,,index ,abrasives1 #bfg-bgj1 #cig ,abyssinia1 potash1 #aab ,adams1 ,frank ,d41 #cfg ,adirondacks1 ,new ,york1 graphite1 #bhb iron ores1 #afj1 #afb1 #afc1 #aga phosphate from magnetic ores1 #aje-ajf use of magnetic surveys in tracing iron rocks1 #cag ,ad valorem method of valuation of mineral deposits1 #cca-cce ,africa1 bauxite1 #bdb coal1 #aaf cobalt1 #bee copper1 #aig-aih1 #bje tin1 #bfj ,see also ,south ,africa2 ,north ,africa2 ,east ,africa2 ,west ,africa4 ,alabama1 bauxite1 #bdc1 #bde graphite1 #bha iron1 #eb-ec1 #afj1 #afb1 #afc1 #aff-afg ,alaska1 antimony1 #bdh copper1 #cf1 #da1 #dg1 #di1 #aii1 #bjj-bja gold1 #bbb1 #bbd1 #bbi silver1 #bcd tin1 #bfa1 #bfb ,algeria1 antimony1 #bdg1 #bdh gypsum1 #bhc iron1 #aef1 #afj1 #afa1 #aid petroleum1 #abh phosphates1 #ajd1 #aje1 #ajf ,see also ,north ,africa4 ,almaden1 ,spain1 mercury ores1 #bef-beg1 #bei ,alsace1 potash1 #aaa-aac ,alsace-,lorraine1 coal and iron of1 under ,peace ,treaty1 #dja-djb ,aluminum ,company of ,america1 #bdc ,aluminum ores1 #bda-bdf1 #cig ,see also ,bauxite4 ,alunite1 #ci1 #da-db1 #aab1 #aad1 #bcj ,anaconda1 ,montana1 arsenic production1 #bej ,anaconda ,copper ,mining ,company1 manufacture of phosphate1 #aje use of geology in development and exploration1 #cbf-cbg ,anamorphism1 defined1 #bg1 #eg ,anamorphism of mineral deposits1 #bf1 #eg-eh ,anhydrite1 occurrence in gypsum deposits1 #bhd-bhe ,anticlines1 occurrence of oil in1 #ada-adb1 #adg-adh ,antimonial lead1 #bdf ,antimony ores1 #bdf-bdi1 #cih ,apex law1 #cdi-cej1 #cec ,aplites1 #ce ,appalachians1 barite1 #bgd bauxite1 #bde graphite1 #bhb-bhc petroleum1 #acb1 #ace pitchblende1 #bff pyrite1 #ajh tin1 #bfb ,see also under individual states4 ,argentina1 borax1 #bge mica1 #bhf petroleum1 #abh tungsten1 #ahc ,arizona1 asbestos1 #bga1 #bgb copper1 #cc1 #ch1 #da1 #dg1 #dh1 #aih-aii1 #bjc1 #bjd-bje1 #bjh1 #cad1 #caf gold1 #bbb manganese1 #age molybdenum1 #ahf1ahg silver1 #bcd tungsten1 #ahc turquoise1 #bic ,arkansas1 bauxite1 #if1 #bdc1 #bdd-bde1 #bdf diamonds1 #bib fuller's earth1 #bgi hones1 oilstones and whetstones1 #bfi phosphates1 #aje zinc1 #bae ,arnold1 ,ralph1 #acd1 #acf1 #adi-aej ,arsenic ores1 #bdi-bea1 #cig ,artesian wells1 #gc ,asbestos1 #bgj-bgb1 #cih ,asphalt and bitumen1 #ef1 #aea-aec1 #cig ,atolia1 ,california1 tungsten ores1 #ahe ,atwood1 ,w4 ,w41 #dad ,australasia1 cement1 #hg coal1 #aaf gold1 #bbb ,australia1 antimony1 #bdg arsenic1 #bej asbestos1 #bga1 #bgb bauxite1 #bdb bismuth1 #beb coal1 #aae copper1 #aig-aih gold1 #da1 #bbb1 #bbd iron1 #aed1 #afd1 #afe lead1 #baj-baa1 #bab molybdenum1 #ahf phosphates1 #aje silver1 #bcb tin1 #bfj tungsten1 #ahc zinc1 #bad-bae1 #baf ,australia1 laws relating to ownership of mineral resources1 #cdc1 #cde ,austria1 cement1 #hg graphite1 #bhj mercury1 #bef1 #beg molybdenum1 #ahf talc1 #bii uranium and radium1 #bfd zinc1 #bad ,austria-,hungary1 barite1 #bgb coal1 #aae1 #aaf