,vol4 ,i4 ,no4 #c4 ,,the ,,national ,,geographic ,,magazine4 ,,published ,,by ,,the ,,national ,,geographic ,,society4 ,,washington1 ,d4 ,c4 ,price #ej ,cents4 ,,contents4 ,the ,rivers and ,valleys of ,pennsylvania3 ,william ,morris ,davis 7,illustrated by one map and twenty-five cuts47 ,topographic ,models3 ,cosmos ,mindeleff 7,illustrated by two plates47 ,national ,geographic ,society--,abstract of ,minutes ,international ,literary ,contest to be held at ,madrid1 ,spain ,july1 #ahhi4 ,,press ,,of ,,tuttle1 ,,morehouse ,,taylor1 ,,new ,,haven1 ,,conn4 ,,the ,,national ,,geographic ,,magazine4 ,vol4 ,i4 #ahhi4 ,no4 #c4 ,,the ,,rivers ,,and ,,valleys ,,of ,,pennsylvania4#a ,,by ,,william ,,morris ,,davis4 ,in ,faltensystemen von sehr hohem ,alter wurde die ursprngliche ,anordnung der ,langenthler durch das ,ueberhandnehmen der transversalen ,erosionsfurchen oft ganz und gar verwischt4 ,l,,wl4 ,petermann's ,mittheilungen1 xxviii1 #ahhb1 #daa4 ,footnote #a3 ,the substance of this essay was presented to the ,society in a lecture on ,february #hth1 #ahhi1 but since then it has been much expanded4 ,,contents4 ,,part ,,first4 ,introductory4 #a4 ,plan of work here proposed4 #b4 ,general description of the topography of ,pennsylvania4 #c4 ,the drainage of ,pennsylvania4 #d4 ,previous studies of ,appalachian drainage4 ,,part ,,second4 ,outline of the geological history of the region4 #e4 ,conditions of formation4 #f4 ,former extension of strata to the southeast4 #g4 ,cambro-,silurian and ,permian deformations4 #h4 ,perm-,triassic denudation4 #i4 ,newark deposition4 #aj4 ,jurassic tilting4 #aa4 ,jura-,cretaceous denudation4 #ab4 ,tertiary elevation and denudation4 #ac4 ,later changes of level4 #ad4 ,illustrations of ,pennsylvanian topography4 ,,part ,,third4 ,general conception of the history of a river4 #ae4 ,the complete cycle of river life3 youth1 adolescence1 maturity and old age4 #af4 ,mutual adjustment of river courses4 #ag4 ,terminology of rivers changed by adjustment4 #ah4 ,examples of adjustments4 #ai4 ,revival of rivers by elevation and drowning by depression4 #bj4 ,opportunity for new adjustments with revival4 #ba4 ,antecedent and superimposed rivers4 #bb4 ,simple1 compound1 composite and complex rivers4 ,,part ,,fourth4 ,the development of the rivers of ,pennsylvania4 #bc4 ,means of distinguishing between antecedent and adjusted consequent rivers4 #bd4 ,postulates of the argument4 #be4 ,constructional ,permian topography and consequent drainage4 #bf4 ,the ,jura mountains homologous with the ,permian ,alleghanies4 #bg4 ,development and adjustment of the ,permian drainage4 #bh4 ,lateral water-gaps near the apex of synclinal ridges4 #bi4 ,departure of the ,juniata from the ,juniata-,catawissa syncline4 #cj4 ,avoidance of the ,broad ,top basin by the ,juniata headwaters4 #ca4 ,reversal of larger rivers to southeast courses4 #cb4 ,capture of the ,anthracite headwaters by the growing ,susquehanna4 #cc4 ,present outward drainage of the ,anthracite basins4 #cd4 ,homologies of the ,susquehanna and ,juniata4 #ce4 ,superimposition of the ,susquehanna on two synclinal ridges4 #cf4 ,evidence of superimposition in the ,susquehanna tributaries4 #cg4 ,events of the ,tertiary cycle4 #ch4 ,tertiary adjustment of the ,juniata on the ,medina anticlines4 #ci4 ,migration of the ,atlantic-,ohio divide4 #dj4 ,other examples of adjustments4 #da4 ,events of the ,quaternary cycle4 #db4 ,doubtful cases4 #dc4 ,complicated history of our actual rivers4 #dd4 ,provisional conclusions4 ,,part ,,first4 ,introductory4 #a4 ,plan of work here proposed4--,no one now regards a river and its valley as ready-made features of the earth's surface4 ,all are convinced that rivers have come to be what they are by slow processes of natural development1 in which every peculiarity of river-course and valley-form has its appropriate cause4 ,being fully persuaded of the gradual and systematic evolution of topographic forms1 it is now desired1 in studying the rivers and valleys of ,pennsylvania1 to seek the causes of the location of the streams in their present courses2 to go back if possible to the early date when central ,pennsylvania was first raised above the sea and trace the development of the several river systems then implanted upon it from their ancient beginning to the present time4 ,the existing topography and drainage system of the ,state will first be briefly described4 ,we must next inquire into the geological structure of the region1 follow at least in a general way the deformations and changes of attitude and altitude that it has suffered1 and consider the amount of denudation that has been accomplished on its surface4 ,we must at the same time bear in mind the natural history of rivers1 their morphology and development2 we must recognize the varying activities of a river in its youth and old age1 the adjustments of its adolescence and maturity1 and the revival of its decrepit powers when the land that it drains is elevated and it enters a new cycle of life4 ,finally we shall attempt to follow out the development of the rivers of ,pennsylvania by applying the general principles of river history to the special case of ,pennsylvania structure4 #b4 ,general description of the topography of ,pennsylvania4--,the strongly marked topographic districts of ,pennsylvania can hardly be better described than by quoting the account given over a century ago by ,lewis ,evans1 of ,philadelphia1 in his ,analysis of a map of the middle ,british colonies in ,america 7#agee71 which is as valuable from its appreciative perception as it is interesting from its early date4 ,the following paragraphs are selected from his early pages3 ,the land southwestward of ,hudson's ,river is more regularly divided and into a greater number of stages than the other4 ,the first object worthy of regard in this part is a rief or vein of rocks of the talky or isinglassy kind1 some two or three or half a dozen miles broad2 rising generally some small matter higher than the adjoining land2 and extending from ,new ,york city southwesterly by the lower falls of ,delaware1 ,schuylkill1 ,susquehanna1 ,gun-,powder1 ,patapsco1 ,potomack1 ,rapahannock1 ,james river and ,ronoak4 ,this was the antient maritime boundary of ,america and forms a very regular curve4 ,the land between this rief and the sea and from the ,navesink hills southwest 444 may be denominated the ,lower ,plains1 and consists of soil washt down from above and sand accumulated from the ocean4 ,where these plains are not penetrated by rivers1 they are a white sea-sand1 about twenty feet deep and perfectly barren1 as no mixture of soil helps to enrich them4 ,but the borders of the rivers1 which descend from the uplands1 are rendered fertile by the soil washt down with the floods and mixt with the sands gathered from the sea4 ,the substratum of sea-mud1 shells and other foreign subjects is a perfect confirmation of this supposition4 ,and hence it is that for #dj or #ej miles inland and all the way from the ,navesinks to ,cape ,florida1 all is a perfect barren where the wash from the uplands has not enriched the borders of the rivers2 or some ponds and defiles have not furnished proper support for the growth of white cedars4444 ,from this rief of rocks1 over which all the rivers fall1 to that chain of broken hills1 called the ,south mountain1 there is the distance of #ej1 #fj or #gj miles of very uneven ground1 rising sensibly as you advance further inland1 and may be denominated the ,upland4 ,this consists of veins of different kinds of soil and substrata some scores of miles in length2 and in some places overlaid with little ridges and chains of hills4 ,the declivity of the whole gives great rapidity to the streams2 and our violent gusts of rain have washt it all into gullies1 and carried down the soil to enrich the borders of the rivers in the ,lower ,plains4 ,these inequalities render half the country not easily capable of culture1 and impoverishes it1 where torn up by the plow1 by daily washing away the richer mould that covers the surface4 ,the ,south mountain is not in ridges like the ,endless mountains1 but in small1 broken1 steep1 stoney hills2 nor does it run with so much regularity4 ,in some places it gradually degenerates to nothing1 not to appear again for some miles1 and in others it spreads several miles in breadth4 ,between ,south mountain and the hither chain of the ,endless mountains 7often for distinction called the ,north mountain1 and in some places the ,kittatinni and ,pequlin71 there is a valley of pretty even good land1 some #h1 #aj or #bj miles wide1 and is the most considerable quantity of valuable land that the ,english are possest of2 and runs through ,new ,jersey1 ,pensilvania1 ,mariland and ,virginia4 ,it has yet obtained no general name1 but may properly enough be called ,piemont1 from its situation4 ,besides conveniences always attending good land1 this valley is everywhere enriched with ,limestone4 ,the ,endless mountains1 so called from a translation of the ,indian name bearing that signification1 come next in order4 ,they are not confusedly scattered and in lofty peaks overtopping one another1 but stretch in long uniform ridges scarce half a mile perpendicular in any place above the intermediate vallies4 ,their name is expressive of their extent1 though no doubt not in a literal sense4444 ,the mountains are almost all so many ridges with even tops and nearly of a height4 ,to look from these hills into the lower lands is but1 as it were1 into an ocean of woods1 swelled and deprest here and there by little inequalities1 not to be distinguished one part from another any more than the waves of the real ocean4 ,the uniformity of these mountains1 though debarring us of an advantage in this respect1 makes some amends in another4 ,they are very regular in their courses1 and confine the creeks and rivers that run between2 and if we know where the gaps are that let through these streams1 we are not at a loss to lay down their most considerable inflections4444 ,to the northwestward of the ,endless mountains is a country of vast extent1 and in a manner as high as the mountains themselves4 ,to look at the abrupt termination of it1 near the sea level1 as is the case on the west side of ,hudson's river below ,albany1 it looks as a vast high mountain2 for the ,kaats ,kills1 though of more lofty stature than any other mountains in these parts of ,america1 are but the continuation of the ,plains on the top1 and the cliffs of them in the front they present towards ,kinderhook4 ,these ,upper ,plains are of extraordinary rich level land1 and extend from the ,mohocks river through the country of the ,confederates4#b ,their termination northward is at a little distance from ,lake ,ontario2 but what it is westward is not known1 for those most extensive plains of ,ohio are part of them4 ,footnote #b3 ,referring to the league of ,indian tribes1 so-called4 ,these several districts recognized by ,evans may be summarized as the coastal plain1 of nearly horizontal ,cretaceous and later beds1 just entering the southeastern corner of ,pennsylvania2 the marginal upland of contorted schists of disputed age2 the ,south ,mountain belt of ancient and much disturbed crystalline rocks1 commonly called ,archean2 a space between these two traversed by the sandstone lowland of the ,newark formation2#c the great ,appalachian valley of crowded ,cambrian limestones and slates2 the region of the even-crested1 linear ,paleozoic ridges1 bounded by ,kittatinny or ,blue mountain on the southeast and by ,alleghany mountain on the northwest1 this being the area with which we are here most concerned2 and finally the ,alleghany plateau1 consisting of nearly horizontal ,devonian and ,carboniferous beds and embracing all the western part of the state4 ,the whole region presents the most emphatic expression not only of its structure but also of the more recent cycles of development through which it has passed4 ,fig4 #a represents the stronger ridges and larger streams of the greater part of the central district3 it is reproduced from the expressive ,topographic ,map of ,pennsylvania 7#ahga7 by ,lesley4 ,the ,susquehanna flows down the middle1 receiving the ,west ,branch from ,lock ,haven and ,williamsport1 the ,east ,branch from ,wilkes-,barre in the ,wyoming basin1 and the ,juniata from the ,broad ,top region1 south of ,huntingdon4 ,the ,anthracite basins lie on the right1 enclosed by zigzag ridges of ,pocono and ,pottsville sandstone2 the ,plateau1 trenched by the ,west ,branch of the ,susquehanna is in the northwest4 ,medina sandstone forms most of the central ridges4 ,footnote #c3 ,russell has lately recommended the revival of this term1 proposed many years ago by ,redfield1 as a non-committal name for the ,new red sandstones of our ,atlantic slope1 commonly called ,triassic4 ,illustration3 ,,fig4 #a4 ,part of ,topographic ,map of ,pennsylvania1 by ,j4 ,p4 ,lesley 7#ahga74 #c4 ,the drainage of ,pennsylvania4--,the greater part of the ,alleghany plateau is drained westward into the ,ohio1 and with this we shall have little to do4 ,the remainder of the plateau drainage reaches the ,atlantic by two rivers1 the ,delaware and the ,susquehanna1 of which the latter is the more special object of our study4 ,the ,north and ,west ,branches of the ,susquehanna rise in the plateau1 which they traverse in deep valleys2 thence they enter the district of the central ranges1 where they unite and flow in broad lowlands among the even-crested ridges4 ,the ,juniata brings the drainage of the ,broad ,top region to the main stream just before their confluent current cuts across the marginal ,blue ,mountain4 ,the rock-rimmed basins of the anthracite region are drained by small branches of the ,susquehanna northward and westward1 and by the ,schuylkill and ,lehigh to the south and east4 ,the ,delaware1 which traverses the plateau between the ,anthracite region and the ,catskill ,mountain front1 together with the ,lehigh1 the ,schuylkill1 the little ,swatara and the ,susquehanna1 cut the ,blue ,mountain by fine water-gaps1 and cross the great limestone valley4 ,the ,lehigh then turns eastward and joins the ,delaware1 and the ,swatara turns westward to the ,susquehanna2 but the ,delaware1 ,schuylkill and ,susquehanna all continue across ,south ,mountain and the ,newark belt1 and into the low plateau of schists beyond4 ,the ,schuylkill unites with the ,delaware near ,philadelphia1 just below the inner margin of the coastal plain2 the ,delaware and the ,susquehanna continue in their deflected estuaries to the sea4 ,all of these rivers and many of their side streams are at present sunk in small valleys of moderate depth and width1 below the general surface of the lowlands1 and are more or less complicated with terrace gravels4 #d4 ,previous studies of ,appalachian drainage4--,there have been no special studies of the history of the rivers of ,pennsylvania in the light of what is now known of river development4 ,a few recent essays of rather general character as far as our rivers are concerned1 may be mentioned4 ,peschel examined our rivers chiefly by means of general maps with little regard to the structure and complicated history of the region4 ,he concluded that the several transverse rivers which break through the mountains1 namely1 the ,delaware1 ,susquehanna and ,potomac1 are guided by fractures1 anterior to the origin of the rivers4#d ,there does not seem to be sufficient evidence to support this obsolescent view1 for most of the water-gaps are located independently of fractures2 nor can ,peschel's method of river study be trusted as leading to safe conclusions4 ,footnote #d3 ,physische ,erdkunde1 #ahhj1 ii1 #ddb4 ,tietze regards our transverse valleys as antecedent2#e but this was made only as a general suggestion1 for his examination of the structure and development of the region is too brief to establish this and exclude other views4 ,footnote #e3 ,jahrbuch ,geol4 ,reichsanstalt1 xxviii1 #ahgh1 #fjj4 ,lwl questions the conclusion reached by ,tietze and ascribes the transverse gaps to the backward or headwater erosion of external streams1 a process which he has done much to bring into its present important position1 and which for him replaces the persistence of antecedent streams of other authors4#f ,footnote #f3 ,pet4 ,mitth41 #ahhb1 #dje2 ,ueber ,thalbildung1 ,prag1 #ahhd4 ,a brief article#g that ,i wrote in comment on ,lwl's first essay several years ago now seems to me insufficient in its method4 ,it exaggerated the importance of antecedent streams2 it took no sufficient account of the several cycles of erosion through which the region has certainly passed2 and it neglected due consideration of the readjustment of initial immature stream courses during more advanced river-life4 ,since then1 a few words in ,lwl's essay have come to have more and more significance to me2 he says that in mountain systems of very great age1 the original arrangement of the longitudinal valleys often becomes entirely confused by means of their conquest by transverse erosion gaps4 ,this suggestion has been so profitable to me that ,i have placed the original sentence at the beginning of this paper4 ,its thesis is the essential element of my present study4 ,footnote #g3 ,origin of ,cross-valleys4 ,science1 i1 #ahhc1 #cbe4 ,phillipson refers to the above-mentioned authors and gives a brief account of the arrangement of drainage areas within our ,appalachians1 but briefly dismisses the subject4#h ,his essay contains a serviceable bibliography4 ,footnote #h3 ,studien ber ,wasserscheiden4 ,leipsig1 #ahhf1 #adi4 ,if these several earlier essays have not reached any precise conclusion1 it may perhaps be because the details of the geological structure and development of ,pennsylvania have not been sufficiently examined4 ,indeed1 unless the reader has already become familiar with the geological maps and reports of the ,pennsylvania surveys and is somewhat acquainted with its geography1 ,i shall hardly hope to make my case clear to him4 ,the volumes that should be most carefully studied are1 first1 the always inspiring classic1 ,coal and its ,topography 7#ahef71 by ,lesley1 in which the immediate relation of our topography to the underlying structure is so finely described2 the ,geological ,map of ,pennsylvania 7#ahef71 the result of the labors of the first survey of the state2 and the ,geological ,atlas of ,counties1 ,volume ,x of the second survey 7#ahhe74 ,besides these1 the ponderous volumes of the final report of the first survey and numerous reports on separate counties by the second survey should be examined1 as they contain many accounts of the topography although saying very little about its development4 ,if1 in addition to all this1 the reader has seen the central district of the state and marvelled at its even-crested1 straight and zigzag ridges1 and walked through its narrow water-gaps into the enclosed coves that they drain1 he may then still better follow the considerations here presented4 ,,part ,,second4 ,outline of the geological history of the region4 #e4 ,conditions of formation4--,the region in which the ,susquehanna and the neighboring rivers are now located is built in chief part of marine sediments derived in paleozoic time from a large land area to the southeast1 whose northwest coast-line probably crossed ,pennsylvania somewhere in the southeastern part of the state2 doubtless varying its position1 however1 by many miles as the sea advanced and receded in accordance with the changes in the relative altitudes of the land and water surfaces1 such as have been discussed by ,newberry and ,claypole4 ,the sediments thus accumulated are of enormous thickness1 measuring twenty or thirty thousand feet from their crystalline foundation to the uppermost layer now remaining4 ,the whole mass is essentially conformable in the central part of the state4 ,some of the formations are resistent1 and these have determined the position of our ridges2 others are weaker and are chosen as the sites of valleys and lowlands4 ,the first are the ,oneida and ,medina sandstones1 which will be here generally referred to under the latter name alone1 the ,pocono sandstone and the ,pottsville conglomerate2 to these may be added the fundamental crystalline mass on which the whole series of bedded formations was deposited1 and the basal sandstone that is generally associated with it4 ,wherever we now see these harder rocks1 they rise above the surrounding lowland surface4 ,on the other hand1 the weaker beds are the ,cambrian limestones 7,trenton7 and slates 7,hudson ,river71 all the ,silurian except the ,medina above named1 the whole of the ,devonian--in which however there are two hard beds of subordinate value1 the ,oriskany sandstone and a ,chemung sandstone and conglomerate1 that form low and broken ridges over the softer ground on either side of them--and the ,carboniferous 7,mauch ,chunk7 red shales and some of the weaker sandstones 7,coal measures74 #f4 ,former extension of strata to the southeast4--,we are not much concerned with the conditions under which this great series of beds was formed2 but1 as will appear later1 it is important for us to recognize that the present southeastern margin of the beds is not by any means their original margin in that direction4 ,it is probable that the whole mass of deposits1 with greater or less variations of thickness1 extended at least twenty miles southeast of ,blue ,mountain1 and that many of the beds extended much farther4 ,the reason for this conclusion is a simple one4 ,the several resistant beds above-mentioned consist of quartz sand and pebbles that cannot be derived from the underlying beds of limestones and shales2 their only known source lay in the crystalline rocks of the paleozoic land to the southeast4 ,south ,mountain may possibly have made part of this paleozoic land2 but it seems more probable that it was land only during the earlier ,archean age1 and that it was submerged and buried in ,cambrian time and not again brought to the light of day until it had been crushed into many local anticlines#i whose crests were uncovered by ,permian and later erosion4 ,the occurrence of ,cambrian limestone on either side of ,south ,mountain1 taken with its compound anticlinal structure1 makes it likely that ,medina time found this crystalline area entirely covered by the ,cambrian beds2 ,medina sands must therefore have come from farther still to the southeast4 ,a similar argument applies to the source of the ,pocono and ,pottsville beds4 ,the measure of twenty miles as the former southeastern extension of the paleozoic formations therefore seems to be a moderate one for the average of the whole series2 perhaps forty would be nearer the truth4 ,footnote #i3 ,lesley1 as below4 #g4 ,cambro-,silurian and ,permian deformations4--,this great series of once horizontal beds is now wonderfully distorted2 but the distortions follow a general rule of trending northeast and southwest1 and of diminishing in intensity from southeast to northwest4 ,in the ,hudson ,valley1 it is well known that a considerable disturbance occurred between ,cambrian and ,silurian time1 for there the ,medina lies unconformably on the ,hudson ,river shales4 ,it seems likely1 for reasons that will be briefly given later on1 that the same disturbance extended into ,pennsylvania and farther southwest1 but that it affected only the southeastern corner of the ,state2 and that the unconformities in evidence of it1 which are preserved in the ,hudson ,valley1 are here lost by subsequent erosion4 ,waste of the ancient land and its ,cambro-,silurian annex still continued and furnished vast beds of sandstone and sandy shales to the remaining marine area1 until at last the subsiding ,paleozoic basin was filled up and the coal marshes extended broadly across it4 ,at this time we may picture the drainage of the southeastern land area wandering rather slowly across the great ,carboniferous plains to the still submerged basin far to the west2 a condition of things that is not imperfectly represented1 although in a somewhat more advanced stage1 by the existing drainage of the mountains of the ,carolinas across the more modern coastal plain to the ,atlantic4 ,this condition was interrupted by the great ,permian deformation that gave rise to the main ranges of the ,appalachians in ,pennsylvania1 ,virginia and ,tennessee4 ,the ,permian name seems appropriate here1 for while the deformation may have begun at an earlier date1 and may have continued into ,triassic time1 its culmination seems to have been within ,permian limits4 ,it was characterized by a resistless force of compression1 exerted in a southeast-northwest line1 in obedience to which the whole series of ,paleozoic beds1 even twenty or more thousand feet in thickness1 was crowded gradually into great and small folds1 trending northeast and southwest4 ,the subjacent ,archean terrane doubtless shared more or less in the disturbance3 for example1 ,south ,mountain is described by ,lesley as not one mountain1 but a system of mountains separated by valleys4 ,it is1 geologically considered1 a system of anticlinals with troughs between4444 ,it appears that the ,south ,mountain range ends eastward in ,cumberland and ,york ,counties in a hand with five anticlinal fingers4#aj ,footnote #aj3 ,proc4 ,amer4 ,phil4 ,soc41 xiii1 #ahgc1 #f4 ,it may be concluded with fair probability that the folds began to rise in the southeast1 where they are crowded closest together1 some of them having begun here while coal marshes were still forming farther west2 and that the last folds to be begun were the fainter ones on the plateau1 now seen in ,negro mountain and ,chestnut and ,laurel ridges4 ,in consequence of the inequalities in the force of compression or in the resistance of the yielding mass1 the folds do not continue indefinitely with horizontal axes1 but vary in height1 rising or falling away in great variety4 ,several adjacent folds often follow some general control in this respect1 their axes rising and falling together4 ,it is to an unequal yielding of this kind that we owe the location of the ,anthracite synclinal basins in eastern ,pennsylvania1 the ,coal ,measures being now worn away from the prolongation of the synclines1 which rise in either direction4 #h4 ,perm-,triassic denudation4--,during and for a long time after this period of mountain growth1 the destructive processes of erosion wasted the land and lowered its surface4 ,an enormous amount of material was thus swept away and laid down in some unknown ocean bed4 ,we shall speak of this as the ,perm-,triassic period of erosion4 ,a measure of its vast accomplishment is seen when we find that the ,newark formation1 which is generally correlated with ,triassic or ,jurassic time1 lies unconformably on the eroded surface of ,cambrian and ,archean rocks in the southeastern part of the ,state1 where we have concluded that the ,paleozoic series once existed2 where the strata must have risen in a great mountain mass as a result of the ,appalachian deformations2 and whence they must therefore have been denuded before the deposition of the ,newark beds4 ,not only so2 the moderate sinuosity of the southeastern or under boundary of the ,newark formation indicates clearly enough that the surface on which that portion of the formation lies is one of no great relief or inequality2 and such a surface can be carved out of an elevated land only after long continued denudation1 by which topographic development is carried beyond the time of its greatest strength or maturity into the fainter expression of old age4 ,this is a matter of some importance in our study of the development of the rivers of ,pennsylvania2 and it also constitutes a good part of the evidence already referred to as indicating that there must have been some earlier deformations of importance in the southeastern part of the ,state2 for it is hardly conceivable that the great ,paleozoic mass could have been so deeply worn off of the ,newark belt between the making of the last of the coal beds and the first of the ,newark4 ,it seems more in accordance with the facts here recounted and with the teachings of geological history in general to suppose1 as we have here1 that something of the present deformation of the ancient rocks underlying the ,newark beds was given at an early date1 such as that of the ,green ,mountain growth2 and that a certain amount of the erosion of the folded beds was thus made possible in middle ,paleozoic time2 then again at some later date1 as ,permian1 a second period of mountain growth arrived1 and further folding was effected1 and after this came deeper erosion2 thus dividing the destructive work that was done into several parts1 instead of crowding it all into the post-,carboniferous time ordinarily assigned to it4 ,it is indeed not impossible that an important share of what we have called the ,permian deformation was1 as above suggested1 accomplished in the southeastern part of the ,state while the coal beds were yet forming in the west2 many grains of sand in the sandstones of the ,coal ,measures may have had several temporary halts in other sandstone beds between the time of their first erosion from the ,archean rocks and the much later time when they found the resting place that they now occupy4#aa ,footnote #aa3 ,these considerations may have value in showing that the time in which the lateral crushing of the ,appalachians was accomplished was not so brief as is stated by ,reade in a recent article in the ,american ,geologist1 iii1 #ahhi1 #ajf4 #i4 ,newark deposition4--,after the great ,paleozoic and ,perm-,triassic erosions thus indicated1 when the southeastern area of ancient mountains had been well worn down and the ,permian folds of the central district had acquired a well developed drainage1 there appeared an opportunity for local deposition in the slow depression of a northeast-southwest belt of the deeply wasted land1 across the southeastern part of the ,state2 and into this trough-like depression1 the waste from the adjacent areas on either side was carried1 building the ,newark formation4 ,this may be referred to as the ,newark or ,trias-,jurassic period of deposition4 ,the volume of this formation is unknown1 as its thickness and original area are still undetermined2 but it is pretty surely of many thousand feet in vertical measure1 and its original area may have been easily a fifth or a quarter in excess of its present area1 if not larger yet4 ,so great a local accumulation seems to indicate that while the belt of deposition was sinking1 the adjacent areas were rising1 in order to furnish a continual supply of material2 the occurrence of heavy conglomerates along the margins of the ,newark formation confirms this supposition1 and the heavy breccias near ,reading indicate the occurrence of a strong topography and a strong transporting agent to the northwest of this part of the ,newark belt4 ,it will be necessary1 when the development of the ancestors of our present rivers is taken up1 to consider the effects of the depression that determined the locus of ,newark deposition and of the adjacent elevation that maintained a supply of material4 #aj4 ,jurassic tilting4--,newark deposition was stopped by a gradual reversal of the conditions that introduced it4 ,the depression of the ,newark belt was after a time reversed into elevation1 accompanied by a peculiar tilting1 and again the waste of the region was carried away to some unknown resting place4 ,this disturbance1 which may be regarded as a revival of the ,permian activity1 culminated in ,jurassic1 or at least in post-,newark time1 and resulted in the production of the singular monoclinal attitude of the formation2 and as far as ,i can correlate it with the accompanying change in the underlying structures1 it involved there an over-pushing of the closed folds of the ,archean and ,paleozoic rocks4 ,this is illustrated in figs4 #b and #c1 in which the original and disturbed attitudes of the ,newark and the underlying formations are roughly shown1 the over-pushing of the fundamental folds causing the monoclinal and probably faulted structure in the overlying beds4#ab ,if this be true1 we might suspect that the unsymmetrical attitude of the ,appalachian folds1 noted by ,rogers as a characteristic of the range1 is a feature that was intensified if not originated in ,jurassic and not in ,permian time4 ,footnote #ab3 ,amer4 ,journ4 ,science1 xxxii1 #ahhf1 #cdb2 and ,seventh ,ann4 ,rept4 ,u4 ,s4 ,geol4 ,survey1 #ahhh1 #dhf4 ,illustration3 ,,fig4 #b4 ,illustration3 ,,fig4 #c4 ,it is not to be supposed that the ,jurassic deformation was limited to the area of the ,newark beds2 it may have extended some way on either side2 but it presumably faded out at no great distance1 for it has not been detected in the history of the ,atlantic and ,mississippi regions remote from the ,newark belt4 ,in the district of the central folds of ,pennsylvania1 with which we are particularly concerned1 this deformation was probably expressed in a further folding and over-pushing of the already partly folded beds1 with rapidly decreasing effect to the northwest2 and perhaps also by slip-faults1 which at the surface of the ground nearly followed the bedding planes3 but this is evidently hypothetical to a high degree4 ,the essential point for our subsequent consideration is that the ,jurassic deformation was probably accompanied by a moderate elevation1 for it allowed the erosion of the ,newark beds and of laterally adjacent areas as well4 #aa4 ,jura-,cretaceous denudation4--,in consequence of this elevation1 a new cycle of erosion was entered upon1 which ,i shall call the ,jura-,cretaceous cycle4 ,it allowed the accomplishment of a vast work1 which ended in the production of a general lowland of denudation1 a wide area of faint relief1 whose elevated remnants are now to be seen in the even ridge-crests that so strongly characterize the central district1 as well as in certain other even uplands1 now etched by the erosion of a later cycle of destructive work4 ,i shall not here take space for the deliberate statement of the argument leading to this end1 but its elements are as follows3 the extraordinarily persistent accordance among the crest-line altitudes of many ,medina and ,carboniferous ridges in the central district2 the generally corresponding elevation of the western plateau surface1 itself a surface of erosion1 but now trenched by relatively deep and narrow valleys2 the generally uniform and consistent altitude of the uplands in the crystalline highlands of northern ,new ,jersey and in the ,south ,mountains of ,pennsylvania2 and the extension of the same general surface1 descending slowly eastward1 over the even crest-lines of the ,newark trap ridges4 ,besides the evidence of less continental elevation thus deduced from the topography1 it may be noted that a lower stand of the land in ,cretaceous time than now is indicated by the erosion that the ,cretaceous beds have suffered in consequence of the elevation that followed their deposition4 ,the ,cretaceous transgression in the western states doubtless bears on the problem also4 ,finally it may be fairly urged that it is more accordant with what is known about old mountains in general to suppose that their mass has stood at different attitudes with respect to base level during their long period of denudation than to suppose that they have held one attitude through all the time since their deformation4 ,it is natural enough that the former maintenance of some lower altitude than the present should have expression in the form of the country1 if not now extinguished by subsequent erosion4 ,it is simply the reverse of this statement that leads us to the above-stated conclusion4 ,we may be sure that the long maintained period of relative quiet was of great importance in allowing time for the mature adjustment of the rivers of the region1 and hence due account must be taken of it in a later section4 ,i say relative quiet1 for there were certainly subordinate oscillations of greater or less value2 ,mc,gee has detected records of one of these about the beginning of ,cretaceous time1 but its effects are not now known to be of geographic value2 that is1 they do not now manifest themselves in the form of the present surface of the land1 but only in the manner of deposition and ancient erosion of certain deposits4#ac ,another subordinate oscillation in the sense of a moderate depression seems to have extended through middle and later ,cretaceous time1 resulting in an inland transgression of the sea and the deposit of the ,cretaceous formation unconformably on the previous land surface for a considerable distance beyond the present margin of the formation4#ad ,this is important as affecting our rivers4 ,although these oscillations were of considerable geological value1 ,i do not think that for the present purposes they call for any primary division of the ,jura-,cretaceous cycle2 for as the result of this long period of denudation we find but a single record in the great lowland of erosion above described1 a record of prime importance in the geographic development of our region1 that will often be referred to4 ,the surface of faint relief then completed may be called the ,cretaceous baselevel lowland4 ,it may be pictured as a low1 undulating plain of wide extent1 with a portion of its ,atlantic margin submerged and covered over with a relatively thin marine deposit of sands1 marls and clays4 ,footnote #ac3 ,amer4 ,jour4 ,science1 xxxv1 #ahhh1 #cfg1 #ddh4 ,footnote #ad3 ,this statement is based on a study of the geographic evolution of northern ,new ,jersey1 in preparation for publication4 #ab4 ,tertiary elevation and denudation4--,this broad lowland is a lowland no longer4 ,it has been raised over the greater part of its area into a highland1 with an elevation of from one to three thousand feet1 sloping gently eastward and descending under the ,atlantic level near the present margin of the ,cretaceous formation4 ,the elevation seems to have taken place early in ,tertiary time1 and will be referred to as of that date4 ,opportunity was then given for the revival of the previously exhausted forces of denudation1 and as a consequence we now see the formerly even surface of the plain greatly roughened by the incision of deep valleys and the opening of broad lowlands on its softer rocks4 ,only the harder rocks retain indications of the even surface which once stretched continuously across the whole area4 ,the best indication of the average altitude at which the mass stood through the greater part of post-,cretaceous time is to be found on the weak shales of the ,newark formation in ,new ,jersey and ,pennsylvania1 and on the weak ,cambrian limestones of the great ,kittatinny valley2 for both of these areas have been actually almost baselevelled again in the ,tertiary cycle4 ,they will be referred to as the ,tertiary baselevel lowlands2 and the valleys corresponding to them1 cut in the harder rocks1 as well as the rolling lowlands between the ridges of the central district of ,pennsylvania will be regarded as of the same date4 ,whatever variations of level occurred in this cycle of development do not seem to have left marks of importance on the inland surface1 though they may have had greater significance near the coast4 #ac4 ,later changes of level4--,again at the close of ,tertiary time1 there was an elevation of moderate amount1 and to this may be referred the trenches that are so distinctly cut across the ,tertiary baselevel lowland by the larger rivers1 as well as the lateral shallower channels of the smaller streams4 ,this will be called the ,quaternary cycle2 and for the present no further mention of the oscillations known to have occurred in this division of time need be considered2 the reader may find careful discussion of them in the paper by ,mc,gee1 above referred to4 ,it is proper that ,i should add that the suggestion of baselevelling both of the crest-lines and of the lowlands1 that ,i have found so profitable in this and other work1 is due largely to personal conference with ,messrs4 ,gilbert and ,mc,gee of the ,geological ,survey2 but it is not desired to make them in any way responsible for the statements here given4 ,illustration3 ,,fig4 #d4 ,illustration3 ,,fig4 #e4 #ad4 ,illustrations of ,pennsylvanian topography4--,a few sketches made during a recent recess-trip with several students through ,pennsylvania may be introduced in this connection4 ,the first1 fig4 #d1 is a view from ,jenny ,jump mountain1 on the northwestern side of the ,new ,jersey highlands1 looking northwest across the ,kittatinny valley-lowland to ,blue or ,kittatinny mountain1 where it is cut at the ,delaware ,water-gap4 ,the extraordinarily level crest of the mountain preserves record of the ,cretaceous baselevel lowland2 since the elevation of this ancient lowland1 its softer rocks have1 as it were1 been etched out1 leaving the harder ones in relief2 thus the present valley-lowland is to be explained4 ,in consequence of the still later elevation of less amount1 the ,delaware has cut a trench in the present lowland1 which is partly seen to the left in the sketch4 ,fig4 #e is a general view of the ,lehigh plateau and caon1 looking south from ,bald ,mountain just above ,penn ,haven ,junction4 ,blue mountain is the most distant crest1 seen for a little space4 ,the ridges near and above ,mauch ,chunk form the other outlines2 all rising to an astonishingly even altitude1 in spite of their great diversity of structure4 ,before the existing valleys were excavated1 the upland surface must have been an even plain--the ,cretaceous baselevel lowland elevated into a plateau4 ,the valleys cut into the plateau during the ,tertiary cycle are narrow here1 because the rocks are mostly hard4 ,the steep slopes of the caon-like valley of the ,lehigh and the even crests of the ridges manifestly belong to different cycles of development4 ,figs4 #f and #g are gaps cut in ,black ,log and ,shade mountain1 by a small upper branch stream of the ,juniata in southeastern ,huntingdon county4 ,the stream traverses a breached anticlinal of ,medina sandstone1 of which these mountains are the lateral members4 ,a long narrow valley is opened on the axial ,trenton limestone between the two4 ,the gaps are not opposite to each other1 and therefore in looking through either gap from the outer country the even crest of the further ridge is seen beyond the axial valley4 ,the gap in ,black ,log mountain1 fig4 #f1 is located on a small fracture1 but in this respect it is unlike most of its fellows4#ae ,the striking similarity of the two views illustrates the uniformity that so strongly characterizes the ,medina ridges of the central district4 ,fig4 #h is in good part an ideal view1 based on sketches on the upper ,susquehanna1 and designed to present a typical illustration of the more significant features of the region4 ,it shows the even crest-lines of a high ,medina or ,pocono ridge in the background1 retaining the form given to it in the ,cretaceous cycle2 the even lowlands in the foreground1 opened on the weaker ,siluro-,devonian rocks in the ,tertiary cycle2 and the uneven ridges in the middle distance marking the ,oriskany and ,chemung beds of intermediate hardness that have lost the ,cretaceous level and yet have not been reduced to the ,tertiary lowland4 ,the ,susquehanna flows distinctly below the lowland plain1 and the small side streams run in narrow trenches of late ,tertiary and ,quaternary date4 ,footnote #ae3 ,second ,geol4 ,surv4 ,pa41 ,report ,t#c1 #ai4 ,illustration3 ,,fig4 #f4 ,illustration3 ,,fig4 #g4 ,illustration3 ,,fig4 #h4 ,if this interpretation is accepted1 and the ,permian mountains are seen to have been once greatly reduced and at a later time worn out1 while the ridges of to-day are merely the relief left by the etching of ,tertiary valleys in a ,cretaceous baselevelled lowland1 then we may well conclude with ,powell that mountains cannot remain long as mountains2 they are ephemeral topographic forms4#af ,footnote #af3 ,geol4 ,uinta ,mountains1 #ahgf1 #aif4 ,,part ,,third4 ,general conception of the history of a river4 #ae4 ,the complete cycle of river life3 youth1 adolescence1 maturity and old age4--,the general outline of an ideal river's history may be now considered1 preparatory to examining the special history of the rivers of ,pennsylvania1 as controlled by the geological events just narrated4 ,rivers are so long lived and survive with more or less modification so many changes in the attitude and even in the structure of the land1 that the best way of entering on their discussion seems to be to examine the development of an ideal river of simple history1 and from the general features thus discovered1 it may then be possible to unravel the complex sequence of events that leads to the present condition of actual rivers of complicated history4 ,a river that is established on a new land may be called an original river4 ,it must at first be of the kind known as a consequent river1 for it has no ancestor from which to be derived4 ,examples of simple original rivers may be seen in young plains1 of which southern ,new ,jersey furnishes a fair illustration4 ,examples of essentially original rivers may be seen also in regions of recent and rapid displacement1 such as the ,jura or the broken country of southern ,idaho1 where the directly consequent character of the drainage leads us to conclude that1 if any rivers occupied these regions before their recent deformation1 they were so completely extinguished by the newly made slopes that we see nothing of them now4 ,once established1 an original river advances through its long life1 manifesting certain peculiarities of youth1 maturity and old age1 by which its successive stages of growth may be recognized without much difficulty4 ,for the sake of simplicity1 let us suppose the land mass1 on which an original river has begun its work1 stands perfectly still after its first elevation or deformation1 and so remains until the river has completed its task of carrying away all the mass of rocks that rise above its baselevel4 ,this lapse of time will be called a cycle in the life of a river4 ,a complete cycle is a long measure of time in regions of great elevation or of hard rocks2 but whether or not any river ever passed through a single cycle of life without interruption we need not now inquire4 ,our purpose is only to learn what changes it would experience if it did thus develop steadily from infancy to old age without disturbance4 ,in its infancy1 the river drains its basin imperfectly2 for it is then embarrassed by the original inequalities of the surface1 and lakes collect in all the depressions4 ,at such time1 the ratio of evaporation to rainfall is relatively large1 and the ratio of transported land waste to rainfall is small4 ,the channels followed by the streams that compose the river as a whole are narrow and shallow1 and their number is small compared to that which will be developed at a later stage4 ,the divides by which the side-streams are separated are poorly marked1 and in level countries are surfaces of considerable area and not lines at all4 ,it is only in the later maturity of a system that the divides are reduced to lines by the consumption of the softer rocks on either side4 ,the difference between constructional forms and those forms that are due to the action of denuding forces is in a general way so easily recognized1 that immaturity and maturity of a drainage area can be readily discriminated4 ,in the truly infantile drainage system of the ,red ,river of the ,north1 the inter-stream areas are so absolutely flat that water collects on them in wet weather1 not having either original structural slope or subsequently developed denuded slope to lead it to the streams4 ,on the almost equally young lava blocks of southern ,oregon1 the well-marked slopes are as yet hardly channeled by the flow of rain down them1 and the depressions among the tilted blocks are still undrained1 unfilled basins4 ,as the river becomes adolescent1 its channels are deepened and all the larger ones descend close to baselevel4 ,if local contrasts of hardness allow a quick deepening of the down-stream part of the channel1 while the part next up-stream resists erosion1 a cascade or waterfall results2 but like the lakes of earlier youth1 it is evanescent1 and endures but a small part of the whole cycle of growth2 but the falls on the small headwater streams of a large river may last into its maturity1 just as there are young twigs on the branches of a large tree4 ,with the deepening of the channels1 there comes an increase in the number of gulleys on the slopes of the channel2 the gulleys grow into ravines and these into side valleys1 joining their master streams at right angles 7,la ,no and ,margerie74 ,with their continued development1 the maturity of the system is reached2 it is marked by an almost complete acquisition of every part of the original constructional surface by erosion under the guidance of the streams1 so that every drop of rain that falls finds a way prepared to lead it to a stream and then to the ocean1 its goal4 ,the lakes of initial imperfection have long since disappeared2 the waterfalls of adolescence have been worn back1 unless on the still young headwaters4 ,with the increase of the number of side-streams1 ramifying into all parts of the drainage basin1 there is a proportionate increase in the surface of the valley slopes1 and with this comes an increase in the rate of waste under atmospheric forces2 hence it is at maturity that the river receives and carries the greatest load2 indeed1 the increase may be carried so far that the lower trunk-stream1 of gentle slope in its early maturity1 is unable to carry the load brought to it by the upper branches1 and therefore resorts to the temporary expedient of laying it aside in a flood-plain4 ,the level of the flood-plain is sometimes built up faster than the small side-streams of the lower course can fill their valleys1 and hence they are converted for a little distance above their mouths into shallow lakes4 ,the growth of the flood-plain also results in carrying the point of junction of tributaries farther and farther down stream1 and at last in turning lateral streams aside from the main stream1 sometimes forcing them to follow independent courses to the sea 7,lombardini74 ,but although thus separated from the main trunk1 it would be no more rational to regard such streams as independent rivers than it would be to regard the branch of an old tree1 now fallen to the ground in the decay of advancing age1 as an independent plant2 both are detached portions of a single individual1 from which they have been separated in the normal processes of growth and decay4 ,in the later and quieter old age of a river system1 the waste of the land is yielded slower by reason of the diminishing slopes of the valley sides2 then the headwater streams deliver less detritus to the main channel1 which1 thus relieved1 turns to its postponed task of carrying its former excess of load to the sea1 and cuts terraces in its flood-plain1 preparatory to sweeping it away4 ,it does not always find the buried channel again1 and perhaps settling down on a low spur a little to one side of its old line1 produces a rapid or a low fall on the lower slope of such an obstruction 7,penck74 ,such courses may be called locally superimposed4 ,it is only during maturity and for a time before and afterwards that the three divisions of a river1 commonly recognized1 appear most distinctly2 the torrent portion being the still young headwater branches1 growing by gnawing backwards at their sources2 the valley portion proper1 where longer time of work has enabled the valley to obtain a greater depth and width2 and the lower flood-plain portion1 where the temporary deposition of the excess of load is made until the activity of middle life is past4 ,maturity seems to be a proper term to apply to this long enduring stage2 for as in organic forms1 where the term first came into use1 it here also signifies the highest development of all functions between a youth of endeavor towards better work and an old age of relinquishment of fullest powers4 ,it is the mature river in which the rainfall is best lead away to the sea1 and which carries with it the greatest load of land waste2 it is at maturity that the regular descent and steady flow of the river is best developed1 being the least delayed in lakes and least overhurried in impetuous falls4 ,maturity past1 and the power of the river is on the decay4 ,the relief of the land diminishes1 for the streams no longer deepen their valleys although the hill tops are degraded2 and with the general loss of elevation1 there is a failure of rainfall to a certain extent2 for it is well known that up to certain considerable altitudes rainfall increases with height4 ,a hyetographic and a hypsometric map of a country for this reason show a marked correspondence4 ,the slopes of the headwaters decrease and the valley sides widen so far