iron1 #afj1 #afa magnesite1 #aia-aic manganese1 #agd silver1 #bcb ,see also ,hungary4 ,austria-,hungary1 commercial and political control of various minerals1 #fd ,ball clay1 #he1 #cih ,bar theory of formation of thick salt beds1 #big ,baraboo1 ,wisconsin1 quartzites of1 #hb ,barite1 #bgb-bgd1 #cig ,basalt1 #ag1 #ai1 #hb1 #ij ,bauxite1 #i1 #ej1 #if1 #bda-bdf1 #cig ,bavaria1 graphite1 #bhj ,bawdwin ,mines1 ,burma1 lead and zinc1 #bji1 #bad ,beaumont ,field1 ,texas1 occurrence of oil1 #adh ,belgian ,congo1 cobalt1 #bee copper1 #bje ,belgium1 barite1 #bgb cement1 #hg coal1 #aae-aag1 #abg1 #dja flint linings1 #bfi iron1 #afj-afa lead1 #ed-ee1 #baj millstones and buhrstones1 #bfi phosphates1 #ajd zinc1 #ed-ee1 #bad ,belgium1 commercial and political control of various minerals1 #fd1 #bhj ,belle ,isle1 ,newfoundland1 iron ores1 #eb-ec1 #afj1 #aff ,bergholm1 ,carl1 #cai ,bergstrom1 ,gunnar1 #cai ,bessemer processes of steel making1 #aeh1 #afa ,bilbao1 ,spain2 iron ores1 #afj1 #agj ,billingsley1 ,paul1 and ,grimes1 ,j4 ,a41 #dd ,bingham1 ,utah1 copper and lead ores1 #cg1 #db1 #dg1 #aii1 #bjc1 #bjd1 #bjg1 #bjh1 #bab1 #cad ,birmingham1 ,alabama1 iron ores1 #afj1 #afb1 #afc1 #aff-afg ,see also ,clinton iron ores4 ,bisbee1 ,arizona1 copper ores1 #dg1 #aih1 #bjd1 #cad1 #caf ,bismuth ores1 #beb-bec1 #cig ,bitumen and asphalt1 #ef1 #aea-aec1 #cig ,black ,hills1 ,south ,dakota1 gold ores1 #bbh1 #bbi tin ores1 #bfb ,blue ground1 occurrence of diamonds in1 #bia ,bluestone1 #hd ,bohemia1 uranium and radium ores1 #bfe ,boise ,basin1 ,idaho1 monazite deposits1 #bhi ,boleo1 ,lower ,california1 copper ores1 #bja ,bolivia1 antimony1 #bdg bismuth1 #beb1 #bec borax1 #bge copper1 #bjf nitrates1 #ajc petroleum1 #abh silver1 #bcb tin1 #bfa1 #bfb-bfc tungsten1 #ahc1 #ahd ,bolivia1 commercial and political control of various minerals1 #fd ,bonne ,terre limestone1 ,missouri1 zinc ores1 #bag ,boone formation1 ,missouri1 zinc ores1 #bag ,borax1 #bgd-bgg1 #cig ,borax ,lake1 ,california1 borax deposits1 #bgf ,borneo1 diamond dust1 #bfh platinum1 #bch ,bort1 #bfg1 #bfh1 #cih ,boulder batholith1 ,montana1 ore-deposits of1 #dd ,boulder ,county1 ,colorado1 tungsten ores1 #ahd ,braden copper ores1 ,chile1 #aii ,brazil1 chromite1 #agi coal1 #aaf diamonds and diamond dust1 #bfh1 #bib graphite1 #bhj iron1 #eb-ec1 #afb1 #afe1 #afg1 #cac manganese1 #agd-age1 #agf mica1 #bhf monazite1 #bhh1 #bhi oil shales1 #aea zirconium1 #ahi-aij ,brazil1 commercial and political control of various minerals1 #fd ,briey district1 ,france1 iron ores1 #afa1 #afc vanadium1 #ahg ,brinton1 ,virginia1 arsenic ores1 #bea ,british ,coal ,commission1 #cfg ,british ,columbia1 laws relating to mineral resources1 #cdd ,british ,empire4 ,see ,great ,britain4 ,british ,guiana1 bauxite1 #bdb1 #bdc ,british ,south ,africa1 coal1 #aaf ,broken ,hill1 ,new ,south ,wales1 lead and zinc ores1 #bji1 #bab ,bromine1 #bgg-bgh1 #cig ,brooks1 ,alfred ,h41 #djd1 #djh ,brooks1 ,alfred ,h41 and ,la,croix1 ,morris ,f41 #djd ,buhrstones1 #bfi ,building stone1 #hj-hd1 #hh-ij1 #cig ,bureau of ,mines1 #djc1 #djf ,burma1 lead1 #bji1 #baj1 #bab rubies1 #bhi1 #bib silver1 #bcc tungsten1 #ahc1 #ahe zinc1 #bad1 #baf ,burrows1 ,j4 ,s41 #cfg ,butler1 ,b4 ,s41 ,loughlin1 ,g4 ,f41 and ,heikes1 ,v4 ,c41 #dd1 #ee1 #bcj ,butte1 ,montana1 arsenic in copper ores1 #bea copper ores1 #dj1 #dg1 #di1 #aih-aii1 #bja-bjc1 #bjg1 #bjh manganese ores1 #agg1 #cad silver ores1 #bcd1 #cad use of placers in locating ores1 #caf zinc ores1 #bae-baf zonal arrangement of minerals1 #db1 #dd ,cadmium ores1 #bec-bed1 #cig ,california1 antimony1 #bdh asbestos1 #bga asphalt and bitumen1 #aeb basalt1 #hb borax1 #bge1 #bgf-bgg chromite1 #agi copper1 #aii1 #bjd diatomaceous earth1 #bfi fuller's earth1 #bgi gold1 #bbb1 #bbd1 #bbg1 #bbi1 #cjh1 #caf1 #cdb granite1 #hb graphite1 #bha grinding pebbles1 #bfh magnesite1 #aia-aic manganese1 #age mercury1 #dj1 #bef1 #beg1 #bei natural gas1 #aea petroleum1 #acb1 #acc1 #ace1 #acg potash1 #aab1 #aac-aad pyrite1 #ajh serpentine1 #hc silver1 #bcd1 #cjh tourmaline1 #bic tungsten1 #ahc ,campbell1 ,j4 ,morrow1 #ahe ,campbell1 ,m4 ,r41 #aba1 #abb1 #cff ,campbell1 ,m4 ,r41 and ,parker1 ,e4 ,w41 #cfg1 #cgj-cga ,canada1 arsenic1 #bej asbestos1 #bgj-bga1 #bgb cement1 #hg chromite1 #agi coal1 #aae1 #aaf cobalt1 #bee copper1 #aig-aih corundum1 #bfh1 #bgj feldspar1 #hf fluorspar1 #aic1 #aid gold1 #bbb graphite1 #bhj-bha grindstones and pulpstones1 #bfi gypsum1 #bhc-bhd iron1 #eb-ec1 #aee1 #aef1 #afj1 #afe magnesite1 #aia-aic mica1 #bhf1 #bhg molybdenum1 #ahf natural gas1 #aea nickel1 #ahj-ahb petroleum1 #abh phosphates1 #aje1 #ajf platinum1 #bch pyrite1 #ajg-ajh salt1 #bid silver1 #bcb1 #bcd-bce talc1 #bii1 #cjj titanium1 #aij zinc1 #bad1 #bae ,canada1 laws relating to ownership to mineral resources1 #cdc use of magnetic surveys in tracing iron rocks1 #cag ,cananea1 ,sonora1 ,mexico1 copper ores1 #bjc ,cannel coal1 #abe ,cape ,colony1 ,south ,africa1 asbestos1 #bgb ,capillarity1 effect on ground-water level1 #gj effect on petroleum migration1 #adb-adc ,capital value of mineral resources1 #fd1 #cbh ,capping1 of copper ores1 #dg ,carbonado1 #bfh ,carey ,act1 classification of public lands under1 #caj ,carmel1 ,new ,york1 arsenic ores1 #bea ,casing-head gasoline1 #aci1 #aea ,caucasus region1 ,russia1 manganese ores1 #agd1 #agf ,cement1 #hf-hh1 #cig ,cementation1 mineral products resulting from1 #bd ,cementing materials1 source of1 #be ,central ,america1 cement1 #hg1 #hh silver1 #bcb ,see also ,costa ,rica1 ,guatemala1 ,panama4 ,central ,powers4 ,see ,germany1 ,austria-,hungary4 ,cerium ores1 ,see ,monazite4 ,ceylon1 graphite1 #bhj-bhc mica1 #bhf ,chalk1 #hc1 #cih ,chamberlin1 ,t4 ,c41 #bag ,chamberlin1 ,t4 ,c41 and ,salisbury1 ,r4 ,d41 #dae ,chance1 ,h4 ,m41 #cfg1 #cfh ,chert1 use for