that the land waste descends from them slower than before4 ,later1 what with failure of rainfall and decrease of slope1 there is perhaps a return to the early imperfection of drainage1 and the number of side streams diminishes as branches fall from a dying tree4 ,the flood-plains of maturity are carried down to the sea1 and at last the river settles down to an old age of well-earned rest with gentle flow and light load1 little work remaining to be done4 ,the great task that the river entered upon is completed4 #af4 ,mutual adjustment of river courses4--,in certain structures1 chiefly those of mountainous disorder on which the streams are at first high above baselevel1 there is a process of adjustment extremely characteristic of quiet river development1 by which the down-hill courses that were chosen in early life1 and as we may say unadvisedly and with the heedlessness and little foresight of youth1 are given up for others better fitted for the work of the mature river system4 ,a change of this kind happens when the young stream taking the lowest line for its guide happens to flow on a hard bed at a considerable height above baselevel1 while its branches on one side or the other have opened channels on softer beds3 a part of the main channel may then be deserted by the withdrawal of its upper waters to a lower course by way of a side stream4 ,the change to better adjustment also happens when the initial course of the main stream is much longer than a course that may be offered to its upper portion by the backward gnawing of an adjacent stream 7,lwl1 ,penck74 ,sometimes the lateral cutting or planation that characterizes the main trunk of a mature river gives it possession of an adjacent smaller stream whose bed is at a higher level 7,gilbert74 ,a general account of these processes may be found in ,phillippson's serviceable ,studien ber ,wasserscheiden 7,leipzig1 #ahhf74 ,this whole matter is of much importance and deserves deliberate examination4 ,it should be remembered that changes in river courses of the kind now referred to are unconnected with any external disturbance of the river basin1 and are purely normal spontaneous acts during advancing development4 ,two examples1 pertinent to our special study1 will be considered4 ,illustration3 ,,fig4 #i4 ,illustration3 ,,fig4 #aj4 ,let ,,ab1 fig4 #i1 be a stream whose initial consequent course led it down the gently sloping axial trough of a syncline4 ,the constructional surface of the syncline is shown by contours4 ,let the succession of beds to be discovered by erosion be indicated in a section1 laid in proper position on the several diagrams1 but revolved into the horizontal plane1 the harder beds being dotted and the baselevel standing at ,,oo4 ,small side streams will soon be developed on the slopes of the syncline1 in positions determined by cross-fractures or more often by what we call accident2 the action of streams in similar synclines on the outside of the enclosing anticlines will be omitted for the sake of simplicity4 ,in time1 the side streams will cut through the harder upper bed ,m and enter the softer bed ,n1 on which longitudinal channels1 indicated by hachures1 will be extended along the strike1 fig4 #aj 7,la ,no and ,margerie74 ,let these be called subsequent streams4 ,consider two side streams of this kind1 ,c and ,d1 heading against each other at ,e1 one joining the main stream lower down the axis of the syncline than the other4 ,the headwaters of ,c will rob the headwaters of ,d1 because the deepening of the channel of ,d is retarded by its having to join the main stream at a point where the hard bed in the axis of the fold holds the main channel well above baselevel4 ,the notch cut by ,d will then be changed from a water-gap to a wind-gap and the upper portion of ,d will find exit through the notch cut by ,c1 as in fig4 #aa4 ,as other subsequent headwaters make capture of ,c1 the greater depth to which the lateral valley is cut on the soft rock causes a slow migration of the divides in the abandoned gaps towards the main stream1 and before long the upper part of the main stream itself will be led out of the synclinal axis to follow the monoclinal valley at one side for a distance1 fig4 #ab1 until the axis can be rejoined through the gap where the axial portion of the controlling hard bed is near or at baselevel4 ,the upper part of the synclinal trough will then be attacked by undercutting on the slope of the quickly deepened channels of the lateral streams1 and the hard bed will be worn away in the higher part of the axis before it is consumed in the lower part4 ,the location of the successful lateral stream on one or the other side of the syncline may be determined by the dip of the beds1 gaps being cut quicker on steep than on gentle dips4 ,if another hard bed is encountered below the soft one1 the process will be repeated2 and the mature arrangement of the streams will be as in fig4 #ac 7on a smaller scale than the preceding71 running obliquely off the axis of the fold where a hard bed of the syncline rises above baselevel1 and returning to the axis where the hard bed is below or at baselevel2 a monoclinal stream wandering gradually from the axis along the strike of the soft bed1 ,,ae1 by which the side-valley is located and returning abruptly to the axis by a cataclinal#ag stream in a transverse gap1 ,,eb1 in the next higher hard bed1 and there rejoining the diminished representative or survivor of the original axial or synclinal stream1 ,,gb4 ,footnote #ag3 ,see the terminology suggested by ,powell4 ,expl4 ,col4 ,r4 of the ,west1 #ahge1 #afj4 ,this terminology is applicable only to the most detailed study of our rivers1 by reason of their crossing so many folds1 and changing so often from longitudinal to transverse courses4 ,illustration3 ,,fig4 #aa4 ,illustration3 ,,fig4 #ab4 ,illustration3 ,,fig4 #ac4 #ag4 ,terminology of rivers changed by adjustment4--,a special terminology is needed for easy reference to the several parts of the streams concerned in such an adjustment4 ,let ,,ab and ,,cd1 fig4 #ad1 be streams of unequal size cutting gaps1 ,h and ,g1 in a ridge that lies transverse to their course4 ,,cd being larger than ,,ab will deepen its gap faster4 ,of two subsequent streams1 ,,je and ,,jf1 growing on the up-stream side of the ridge1 ,,je will have the steeper slope1 because it joins the deeper master-stream4 ,the divide1 ,j1 will therefore be driven towards ,,ab1 and if all the conditions concerned conspire favorably1 ,,je will at last tap ,,ab at ,f1 and lead the upper part1 ,,af1 out by the line ,,fegd1 fig4 #ae1 through the deeper gap1 ,g4 ,we may then say that ,,je becomes the divertor of ,,af1 which is diverted2 and when the process is completed1 by the transfer of the divide from ,j1 on the soft rocks1 to a stable location1 ,h1 on the hard rocks1 there will be a short inverted stream1 ,,hf2 while ,,hb is the remaining beheaded portion of the original stream1 ,,ab1 and the water-gap of ,,ab becomes a wind-gap1 ,h4 ,it is very desirable that geographic exploration should discover examples of the process of adjustment in its several stages4 ,the preparatory stage is easily recognized by the difference in the size of the two main streams1 the difference in the depth of their gaps1 and the unsymmetrical position of the divide1 ,j4 ,the very brief stage of transition gives us the rare examples of bifurcating streams4 ,for a short time after capture of the diverted stream by the divertor1 the new divide will lie between ,f and ,h1 in an unstable position1 the duration of this time depending on the energy of the process of capture4 ,illustration3 ,,fig4 #ad4 ,illustration3 ,,fig4 #ae4 ,the consequences resulting from readjustments of this kind by which their recent occurrence can be detected are3 a relatively sudden increase of volume of the divertor and hence a rapid deepening of the course of the diverting stream1 ,,fe1 and of the diverted1 ,,af1 near the point of capture2 small side-streams of these two being unable to keep pace with this change will join their masters in local rapids1 which work up stream gradually and fade away 7,lwl1 ,penck1 ,mc,gee74 ,the expanded portion1 ,,ed1 of the larger stream1 ,,cd1 already of faint slope1 may be locally overcome for a time with the increase of detritus that will be thus delivered to it at the entrance1 ,e1 of the divertor2 while the beheaded stream1 ,,hb1 will find itself embarrassed to live up to the habits of its large valley ,heim4 ,geographic exploration with these matters in mind offers opportunity for the most attractive discoveries4 ,illustration3 ,,fig4 #af4 ,illustration3 ,,fig4 #ag4 ,illustration3 ,,fig4 #ah4 #ah4 ,examples of adjustment4--,another case is roughly figured in the next three diagrams1 figs4 #af1 #ag1 #ah4 ,two adjacent synclinal streams1 ,,ea and ,,hb1 join a transverse master stream1 ,c1 but the synclines are of different forms2 the surface axis of one1 ,,ea1 stands at some altitude above baselevel until it nearly reaches the place of the transverse stream2 while the axis of the other1 ,,hb1 descends near baselevel at a considerable distance from the transverse stream4 ,as lateral valleys1 ,e and ,d1 are opened on the anticline between the synclines by a process similar to that already described1 the divide separating them will shift towards the stream of fainter slope1 that is1 towards the syncline1 ,,ea1 whose axis holds its hard beds above baselevel2 and in time the upper part of the main stream will be withdrawn from this syncline to follow an easier course by crossing to the other1 as in fig4 #ag4 ,if the elevation of the synclinal axis1 ,,aes1 take the shape of a long flat arch1 descending at the further end into a synclinal lake basin1 ,s1 whose outlet is along the arching axis1 ,,sa1 then the mature arrangement of stream courses will lead the lake outlet away from the axis by some gap in the nearer ascending part of the arch where the controlling hard bed falls near to baselevel1 as at ,f1 fig4 #ah1ah and will take it by some subsequent course1 ,,fd1 across the lowland that is opened on the soft beds between the synclines1 and carry it into the lower syncline1 ,,hb1 at ,d where the hard beds descend below baselevel4 ,footnote #ah3 ,this figure would be improved if a greater amount of wasting around the margin of the hard bed were indicated in comparison with the preceding figure4 ,the variety of adjustments following the general principle here indicated is infinite4 ,changes of greater or less value are thus introduced in the initial drainage areas1 until1 after attaining an attitude of equilibrium1 further change is arrested1 or if occurring1 is relatively insignificant4 ,it should be noticed that the new stream courses thus chosen are not named by any of the terms now current to express the relation of stream and land history2 they are neither consequent1 antecedent nor superimposed4 ,the stream is truly still an original stream1 although no longer young2 but its channel is not in all parts strictly consequent on the initial constructional form of the land that it drains4 ,streams thus re-arranged may therefore be named original streams of mature adjustment4 ,it should be clearly recognized that the process of adjustment is a very slow one1 unless measured in the extremely long units of a river's life4 ,it progresses no faster than the weathering away of the slopes of a divide1 and here as a rule weathering is deliberate to say the least1 unless accelerated by a fortunate combination of favoring conditions4 ,among these conditions1 great altitude of the mass exposed to erosion stands first1 and deep channeling of streams below the surface--that is1 the adolescent stage of drainage development--stands second4 ,the opportunity for the lateral migration of a divide will depend on the inequality of the slopes on its two sides1 and here the most important factors are length of the two opposite stream courses from the water parting to the common baselevel of the two1 and inequality of structure by which one stream may have an easy course and the other a hard one4 ,it is manifest that all these conditions for active shifting of divides are best united in young and high mountain ranges1 and hence it is that river adjustments have been found and studied more in the ,alps than elsewhere4 #ai4 ,revival of rivers by elevation and drowning by depression4--,i make no contention that any river in the world ever passed through a simple uninterrupted cycle of the orderly kind here described4 ,but by examining many rivers1 some young and some old1 ,i do not doubt that this portrayal of the ideal would be found to be fairly correct if opportunity were offered for its development4 ,the intention of the sketch is simply to prepare the way for the better understanding of our actual rivers of more complicated history4 ,at the close or at any time during the passage of an initial cycle such as the one just considered1 the drainage area of a river system may be bodily elevated4 ,the river is then turned back to a new youth and enters a new cycle of development4 ,this is an extremely common occurrence with rivers1 whose life is so long that they commonly outlive the duration of a quiescent stage in the history of the land4 ,such rivers may be called revived4 ,examples may be given in which streams are now in their second or third period of revival1 the elevations that separate their cycles following so soon that but little work was accomplished in the quiescent intervals4 ,the antithesis of this is the effect of depression1 by which the lower course may be drowned1 flooded or fjorded4 ,this change is1 if slow1 favorable to the development of flood-plains in the lower course2 but it is not essential to their production4 ,if the change is more rapid1 open estuaries are formed1 to be transformed to delta-lowlands later on4 #bj4 ,opportunity for new adjustments with revival4--,one of the most common effects of the revival of a river by general elevation is a new adjustment of its course to a greater or less extent1 as a result of the new relation of baselevel to the hard and soft beds on which the streams had adjusted themselves in the previous cycle4 ,synclinal mountains are most easily explained as results of drainage changes of this kind ,science1 ,dec4 #bast1 #ahhh4 ,streams thus rearranged may be said to be adjusted through elevation or revival4 ,it is to be hoped that1 as our study advances1 single names of brief and appropriate form may replace these paraphrases2 but at present it seems advisable to keep the desired idea before the mind by a descriptive phrase1 even at the sacrifice of brevity4 ,a significant example may be described4 ,illustration3 ,,fig4 #ai4 ,illustration3 ,,fig4 #bj4 ,let it be supposed that an originally consequent river system has lived into advanced maturity on a surface whose structure is1 like that of ,pennsylvania1 composed of closely adjacent anticlinal and synclinal folds with rising and falling axes1 and that a series of particularly resistant beds composes the upper members of the folded mass4 ,the master stream1 ,a1 fig4 #ai1 at maturity still resides where the original folds were lowest1 but the side streams have departed more less from the axes of the synclinals that they first followed1 in accordance with the principles of adjustment presented above4 ,the relief of the surface is moderate1 except around the synclinal troughs1 where the rising margins of the hard beds still appear as ridges of more or less prominence4 ,the minute hachures in figure #ai are drawn on the outcrop side of these ridges4 ,now suppose a general elevation of the region1 lifting the synclinal troughs of the hard beds up to baselevel or even somewhat above it4 ,the deepening of the revived master-stream will be greatly retarded by reason of its having to cross so many outcrops of the hard beds1 and thus excellent opportunity will be given for readjustment by the growth of some diverting stream1 ,b1 whose beginning on adjacent softer rocks was already made in the previous cycle4 ,this will capture the main river at some up-stream point1 and draw it nearly all away from its hard path across the synclinal troughs to an easier path across the lowlands that had been opened on the underlying softer beds1 leaving only a small beheaded remnant in the lower course4 ,the final re-arrangement may be indicated in fig4 #bj4 ,it should be noted that every capture of branches of the initial main stream made by the diverting stream adds to its ability for further encroachments1 for with increase of volume the channel is deepened and a flatter slope is assumed1 and the whole process of pushing away the divides is thereby accelerated4 ,in general it may be said that the larger the stream and the less its elevation above baselevel1 the less likely is it to be diverted1 for with large volume and small elevation it will early cut down its channel so close to baselevel that no other stream can offer it a better course to the sea2 it may also be said that1 as a rule1 of two equal streams1 the headwaters of the one having a longer or a harder course will be diverted by a branch of the stream on the shorter or easier course4 ,every case must therefore be examined for itself before the kind of re-arrangement that may be expected or that may have already taken place can be discovered4 #ba4 ,antecedent and superimposed rivers4--,it not infrequently happens that the surface1 on which a drainage system is more or less fully developed1 suffers deformation by tilting1 folding or faulting4 ,then1 in accordance with the rate of disturbance1 and dependent on the size and slope of the streams and the resistance of the rocks1 the streams will be more or less re-arranged1 some of the larger ones persisting in their courses and cutting their channels down almost as fast as the mass below them is raised and offered to their action4 ,it is manifest that streams of large volume and considerable slope are the ones most likely to persevere in this way1 while small streams and large ones of moderate slope may be turned from their former courses to new courses consequent on the new constructional form of the land4 ,hence1 after a disturbance1 we may expect to find the smaller streams of the former cycle pretty completely destroyed1 while some of the larger ones may still persist2 these would then be called antecedent streams in accordance with the nomenclature introduced by ,powell4#ai ,a fuller acquaintance with the development of our rivers will probably give us examples of river systems of all degrees of extinction or persistence at times of disturbance4 ,footnote #ai3 ,exploration of the ,colorada ,river of the ,west1 #ahge1 #aec1 #afc-aff4 ,since ,powell introduced the idea of antecedent valleys and ,tietze1 ,medlicott and others showed the validity of the explanation in other regions than the one for which it was first proposed1 it has found much acceptance4 ,lwl's objection to it does not seem to me to be nearly so well founded as his suggestion of an additional method of river development by means of backward headwater erosion and subsequent capture of other streams1 as already described4 ,and yet ,i cannot help thinking that the explanation of transverse valleys as antecedent courses savors of the ,gordian method of explaining a difficult matter4 ,the case of the ,green river1 to which ,powell first gave this explanation1 seems well supported2 the examples given by ,medlicott in the ,himalayas are as good3 but still it does not seem advisable to explain all transverse streams in this way1 merely because they are transverse4 ,perhaps one reason why the explanation has become so popular is that it furnishes an escape from the old catastrophic idea that fractures control the location of valleys1 and is at the same time fully accordant with the ideas of the uniformitarian school that have become current in this half of our century4 ,but when it is remembered that most of the streams of a region are extinguished at the time of mountain growth1 that only a few of the larger ones can survive1 and that there are other ways in which transverse streams may originate1#bj it is evident that the possibility of any given transverse stream being antecedent must be regarded only as a suggestion1 until some independent evidence is introduced in its favor4 ,this may be difficult to find1 but it certainly must be searched for2 if not then forthcoming1 the best conclusion may be to leave the case open until the evidence appears4 ,certainly1 if we find a river course that is accordant in its location with the complicated results of other methods of origin1 then the burden of proof may be said to lie with those who would maintain that an antecedent origin would locate the river in so specialized a manner4 ,even if a river persist for a time in an antecedent course1 this may not prevent its being afterwards affected by the various adjustments and revivals that have been explained above3 rivers so distinctly antecedent as the ,green and the ,sutlej may hereafter be more or less affected by processes of adjustment1 which they are not yet old enough to experience4 ,hence in mountains as old as the ,appalachians the courses of the present rivers need not coincide with the location of the pre-,permian rivers1 even if the latter persisted in their courses through the growth of the ,permian folding2 subsequent elevations and adjustments to hard beds1 at first buried and unseen1 may have greatly displaced them1 in accordance with ,lwl's principle4 ,footnote #bj3 ,hilber1 ,pet4 ,mitth41 xxxv1 #ahhi1 #ac4 ,when the deeper channelling of a stream discovers an unconformable subjacent terrane1 the streams persist at least for a time in the courses that were determined in the overlying mass2 they are then called superimposed 7,powell71 inherited 7,shaler71 or epigenetic 7,richthofen74 ,such streams are particularly liable to readjustment by transfer of channels from courses that lead them over hard beds to others on which the hard beds are avoided2 for the first choice of channels1 when the unconformable cover was still present1 was made without any knowledge of the buried rock structure or of the difficulties in which the streams would be involved when they encountered it4 ,the examples of falls produced when streams terrace their flood-plains and run on buried spurs has already been referred to as superimposed2 and the rivers of ,minnesota now disclosing half-buried ledges here and there may be instanced as illustrating the transition stage between simple consequent courses1 determined by the form of the drift sheet on which their flow began1 and the fully inconsequent courses that will be developed there in the future4 #bb4 ,simple1 compound1 composite and complex rivers4--,we have thus far considered an ideal river4 ,it now seems advisable to introduce a few terms with which to indicate concisely certain well marked peculiarities in the history of actual rivers4 ,an original river has already been defined as one which first takes possession of a land area1 or which replaces a completely extinguished river on a surface of rapid deformation4 ,a river may be simple1 if its drainage area is of practically one kind of structure and of one age2 like the rivers of southern ,new ,jersey4 ,such rivers are generally small4 ,it may be composite1 when drainage areas of different structure are included in the basin of a single stream4 ,this is the usual case4 ,a compound river is one which is of different ages in its different parts2 as certain rivers of ,north ,carolina1 which have old headwaters rising in the mountains1 and young lower courses traversing the coastal plain4 ,a river is complex when it has entered a second or later cycle of development2 the headwaters of a compound river are therefore complex1 while the lower course may be simple1 in its first cycle4 ,the degree of complexity measures the number of cycles that the river has entered4 ,when the study of rivers is thus attempted1 its necessary complications may at first seem so great as to render it of no value2 but in answer to this ,i believe that it may be fairly urged that1 although complicated1 the results are true to nature1 and if so1 we can have no ground of complaint against them4 ,moreover1 while it is desirable to reduce the study of the development of rivers to its simplest form1 in order to make it available for instruction and investigation1 it must be remembered that this cannot be done by neglecting to investigate the whole truth in the hope of avoiding too great complexity1 but that simplicity can be reached safely only through fullness of knowledge1 if at all4 ,it is with these points in mind that ,i have attempted to decipher the history of the rivers of ,pennsylvania4 ,we find in the ,susquehanna1 which drains a great area in the central part of the state1 an example of a river which is at once composite1 compound and highly complex4 ,it drains districts of divers structure2 it traverses districts of different ages2 and it is at present in its fourth or fifth degree of complexity1 its fourth or fifth cycle of development at least4 ,in unravelling its history and searching out the earlier courses of streams which may have long since been abandoned in the processes of mature adjustment1 it will be seen that the size of the present streams is not always a measure of their previous importance1 and to this we may ascribe the difficulty that attends the attempt to decipher a river's history from general maps of its stream lines4 ,nothing but a detailed examination of geological structure and history suffices to detect facts and conditions that are essential to the understanding of the result4 ,if the postulates that ,i shall use seem unsound and the arguments seem overdrawn1 error may at least be avoided by not holding fast to the conclusions that are presented1 for they are presented only tentatively4 ,i do not feel by any means absolutely persuaded of the correctness of the results1 but at the same time deem them worth giving out for discussion4 ,the whole investigation was undertaken as an experiment to see where it might lead1 and with the hope that it might lead at least to a serious study of our river problems4 ,,part ,,fourth4 ,the development of the rivers of ,pennsylvania4 #bc4 ,means of distinguishing between antecedent and adjusted consequent rivers4--,the outline of the geological history of ,pennsylvania given above affords means of dividing the long progress of the development of our rivers into the several cycles which make up their complete life4 ,we must go far back into the past and imagine ancient streams flowing down from the ,archean land towards the paleozoic sea2 gaining length by addition to their lower portions as the land grew with the building on of successive mountain ranges2 for example1 if there were a ,cambro-,silurian deformation1 a continuation of the ,green ,mountains into ,pennsylvania1 we suppose that the pre-existent streams must in some manner have found their way westward to the new coastline2 and from the date of this mountain growth1 it is apparent that any streams then born must have advanced far in their history before the greater ,appalachian disturbance began4 ,at the beginning of the latter1 as of the former1 there must have been streams running from the land into the sea1 and at times of temporary elevation of the broad sand-flats of the coal measures1 such streams must have had considerable additions to their lower length2 rising in long-growing ,archean highlands or mountains1 snow-capped and drained by glaciers for all we can say to the contrary1 descending across the ,green ,mountain belt1 by that time worn to moderate relief in the far advanced stage of its topographic development1 and finally flowing across the coal-measure lowlands of recent appearance4 ,it was across the lower courses of such rivers that the ,appalachian folds were formed1 and the first step in our problem consists in deciding if possible whether the streams held their courses after the antecedent fashion1 or whether they were thrown into new courses by the growing folds1 so that a new drainage system would be formed4 ,possibly both conditions prevailed2 the larger streams holding their courses little disturbed1 and the smaller ones disappearing1 to be replaced by others as the slopes of the growing surface should demand4 ,it is not easy to make choice in this matter4 ,to decide that the larger streams persisted and are still to be seen in the greater rivers of to-day1 only reversed in direction of flow1 is certainly a simple method of treating the problem1 but unless some independent reasons are found for this choice1 it savors of assumption4 ,moreover1 it is difficult to believe that any streams1 even if antecedent and more or less persistent for a time during the mountain growth1 could preserve till now their pre-,appalachian courses through all the varying conditions presented by the alternations of hard and soft rocks through which they have had to cut1 and at all the different altitudes above baselevel in which they have stood4 ,a better means of deciding the question will be to admit provisionally the occurrence of a completely original system of consequent drainage1 located in perfect accord with the slopes of the growing mountains2 to study out the changes of stream-courses that would result from later disturbances and from the mutual adjustments of the several members of such a system in the different cycles of its history2 and finally to compare the courses thus deduced with those now seen4 ,if there be no accord1 either the method is wrong or the streams are not consequent but of some other origin1 such as antecedent2 if the accord between deduction and fact be well marked1 varying only where no definite location can be given to the deduced streams1 but agreeing where they can be located more precisely1 then it seems to me that the best conclusion is distinctly in favor of the correctness of the deductions4 ,for it is not likely1 even if it be possible1 that antecedent streams should have accidentally taken1 before the mountains were formed1 just such locations as would have resulted from the subsequent growth of the mountains and from the complex changes in the initial river courses due to later adjustments4 ,i shall therefore follow the deductive method thus indicated and attempt to trace out the history of a completely original1 consequent system of drainage accordant with the growth of the central mountain district4 ,in doing this1 it is first necessary to restore the constructional topography of the region2 that is1 the form that the surface would have had if no erosion had accompanied its deformation4 ,this involves certain postulates which must be clearly conceived if any measure of confidence is to be gained in the results based upon them4 #bd4 ,postulates of the argument4--,in the first place1 ,i assume an essential constancy in the thickness of the paleozoic sediments over the entire area in question4 ,this is warranted here because the known variations of thickness are relatively of a second order1 and will not affect the distribution of high and low ground as produced by the intense ,permian folding4 ,the reasons for maintaining that the whole series had a considerable extension southeast of the present margin of the ,medina sandstone have already been presented4 ,in the second place1 ,i shall assume that the dips and folds of the beds now exposed at the surface of the ground may be projected upwards into the air in order to restore the form of the eroded beds4 ,this is certainly inadmissible in detail1 for it cannot be assumed that the folded slates and limestones of the ,nittany valley1 for instance1 give any close indication of the form that the coal measures would have taken1 had they extended over this district1 unworn4 ,but in a general way1 the ,nittany massif was a complex arch in the coal measures as well as in the ,cambrian beds2 for our purpose and in view of the moderate relief of the existing topography1 it suffices to say that wherever the lower rocks are now revealed in anticlinal structure1 there was a great upfolding and elevation of the original surface2 and wherever the higher rocks are still preserved1 there was a relatively small elevation4 ,in the third place1 ,i assume that by reconstructing from the completed folds the form which the country would have had if unworn1 we gain a sufficiently definite picture of the form through which it actually passed at the time of initial and progressive folding4 ,the difference between the form of the folds completely restored and the form that the surface actually reached is rather one of degree than of kind2 the two must correspond in the general distribution of high and low ground and this is the chief consideration in our problem4 ,when we remember how accurately water finds its level1 it will be clearer that what is needed in the discussion is the location of the regions that were relatively raised and lowered1 as we shall then have marked out the general course of the consequent water ways and the trend of the intervening constructional ridges4 ,accepting these postulates1 it may be said in brief that the outlines of the formations as at present exposed are in effect so many contour lines of the old constructional surface1 on which the ,permian rivers took their consequent courses4 ,where the ,trenton limestone is now seen1 the greatest amount of overlying strata must have been removed2 hence the outline of the ,trenton formation is our highest contour line4 ,where the ,helderberg limestone appears1 there has been a less amount of material removed2 hence the ,helderberg outcrop is a contour of less elevation4 ,where the coal beds still are preserved1 there has been least wasting1 and these beds therefore mark the lowest contour of the early surface4 ,it is manifest that this method assumes that the present outcrops are on a level surface2 this is not true1 for the ridges through the ,state rise a thousand feet more or less over the intervening valley lowlands1 and yet the existing relief does not count for much in discussing the enormous relief of the ,permian surface that must have been measured in tens of thousands of feet at the time of its greatest strength4 ,illustration3 ,,fig4 #ba4 ,constructional ,permian topography of ,pennsylvania4 #be4 ,constructional ,permian topography and consequent drainage4--,a rough restoration of the early constructional topography is given in fig4 #ba for the central part of the ,state1 the closest shading being the area of the ,trenton limestone1 indicating the highest ground1 or better1 the places of greatest elevation1 while the ,carboniferous area is unshaded1 indicating the early lowlands4 ,the prevalence of northeast and southwest trends was then even more pronounced than now4 ,several of the stronger elements of form deserve names1 for convenient reference4 ,thus we have the great ,kittatinny or ,cumberland highland1 ,c1 ,c1 on the southeast1 backed by the older mountains of ,cambrian and ,archean rocks1 falling by the ,kittatinny slope to the synclinal lowland troughs of the central district4 ,in this lower ground lay the synclinal troughs of the eastern coal regions1 and the more local ,broad ,top basin1 ,,bt1 on the southwest1 then better than now deserving the name of basins4 ,beyond the corrugated area that connected the coal basins rose the great ,nittany highland1 ,n1 and its southwest extension in the ,bedford range1 with the less conspicuous ,kishicoquilas highland1 ,k1 in the foreground4 ,beyond all stretched the great ,alleghany lowland plains4 ,the names thus suggested are compounded of the local names of to-day and the morphological names of ,permian time4 ,what would be the drainage of such a country8 ,deductively we are led to believe that it consisted of numerous streams as marked in full lines on the figure1 following synclinal axes until some master streams led them across the intervening anticlinal ridges at the lowest points of their crests and away into the open country to the northwest4 ,all the enclosed basins would hold lakes1 overflowing at the lowest part of the rim4 ,the general discharge of the whole system would be to the northwest4 ,here again we must resort to special names for the easy indication of these well-marked features of the ancient and now apparently lost drainage system4 ,the master stream of the region is the great ,anthracite river1 carrying the overflow of the ,anthracite lakes off to the northwest and there perhaps turning along one of the faintly marked synclines of the plateau and joining the original ,ohio1 which was thus confirmed in its previous location across the ,carboniferous marshes4 ,the synclinal streams that entered the ,anthracite lakes from the southwest may be named1 beginning on the south1 the ,swatara1 ,s1 fig4 #ba1 the ,wiconisco1 ,wo1 the ,tuscarora-,mahanoy1 ,m1 the ,juniata-,catawissa1 ,c1 and the ,wyoming1 ,wy4 ,one of these1 probably the fourth1 led the overflow from the ,broad ,top lake into the ,catawissa lake on the middle ,anthracite river4 ,the ,nittany highland formed a strong divide between the central and northwestern rivers1 and on its outer slope there must have been streams descending to the ,alleghany lowlands2 and some of these may be regarded as the lower courses of ,carboniferous rivers1 that once rose in the ,archean mountains1 now beheaded by the growth of mountain ranges across their middle4 #bf4 ,the ,jura mountains homologous with the ,permian ,alleghanies4--,however willing one may be to grant the former existence of such a drainage system as the above1 an example of a similar one still in existence would be acceptable as a witness to the possibilities of the past4 ,therefore we turn for a moment to the ,jura mountains1 always compared to the ,appalachians on account of the regular series of folds by which the two are characterized4 ,but while the initial topography is long lost in our old mountains1 it is still clearly perceptible in the young ,jura1 where the anticlines are still ridges and the longitudinal streams still follow the synclinal troughs2 while the transverse streams cross from one synclinal valley to another at points where the intervening anticlinal arches are lowest4#ba ,we could hardly ask for better illustration of the deductive drainage system of our early ,appalachians than is here presented4 ,footnote #ba3 ,this is beautifully illustrated in the recent monograph by ,la ,no and ,margerie on ,les ,formes du ,terrain4 #bg4 ,development and adjustment of the ,permian drainage4--,the problem is now before us4 ,can the normal sequence of changes in the regular course of river development1 aided by the post-,permian deformations and elevations1 evolve the existing rivers out of the ancient ones8 ,in order to note the degree of comparison that exists between the two1 several of the larger rivers of to-day are dotted on the figure4 ,the points of agreement are indeed few and small4 ,perhaps the most important ones are that the ,broad ,top region is drained by a stream1 the ,juniata1 which for a short distance follows near the course predicted for it2 and that the ,nittany district1 then a highland1 is still a well-marked divide although now a lowland4 ,but there is no ,anthracite river1 and the region of the ancient coal-basin lakes is now avoided by large streams2 conversely1 a great river--the ,susquehanna--appears where no consequent river ran in ,permian time1 and the early synclinal streams frequently turn from the structural troughs to valleys located on the structural arches4 #bh4 ,lateral water-gaps near the apex of synclinal ridges4--,one of the most frequent discrepancies between the hypothetical and actual streams is that the latter never follow the axis of a descending syncline along its whole length1 as the original streams must have done1 but depart for a time from the axis and then return to it1 notching the ridge formed on any hard bed at the side instead of at the apex of its curve across the axis of the syncline4 ,there is not a single case in the state of a stream cutting a gap at the apex of such a synclinal curve1 but there are perhaps hundreds of cases where the streams notch the curve to one side of the apex4 ,this1 however1 is precisely the arrangement attained by spontaneous adjustment from an initial axial course1 as indicated in figure #ac4 ,the gaps may be located on small transverse faults1 but as a rule they seem to have no such guidance4 ,it is true that most of our streams now run out of and not into the synclinal basins1 but a reason for this will be found later2 for the present we look only at the location of the streams1 not at their direction of flow4 ,as far as this illustration goes1 it gives evidence that the smaller streams at least possess certain peculiarities that could not be derived from persistence in a previous accidental location1 but which would be necessarily derived from a process of adjustment following the original establishment of strictly consequent streams4 ,hence the hypothesis that these smaller streams were long ago consequent on the ,permian folding receives confirmation2 but this says nothing as to the origin of the larger rivers1 which might at the same time be antecedent4 #bi4 ,departure of the ,juniata from the ,juniata-,catawissa syncline4--,it may be next noted that the drainage of the ,broad ,top region does not follow a single syncline to the ,anthracite region1 as it should have in the initial stage of the consequent ,permian drainage1 but soon turns aside from the syncline in which it starts and runs across country to the ,susquehanna4 ,it is true that in its upper course the ,juniata departs from the ,broad ,top region by one of the two synclines that were indicated as the probable line of discharge of the ancient ,broad ,top lake in our restoration of the constructional topography of the ,state2 there does not appear to be any significant difference between the summit altitudes of the ,tuscarora-,mahanoy and the ,juniata-,catawissa synclinal axes and hence the choice must have been made for reasons that cannot be detected2 or it may be that the syncline lying more to the northwest was raised last1 and for this reason was taken as the line of overflow4 ,the beginning of the river is therefore not discordant with the hypothesis of consequent drainage1 but the southward departure from the ,catawissa syncline at ,lewistown remains to be explained4 ,it seems to me that some reason for the departure may be found by likening it to the case already given in figs4 #af-ah4 ,the several synclines with which the ,juniata is concerned have precisely the relative attitudes that are there discussed4 ,the ,juniata-,catawissa syncline has parallel sides for many miles about its middle1 and hence must have long maintained the initial ,juniata well above baselevel over all this distance2 the progress of cutting down a channel through all the hard ,carboniferous sandstones for so great a distance along the axis must have been exceedingly slow4 ,but the synclines next south1 the ,tuscarora-,mahanoy and the ,wiconisco1 plunge to the northeast more rapidly1 as the rapid divergence of their margins demonstrates1 and must for this reason have carried the hard sandstones below baselevel in a shorter distance and on a steeper slope than in the ,catawissa syncline4 ,the further southwestward extension of the ,pocono sandstone ridges in the southern than in the northern syncline gives further illustration of this peculiarity of form4 ,lateral capture of the ,juniata by a branch of the initial ,tuscarora1 and of the latter by a branch of the ,wiconisco therefore seems possible1 and the accordance of the facts with so highly specialized an arrangement is certainly again indicative of the correctness of the hypothesis of consequent drainage1 and this time in a larger stream than before4 ,at first sight1 it appears that an easier lateral capture might have been made by some of the streams flowing from the outer slope of the ,nittany highland2 but this becomes improbable when it is perceived that the heavy ,medina sandstone would here have to be worn through as well as the repeated arches of the ,carboniferous beds in the many high folds of the ,seven ,mountains4 ,again1 as far as present appearances go1 we can give no sufficient reason to explain why possession of the headwaters of the ,juniata was not gained by some subsequent stream of its own1 such as ,g1 fig4 #ah1 instead of by a side-stream of the river in the neighboring syncline2 but it may be admitted1 on the other hand1 that as far as we can estimate the chances for conquest1 there was nothing distinctly in favor of one or the other of the side-streams concerned2 and as long as the problem is solved indifferently in favor of one or the other1 we may accept the lead of the facts and say that some control not now apparent determined that the diversion should be1 as drawn1 through ,d and not through ,g4 ,the detailed location of the ,juniata in its middle course below ,lewistown will be considered in a later section4 ,illustration3 ,,fig4 #bb4 ,illustration3 ,,fig4 #bc4 ,illustration3 ,,fig4 #bd4 #cj4 ,avoidance of the ,broad ,top basin by the ,juniata headwaters4--,another highly characteristic change that the ,juniata has suffered is revealed by examining the adjustments that would have taken place in the general topography of the ,broad ,top district during the ,perm-,triassic cycle of erosion4 ,when the basin1 ,,bt1 fig4 #bb1 was first outlined1 centripetal streams descended its slopes from all sides and their waters accumulated as a lake in the center1 overflowing to the east into the subordinate basin1 ,a1 in the ,juniata syncline along side of the larger basin1 and thence escaping northeast4 ,in due time1 the breaching of the slopes opened the softer ,devonian rocks beneath and peripheral lowlands were opened on them4 ,the process by which the ,juniata departed from its original axial location1 ,j1 fig4 #bb1 to a parallel course on the southeastern side of the syncline1 ,j1 fig4 #bc1 has been described 7fig4 #ah74 ,the subsequent changes are manifest4 ,some lateral branch of the ,juniata1 like ,n1 fig4 #bc1 would work its way around the northern end of the ,broad ,top canoe on the soft underlying rocks and capture the axial stream1 ,c1 that came from the depression between ,nittany and ,kishicoquillas highlands2 thus renforced1 capture would be made of a radial stream from the west1 ,tn1 the existing ,tyrone branch of the ,juniata2 in a later stage the other streams of the western side of the basin would be acquired1 their divertor constituting the ,little ,juniata of to-day2 and the end would be when the original ,juniata1 ,a1 fig4 #bb1 that once issued from the subordinate synclinal as a large stream1 had lost all its western tributaries1 and was but a shrunken beheaded remnant of a river1 now seen in ,aughwick creek1 ,a1 fig4 #bd4 ,in the meantime1 the former lake basin was fast becoming a synclinal mountain of diminishing perimeter4 ,the only really mysterious courses of the present streams are where the ,little ,juniata runs in and out of the western border of the ,broad ,top synclinal1 and where the ,frankstown 7,,ft7 branch of the ,juniata maintains its independent gap across ,tussey's mountain 7,medina71 although diverted to the ,tyrone or main ,juniata 7,tn7 by ,warrior's ridge 7,oriskany7 just below4 ,at the time of the early predatory growth of the initial divertor1 ,n1 its course lay by the very conditions of its growth on only the weakest rocks2 but after this little stream had grown to a good-sized river1 further rising of the land1 probably in the time of the ,jurassic elevation1 allowed the river to sink its channel to a greater depth1 and in doing so1 it encountered the hard ,medina anticline of ,jack's mountain2 here it has since persisted1 because1 as we may suppose1 there has been no stream able to divert the course of so large a river from its crossing of a single hard anticlinal4 ,the doubt that one must feel as to the possibility of the processes just outlined arises1 if ,i may gauge it by my own feeling1 rather from incredulity than from direct objections4 ,it seems incredible that the waste of the valley slopes should allow the backward growth of ,n at such a rate as to enable it to capture the heads of ,c1 ,tn1 ,f1 and so on1 before they had cut their beds down close enough to the baselevel of the time to be safe from capture4 ,but it is difficult to urge explicit objections against the process or to show its quantitative insufficiency4 ,it must be remembered that when these adjustments were going on1 the region was one of great altitude1 its rocks then had the same strong contrasts of strength and weakness that are so apparent in the present relief of the surface and the streams concerned were of moderate size2 less than now1 for at the time1 the ,tyrone1 ,frankstown and ,bedford head branches of the ,juniata had not acquired drainage west of the great ,nittany-,bedford anticlinal axis1 but were supplied only by the rainfall on its eastern slope 7see section #ci7--;and all these conditions conspired to favor the adjustment4 ,finally1 while apparently extraordinary and difficult of demonstration1 the explanation if applicable at all certainly gives rational correlation to a number of peculiar and special stream courses in the upper ,juniata district that are meaningless under any other theory that has come to my notice4 ,it is chiefly for this reason that ,i am inclined to accept the explanation4 #ca4 ,reversal of larger rivers to southeast courses4--,our large rivers at present flow to the southeast1 not to the northwest4 ,it is difficult to find any precise date for this reversal of flow from the initial hypothetical direction1 but it may be suggested that it occurred about the time of the ,triassic depression of the ,newark belt4 ,we have been persuaded that much time elapsed between the ,permian folding and the ,newark deposition1 even under the most liberal allowance for pre-,permian erosion in the ,newark belt2 hence when the depression began1 the rivers must have had but moderate northwestward declivity4 ,the depression and submergence of the broad ,newark belt may at this time have broken the continuity of the streams that once flowed across it4 ,the headwater streams from the ancient ,archean country maintained their courses to the depression2 the lower portions of the rivers may also have gone on as before2 but the middle courses were perhaps turned from the central part of the state back of the ,newark belt4 ,no change of attitude gives so fitting a cause of the southeastward flow of our rivers as this4 ,the only test that ,i have been able to devise for the suggestion is one that is derived from the relation that exists between the location of the ,newark belt along the ,atlantic slope and the course of the neighboring transverse rivers4 ,in ,pennsylvania1 where the belt reaches somewhat beyond the northwestern margin of the crystalline rocks in ,south mountain1 the streams are reversed1 as above stated2 but in the ,carolinas where the ,newark belt lies far to the east of the boundary between the ,cambrian and crystalline rocks1 the ,tennessee streams persevere in what we suppose to have been their original direction of flow4 ,this may be interpreted as meaning that in the latter region1 the ,newark depression was not felt distinctly enough1 if at all1 within the ,alleghany belt to reverse the flow of the streams2 while in the former region1 it was nearer to these streams and determined a change in their courses4 ,the original ,anthracite river ran to the northwest1 but its middle course was afterwards turned to the southeast4 ,i am free to allow that this has the appearance of heaping hypothesis on hypothesis2 but in no other way does the analysis of the history of our streams seem possible1 and the success of the experiment can be judged only after making it4 ,at the same time1 ,i am constrained to admit that this is to my own view the least satisfactory of the suggestions here presented4 ,it may be correct1 but there seems to be no sufficient exclusion of other possibilities4 ,for example1 it must not be overlooked that1 if the ,anthracite river ran southeast during ,newark deposition1 the formation of the ,newark northwestward monocline by the ,jurassic tilting would have had a tendency to turn the river back again to its northwest flow4 ,but as the drainage of the region is still southeastward1 ,i am tempted to think that the ,jurassic tilting was not here strong enough to reverse the flow of so strong and mature a river as the ,anthracite had by that time come to be2 and that the elevation that accompanied the tilting was not so powerful in reversing the river to a northwest course as the previous depression of the ,newark basin had been in turning it to the southeast4 ,if the ,anthracite did continue to flow to the southeast1 it may be added that the down-cutting of its upper