abrasives1 #bfg1 #bfh1 #bgj ,chile1 borax1 #bge1 #bgf bromine1 #bgg coal1 #aaf copper1 #aig-aii1 #bjc iron1 #aee1 #afa1 #afb1 #afd1 #aga manganese1 #agf nitrates1 #ajj1 #aja-ajd phosphates1 #aje1 #ajf potash1 #aab silver1 #bcb sulphur1 #aji-aaj ,chile1 commercial and political control of various minerals1 #fd1 #bfa ,china1 antimony1 #bdg-bdh1 #bdi arsenic1 #bej1 #bea bismuth1 #beb coal1 #aae1 #aaf1 #abg1 #aed iron1 #aed1 #afj1 #afd1 #afe1 #aga petroleum1 #abh salt1 #bid silver1 #bcb tin1 #bfj tungsten1 #ahc1 #ahd ,china1 commercial and political control of various minerals1 #fd ,chloriding for silver ores1 #cad ,chrome 7or chromite7 ores1 #agh-ahj1 #cjg1 #cfe-cff1 #cih ,clarke1 ,f4 ,w41 #ac1 #ag1 #ah ,classification of mineral deposits1 #bg-ei of mineral lands1 #cji-caa of mineral materials1 adjustment of scientific to commercial names1 #cef ,clays1 #ah1 #he1 #ia-ib1 #cih ,cle ,elum1 ,washington1 iron ores1 #eh ,cleavage1 #bf ,cleveland district1 ,england1 iron ores1 #afa ,clifton-,morenci district1 ,arizona1 copper ores1 #ch1 #aih ,climate1 as a factor in exploration1 #cae effect of in formation of bauxites1 #bdf ,clinton iron ores1 #i1 #eb-ec1 #afc1 #aff-afg1 #bah1 #cac1 #cag ,coal1 conservation of1 #cfe1 #cff-chb ,european international situation1 #aaf-aag1 #chf1 #chg1 #cic1 #djj-djc general economic and geologic features1 #ef1 #aae-abg1 #cji1 #cig reserves1 #aaf1 #cfj-cfa1 #cff-cfg ,cobalt district1 ,ontario1 arsenic1 #bea cobalt1 #bee silver ores1 #bcb1 #bcd-bce1 #cjh1 #caf use of coefficient to estimate future output1 #cbb ,cobalt ores1 #bed-bee1 #cih ,coeur d',alene district1 ,idaho1 lead-silver ores1 #ci1 #de1 #baa1 #bab-bac1 #baf1 #bcd ,coke1 #aah-aai ,colloids1 content of in clays1 #ib ,colombia1 coal1 #aaf emeralds1 #bhi1 #bic gold1 #bbb platinum1 #bch ,colombia1 commercial and political control of various minerals1 #fd ,colorado1 #cac ,colorado1 arsenic1 #bej asphalt and bitumen1 #aeb bismuth1 #bec coal1 #aag fluorspar1 #aid gold1 #bbb1 #bcj graphite1 #bha lead1 #baa1 #bab molybdenum1 #ahf oil shales1 #aej petroleum1 #acc silver1 #bcd tungsten1 #ahc1 #ahd turquoise1 #bic uranium and radium1 #bfd-bfe1 #bff vanadium1 #ahg-ahh zinc1 #baf1 #bai-bbj ,commercial and political control of mineral resources1 #fe1 #chg1 #chh ,see also under individual resources4 ,common rocks1 as mineral resources1 #hj-id ,comstock ,lode1 ,nevada1 silver ores1 #bce-bcf1 #cjh ,congo4 ,see ,belgian ,congo ,connecticut1 basalt1 #hb diatomaceous earth1 #bfi tourmaline1 #bic ,conover1 ,julian ,d41 #ab ,conservation1 #cei-chb1 #cic-cie application of economic geology to1 #a-b of coal1 #cff-chb of common rocks1 #ha of human energy1 #cfb international aspects1 #cfb-cfc1 #cge1 #cgf-cgg1 #cic-cie of petroleum1 #acg-aci ,conservation ,commission of ,canada1 #cfg ,contact metamorphism1 #bj1 #bd1 #be-bg1 #cf-cg ,see also ,igneous after-effects4 ,contracts1 classification