branches was greatly retarded by the decrease of slope in its lower course when the monocline was formed4 ,the only other method of reversing the original northwestward flow of the streams that ,i have imagined is by capture of their headwaters by ,atlantic rivers4 ,this seems to me less effective than the method just considered2 but they are not mutually exclusive and the actual result may be the sum of the two processes4 ,the outline of the idea is as follows4 ,the long continued supply of sedimentary material from the ,archean land on the southeast implies that it was as continually elevated4 ,but there came a time when there is no record of further supply of material1 and when we may therefore suppose the elevation was no longer maintained4 ,from that time onward1 the ,archean range must have dwindled away1 what with the encroachment of the ,atlantic on its eastern shore and the general action of denuding forces on its surface4 ,the ,newark depression was an effective aid to the same end1 as has been stated above1 and for a moderate distance westward of the depressed belt1 the former direction of the streams must certainly have been reversed2 but the question remains whether this reversal extended as far as the ,wyoming basin1 and whether the subsequent formation of the ,newark monocline did not undo the effect of the ,newark depression4 ,it is manifest that as far as our limited knowledge goes1 it is impossible to estimate these matters quantitatively1 and hence the importance of looking for additional processes that may supplement the effect of the ,newark depression and counteract the effect of the ,newark uplift in changing the course of the rivers4 ,let it be supposed for the moment that at the end of the ,jurassic uplift by which the ,newark monocline was formed1 the divide between the ,ohio and the ,atlantic drainage lay about the middle of the ,newark belt4 ,there was a long gentle descent westward from this watershed and a shorter and hence steeper descent eastward4 ,under such conditions1 the divide must have been pushed westward1 and as long as the rocks were so exposed as to open areas of weak sediments on which capture by the ,atlantic streams could go on with relative rapidity1 the westward migration of the divide would be important4 ,for this reason1 it might be carried from the ,newark belt as far as the present ,alleghany front1 beyond which further pushing would be slow1 on account of the broad stretch of country there covered by hard horizontal beds4 ,the end of this is that1 under any of the circumstances here detailed1 there would be early in the ,jurassic-,cretaceous cycle a distinct tendency to a westward migration of the ,atlantic-,ohio divide2 it is the consequences of this that have now to be examined4 #cb4 ,capture of the ,anthracite headwaters by the growing ,susquehanna4--,throughout the ,perm-,triassic period of denudation1 a great work was done in wearing down the original ,alleghanies4 ,anticlines of hard sandstone were breached1 and broad lowlands were opened on the softer rocks beneath4 ,little semblance of the early constructional topography remained when the period of ,newark depression was brought to a close2 and all the while the headwater streams of the region were gnawing at the divides1 seeking to develop the most perfect arrangement of waterways4 ,several adjustments have taken place1 and the larger streams have been reversed in the direction of their flow2 but a more serious problem is found in the disappearance of the original master stream1 the great ,anthracite river1 which must have at first led away the water from all the lateral synclinal streams4 ,being a large river1 it could not have been easily diverted from its course1 unless it was greatly retarded in cutting down its channel by the presence of many beds of hard rocks on its way4 ,the following considerations may perhaps throw some light on this obscure point4 ,illustration3 ,,fig4 #be4 ,general distribution of high and low land and drainage in early ,jurassic time4 ,it may be assumed that the whole group of mountains formed by the ,permian deformation had been reduced to a moderate relief when the ,newark deposition was stopped by the ,jurassic elevation4 ,the harder ribs of rock doubtless remained as ridges projecting above the intervening lowlands1 but the strength of relief that had been given by the constructional forces had been lost4 ,the general distribution of residual elevations then remaining unsubdued is indicated in fig4 #be1 in which the ,crystalline1 the ,medina1 and the two ,carboniferous sandstone ridges are denoted by appropriate symbols4 ,in restoring this phase of the surface form1 when the country stood lower than now1 ,i have reduced the anticlines from their present outlines and increased the synclines1 the change of area being made greatest where the dips are least1 and hence most apparent at the ends of the plunging anticlines and synclines4 ,some of the ,medina anticlines of ,perry and ,juniata counties are not indicated because they were not then uncovered4 ,the country between the residual ridges of ,jurassic time was chiefly ,cambrian limestone and ,siluro-,devonian shales and soft sandstones4 ,the moderate ridges developed on the ,oriskany and ,chemung sandstones are not represented4 ,the drainage of this stage retained the original courses of the streams1 except for the adjustments that have been described1 but the great ,anthracite river is drawn as if it had been controlled by the ,newark depression and reversed in the direction of its flow1 so that its former upper course on the ,cambrian rocks was replaced by a superimposed ,newark lower course4 ,fig4 #be therefore represents the streams for the most part still following near their synclinal axes1 although departing from them where they have to enter a synclinal cove-mountain ridge2 the headwaters of the ,juniata avoid the mass of hard sandstones discovered in the bottom of old ,broad ,top lake1 and flow around them to the north1 and then by a cross-country course to the ,wiconisco synclinal1 as already described in detail4 ,several streams come from the northeast1 entering the ,anthracite district after the fashion generalized in fig4 #ac4 ,three of the many streams that were developed on the great ,kittatinny slope are located1 with their direction of flow reversed2 these are marked ,sq1 ,l and ,d1 and are intended to represent the ancestors of the existing ,susquehanna1 ,lehigh and ,delaware4 ,we have now to examine the opportunities offered to these small streams to increase their drainage areas4 ,the ,jurassic elevation1 by which the ,newark deposition was stopped1 restored to activity all the streams that had in the previous cycle sought and found a course close to baselevel4 ,they now all set to work again deepening their channels4 ,but in this restoration of lost activity with reference to a new baselevel1 there came the best possible chance for numerous re-arrangements of drainage areas by mutual adjustment into which we must inquire4 ,i have already illustrated what seems to me to be the type of the conditions involved at this time in figs4 #ai and #bj4 ,the master stream1 ,a1 traversing the synclines1 corresponds to the reversed ,anthracite river2 the lowlands at the top are those that have been opened out on the ,siluro-,devonian beds of the present ,susquehanna middle course between the ,pocono and the ,medina ridges4 ,the small stream1 ,b1 that is gaining drainage area in these lowlands1 corresponds to the embryo of the present ,susquehanna1 ,sq1 fig4 #be1 this having been itself once a branch on the south side of the ,swatara synclinal stream1 fig4 #ba1 from which it was first turned by the change of slope accompanying the ,newark depression2 but it is located a little farther west than the actual ,susquehanna1 so as to avoid the two synclinal cove mountains of ,pocono sandstone that the ,susquehanna now traverses1 for reasons to be stated below 7section #ce74 ,this stream had to cross only one bed of hard rock1 the outer wall of ,medina sandstone1 between the broad inner lowlands of the relatively weak ,siluro-,devonian rocks and the great valley lowlands on the still weaker ,cambrian limestones4 ,step by step it must have pushed its headwater divide northward1 and from time to time it would have thus captured a subsequent stream1 that crossed the lowlands eastward1 and entered a ,carboniferous syncline by one of the lateral gaps already described4 ,with every such capture1 the power of the growing stream to capture others was increased4 ,fig4 #ai represents a stage after the streams in the ,swatara and ,wiconisco synclines 7the latter then having gained the ,juniata7 had been turned aside on their way to the ,carboniferous basins4 ,on the other hand1 the ,anthracite river1 rising somewhere on the plains north of the ,wyoming syncline and pursuing an irregular course from one coal basin to another1 found an extremely difficult task in cutting down its channel across the numerous hard beds of the ,carboniferous sandstones1 so often repeated in the rolling folds of the coal fields4 ,it is also important to remember that an aid to other conditions concerned in the diversion of the upper ,anthracite is found in the decrease of slope that its lower course suffered in crossing the coal fields1 if that area took any part in the deformation that produced the ,newark monocline--whichever theory prove true in regard to the origin of the southeastward flow of the rivers--for loss of slope in the middle course1 where the river had to cross many reefs of hard sandstone1 would have been very effective in lengthening the time allowed for the diversion of the headwaters4 ,the question is1 therefore1 whether the retardation of down-cutting here experienced by the ,anthracite was sufficient to allow the capture of its headwaters by the ,susquehanna4 ,there can be little doubt as to the correct quality of the process1 but whether it was quantitatively sufficient is another matter4 ,in the absence of any means of testing its sufficiency1 may the result not be taken as the test8 ,is not the correspondence between deduction and fact close enough to prove the correctness of the deduction8 #cc4 ,present outward drainage of the ,anthracite basins4--,the ,lehigh1 like the ,susquehanna1 made an attempt to capture the headwaters of adjacent streams1 but failed to acquire much territory from the ,anthracite because the ,carboniferous sandstones spread out between the two in a broad plateau of hard rocks1 across which the divide made little movement4 ,the plateau area that its upper branches drain is1 ,i think1 the conquest of a later cycle of growth4 ,the ,delaware had little success1 except as against certain eastern synclinal branches of the ,anthracite1 for the same reason4 ,the ancestor of the ,swatara of to-day made little progress in extending its headwaters because its point of attack was against the repeated ,carboniferous sandstones in the ,swatara synclinal4 ,one early stream alone found a favorable opportunity for conquest1 and thus grew to be the master river--the ,susquehanna of to-day4 ,the head of the ,anthracite was carried away by this captor1 and its beheaded lower portion remains in our ,schuylkill4 ,the ,anthracite coal basins1 formerly drained by the single master stream1 have since been apportioned to the surrounding rivers4 ,as the ,siluro-,devonian lowlands were opened around the coal-basins1 especially on the north and west1 the streams that formerly flowed into the basins were gradually inverted and flowed out of them1 as they still do4 ,the extent of the inversion seems to be in a general way proportionate to its opportunity4 ,the most considerable conquests were made in the upper basins1 where the ,catawissa and ,nescopec streams of to-day drain many square miles of wide valleys opened on the ,mauch ,chunk red shale between the ,pocono and ,pottsville sandstone ridges2 the ancient middle waters of the ,anthracite here being inverted to the ,susquehanna tributaries1 because the northern coal basins were degraded very slowly after the upper ,anthracite had been diverted4 ,the ,schuylkill as the modern representative of the ,anthracite retains only certain streams south of a medial divide between ,nescopec and ,blue mountains4 ,the only considerable part of the old ,anthracite river that still retains a course along the axis of a synclinal trough seems to be that part which follows the ,wyoming basin2 none of the many other coal basins are now occupied by the large stream that originally followed them4 ,the reason for this is manifestly to be found in the great depth of the ,wyoming basin1 whereby the axial portion of its hard sandstones are even now below baselevel1 and hence have never yet acted to throw the river from its axial course4 ,indeed1 during the early cycles of denudation1 this basin must have been changed from a deep lake to a lacustrine plain by the accumulation in it of waste from the surrounding highlands1 and for a time the streams that entered it may have flowed in meandering courses across the ancient alluvial surface2 the lacustrine and alluvial condition may have been temporarily revived at the time of the ,jurassic elevation4 ,it is perhaps as an inheritance from a course thus locally superimposed that we may come to regard the deflection of the river at ,nanticoke from the axis of the syncline to a narrow shale valley on its northern side1 before turning south again and leaving the basin altogether4 ,but like certain other suggestions1 this can only be regarded as an open hypothesis1 to be tested by some better method of river analysis than we now possess2 like several of the other explanations here offered1 it is presented more as a possibility to be discussed than as a conclusion to be accepted4 ,i believe that it was during the earlier part of the great ,jura-,cretaceous cycle of denudation that the ,susquehanna thus became the master stream of the central district of the state4 ,for the rest of the cycle1 it was occupied in carrying off the waste and reducing the surface to a well finished baselevel lowland that characterized the end of ,cretaceous time4 ,from an active youth of conquest1 the ,susquehanna advanced into an old age of established boundaries2 and in later times1 its area of drainage does not seem to have been greatly altered from that so long ago defined2 except perhaps in the districts drained by the ,west and ,north ,branch headwaters4 #cd4 ,homologies of the ,susquehanna and ,juniata4--,looking at the change from the ,anthracite to the ,susquehanna in a broad way1 one may perceive that it is an effect of the same order as the peripheral diversion of the ,broad ,top drainage1 illustrated in figures #bb1 #bc and #bd2 another example of a similar change is seen in the lateral diversion of the ,juniata above ,lewistown and its rectilinear continuation in ,aughwick creek1 from their original axial location when they formed the initial ,broad ,top outlet4 ,they have departed from the axis of their syncline to the softer beds on its southern side2 ,,fe of fig4 #ag has been diverted to ,,fd of fig4 #ah4 ,all of these examples are truly only special cases of the one already described in which the ,juniata left its original syncline for others to the south4 ,the general case may be stated in a few words4 ,a stream flowing along a syncline of hard beds 7,carboniferous sandstones7 develops side streams which breach the adjacent anticlines and open lowlands in the underlying softer beds 7,devonian and ,silurian74 ,on these lowlands1 the headwaters of side streams from other synclines are encountered and a contest ensues as to possession of the drainage territory4 ,the divides are pushed away from those headwaters whose lower course leads them over the fewest hard barriers2 this conquest goes on until the upper course of the initial main stream is diverted to a new and easier path than the one it chose in its youth in obedience to the first deformation of the region4 ,thus the ,juniata now avoids the center and once deepest part of the old ,broad ,top lake1 because in the general progress of erosion1 lowlands on soft ,devonian beds were opened all around the edge of the great mass of sandstones that held the lake2 the original drainage across the lake1 from its western slopes to its outlet just south of the ,jack's mountain anticline1 has now taken an easier path along the ,devonian beds to the west of the old lake basin1 and is seen in the ,little ,juniata1 flowing along the outer side of ,terrace mountain and rounding the northern synclinal point where ,terrace mountain joins ,sideling hill4 ,it then crosses ,jack's mountain at a point where the hard ,medina sandstones of the mountain were still buried at the time of the choice of this channel4 ,in the same way1 the drainage of the subordinate basin1 through which the main lake discharged eastward1 is now not along the axis of the ,juniata-,catawissa syncline1 but on the softer beds along one side of it2 and along the southern side because the easier escape that was provided for it lay on that side1 namely1 via the ,tuscarora and ,wiconisco synclines1 as already described4 ,the much broader change from the ,anthracite to the ,susquehanna was only another form of the same process4 ,taking a transverse view of the whole system of central folds1 it is perceived that their axes descend into the ,anthracite district from the east and rise westward therefrom2 it is as if the whole region had received a slight transverse folding1 and the transverse axis of depression thus formed defined the initial course of the first master stream4 ,but this master stream deserted its original course on the transverse axis of depression because a lateral course across lowlands on softer beds was opened by its side streams2 and in the contest on these lowlands with an external stream1 the ,susquehanna1 the upper portion of the ,anthracite was diverted from the hard rocks that had appeared on the transverse axis4 ,the distance of diversion from the axial to the lateral course in this case was great because of the gentle quality of the transverse folding2 or1 better said1 because of the gentle dips of the axes of the longitudinal folds4 ,this appearance of systematic re-arrangement in the several river courses where none was expected is to my mind a strong argument in favor of the originally consequent location of the rivers and their later mutual adjustment4 ,it may perhaps be conceived that antecedent streams might imitate one another roughly in the attitude that they prophetically chose with regard to folds subsequently formed1 but no reason has been suggested for the imitation being carried to so remarkable and definite a degree as that here outlined4 #ce4 ,superimposition of the ,susquehanna on two synclinal ridges4--,there is however one apparently venturesome postulate that may have been already noted as such by the reader2 unless it can be reasonably accounted for and shown to be a natural result of the long sequence of changes here considered1 it will seriously militate against the validity of the whole argument4 ,the present course of the middle ,susquehanna leads it through the apical curves of two ,pocono synclinal ridges1 which were disregarded in the statement given above4 ,it was then assumed that the embryonic ,susquehanna gained possession of the ,siluro-,devonian lowland drainage by gnawing out a course to the west of these synclinal points2 for it is not to be thought of that any conquest of the headwaters of the ,anthracite river could have been made by the ,susquehanna if it had had to gnaw out the existing four traverses of the ,pocono sandstones before securing the drainage of the lowlands above them4 ,the backward progress of the ,susquehanna could not in that case have been nearly fast enough to reach the ,anthracite before the latter had sunk its channel to a safe depth4 ,it is therefore important to justify the assumption as to the more westerly location of the embryonic ,susquehanna2 and afterwards1 to explain how it should have since then been transferred to its present course4 ,a short cut through all this round-about method is open to those who adopt in the beginning the theory that the ,susquehanna was an antecedent river2 but as ,i have said at the outset of this inquiry1 it seems to me that such a method is not freer from assumption1 even though shorter than the one here adopted2 and it has the demerit of not considering all the curious details that follow the examination of consequent and adjusted courses4 ,the sufficient reason for the assumption that the embryonic ,susquehanna lay farther west than the present one in the neighborhood of the ,pocono synclinals is simply that--in the absence of any antecedent stream--it must have lain there4 ,the whole explanation of the development of the ,siluro-,devonian lowlands between the ,pocono and ,medina ridges depends simply on their being weathered out where the rocks are weak enough to waste faster than the enclosing harder ridges through which the streams escape4 ,in this process1 the streams exercise no control whatever over the direction in which their headwaters shall grow2 they leave this entirely to the structure of the district that they drain4 ,it thus appears that1 under the postulate as to the initial location of the ,susquehanna as one of the many streams descending the great slope of the ,kittatinny 7,cumberland7 highland into the ,swatara syncline1 its course being reversed from northward to southward by the ,newark depression1 we are required to suppose that its headwater 7northward7 growth at the time of the ,jurassic elevation must have been on the ,siluro-,devonian beds1 so as to avoid the harder rocks on either side4 ,many streams competed for the distinction of becoming the master1 and that one gained its ambition whose initial location gave it the best subsequent opportunity4 ,it remains then to consider the means by which the course of the conquering ,susquehanna may have been subsequently changed from the lowlands on to the two ,pocono synclines that it now traverses4 ,some departure from its early location may have been due to eastward planation in its advanced age1 when it had large volume and gentle slope and was therefore swinging and cutting laterally in its lower course4 ,this may have had a share in the result1 but there is another process that seems to me more effective4 ,in the latter part of the ,jura-,cretaceous cycle1 the whole country hereabout suffered a moderate depression1 by which the ,atlantic transgressed many miles inland from its former shoreline1 across the lowlands of erosion that had been developed on the litoral belt4 ,such a depression must have had a distinct effect on the lower courses of the larger rivers1 which having already cut their channels down close to baselevel and opened their valleys wide on the softer rocks1 were then estuaried1 or at least so far checked as to build wide flood-plains over their lower stretches4 ,indeed1 the flood-plains may have been begun at an earlier date1 and have been confirmed and extended in the later time of depression4 ,is it possible that in the latest stage of this process1 the almost baselevelled remnants of ,blue mountain and the ,pocono ridges could have been buried under the flood-plain in the neighborhood of the river8 ,if this be admitted1 it is then natural for the river to depart from the line of its buried channel and cross the buried ridges on which it might settle down as a superimposed river in the next cycle of elevation4 ,it is difficult to decide such general questions as these2 and it may be difficult for the reader to gain much confidence in the efficacy of the processes suggested2 but there are certain features in the side streams of the ,susquehanna that lend some color of probability to the explanation as offered4 ,admit1 for the moment1 that the aged ,susquehanna1 in the later part of the ,jura-,cretaceous cycle1 did change its channel somewhat by cutting to one side1 or by planation1 as it is called4 ,admit1 also1 that in the natural progress of its growth it had built a broad flood plain over the ,siluro-,devonian lowlands1 and that the depth of this deposit was increased by the formation of an estuarine delta upon it when the country sank at the time of the mid-,cretaceous transgression of the sea4 ,it is manifest that one of the consequences of all this might be the peculiar course of the river that is to be explained1 namely1 its superimposition on the two ,pocono synclinal ridges in the next cycle of its history1 after the ,tertiary elevation had given it opportunity to re-discover them4 ,it remains to inquire what other consequences should follow from the same conditions1 and from these to devise tests of the hypothesis4 #cf4 ,evidence of superimposition in the ,susquehanna tributaries4--,one of the peculiarities of flood-plained rivers is that the lateral streams shift their points of union with the main stream farther and farther down the valley1 as ,lombardini has shown in the case of the ,po4 ,if the ,susquehanna were heavily flood-plained at the close of the ,jura-,cretaceous cycle1 some of its tributaries should manifest signs of this kind of deflection from their structural courses along the strike of the rocks4 ,side streams that once joined the main stream on the line of some of the softer northeast-southwest beds1 leaving the stronger beds as faint hills on either side1 must have forgotten such control after it was baselevelled and buried2 as the flood plain grew1 they properly took more and more distinctly downward deflected courses1 and these deflections should be maintained in subsequent cycles as superimposed courses independent of structural guidance4 ,such ,i believe to be the fact4 ,the downstream deflection is so distinctly a peculiarity of a number of tributaries that join the ,susquehanna on the west side 7see figure #a7 that it cannot be ascribed to accident1 but must be referred to some systematic cause4 ,examples of deflection are found in ,penn's creek1 ,middle creek and ,north ,mahantango creek in ,snyder county2 ,west ,mahantango between the latter and ,juniata county2 and in the ,juniata and ,little ,juniata rivers of ,perry county4 ,on the other side of the ,susquehanna1 the examples are not so distinct1 but the following may be mentioned3 ,delaware and ,warrior runs1 ,chillisquaque creek and ,little ,shamokin creek1 all in ,northumberland county4 ,it may be remarked that it does not seem impossible that the reason for the more distinct deflection of the western streams may be that the ,susquehanna is at present east of its old course1 and hence towards the eastern margin of its flood plain1 as1 indeed its position on the ,pocono synclinals implies4 ,a reason for the final location of the superimposed river on the eastern side of the old flood plain may perhaps be found in the eastward tilting that is known to have accompanied the elevation of the ,cretaceous lowland4 ,it follows from the foregoing that the present lower course of the ,susquehanna must also be of superimposed origin2 for the flood plain of the middle course must have extended down stream to its delta1 and there have become confluent with the sheet of ,cretaceous sediments that covered all the southeastern lowland1 over which the sea had transgressed4 ,mc,gee has already pointed out indications of superimposed stream courses in the southeastern part of the ,state2#bb but ,i am not sure that he would regard them as of the date here referred to4 ,footnote #bb3 ,amer4 ,journ4 ,science1 xxxv1 #ahhh1 #aba1 #acd4 ,the theory of the location of the ,susquehanna on the ,pocono synclinal ridges therefore stands as follows4 ,the general position of the river indicates that it has been located by some process of slow self-adjusting development and that it is not a persistent antecedent river2 and yet there is no reason to think that it could have been brought into its present special position by any process of shifting divides4 ,the processes that have been suggested to account for its special location1 as departing slightly from a location due to slow adjustments following an ancient consequent origin1 call for the occurrence of certain additional peculiarities in the courses of its tributary streams1 entirely unforeseen and unnoticed until this point in the inquiry is reached2 and on looking at the map to see if they occur1 they are found with perfect distinctness4 ,the hypothesis of superimposition may therefore be regarded as having advanced beyond the stage of mere suggestion and as having gained some degree of confirmation from the correlations that it detects and explains4 ,it only remains to ask if these correlations might have originated in any other way1 and if the answer to this is in the negative1 the case may be looked upon as having a fair measure of evidence in its favor4 ,the remaining consideration may be taken up at once as the first point to be examined in the ,tertiary cycle of development4 #cg4 ,events of the ,tertiary cycle4--,the elevation given to the region by which ,cretaceous baselevelling was terminated1 and which ,i have called the early ,tertiary elevation1 offered opportunity for the streams to deepen their channels once more4 ,in doing so1 certain adjustments of moderate amount occurred1 which will be soon examined4 ,as time went on1 much denudation was effected1 but no wide-spread baselevelling was reached1 for the ,cretaceous crest lines of the hard sandstone ridges still exist4 ,the ,tertiary cycle was an incomplete one4 ,at its close1 lowlands had been opened only on the weaker rocks between the hard beds4 ,is it not possible that the flood-plaining of the ,susquehanna and the down-stream deflection of its branches took place in the closing stages of this cycle1 instead of at the end of the previous cycle8 ,if so1 the deflection might appear on the branches1 but the main river would not be transferred to the ,pocono ridges4 ,this question may be safely answered in the negative2 for the ,tertiary lowland is by no means well enough baselevelled to permit such an event4 ,the beds of intermediate resistance1 the ,oriskany and certain ,chemung sandstones1 had not been worn down to baselevel at the close of the ,tertiary cycle2 they had indeed lost much of the height that they possessed at the close of the previous cycle1 but they had not been reduced as low as the softer beds on either side4 ,they were only reduced to ridges of moderate and unequal height over the general plain of the ,siluro-,devonian low country1 without great strength of relief but quite strong enough to call for obedience from the streams along side of them4 ,and yet near ,selin's ,grove1 for example1 in ,snyder county1 ,penn's and ,middle creeks depart most distinctly from the strike of the local rocks as they near the ,susquehanna1 and traverse certain well-marked ridges on their way to the main river4 ,such aberrant streams cannot be regarded as superimposed at the close of the incomplete ,tertiary cycle2 they cannot be explained by any process of spontaneous adjustment yet described1 nor can they be regarded as vastly ancient streams of antecedent courses2 ,i am therefore much tempted to consider them as of superimposed origin1 inheriting their present courses from the flood-plain cover of the ,susquehanna in the latest stage of the ,jura-,cretaceous cycle4 ,with this tentative conclusion in mind as to the final events of ,jura-,cretaceous time1 we may take up the more deliberate consideration of the work of the ,tertiary cycle4 ,the chief work of the ,tertiary cycle was merely the opening of the valley lowlands2 little opportunity for river adjustment occurred except on a small scale4 ,the most evident cases of adjustment have resulted in the change of water-gaps into wind-gaps1 of which several examples can be given1 the one best known being the ,delaware wind-gap between the ,lehigh and ,delaware water-gaps in ,blue mountain4 ,the wind-gap marks the unfinished notch of some stream that once crossed the ridge here and whose headwaters have since then been diverted1 probably to the ,lehigh4 ,the difficulty in the case is not at all how the stream that once flowed here was diverted1 but how a stream that could be diverted in the ,tertiary cycle could have escaped diversion at some earlier date4 ,the relative rarity of wind-gaps indicates that nearly all of the initial lateral streams1 which may have crossed the ridges at an early epoch in the history of the rivers1 have been beheaded in some cycle earlier than the ,tertiary and their gaps thereafter obliterated4 ,why the ,delaware wind-gap stream should have endured into a later cycle does not at present appear4 ,other wind-gaps of apparently similar origin may be found in ,blue mountain west of the ,schuylkill and east of the ,susquehanna4 ,it is noteworthy that if any small streams still persevere in their gaps across a hard ridge1 they are not very close to any large river-gap2 hence it is only at the very headwaters of ,conedogwinet creek1 in the northern part of ,franklin county1 that any water is still drawn from the back of ,blue mountain4 ,again1 these small stream gaps do not lie between large river-gaps and wind-gaps1 but wind-gaps lie between the gaps of large rivers and those of small streams that are not yet diverted4 ,excellent illustration of this is found on the ,piedmont sheet of the contoured maps issued by the ,united ,states ,geological ,survey4 ,the sheet covers part of ,maryland and ,west ,virginia1 near where the ,north ,branch of the ,potomac comes out of the plateau and crosses ,new ,creek mountain4 ,eleven miles south of the ,potomac gap there is a deep wind-gap2 but further on1 at twenty1 twenty-five and twenty-nine miles from the river-gap are three fine water-gaps occupied by small streams4 ,this example merely shows how many important points in the history of our rivers will be made clear when the country is properly portrayed on contoured maps4 ,a few lines may be given to the general absence of gaps in ,blue ,mountain in ,pennsylvania4 ,when the initial consequent drainage was established1 many streams must have been located on the northward slope of the great ,cumberland highland1 ,c1 ,c1 fig4 #ba2 they must have gullied the slope to great depths and carried away great volumes of the weak ,cambrian beds that lay deep within the hard outer casings of the mass4 ,minor adjustments served to diminish the number of these streams1 but the more effective cause of their present rarity lay in the natural selection of certain of them to become large streams2 the smaller ones were generally beheaded by these4 ,the only examples of streams that still cross this ridge with their initial ,permian direction of flow to the northwest are found in two southern branches of ,tuscarora creek at the southern point of ,juniata county2 and these survive because of their obscure location among the many ,medina ridges of that district1 where they were not easily accessible to capture by other streams4 #ch4 ,tertiary adjustment of the ,juniata on the ,medina anticlines4--,the lower course of the ,juniata presents several examples of adjustment referable to the last part of the ,jura-,cretaceous cycle and to the ,tertiary cycle4 ,the explanation offered for the escape of this river from its initial syncline did not show any reason for its peculiar position with respect to the several ,medina anticlines that it now borders1 because at the time when it was led across country to the ,wiconisco syncline1 the hard ,medina beds of these anticlines were not discovered4 ,it is therefore hardly to be thought that the location of the ,juniata in the ,narrows below ,lewistown between ,blue ,ridge and ,shade mountain and its avoidance of ,tuscarora mountain could have been defined at that early date4 ,but all these ,medina anticlines rise more or less above the ,cretaceous baselevel1 and must have had some effect on the position taken by the river about the middle of that cycle when its channel sank upon them4 ,blue ,ridge and ,black ,log anticlines rise highest4 ,the first location of the cross-country stream that led the early ,juniata away from its initial syncline probably traversed the ,blue ,ridge and ,black ,log anticlines while they were yet buried2 but its channel-cutting was much retarded on encountering them1 and some branch stream working around from the lower side of the obstructions may have diverted the river to an easier path4 ,the only path of the kind is the narrow one between the overlapping anticlines of ,blue ,ridge and ,shade mountains1 and there the ,juniata now flows4 ,if another elevation should occur in the future1 it might happen that the slow deepening of the channel in the hard ,medina beds which now floor the ,narrows would allow ,middle creek of ,snyder county to tap the ,juniata at ,lewistown and lead it by direct course past ,middleburgh to the ,susquehanna2 thus it would return to the path of its youth4 ,the location of the ,juniata at the end of ,tuscarora mountain is again so definite that it can hardly be referred to a time when the mountain had not been revealed4 ,the most likely position of the original cross-country stream which brought the ,juniata into the ,wiconisco syncline was somewhere on the line of the existing mountain1 and assuming it to have been there1 we must question how it has been displaced4 ,the process seems to have been of the same kind as that just given2 the retardation of channel-cutting in the late ,cretaceous cycle1 when the ,medina beds of ,tuscarora anticline were discovered1 allowed a branch from the lower part of the river to work around the end of the mountain and lead the river out that way4 ,the occurrence of a shallow depression across the summit of the otherwise remarkably even crest of ,tuscarora mountain suggests that this diversion was not finally accomplished until shortly after the ,tertiary elevation of the country2 but at whatever date the adjustment occurred1 it is natural that it should pass around the eastern end of the mountain and not around the western end1 where the course would have been much longer1 and therefore not successfully to be taken by a diverting stream4 ,while the quality of these processes appears satisfactory1 ,i am not satisfied as to the sufficiency of their quantity4 ,if diversion was successfully practiced at the crossing of the ,tuscarora anticline1 why not also at the crossing of ,jack's mountain anticline1 on which the river still perseveres4 ,it is difficult here to decide how much confidence may be placed in the explanation1 because of its giving reason for the location of certain streams1 and how much doubt must be cast upon it1 because it seems impossible and is not of universal application4 #ci4 ,migration of the ,atlantic-,ohio divide4--,there are certain shifted courses which cannot be definitely referred to any particular cycle1 and which may therefore be mentioned now4 ,among the greatest are those by which the divide between the ,atlantic and the ,ohio streams has been changed from its initial position on the great constructional ,nittany highland and ,bedford range4 ,there was probably no significant change until after ,newark depression1 for the branches of the ,anthracite river could not have begun to push the divide westward till after the eastward flow of the river was determined2 until then1 there does not seem to have been any marked advantage possessed by the eastward streams over the westward4 ,but with the eastward escape of the ,anthracite1 it probably found a shorter course to the sea and one that led it over alternately soft and hard rocks1 instead of the longer course followed by the ,ohio streams over continuous sandstones4 ,the advantage given by the greater extent of soft beds is indicated by the great breadth of the existing valleys in the central district compared with the less breadth of those in the plateau to the west4 ,consider the effect of this advantage at the time of the ,jurassic elevation4 ,as the streams on the eastern slope of the ,nittany divide had the shortest and steepest courses to the sea1 they deepened their valleys faster than those on the west and acquired drainage area from them2 hence we find reason for the drainage of the entire ,nittany and ,bedford district by the ,atlantic streams at present4 ,various branches of what are now the ,alleghany and ,monongahela originally rose on the western slope of the dividing range4 ,these probably reached much farther east in pre-,permian time1 but had their headwaters turned another way by the growth of the great anticlinal divide2 but the smaller anticlines of ,laurel ridge and ,negro mountain farther west do not seem to have been strong enough to form a divide1 for the rivers still traverse them4 ,now as the headwaters of the ,juniata breached the eastern slope of the ,nittany-,bedford range and pushed the divide westward1 they at last gained possession of the ,siluro-,devonian monocline on its western slope2 but beyond this it has not been possible for them yet to go4 ,as the streams cut down deeper and encountered the ,medina anticline near the core of the ridge1 they sawed a passage through it2 the ,cambrian beds were discovered below and a valley was opened on them as the ,medina cover wore away4 ,the most important point about this is that we find in it an adequate explanation of the opposite location of water-gaps in pairs1 such as characterize the branches of the ,juniata below ,tyrone and again below ,bedford4 ,this opposite location has been held to indicate an antecedent origin of the river that passes through the gaps1 while gaps formed by self-developed streams are not thought to present such correspondence 7,hilber74 ,yet this special case of paired gaps in the opposite walls of a breached anticline is manifestly a direct sequence of the development of the ,juniata headwaters4 ,the settling down of the main ,juniata on ,jack's mountain anticline below ,huntingdon is another case of the same kind1 in which the relatively low anticlinal crest is as yet not widely breached2 the gaps below ,bedford stand apart1 as the crest is there higher1 and hence wider opened2 and the gaps below ,tyrone are separated by some ten or twelve miles4 ,when the headwater streams captured the drainage of the ,siluro-,devonian monocline on the western side of the ancient dividing anticline1 they developed subsequent rectangular branches growing like a well-trained grape vine4 ,most of this valley has been acquired by the west branch of the ,susquehanna1 probably because it traversed the ,medina beds less often than the ,juniata4 ,for the same reason1 it may be1 the ,west ,branch has captured a considerable area of plateau drainage that must have once belonged to the ,ohio1 while the ,juniata has none of it2 but if so1 the capture must have been before the ,tertiary cycle1 for since that time the ability of the ,west ,branch and of the ,juniata as regards such capture appears about alike4 ,on the other hand1 ,castleman's river1 a branch of the ,monongahela1 still retains the drainage of a small bit of the ,siluro-,devonian monocline1 at the southern border of the ,state1 where the ,juniata headwaters had the least opportunity to capture it2 but the change here is probably only retarded1 not prevented entirely2 the ,juniata will some day push the divide even here back to the ,alleghany ,front1 the frontal bluff of the plateau4 ,illustration3 ,,fig4 #bf4 #dj4 ,other examples of adjustments4--,other examples of small adjustments are found around the ,wyoming basin1 fig4 #bf4 ,originally all these streams ran centripetally down the enclosing slopes1 and in such locations they must have cut gullies and breaches in the hard ,carboniferous beds and opened low back country on the weaker ,devonians4 ,some of the existing streams still do so1 and these are precisely the ones that are not easily reached by divertors4 ,the ,susquehanna in its course outside of the basin has sent out branches that have beheaded all the centripetal streams within reach2 where the same river enters the basin1 the centripetal streams have been shortened if not completely beheaded4 ,a branch of the ,delaware has captured the heads of some of the streams near the eastern end of the basin4 ,elsewhere1 the centripetal streams still exist of good length4 ,the contrast between the persistence of some of the centripetal streams here and their peripheral diversion around ,broad ,top is a consequence of the difference of altitude of the old lake bottoms in the two cases4 ,it is not to be doubted that we shall become acquainted with many examples of this kind as our intimacy with rivers increases4 #da4 ,events of the ,quaternary cycle4--,the brief quaternary cycle does not offer many examples of the kind that we have considered1 and all that are found are of small dimensions4 ,the only capturing stream that need be mentioned has lately been described as a river pirate2#bc but its conquest is only a ,schleswig-,holstein affair compared to the ,goth- and ,hun-like depredations of the greater streams in earlier cycles4 ,footnote #bc3 ,science1 xiii1 #ahhi1 #ajh4 ,the character of the streams and their valleys as they now exist is strikingly dependent in many ways on the relation of the incipient quaternary cycle to the longer cycles of the past4 ,no lakes occur1 exception being made only of the relatively small ponds due to drift obstruction within the glaciated area4 ,waterfalls are found only at the headwaters of small streams in the plateau district1 exception again being made only for certain cases of larger streams that have been thrown from their pre-glacial courses by drift barriers1 and which are now in a very immature state on their new lines of flow4 ,the small valleys of this cycle are shallow and narrow1 always of a size strictly proportional to the volume of the stream and the hardness of the enclosing rocks1 exception being made only in the case of post-glacial gorges whose streams have been displaced from their pre-glacial channels4 ,the terraces that are seen1 especially on the streams that flow in or from the glaciated district1 are merely a temporary and subordinate complication of the general development of the valleys4 ,in the region that has been here considered1 the streams have been seldom much displaced from their pre-glacial channels2 but in the northwestern part of the ,state1 where the drift in the valleys seems to be heavier1 more serious disturbance of pre-glacial courses is reported4 ,the facts here referred to in regard to lakes1 falls1 gorges1 terraces and displaced streams are to be found in the various volumes of the ,second ,geological ,survey of the ,state2#bd in regard to the terraces and the estuarine deflections of the ,delaware and ,susquehanna1 reference should be made also to ,mc,gee's studies4#be ,footnote #bd3 ,especially ,carll1 ,reports ,i#c1 ,i#d2 ,white1 ,reports ,g#e1 ,g#f2 ,lewis1 ,report ,z4 ,footnote #be3 ,amer4 ,journ4 ,science1 xxxv1 #ahhh1 #cfg1 #ddh2 ,seventh ,annual ,rep4 ,u4 ,s4 ,g4 ,s41 #ahhh1 #ede4 #db4 ,doubtful cases4--,it is hardly necessary to state that there are many facts for which no satisfactory explanation is found under the theory of adjustments that we have been considering4 ,some will certainly include the location of the ,susquehanna on the points of the ,pocono synclines under this category2 all must feel that such a location savors of an antecedent origin4 ,the same is true of the examples of the alignment of water-gaps found on certain streams2 for example1 the four gaps cut in the two pairs of ,pocono and ,pottsville outcrops at the west end of the ,wyoming syncline1 and the three gaps where the ,little ,schuylkill crosses the coal basin at ,tamaqua2 the opposite gaps in pairs at ,tyrone and ,bedford have already been sufficiently explained4 ,the location of the upper ,north ,branch of the ,susquehanna is also unrelated to processes of adjustment as far as ,i can see them1 and the great area of plateau drainage that is now possessed by the ,west ,branch is certainly difficult to understand as the result of conquest4 ,the two independent gaps in ,tussey's mountain1 maintained by the ,juniata and its ,frankstown branch below ,tyrone are curious1 especially in view of the apparent diversion of the branch to the main stream on the upper side of ,warrior's ridge 7,oriskany71 just east of ,tussey's mountain4 #dc4 ,complicated history of our actual rivers4--,if this theory of the history of our rivers is correct1 it follows that any one river as it now exists is of so complicated an origin that its development cannot become a matter of general study and must unhappily remain only a subject for special investigation for some time to come4 ,it was my hope on beginning this essay to find some teachable sequence of facts that would serve to relieve the usual routine of statistical and descriptive geography1 but this is not the result that has been attained4 ,the history of the ,susquehanna1 the ,juniata1 or the ,schuylkill1 is too involved with complex changes1 if not enshrouded in mystery1 to become intelligible to any but advanced students2 only the simplest cases of river development can be introduced into the narrow limits of ordinary instruction4 ,the single course of an ancient stream is now broken into several independent parts2 witness the disjointing and diversion of the original ,juniata1 which1 as ,i have supposed1 once extended from ,broad ,top lake to the ,catawissa basin4 ,now the upper part of the stream1 representing the early ,broad ,top outlet1 is reduced to small volume in ,aughwick creek2 the continuation of the stream to ,lewistown is first set to one side of its original axial location and is then diverted to another syncline2 the beheaded portion now represented by ,middle creek is diverted from its course to the ,catawissa basin by the ,susquehanna2 perhaps the ,catawissa of the present day represents the reversed course of the lower ,juniata where it joined the ,anthracite4 ,this unserviceably complicated statement is not much simplified if instead of beginning with an original stream and searching out its present disjointed parts1 we trace the composition of a single existing stream from its once independent parts4 ,the ,juniata of to-day consists of headwaters acquired from ,ohio streams2 the lake in which the river once gathered its upper branches is now drained and the lake bottom has become a mountain top2 the streams flow around the margin of the lake1 not across its basin2 a short course towards ,lewistown nearly coincides with the original location of the stream1 but to confound this with a precise agreement is to lose the true significance of river history2 the lower course is the product of diversion at least at two epochs and certainly in several places2 and where the river now joins the ,susquehanna1 it is suspected of having a superimposed course unlike any of the rest of the stream4 ,this is too complicated1 even if it should ever be demonstrated to be wholly true1 to serve as material for ordinary study2 but as long as it has a savor of truth1 and as long as we are ignorant of the whole history of our rivers1 through which alone their present features can be rightfully understood1 we must continue to search after the natural processes of their development as carefully and thoroughly as the biologist searches for the links missing from his scheme of classification4 #dd4 ,provisional ,conclusions4--,it is in view of these doubts and complications that ,i feel that the history of our rivers is not yet settled2 but yet the numerous accordances of actual and deductive locations appear so definite and in some cases so remarkable that they cannot be neglected1 as they must be if we should adhere to the antecedent origin of the river courses4 ,the method adopted on an early page therefore seems to be justified4 ,the provisional system of ancient consequent drainage1 illustrated on fig4 #ba1 does appear to be sufficiently related to the streams of to-day to warrant the belief that most of our rivers took their first courses between the primitive folds of our mountains1 and that from that distant time to the present the changes they have suffered are due to their own interaction--to their own mutual adjustment more than to any other cause4 ,the ,susquehanna1 ,schuylkill1 ,lehigh and ,delaware are compound1 composite and highly complex rivers1 of repeated mature adjustment4 ,the middle ,susquehanna and its branches and the upper portions of the ,schuylkill and ,lehigh are descendants of original ,permian rivers consequent on the constructional topography of that time2 ,newark depression reversed the flow of some of the transverse streams1 and the spontaneous changes or adjustments from immature to mature courses in the several cycles of development are so numerous and extensive that1 as ,lwl truly says1 the initial drainage has almost disappeared4 ,the larger westward-flowing streams of