of earth materials in1 #cef-ceg ,copper ores1 #i1 #cf-ej1 #ea-eb1 #ee1 #aig1 #bji1 #cjg1 #cjh-cji1 #cac-cad1 #cah1 #cif ,cornwall1 ,england1 tin ores1 #db1 #bfj1 #bfb1 #bfc uranium and radium ores1 #bfd ,corocoro1 ,bolivia1 copper ores1 #bjf ,corundum1 #bfg-bfh1 #bgj1 #cih ,costa ,rica1 manganese1 #agf ,cracking processes for refining petroleum1 #acg1 #aci ,cripple ,creek district1 ,colorado1 gold ores1 #bcj ,cuba1 chromite1 #agi copper1 #aig iron1 #h-i1 #ej1 #eh1 #if1 #aee1 #afj1 #afc1 #aga-agc1 #cac1 #cdi manganese1 #age nickel1 #aha petroleum1 #abh ,cuyuna ,range1 ,minnesota1 manganese ores1 #age1 #agg ,cycle1 erosion or topographic1 #f-g ,cyclic nature of ore concentration1 #g-h1 #dg-dh1 #ef1 #afi1 #bja1 #bje1 #bjh1 #cbe ,cyprus1 asbestos1 #bga1 #bgb ,dams1 geologic problems involved in construction1 #dad ,davis1 ,w4 ,m41 #djh ,death ,valley1 ,california1 borax deposits1 #bgf ,degree of economic geology1 #dbg-dbh ,denmark1 cement1 #hg chalk1 #hc grinding pebbles1 #bfh ,depletion of mineral deposits1 as factor in valuation and taxation1 #cca1 #ccg1 #cci ,depth as a factor in mineral deposition1 #dc1 #di1 #eh-ei ,diamond dust1 #bfg1 #bfh1 #cih ,diamonds1 #bhi-bib1 #caf1 #cag ,diatomaceous earth1 #bfg1 #bfi1 #cih ,diorite1 #hb ,dolomite1 #bc1 #aib ,domes1 occurrence of oil in4 ,see ,anticlines4 ,domes1 salt and sulphur1 ,gulf ,coast1 #aaj1 #bih ,drilling1 exploration of mineral deposits by1 #cbj-cba ,drilling records1 public registration of1 #cje-cjf ,ducktown1 ,tennessee1 copper ores1 #bjd ,dutch ,east ,indies1 natural gas1 #aea petroleum1 #abh1 #abi tin1 #bfj use of coefficient to estimate tin reserves1 #cbb ,dutch ,guiana1 bauxite1 #bdc ,dutch ,west ,indies1 phosphates1 #aje1 #ajf ,dynamic metamorphism1 #be-bf ,east ,africa1 mica1 #bhf ,east ,indies4 ,see ,dutch ,east ,indies4 ,eckel1 ,e4 ,c41 #djd ,economic ,liaison ,committee1 #djf ,egypt1 petroleum1 #abh phosphates1 #ajd ,eiserner ,hut1 #cac ,electrical conductivity1 use in exploration of mineral deposits1 #cai ,ely1 ,nevada1 copper ores1 #da1 #bjc ,emeralds1 #bhi1 #bia1 #bic ,emery1 #bfg-bfh1 #bgj1 #cig1 #cih ,emmons1 ,w4 ,h41 #dc ,empire1 ,colorado1 molybdenum ores1 #ahf ,energy resources1 #aae-aec accelerating production of1 #fd1 #acj-aca1 #cfa1 #cff-cfg ,engineering1 application of economic geology to1 #b1 #dac-dai ,england4 ,see ,great ,britain ,enrichment1 secondary1 #g-h1 #be1 #df-ej4 ,see also under ,copper ores1 silver ores1 etc4 ,epigenetic ore deposits1 use of term1 #cb1 #cf ,equated ,income method of taxation1 #cce-ccf ,erosion1 relation to oxide zones1 #dg-dh ,erosion cycle1 description of1 #f-g ,ethics1 questions of1 #dcj-dca ,europe1 coal and iron situation under terms of ,peace ,treaty1 #djj-djc ,expert witnesses1 use of geologists as1 #cdi-cee1 #ceg-ceh ,exploitation of mineral deposits1 functions of geologist1 #cbf-cbg ,exploration of mineral deposits1 #cja-cbg