the plateau are of earlier1 ,carboniferous birth1 and have suffered little subsequent change beyond a loss of headwaters4 ,the lower courses of the ,atlantic rivers are younger1 having been much shifted from their ,permian or pre-,permian courses by ,newark and ,cretaceous superimposition1 as well as by recent downward deformation of the surface in their existing estuaries4 ,no recognizable remnant of rivers antecedent to the ,permian deformation are found in the central part of the ,state2 and with the exception of parts of the upper ,schuylkill and of the ,susquehanna near ,wilkes-,barre1 there are no large survivors of ,permian consequent streams in the ordinary meaning of the term consequent4 ,the shifting of courses in the progress of mature adjustment has had more to do with determining the actual location of our rivers and streams than any other process4 ,harvard ,college1 ,june1 #ahhi4 ,,topographic ,,models4 ,,by ,,cosmos ,,mindeleff4 ,of the many methods by which it has been sought to represent the relief of a country or district1 only two have been at all widely used4 ,these methods are1 in the order of their development1 by hachured and by contoured maps4 ,both have advantages and both have serious disadvantages4 ,without entering into the controversy that is even yet raging over the relative merits of the two systems1 some slight notice of what each claims to accomplish is necessary4 ,the representation of relief by hachures is a graphic system1 and in the best examples we have is an attempt to show1 upon a plane surface1 the actual appearance of a given area under given conditions of lighting1--as in the ,dufour map of the ,alps4 ,of course certain details that would really disappear if the assumed conditions were actual ones1 must be shown upon the map1--so that it is1 after all1 but a conventional representation4 ,the very best examples are1 for this and other reasons1 unsatisfactory1 and far more so is this the case in the vastly larger class of medium grade and poor work4 ,the contour system represents relief by a series of lines1 each of which is1 at every point throughout its length1 at a certain stated elevation above sea-level1 or some other datum-plane2 in other words1 each contour line represents what would be the water's edge1 if the sea were to rise to that elevation4 ,it possesses the advantage of great clearness1 but fails to a large degree in the representation of surface detail2 moreover1 one must have considerable knowledge of topography1 in order to read the map correctly4#a ,footnote #a3 ,for specimens of representation of the same subject on different scales1 in both the hachure and contour systems1 see plate from ,enthoffer's ,topographical ,atlas4 ,to those who must give first place to the quantity of relief rather than the quality1 as1 for example1 the geologist or the engineer1 a contoured map is now considered essential4 ,on the other hand1 where quality of relief is the prime consideration and the quantity a secondary one1 as1 for example1 for the use of the army1 a hachured map is considered the best4 ,the method of hachures may be roughly characterized as a graphic system with a conventional element1 and the contour method as a conventional system with a graphic element1--for if the contour interval is small enough a sort of shading is produced which helps considerably the idea of relief4 ,in addition to these two great systems1 with which everyone is more or less familiar1 there is another method of representing a country or district1--a method that succeeds where others fail1 and which although by no means new1 has not received the attention it deserves3 this is the representation of a country by a model in relief4 ,certain striking advantages of models over maps of all kinds are1 indeed1 so apparent that one almost loses sight of such slight disadvantages as can1 of course1 be urged against them4 ,in the graphic representation of the surface they are far superior to the hachured map1 and they have the further advantage of expressing the relative relief1 which the hachured map fails to do1 except in a very general way4 ,they have also the advantage of showing actual shadows1 exactly as they would be seen in a bird's-eye view of the district1 instead of more or less conventional ones1 and are1 consequently1 more easily comprehended by the layman1 without becoming any less valuable to the skilled topographer4 ,in short1 they combine all the graphic features of a hachured map with all the advantages of the best class of contoured maps1 and in addition they show more of the surface detail1 upon which so much of the character of the country depends and which is very inadequately expressed by hachures and almost completely ignored in a contoured map of large interval4 ,the contours themselves can be made to appear upon the model very easily and without interfering with other features4 ,the uses of models are many and various4 ,within the past few years their usefulness has been much extended1 and1 now that they are becoming better known1 will probably receive a still further extension4 ,to the geologist they are often of great value in working out the structure of complicated districts1 for the reason that so many important structural relations can be presented to the eye at a single glance4 ,similarly1 for the graphic presentation of results there is no better method1 as the topography1 the surface geology1 and any number of sections can be shown together and seen in their proper relationship4 ,to the engineer an accurate model is often of the greatest assistance in working out his problems1 and it is simply invaluable to explain the details of a plan to anyone who has little or no technical training2 for1 as has been stated1 a model is easily comprehended by anyone1 while more or less technical knowledge is required for the proper understanding of even the best maps4 ,i might go on cataloguing in detail the many uses to which models may be put1 but shall now mention only one more--perhaps the most important of all--their use in the education of the young4 ,no method has yet been devised that is capable of giving so clear and accurate a conception of the principles of physical geography as a series of well selected models2 models have1 indeed1 already been used for this purpose1 but unfortunately their great cost has prevented their general use in schools4 ,since1 however1 the study of geography has been placed upon a new basis and a new life has been infused into it1 many men have given their attention to the subject of models1 and have experimented with a view to cheapen the cost of reproduction1 which has hitherto prevented their wide distribution2 and probably this objection will soon be remedied4 ,the ability to read a map correctly1--to obtain from a study of the map a clear conception of the country represented1--is more uncommon than is usually supposed4 ,some of the recent methods of teaching geography are intended to cultivate this very faculty1 but it is doubtful whether there is any better method than that which consists in the study of a series of good models in conjunction with a series of maps1 all on the same scale and of the same areas4 ,the value of a series of good models in teaching geology is so apparent that it need only be mentioned4 ,it is often1 for reasons stated above1 far more valuable even1 than field instruction4 ,for the construction of a good relief map the first requisite is a good contoured map4 ,to this should be added1 when possible1 a good hachured map1 upon which the elevations of the principal points are stated1--if the interval in the contoured map is a large one1--and as much material in the way of photographs and sketches as it is possible to procure4 ,the modeler should1 moreover1 have some personal acquaintance with the region to be represented1 or1 failing that1 a general knowledge of topographic forms1 and at least a clear conception of the general character of the country which he seeks to represent4 ,this is very important1 for it is here that many modelers fail3 the mechanical portion of the work any ordinarily intelligent person can do4 ,a model may be as accurate as the map from which it is made1 every contour may be placed exactly where it belongs1 and yet the resulting model may be1--indeed1 often is--flat1 expressionless1 and unsatisfactory4 ,every topographer in drawing his map is compelled to generalize more or less1 and it is fortunate for the map if this be done in the field instead of in the draughtsman's office4 ,but topographers differ among themselves3 there may be1 and often is1 considerable difference in two maps of the same region made by different men2 in other words1 the personal equation is a larger element in a map than is usually supposed4 ,this being the case1 there is something more required in a modeler than the mere transferring of the matter in the map1--giving it three dimensions instead of two3 he must supply through his special knowledge of the region 7or1 failing that through his general knowledge7 certain characteristics that do not appear upon the map1 and undo1 so far as it is necessary1 certain generalizations of the topographer and draughtsman4 ,this artistic or technical skill required correctly to represent the individuality of a given district is especially important in the modeler2 it is more important1 perhaps1 in small-scale maps of large districts than in large-scale maps of small ones1--for in the latter the generalizing process has not been carried so far1 and the smaller interval of the contour lines preserves much of the detail4 ,the methods by which relief maps are made have always received more attention than would1 at first sight1 appear to be their proper proportion4 ,it may be due1 however1 to the difficulty of applying any test to determine the accuracy of the finished model1 and perhaps also to the general impression that any one can make a relief map1--and so he can1 though of course there will be a wide difference in the value of the results4 ,some1 indeed1 have devoted their attention to methods exclusively1 letting the result take care of itself1--and the models show it4 ,there is no more reason why a modeler should tie himself down to one method of work1 than that a water-colorist1 or a chemist1 or anyone engaged in technical work1 should do so2 though in some cases he might be required1 as the chemist is1 to show his methods as well as his results4 ,one of the earliest methods1 with any pretension to what we may term mechanical control1 is that described by the ,messrs4 ,harden in a paper on ,the construction of maps in relief1 read before the ,american ,institute of ,mining ,engineers in #ahhg4 ,the method was published in #ahch4 ,upon a contoured map as a basis cross-section lines are drawn at small and regular intervals1 and1 if the topography be intricate1 corresponding lines at right angles4 ,the sections thus secured are transferred to thin strips of some suitable material1 such as card-board or metal1 and cut down to the surface line1--the strips themselves thus forming the cross-sections4 ,these cross-sections are mounted upon a suitable base-board1 and the cavities or boxes are then filled up with some easily carved material1 such as plaster or wax4 ,the top is then carved down to the form of the country or district1--the necessary guidance being obtained by the upper edges of the strips that form the cross-sections4 ,it will be readily seen that this method is a very crude and laborious one4 ,it necessitates in the first place a good contoured map upon which to draw the sections1 but sacrifices much of the advantage thus gained because only a number of points on each contour line are used1 instead of the entire line4 ,it is no better1 although actually more laborious1 than the later method of driving contour pins 7whose height above a base-board may be accurately measured17 along the contour lines1 and then filling in4 ,a slight modification of the latter method can be used to advantage when no contoured map is available1 and when the points whose elevation is known are not numerous enough to permit the construction of one4 ,in this case the only control that can be secured is by means of a number of pins driven into the base-board at those points whose elevation is known4 ,the remainder of the map is then sketched in4 ,this method is perhaps as satisfactory as any1 when the material upon the map is scanty4 ,another method1 however1 growing out of the same scantiness of material1 is in some cases to be preferred1 especially for large models4 ,the map is enlarged to the required size1 and a tracing of it is mounted upon a frame4 ,another deep frame1 just large enough to contain the mounted tracing1 is made1 and laid upon a suitable base-board upon which a copy of the map has been mounted4 ,upon this base-board the model is then commenced1 in clay or wax4 ,the low areas are modeled first1--horizontal control being obtained by pricking through the mounted tracing of the map with a needle point1 and vertical control by measuring down from a straight edge sliding on the top of the deep frame4 ,this system is rather crude1 and only useful where the material upon the map is very scanty1 but it gives excellent control4 ,a method used by ,mr4 ,f4 ,h4 ,king in the preparation of his large map of the ,united ,states is described by him in a letter to ,messrs4 ,harden1 and published by them in the place mentioned4 ,a solid block of plaster is used1--the contoured map being transferred to it--and the plaster is carved down to produce a series of steps like those made by building up the contours4 ,the shoulders are then carved down to produce a continuous surface4 ,this method is one of the best of those that require carving instead of modeling4 ,many other methods of producing relief maps might be mentioned1 but1 as most of them have been used only to make special models1 they need not be described4 ,the method that has been more used than any other still remains to be described4 ,it is that which the writer has used almost exclusively1 and consists in building up the model and modeling the detail1 instead of carving it4 ,it is a maxim of the modeler that the subject should be built up as far as possible1 should be produced by adding bits of clay or wax1 or other material1 and not by carving away what is already on1--by addition and not by subtraction4 ,this may be illustrated by a reference to the methods of the sculptor4 ,the bust1 or figure1 or whatever the subject may be1 is first modeled in clay or wax2 from this model a plaster mould is made1 and from this mould a plaster cast is taken4 ,this cast is called the original1 and the finished production1 whether in marble1 bronze1 or any other hard substance1 is simply a copy of this original4 ,no one ever attempts to produce the finished bust or figure directly from the object itself4 ,even where the artist has for a guide a death mask1 the procedure does not change4 ,the bust is first made in clay1 and this clay model1 as a rule1 contains all the detail which subsequently appears in the finished bust4 ,it seems strange1 therefore1 that the relief map maker should use a method which the sculptor1 with infinitely more skill and judgment1 is afraid to use2 and this on subjects that do not differ as much as might be imagined4 ,the contour interval to be used depends on the use to which the model is to be put4 ,it is not always necessary to carry into the model all the contour lines upon the map3 ,i may go further and say that it is not always desirable to do so4 ,the number to be used depends to some extent on the skill of the modeler4 ,as already stated1 the contours are only a means of control1 and one modeler requires more than another4 ,to build into a model every contour in a contoured map of ten foot interval is a very laborious proceeding1 and not worth the time it takes1 as in nine out of ten maps of such interval only the fifty-foot or the one hundred-foot curves are definitely fixed1 the intermediate lines being merely filled in4 ,this filling in can be done as well1 or better1 by the modeler4 ,the question as to the proper amount of exaggeration to be given the vertical scale1 as compared with the horizontal1 is the question about which has raged most of the controversy connected with relief map making4 ,this controversy has been rather bitter2 some of the opponents of vertical exaggeration going to the length of saying that no exaggeration is necessary1 and that he that will distort or exaggerate the scale of anything will lie4 ,on the other hand the great majority of those who have made relief maps insist upon the necessity of more or less exaggeration of the vertical scale--generally more than seems to me necessary1 however4 ,an increase of angle of slope accompanies all vertical exaggeration1 and this is apparent even in models in which the vertical element is only very slightly exaggerated4 ,it produces a false effect by diminishing the proportionate width of the valleys1 and by making the country seem much more rugged and mountainous than it really is4 ,a secondary effect is to make the region represented look very small--all idea of the extent of the country being lost4 ,this can be illustrated better than described4 ,the ,king model of the ,united ,states is an example of one extreme2 it is worthy of note that no examples of the other extreme--too little exaggeration--are known4 ,in small-scale models of large districts some exaggeration of the vertical scale is necessary in order to make the relief apparent1 but the amount of this exaggeration is often increased much beyond what is essential4 ,the proportion of scales must depend to a large extent on the character of the country represented1 and on the purposes for which the model is made4 ,it has been suggested by a writer1 quoted by the ,messrs4 ,harden1 that the following exaggeration would afford a pleasing relief3 ,for a map1 scale #f inches to #a mile3 if mountainous1 #a3c2 if only hilly1 #a3b2 if gently undulating1 #b3c4 ,for smaller scales1 except for very rugged tracts1 the exaggeration should be correspondingly increased4 ,for a tract consisting wholly of mountains no exaggeration is necessary4 ,i know of no country of such a character that its relief1 in all its detail1 cannot be shown upon a scale of #f inches to #a mile without any exaggeration at all4 ,it seems to me that the absolute and not the relative amount of relief is the desideratum1 and ,i have always used this as my guiding principle4 ,for small scale models ,i have found half an inch of relief ample4 ,it may be worth while to state that in a model of the ,united ,states made for the ,messrs4 ,butler1 of ,philadelphia1 the horizontal scale was #gg miles to #a inch1 the vertical scale #dj1jjj feet to #a inch1 and the proportion of scales as #a to #aj4 ,this proportion could have been brought down as low as #a3f with advantage4 ,one-fortieth of an inch to a thousand feet seems a very small vertical scale1 but it sufficed to show all the important features of the relief4 ,it should be stated1 moreover1 that the model in question was very hurriedly made--in fact1 was hardly more than a sketch-model--and that more care and more minute work would have brought out many details that do not now appear4 ,this amount of care was not considered necessary in this instance1 as the model was made to be photographed and published as a photo-engraving1 and was to suffer an enormous reduction--coming down to five by seven inches4#b ,footnote #b3 ,see plate from ,butler's ,complete ,geography4 ,it has been frequently urged by the advocates of large exaggeration that the details of a country cannot be shown unless the vertical scale is exaggerated2 that hills #bjj1 #cjj1 or even #ejj feet high--depending of course upon the scale--flatten out or disappear entirely4 ,this seems plausible1 but the advantages of great exaggeration are more apparent than real4 ,its effect upon the model has already been mentioned2 it should be added that1 with the proper amount of care in finishing the model1 exceedingly small relief can be so brought out as to be readily seen4 ,with ordinary care1 one-fortieth of an inch can be easily shown1 and with great care and skill certainly one-eightieth and probably one-hundredth of an inch4 ,another plausible argument that has been advanced in favor of vertical exaggeration as a principle1 is well stated by ,mr4 ,a4 ,e4 ,lehman1 of the ,pennsylvania ,geological ,survey1 in a paper on ,topographical ,models1 read before the ,american ,institute of ,mining ,engineers in #ahhe4 ,a perfectly natural expression is of course desired2 and to cause this the features of the topography should be distorted and exaggerated in vertical scale just enough to produce the same effect on the beholder or student of the district of country exhibited as his idea of it would be if he were on the real ground itself4 ,care should be taken1 however1 not to make the scales so disproportionate as to do violence to mental impressions4 ,often1 indeed1 prominent or important features1 when they will bear it1 may be still more effectively shown by additional exaggeration in the vertical scale4 ,the fallacy of this argument is obvious4 ,it assumes that the object of a model is to show the country as it appears to one passing through it1 and not as it really is--and there is often a very wide difference between the two4 ,the impression derived from passing through a country is1 if ,i may use the term1 a very large-scale impression1 as any one who has tried it can certify2 it is certainly a mistake to attempt to reproduce this impression in a small-scale model1 with the help of vertical exaggeration4 ,even if the principle were a good one1 its application would be very limited4 ,it could only be used in large-scale models2 to apply it to a model of a large area--the ,united ,states1 for example--is obviously absurd4 ,the method referred to as being now generally in use may be briefly described as follows3 requisites1 a good contoured map2 a hachured map in addition1 if possible2 a clear conception on the part of the modeler of the country to be represented2 and a fair amount of skill4 ,materials3 a base-board of wood or other suitable material2 card-board or wood of the thickness required by the contour interval and the scale2 and modeling wax or clay4 ,procedure3 reproduce the contours in the wood or other material2 mount these upon the base-board in their proper relationship2 then fill in the intervening spaces1 and the space above the topmost contour1 with the modeling material4 ,in a series of models of the ,grand ,divisions of the earth1 made about a year and a half ago1 the contours of card-board were made as follows3 the map was photographed up to the required scale1 and as many prints were made as there were contour intervals to be represented--in a model of the ,united ,states of #a1jjj feet contour interval there were fourteen prints4 ,thirteen of these were mounted upon card-board of the exact thickness required by the vertical scale1 and one upon the base-board4 ,all large paper companies use a micrometer gauge1 and card-board can easily be obtained of the exact thickness required--even to less than the thousandth part of an inch4 ,the lowest contour was then sawed out upon a scroll saw1 and placed upon the corresponding line of the map mounted upon the base-board4 ,this process was repeated with each of the succeeding contours until all were placed and glued into their proper positions4 ,at this stage the model presents the relief in a series of steps1 each step representing a rise corresponding to the contour interval4 ,the disadvantages of the method lie in the fact that unless the greatest care is exercised in making the photographic prints there will be considerable distortion1 owing to the stretching of the paper in different directions1 and consequently much trouble in fitting the contours4 ,if care be exercised in having the grain of the paper run in the same direction in all the prints1 trouble in fitting the contours will be much reduced1 but the distortion in one direction will remain4 ,in our experience this distortion amounts to about two per cent42 in other words1 a model that should be fifty inches long will in reality be fifty-one inches2 but1 as this error is distributed over the whole fifty inches1 it is not too great for an ordinary model4 ,if greater accuracy be required1 it can be secured by transferring the contours to the card-board by means of tracing or transfer paper4 ,the great advantage of the photographic method lies in the fact that when the model has been built up1 with all the contours in position1 it presents a copy of the map itself1 with all the details1 drainage1 etc41 in position1 instead of blank intervals between the contours4 ,such details and drainage are a great help in the subsequent modeling4 ,the next step in the process is to fill in with clay or wax the intervals between the contours4 ,i have always found wax more convenient than clay for this purpose as1 unless the surface coating is a thick one1 the clay is difficult to keep moist4 ,to obviate this difficulty1 some modelers have used clay mixed with glycerine instead of water2 this1 of course1 does not become dry1 but the material is1 at its best1 unsatisfactory4 ,the filling-in process is the most important one in relief map making1 for it is here that the modeler must show his knowledge of1 and feeling for1 topographic forms4 ,some models seem to have been constructed with the idea that when the contours have been accurately placed the work of the modeler is practically done4 ,this is a great mistake4 ,the card-board contours are only a means of control1 occupying somewhat the same relation to the relief map that a core or base of bricks1 or a frame of wood1 does to other constructions as1 for example1 an architectural ornament or a bust4 ,it is sometimes necessary to cut away the contour card2 for1 as has been already explained1 a map is more or less generalized1 and a contour is frequently carried across a ravine1 instead of following it up1 as it would do if the map were on a larger scale4 ,such generalizing is of course perfectly proper in a map1 but1 with the same scale1 we expect more detail in a model4 ,the modeler must have judgment enough and skill enough to read between the lines1 and to undo the generalizing of the topographer and draughtsman1 thus supplying the material omitted from the map4 ,this can be done without materially affecting the accuracy of the model1 considered even as a copy of the contoured map4 ,the contours of card-board or other material are1 let me repeat1 only a means of control4 ,the perfect modeler--a variety1 by the way1 yet to be evolved--would be able to make an accurate relief map without them1 in the same way that other subjects are made2 as1 for example1 a flower panel1 an architectural ornament1 or any other subject in low relief1 where the object sought is artistic effect and great accuracy is not a desideratum4 ,it is the converse of this idea that has produced the numerous models that one sees2 accurate enough1 perhaps1 but wholly expressionless and absolutely without feeling4 ,this is the great fault of nearly all models made by building up the contours in wood and then carving down the shoulders4 ,it is then necessary to sand-paper them1 and what little character they might otherwise have had is completely obliterated by the sand-paper4 ,such models almost invariably look wooden4 ,let the modeler1 then1 have a clear conception of his subject and not depend wholly on the contours1 and let him work out that conception in his model1 controlled and helped by the contours1 but not bound by them2 the resulting model will thus be far more satisfactory and a far better representation of his subject1 in other words1 it will be more life-like--more nearly true to nature4 ,the model1 provided it be not of clay1 is sometimes used in the state in which it is left when finished4 ,it is much more common1 however1 to make a plaster mould1 and from this a plaster cast4 ,for this purpose a moulder is usually called in2 but moulders as a rule are ignorant men1 accustomed to one line of work only1 and the result is not always satisfactory4 ,it is much better for the modeler himself to do this work1 though to obtain good results from plaster it is necessary to know the material thoroughly1 and this knowledge comes only from experience4 ,the mould is generally made quite heavy1 in order to stand the subsequent hard treatment that it may receive1 and should be retouched and thoroughly dried before being prepared for the cast4 ,the method used by some modelers of placing a frame about the model and pouring in the plaster1 filling the frame to the top1 is a crude and very wasteful one and not at all to be recommended4 ,in a model of large size--say seven or eight feet square--it would require a derrick to move the mould4 ,it is wholly unnecessary1 as1 with a small amount of care1 a good mould can be made not more than an inch thick1 or1 at most1 an inch and a half4 ,the drying of the mould before use can sometimes be dispensed with1 but is always desirable4 ,nearly all ,american moulders 7as distinguished from ,french and ,italian ones7 varnish the mould1 and thus lose some of the finest detail and sharpness4 ,this is unnecessary4 ,the mould can be easily prepared with a solution of soap so as to leave nothing on the surface but a very thin coating of oil1 which is taken up and replaced by the plaster of the cast4 ,of course1 if the model has been sand-papered1 no fine work in moulding or casting is necessary1 as there is nothing to save4 ,if the subject is a very intricate one1 with undercuts 7as they are called71 it is customary to make a waste mould2 as this is very seldom necessary in relief map work1 however1 the process need not be described4 ,to make the cast it is only necessary to repeat the processes used in making the mould4 ,with great care and some skill a cast can be produced but little inferior in point of sharpness and detail to the original model4 ,it is customary to make the cast very thick1 and1 consequently1 very heavy2 this is unnecessary4 ,in our work we seldom make a cast thicker than one inch1 and yet are never troubled with changes in the model after it is finished4 ,even in a very large cast 7now in the ,national ,museum71 weighing nearly #a1ejj pounds and presenting a surface of over #afj square feet1 the average thickness is less than one inch1 although it required over five barrels of plaster to make it4 ,the cast1 after being thoroughly dried1 should be finished--all its imperfections being carefully repaired4 ,the surface1 however1 should be touched as little as possible1 as the slight roughness of surface that comes from the original model1 through the mould1 is removed by any tooling4 ,this roughness adds much to the effect of the model2 in fact1 where the scale is large enough1 it is sometimes desirable to emphasize it4 ,the proper way to paint a model is a matter that must rest principally upon the judgment of the modeler1 depending to some extent1 also1 on the use to which the model is to be put4 ,the plain cast is sometimes used1 drainage1 lettering1 etc41 being put directly upon it4 ,this has the advantage of preserving all the detail that comes from the mould1 but it has also the disadvantage of a surface easily soiled and impossible to clean4 ,if the model is to be photographed1 the surface should be nearly white--in our practice we use a small amount of yellow with the white4 ,this yellow is hardly appreciable by the eye1 but its effect upon the photographic negative is quite marked4 ,yellow becomes grey in a photograph1 and1 in a photograph of a model colored as described1 a grey tint is given to the whole surface4 ,the high lights are not pure white1 and there is no harsh contrast between light and shade4 ,there is another point of great importance in photographing models3 the surface should have a dead finish--that is1 should have no gloss1 or1 at most1 should have only what is known among painters as an egg-shell gloss4 ,it is almost impossible satisfactorily to photograph a model that has a shiny surface4 ,any portion of a model that it is desired to separate from the rest should be painted a different color--the water1 for example1 should be painted a light blue2 not a blue composed of indigo1 however1 or any of the grey blues1 as these produce in the photograph a dead grey1 and are not pleasant to the eye4 ,the most satisfactory color that we have used is a mixture of cobalt--the purest of the blues--with ,antwerp blue--which is quite green--and white4 ,this gives a color that is pleasant to the eye1 has the retreating quality to perfection1 and photographs well4 ,models intended for exhibition as such should be painted realistically4 ,there is room here for an immense improvement in the usual practice1 which is to paint the model either in some conventional scheme of light and shade1 or else to put a single flat tint upon it4 ,if the model is to be colored conventionally it is1 in my opinion1 much better to use a flat tint1 light in tone1 and with a dead surface4 ,the use of a variety of colors upon the face of a model interferes materially with the relief1 especially if the relief is finely modeled4 ,for this reason models colored to indicate geologic formations should always be accompanied by duplicates representing topography only1 colored realistically1 if possible1 and without lettering4 ,well-defined lines other than those pertaining to the model itself1 such1 for example1 as those used to define the boundaries of geologic formations1 should not be allowed upon a model when it is desired to bring out all the relief4 ,the lettering on such models should be kept down as small as possible1 or wholly dispensed with4 ,the latter is much the better method4 ,the cheap reproduction of models is the most important problem connected with the art1 and the one that is attracting most attention among those engaged in it2 as1 until models can be reproduced cheaply1 they will never have any wide distribution and there will be far less incentive to the modeler4 ,various materials have been suggested and experimented on1 but nine-tenths of the models that are made to-day are made of plaster of ,paris4 ,although this material was the first to be used for this purpose1 it has not yet been superseded4 ,a plaster cast is heavy1 expensive and easily injured2 but plaster gives an accurate copy of the original1 retains permanently the form given it1 and is easily finished and repaired4 ,the weight is an obstacle that can be easily overcome4 ,by the incorporation in the plaster of fine tow1 or of bagging or netting of various kinds1 the cast can be made very light and at the same time strong1 but the expense is increased rather than diminished by this method4 ,models made in this way1 however1 have the advantage that when broken the pieces do not fall out1 they are1 however1 fully as liable to surface injury as the other kind4 ,the large cast in the ,national ,museum1 before referred to1 was made in this way4 ,it weighed nearly #b1jjj pounds when boxed--not an easy thing to handle--but it stood shipment to ,new ,orleans and back without suffering any material injury4 ,this would hardly have been possible had the cast been made from plaster alone4 ,paper seems1 at first sight1 to be the material best adapted for the reproduction of models2 but no one has succeeded well enough with it to bring it into use4 ,like nearly all those who have given this subject attention1 ,i have experimented with paper1 but the only positive result has been a loss of a large part of the confidence that ,i once had in the suitability of the material4 ,paper has been used extensively for large scale models of pueblos1 ruins1 etc41 but ,i have never obtained a satisfactory result with subjects in low relief and fine detail4 ,a paper cast may look well when first made1 but it absorbs moisture from the atmosphere1 and contracts and expands with the weather4 ,the contraction is apt to flatten out the model and the expansion to make it buckle up4 ,casts of models have been made in iron2 but this1 while suitable perhaps for models of mounds and subjects of like character1 would hardly be applicable to small scale models with fine detail2 such casts require too much surface finishing4 ,the material known as ,lincrusta-,walton seems to me to be the ideal material for this purpose4 ,it is tougher than rubber1 will take the finest detail1 and its surface can be treated in any way desired4 ,unfortunately the manufacture of models in this material would require expensive machinery1 and is outside the scope of a modeling room4 ,should it ever become commercially advantageous1 however1 casts of a model of ordinary size1 in every way equal to the original1 can be turned out in this material at a very small cost4 ,it remains to speak of the reproduction of models by process-engravings--a method that will probably receive much more attention in the future than it has in the past4 ,it is perhaps along this line that the cheap reproduction of models will develop2 but the subject is too large a one to be adequately treated here1 and must be postponed until some future occasion4 ,illustration3 ,,hachured ,,and ,,contoured ,,maps4 ,,representation ,,of ,a ,,hill ,,according ,,to ,,the ,,two ,,systems ,,and ,,on ,,different ,,scales4 ,from ,supplement to ,enthoffer's ,topographical ,atlas by permission of ,mr4 ,enthoffer4 ,illustration3 ,,from ,,butler',s ,,complete ,,geography4 ,,copyright1 #ahhh1 ,,by ,e4 ,h4 ,,butler ,,co4 ,printed by permission4 ,,national ,,geographic ,,society4 ,,abstract ,,of ,,minutes4 ,october #e1 #ahhh1 ,ninth ,meeting4 ,a paper was read entitled1 ,topographic ,models1 by ,mr4 ,cosmos ,mindeleff4 ,published in the ,national ,geographic ,magazine1 ,vol4 ,i1 ,no4 #c4 ,october #ai1 #ahhh1 ,tenth ,meeting4 ,the attendance being very small1 no paper was read4 ,november #b1 #ahhh1 ,eleventh ,meeting4 ,the paper of the evening was entitled1 ,surveys1 their ,kinds and ,purposes1 by ,mr4 ,marcus ,baker4 ,the paper was discussed by ,messrs4 ,ogden1 ,goodfellow1 ,gannett and ,baker4 ,published in ,science1 ,vol4 ,,xii1 ,no4 #cjd4 ,november #af1 #ahhh1 ,twelfth ,meeting4 ,a paper was read by ,mr4 ,henry ,gannett1 giving certain ,physical ,statistics ,relating to ,massachusetts1 derived from the map of that ,state recently prepared by the ,united ,states ,geological ,survey4 ,a discussion followed which was participated in by ,messrs4 ,baker1 ,kenaston1 ,fernow1 ,weed1 and the author4 ,a second paper entitled1 ,something about ,tornadoes1 was read by ,lieut4 ,j4 ,p4 ,finley1 ,u4 ,s4 ,signal ,corps4 ,november #cj1 #ahhh1 ,thirteenth ,meeting4 ,the annual reports of vice-,presidents ,herbert ,g4 ,ogden and ,gen4 ,a4 ,w4 ,greely were delivered4 ,published in the ,national ,geographic ,magazine1 ,vol4 ,i1 ,no4 #b4 ,december #bj1 #ahhh1 ,fourteenth ,meeting4 ,held in the ,law ,lecture ,room of the ,columbian ,university4 ,the ,president delivered his ,annual ,address1 entitled1 ,africa4 ,published in the ,national ,geographic ,magazine1 ,vol4 ,i1 ,no4 #b4 ,december #bh1 #ahhh1 ,fifteenth ,meeting4 ,the ,society met in the ,society ,hall of the ,cosmos ,club1 ,president ,hubbard in the chair4 ,owing to the absence from the city of the ,secretaries1 ,mr4 ,o4 ,h4 ,tittmann was requested to act as ,secretary of the meeting4 ,the minutes of the first and fourteenth meetings were read and approved4 ,the report of the ,secretaries was read1 in their absence1 by the temporary ,secretary1 and was approved4 ,the ,treasurer's report1 showing a balance on hand of #fbf4gj1 was read and approved1 as was also that of the auditing committee4 ,the ,president announced that vacancies caused by the resignation of two of the managers1 ,messrs4 ,w4 ,d4 ,johnson and ,henry ,mitchell1 had been filled by the ,board on the #aeth of ,november1 by the election of ,messrs4 ,o4 ,h4 ,tittmann and ,c4 ,a4 ,kenaston2 and that a vacancy caused by the resignation of ,vice-,president ,john ,r4 ,bartlett1 had been filled by the election of ,lieut4 ,george ,l4 ,dyer1 on ,november #cjth4 ,the ,society then proceeded to the election of officers1 with following result3 ,president--,,gardiner ,g4 ,,hubbard4 ,vice-,presidents--,,herbert ,g4 ,,ogden1 land2 ,,george ,l4 ,,dyer1 sea2 ,a4 ,w4 ,,greely1 air2 ,c4 ,,hart ,,merriam1 life2 ,a4 ,h4 ,,thompson1 art4 ,treasurer--,,charles ,j4 ,,bell4 ,recording ,secretary--,,henry ,,gannett4 ,corresponding ,secretary--,,george ,,kennan4 ,managers--,,cleveland ,,abbe1 ,,marcus ,,baker1 ,,rogers ,,birnie1 ,,jr41 ,g4 ,,browne ,,goode1 ,w4 ,b4 ,,powell1 ,j4 ,c4 ,,welling1 ,c4 ,a4 ,,kenaston1 ,o4 ,h4 ,,tittmann4 ,january #aa1 #ahhi1 ,sixteenth ,meeting4 ,the paper of the evening was entitled1 ,the ,great ,plains of ,canada1 and was presented by ,professor ,c4 ,a4 ,kenaston1 of ,howard ,university4 ,january #be1 #ahhi1 ,seventeenth ,meeting4 ,the paper of the evening was entitled1 ,irrigation in ,california1 by ,mr4 ,william ,hammond ,hall1 ,state ,engineer of ,california4 ,to be published in the ,national ,geographic ,magazine1 ,vol4 ,i1 ,no4 #d4 ,february #h1 #ahhi1 ,eighteenth ,meeting4 ,the following papers were read by ,prof4 ,w4 ,m4 ,davis1 of ,harvard ,university3 ,topographic ,models1 and ,certain ,peculiarities of the ,rivers of ,pennsylvania4 ,published in the ,national ,geographic ,magazine1 ,vol4 ,i1 ,no4 #c4 ,february #bb1 #ahhi1 ,nineteenth ,meeting4 ,the paper of the evening was entitled1 ,round about ,asheville1 ,n4 ,c41 by ,mr4 ,bailey ,willis4 ,the paper was illustrated by charcoal sketches and lantern slides4 ,discussion followed1 which was participated in by ,messrs4 ,baker1 ,merriam and ,mc,gee4 ,to be published in the ,national ,geographic ,magazine1 ,vol4 ,i1 ,no4 #d4 ,march #h1 #ahhi1 ,twentieth ,meeting4 ,the following amendments to the ,by-,laws were adopted4 ,for ,article ,,vi substitute the following3 ,,article ,,vi4 ,,meetings4 ,regular meetings of the ,society shall be held on alternate ,fridays1 from ,november until ,may1 and excepting the annual meeting1 they shall be devoted to communications4 ,the ,board of ,managers shall1 however1 have power to postpone or omit meetings1 when deemed desirable4 ,special meetings may be called by the ,president4 ,the annual meeting for the election of officers shall be the last regular meeting in ,december4 ,the meeting preceding the annual meeting shall be devoted to the ,president's annual address4 ,the reports of the retiring ,vice-,presidents shall be presented at the meetings in ,january4 ,a quorum for the transaction of business shall consist of twenty-five active members4 ,in ,article ,v1 the following paragraph was introduced immediately after the first paragraph of the article3 ,the dues of members elected in ,november and ,december shall be credited to the succeeding year4 ,the following papers were then presented3 ,a ,trip to ,panama and ,darien1 by ,mr4 ,r4 ,u4 ,goode1 and ,survey of ,mason and ,dixon's ,line1 by ,mr4 ,mark ,b4 ,kerr4 ,a ,trip to ,panama and ,darien1 to be published in the ,national ,geographic ,magazine1 ,vol4 ,i1 ,no4 #d4 ,march #bb1 #ahhi1 ,twenty-first ,meeting4 ,the paper of the evening was entitled1 ,recent ,events in the ,u4 ,s4 of ,columbia1 by ,mr4 ,w4 ,e4 ,curtis4 ,the discussion which followed was participated in by ,messrs4 ,baker1 ,gannett1 and others4 ,april #e1 #ahhi1 ,twenty-second ,meeting4 ,the paper of the evening was entitled1 ,house ,life in ,mexico1 by ,mr4 ,a4 ,b4 ,johnson4 ,april #ai1 #ahhi1 ,twenty-third ,meeting4 ,this meeting was devoted to papers upon the ,samoan ,islands4 ,the following programme was presented3 ,samoa2 the ,general ,geography and ,hydrography of the ,islands and ,adjacent ,seas1 by ,mr4 ,everett ,hayden4 ,climate1 by ,prof4 ,cleveland ,abbe4 ,narrative of a ,cruise ,among the ,islands1 by ,capt4 ,r4 ,w4 ,meade1 ,u4 ,s4 ,n4 ,the ,home ,life of the ,samoans and the ,botany of the ,islands1 by ,mr4 ,w4 ,e4 ,safford1 ,u4 ,s4 ,n4 ,may #c1 #ahhi1 ,twenty-fourth ,meeting4 ,the paper of the evening was entitled1 ,across ,nicaragua with ,transit and ,machte1 by ,mr4 ,r4 ,e4 ,peary1 ,u4 ,s4 ,n4 ,to be published in the ,national ,geographic ,magazine1 ,vol4 ,i1 ,no4 #d4 ,may #ag1 #ahhi1 ,twenty-fifth ,meeting4 ,the paper of the evening was entitled1 ,the ,krakatoa ,eruption1 by ,dr4 ,a4 ,graham ,bell4 ,the paper was discussed by ,captain ,c4 ,e4 ,dutton4 7,translated by ,mr4 ,r4 ,l4 ,lerch47 ,,international ,,literary ,,contest ,to be held at ,madrid1 ,spain1 under the auspices of the ,commission in charge of the celebration of the ,fourth ,centennial ,anniversary of the ,discovery of ,america4 ,,program4 ,the work for which a prize is offered is to be a prose essay1 a true historic picture giving a just estimate of the grandeur of the occasion to be celebrated4 ,so much has been written on this subject since the opening of the ,x,v,ith century that it would seem difficult to say anything new and good4 ,perhaps the details1 perhaps the circumstances in the life and acts of ,columbus are worthy of no little research2 but already the ,royal ,academy of ,history is engaged in the erudite and diligent task of bringing together and publishing the un-edited or little known papers bearing on this question4 ,the book required by this contest must be of a different nature3 it must be comprehensive and synoptic1 and must be sufficiently concise without being either obscure or dry4 ,although there is an abundance of histories of ,america1 of voyages and discoveries1 of geographic science1 and of the establishment of ,europeans in remote regions of the earth1 there is no book that sets forth as it can be done the combined efforts of the nations of the ,iberian peninsula1 who1 since the commencement of the ,x,vth century1 have1 with a fixity of purpose and marvelous tenacity1 in almost a single century of silent efforts brought about the exploration of vast continents and islands1 traversed seas never before cut by ,christian prows1 and in emulous strife obtained almost a complete knowledge of the planet on which we live4 ,there is a growing interest and manifest unity in all those more important events2 not to mention the circumstantial evidence borne by the charts of #acge and the semi-fabulous voyages1 such as that of ,doria y ,vivaldi and others less apocryphal though isolated and barren of results1 like that of ,ferrer1 begun in #adcd1 when ,gil ,eannes doubled ,cape ,bojador1 discovered ,guinea1 and dispelled the terror inspired by the unknown ocean1 and ended in #aebb with ,elcano's arrival at ,sanlucar after circumnavigating the globe4 ,in all this activity very little occurs by chance4 ,the progressive series of geographic discoveries1 due to persistent premeditation and not to accident1 was inaugurated at ,sagres by the ,infante ,d4 ,enrique and his illustrious pilot ,jaime de ,mallorca4 ,well might ,pedro ,nues exclaim that from that time forth until the form and size of the terraqueous globe were thoroughly known1 the most to be obtained would not be firmly established1 unless our mariners sailed away better instructed and provided with better instruments and rules of ,astronomy and ,geography than the things with which cosmographers supplied them4 ,the culmination in the progress of that beautiful history falls on the #abth of ,october1 #adib1 when ,columbus was the first ,european to set foot upon the intertropical shores of the ,new ,world4 ,but this act1 considered apart from its intrinsic value1 as purely the individual inspiration of a mariner and the generous enthusiasm of a patron ,queen1 derives a higher value when regarded as part of a summation of efforts1 a grand development of an idea1 a purpose to explore and know the whole globe1 to spread the name and the law of ,christ together with the civilization of ,europe1 and to reap a harvest of gold1 spices1 and all the riches of which costly samples and exaggerated reports were furnished by the traffic of the ,venetians1 ,genoese and ,catalonians1 who in turn got them from ,mussulmans4 ,doubtless the moving cause1 whose gorgeous banner so many men of our peninsula followed1 was clothed in great sentiments1 good or bad2 their hearts were filled with religious fervor1 thirst for glory1 ambition1 ,christian love1 cupidity1 curiosity1 and violent dissatisfaction 7even during the ,renaissance71 to seek and undergo real adventures that should surpass the vain1 fruitless1 and fanciful adventures of chivalry2 and to make voyages and conquests eclipsing those of the ,greeks and ,romans1 many of which1 recorded in classic histories and fables1 were now disinterred by the learned4 ,what must be described is the complete picture in all its sumptuousness so that its magnificent meaning may stand out distinctly1 without which the conviction would be lacking that the studies1 voyages1 and happy audacity of ,bartolom ,diaz1 ,gama1 ,alburquerque1 ,cabral1 ,balboa1 ,magallanes1 ,cortes1 ,pizarro1 ,orellana1 and a host of others1 do not dim the glory of the hero whose centennary is to be celebrated1 even though it heighten and add greater luster to the work of civilization begun by ,portugal4444 ,the book here vaguely outlined must also contain a compendious introduction1 notices of voyages1 ideas1 and geographic progress up to the date of ,d4 ,enrique's establishment at ,sagres1 and an epilogue or conclusion of greater extent1 in which are examined and weighed the changes and progress that our subject has made1 collectively1 in the civilization of the world--in the commerce1 economics and politics of the peoples1 in regard to the broad field opened to the intelligent activity of ,europe1 over which it could spread and dominate2 the abundance of data1 sunken hopes1 and more secure basis lent to the studious and wise for the extension of our knowledge of ,nature1 the unraveling of her laws1 and penetration of her mysteries4 ,the vast1 elevated argument of the book requires it be a finished work of art1 not in fullness and richness of diction1 but in plan and order1 in sobriety and unity of style1 whose nobility and beauty must lie in simplicity of phrase1 correctness of judgment and richness of thought4 ,there may enter into this contest any unpublished work written to this end in ,spanish1 ,portuguese1 ,english1 ,german1 ,french or ,italian4 ,the tribunal that is to award the prize will be composed of two members of the ,r4 ,acad4 of ,history1 and one member from each of the ,spanish ,r4 ,academies of ,moral ,sciences and ,politics1 and ,exact and ,natural ,sciences--all to be chosen by the ,academies themselves4 ,furthermore1 there will be included in the tribunal the diplomatic representative of every power whose subject or subjects wish to enter the contest1 which is to be done through said representative or some person duly appointed to act in his place4 ,the tribunal will elect its presiding officer and will decide on the best works by an absolute majority of all the jurors who take part in the vote4 ,each work submitted in this contest must be neatly copied1 in legible writing1 on good paper1 without the author's name but with a quotation to identify him afterwards4 ,each author will inclose a separate folded sheet on whose exterior is written the quotation he has chosen and the opening sentence of his work2 within1 he will write his name and residence4 ,the folded sheets corresponding to the works that did not get a prize will be burnt publicly without being opened4 ,though it is difficult to set a limit as to size1 the works should not have more reading matter than is contained in two volumes of the shape and size of the complete works of ,cervantes issued by ,rivadeneyra in #ahfc-d4 ,if the plan or purpose of any of the works require it1 there may be added another volume of documents1 maps1 or other illustrations4 ,as it will take time to examine and judge the works1 they should be sent to the ,secretary of the ,r4 ,acad4 of ,hist4 prior to ,january #a1 #ahib4 ,there will be first prize of #cj1jjj pesetas 7#e1gij7 and a second of #ae1jjj pesetas 7#b1hie74 ,besides this1 each of the two successful authors will receive #ejj copies of the printed edition of his work4 ,it rests with the ,centennial ,commission to determine the number of copies in the edition of each of the two prize works1 and what disposition is to be made of the copies that are not given to the authors4 ,these 7the authors7 keep the right to re-print and to sell their works1 and to translate them into other tongues4 ,the ,commission1 however1 will have the right1 if either or both prize works are in a foreign tongue1 to have them translated and published in ,castilian4 ,the ,commission affix their seal to the preceding directions for the information of the public and government of those persons who desire to participate in the contest4 ,madrid1 ,june #ai1 #ahhi4 ,the ,vice ,president1 ,,duke ,,of ,,veragua4 ,secretaries1 ,,juan ,,valera1 ,,juan ,f4 ,,ria,o4