effect of ownership laws on1 #cdg-cdi effect of taxation on1 #cci-cda quantitative aspects of1 #cba-cbb1 #cbd-cbf relation to international conditions1 #cie-cif ,extralateral rights1 litigation affecting1 #cdi-cee ,extrusive rocks1 formation of1 #ai ,federated ,malay ,states4 ,see ,malay ,states4 ,feldspar1 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#ahh1 #cih zinc1 #bad-bbj1 #cih zirconium1 #ahi1 #cih ,united ,states1 control of various minerals in other countries1 #fd1 #ajb1 #abi1 #aeb1 #afc-afd1 #afe1 #age1 #ahj-aha1 #ahd1 #ahg1 #ahi1 #aia1 #aih1 #bbb1 #bcb1 #bch1 #bdc1 #bfa laws relating to ownership of mineral resources1 #cdc-cde quantitative feature of mineral production1 #fj-ff relative position in regard to supplies of minerals1 #cif-djj tendencies toward nationalization of mineral resources1 #cde-cdf ,united ,states ,bituminous ,coal ,commission1 #cgf ,united ,states ,bureau of ,mines1 activities in the war1 #djf literature or international mineral relations1 #djc ,united ,states ,geological ,survey1 activities in the war1 #djf1 #djg classification of mineral lands1 #caj-caa employment by1 #dbh literature on international mineral relations1 #djc ,united ,states ,shipping ,board1 #cef1 #djf ,uranium ores1 #ee1 #bfc-bfd1 #cig ,utah1 arsenic1 #bej1 #bea asphalt and bitumen1 #aeb bismuth1 #bec copper1 #cg1 #db1 #dg1 #ee1 #aii1 #bjc1 #bjd1 #bjg1 #bjh1 #cad gold1 #bbb1 #cad lead1 #db1 #baa1 #bab manganese1 #ee oil shales1 #aea phosphates1 #aje potash1 #aab1 #aad silver1 #db1 #ee1 #bcd1 #bce uranium and radium1 #ee1 #bfd1 #bfe vanadium1 #ee1 #ahg-ahh ,utah1 ore deposits1 relation to intrusive stocks1 #dd ,vadose zone1 #gj ,valuation of ,lorraine iron ores at ,peace ,conference1 #cfd ,valuation of mineral resources1 #ha1 #cbh-cda1 #cif ,value1 capital1 of mineral resources1 #fd1 #cbh ,value of ,united ,states mineral production and imports1 #fb ,value of world mineral production1 #fb-fc ,vanadium ores1 #ee1 #ahg-ahh1 #cih ,van ,hise1 ,c4 ,r41 #cfg1 #cgd ,van ,hise1 ,c4 ,r41 and ,leith1 ,c4 ,k41 #ef1 #cbd ,vein1 application of legal term to diverse mineral deposits1 #cej ,venezuela1 asphalt1 #aeb1 #aec magnesite1 #aia-aic petroleum1 #abh phosphates1 #aje ,verde district1 ,arizona4 ,see ,jerome district4 ,vermilion district1 ,minnesota1 iron ore outcrops1 #cab ,vermont1 granite1 #hb marble1 #hc serpentine1 #hc slate1 #he talc1 #bii ,virginia1 arsenic1 #bej1 #bea emery1 #bfh manganese1 #age millstones and buhrstones1 #bfi pyrite1 #ajh talc and soapstone1 #bii1 #cjj titanium1 #aij zinc1 #ed-ee1 #bai ,virginia ,city1 ,nevada4 ,see ,comstock ,lode ,volcanic ash1 use as abrasive1 #bgj ,wabana1 ,newfoundland1 iron ores1 #eb-ec1 #afj1 #aff ,wales1 coal1 #abf ,war1 anti-conservational effects of1 #cfe-cff application of geology to1 #dje-dab effect on ad valorem valuations1 #cce ,war ,industries ,board1 #cef1 #djf ,war ,minerals ,committee1 #djf ,war ,trade ,board1 #cef1 #djf ,wash1 use in tracing mineral outcrops1 #caf-cag ,washington1 arsenic1 #bej chromite1 #agi magnesite1 #aia-aic ,water1 applications of economic geology to1 #fh as a mineral resource1 #fa1 #fb1 #fg-gi general geologic relations1 #fg-fh hygroscopic1 defined1 #fh of constitution1 defined1 #fh quantity absorbed by soils and rocks1 #fi relative abundance of1 #ah source of1 #fg use of1 litigation arising from1 #ceg-ceh ,see also ,ground-waters1 ,surface waters1 ,hot waters1 ,meteoric waters1 ,magmatic waters4 ,water power1 possibilities of substituting for coal1 #cgh-cgi ,water supplies1 #gb-gh ,water supply maps for military use1 #daa-dab ,water table1 defined1 #gj ,see also ,ground-water level4 ,waters1 thermal1 #gb ,watson1 ,t4 ,l41 and ,ries1 ,h41 #dac ,weathering1 of igneous rocks and veins1 #bj-bb of igneous rocks1 formation of mineral deposits by1 #ej of mineral deposits1 #df-ej of sedimentary rocks1 #bc-bd production of clay by1 #ia production of soils by1 #id-if zone of1 #gj ,welfare work1 in interests of conservation1 #cgb-cgc ,wells1 #gb-gc ,west ,africa1 gold1 #bbb manganese1 #agf ,west ,indies1 cement1 #hg phosphates1 #aje1 #ajf salt1 #bid ,west ,virginia1 bromine1 #bgg coal1 #aag grindstones and pulpstones1 #bfi natural gas1 #aea petroleum1 #acb1 #acc ,whetstones1 #bfi ,white1 ,david1 #abh1 #abi1 #adj1 #adc1 #adf ,white ,signal district1 ,new ,mexico1 uranium and radium ores1 #bfe-bff ,wisconsin1 artesian wells1 #gc diamonds in glacial drift1 #bib1 #cag granite1 #hb iron4 ,see ,lake ,superior iron ores1 ,gogebic district1 etc4 quartzite1 #hb1 #hd1 #aie zinc1 #baf ,wisconsin1 equated income method of taxation1 #cce-ccf taxation of iron ores1 #cce ,witwatersrand1 ,south ,africa1 gold ores1 #bbh ,wolfram ores4 ,see ,tungsten ores4 ,woodward1 ,h4 ,b41 #fi ,wyoming1 chromite1 #agi oil shales1 #aea petroleum1 #acc phosphates1 #aje platinum1 #bci potash1 #aab uranium and radium ores1 #bfe ,yellow ,pine district1 ,nevada1 platinum ores1 #bci-bdj ,yellowstone ,park1 springs and geysers of1 #gb ,zinc and lead ores1 ,wisconsin1 equated income method of taxation1 #cce-ccf ,zinc ores1 #cf-ej1 #ed-ee1 #bac-bbj1 #cjh1 #cac-cad1 #cih ,zinc ,syndicate1 ,german1 #bae ,zirconium ores1 #ahi-aij1 #cih 99-------------------------------------- ----------- ,transcriber's ,note ,some inconsistent spelling in the text has been retained4 ,page #ae ,in the symbol ,fe,c,o#c the #c is subscript4 ,page x ,,developmnet changed to ,,development ,page #hg ,unites changed to ,united ,page #hi heterogenous changed to heterogeneous ,page #agi ,guatemela changed to ,guatemala ,paqe #cbi familar changed to familiar ,page #dcc ,afrcia changed to ,africa ,page #dcd ,winconsin changed to ,wisconsin ,page #ddd westtern changed to western ,page #dej ownnership changed to ownership 99-------------------------------------- -----------99