file which includes the original illustrations4 ,see #dhabf-;h4htm or #dhabf-;h4zip3 7https3_/_/www4gutenberg4org_/cache_/epu b_/#dhabf_/pg#dhabf-;images4html7 or 7https3_/_/www4gutenberg4org_/files_/#dh abf_/dhabf-;h4zip7 ,transcriber's note3 ,text enclosed by underscores is in italics 7italics74 ,illustration3 ,,the ,,grand ,,canyon--#a4 ,,schists ,,and ,,granites 7,,archean ,,era73 #b4 ,,sandstones1 ,,limestones1 ,,shales 7,,algonkian ,,era73 #c4 ,,tonto ,,formations 7,,cambrian ,,period73 #d4 ,,redwall ,,limestone 7,,mississippian ,,period73 #e4 ,,supai ,,sandstone ,,and ,,shale 7,,permian ,,period73 #f4 ,,hermit ,,shale 7,,permian ,,period73 #g4 ,,coconino ,,sandstone 7,,permian ,,period73 #h4 ,,toroweap ,,and ,,kaibab ,,formations 7,,permian ,,period74 ,,national ,,park ,,service ,,ancient ,,landscapes ,,of ,,the ,,grand ,,canyon ,,region ,the ,geology of ,grand ,canyon1 ,zion1 ,bryce1 ,petrified ,forest ,painted ,desert by ,,edwin ,d4 ,mc,k,e,e1 ,asst4 ,director ,museum of ,northern ,arizona ,sketches and ,charts by ,louis ,schellbach #crd ,park ,naturalist1 ,grand ,canyon ,national ,park1 and ,russell ,hastings ,published by ,edwin ,d4 ,mc,kee #aica ,copyright #aica ,edwin ,d4 ,mc,kee ,thirteenth ,edition1 #aieb ,printed by ,coconino ,sun ,co4 ,flagstaff1 ,arizona ,,table ,,of ,,contents ,,page ,introduction ix ,chapter ,i--,the ,archean ,era #a ,the ,earth's ,oldest ,rocks1 ,grand ,canyon #b ,granite in ,grand ,canyon #d ,chapter ,,ii--,the ,algonkian ,era #e ,algonkian ,rocks in ,grand ,canyon #e ,formation of ,mountains #f ,early ,climates #f ,oldest ,known ,life #g ,chapter ,,iii--,the ,paleozoic ,era #i ,first ,animal ,life--,the ,tonto ,rocks #i ,the ,missing ,periods of the ,third ,era #aa ,the ,age of ,fish #ab ,sea ,life ,from the ,north--,redwall ,limestone #ab ,tracks in the ,supai ,sandstone #ad ,landscapes of the ,hermit ,shale #ae ,wind-blown ,sand--,the ,coconino ,sandstone #ag ,warm ,seas from the ,west--,the ,toroweap and ,kaibab ,formations #ah ,chapter ,,iv--,the ,mesozoic ,era #ba ,remnants of ,younger ,strata--,red ,butte and ,cedar ,mountain #ba ,the ,petrified ,forest #bb ,dinosaur ,tracks--,the ,painted ,desert #bd ,the ,rocks of ,zion ,canyon and ,rainbow ,natural ,bridge #bf ,from ,seashells to ,coalbeds #bg ,chapter ,v--,the ,cenozoic ,era #bi ,bryce ,canyon ,formation #cj ,a ,great ,erosion ,surface #cb ,crustal ,movement at ,grand ,canyon #cc ,cutting the ,grand ,canyon #cd ,the ,forming of ,zion ,canyon #cg ,glaciers #ch ,san ,francisco ,mountain ,volcanic ,field #ci ,elephants and ,camels #da ,advent of ,man in the ,southwest #db ,bibliography #de ,,illustrations ,,page ,the ,grand ,canyon ,frontispiece ,diagrammatic ,sections of ,grand ,canyon ,region x ,rocks of ,first ,era1 ,inner ,gorge of ,grand ,canyon #a ,block ,diagrams of ,events of ,first ,era #c ,tilted ,rocks of the ,second ,era1 ,grand ,canyon #e ,diagrammatic ,section of ,third ,era ,formations1 ,grand ,canyon #h ,scene on ,cambrian ,sea ,floor in ,grand ,canyon ,region #aj ,trilobites ,preserved in ,green ,shale of ,grand ,canyon ,walls #aa ,a ,fresh-water ,fish of ,devonian ,age 7,sketch7 #ab ,sea ,life from the ,redwall1 ,grand ,canyon 7,sketches7 #ab ,havasu ,falls in ,redwall ,limestone1 ,grand ,canyon #ac ,tracks of ,short-legged1 ,prehistoric ,animal1 ,supai ,formation1 ,grand ,canyon #ad ,landscape at ,time ,hermit ,shale was ,forming #ae ,fossil ,fern ,from the ,hermit ,shale1 ,grand ,canyon #ae ,wind-blown ,sand1 ,coconino ,formation1 ,grand ,canyon #ag ,tracks of ,primitive ,four-footed ,animals1 ,coconino ,sandstone1 ,grand ,canyon #ag ,marine ,life ,from the ,kaibab ,limestone1 ,grand ,canyon 7,sketches7 #ah1 #ai ,diagrammatic ,section of ,fourth ,era ,formations1 ,southern ,utah and ,painted ,desert ,regions #bj ,cedar ,mountain #bb ,red ,butte #bb ,petrified ,forest1 ,arizona #bc ,petrified ,logs of ,triassic ,age #bc ,dinosaur ,tracks1 ,painted ,desert #bd ,the ,painted ,desert #be ,zion ,canyon1 ,navajo ,sandstone #bf ,rainbow ,natural ,bridge1 ,navajo ,sandstone #bf ,cretaceous ,shells ,from ,southern ,utah 7,sketches7 #bg ,coal ,canyon1 ,painted ,desert ,country #bh ,bryce ,canyon #cj ,map of ,colorado ,river #ca ,a ,great ,erosion ,surface #cb ,diagrammatic ,cross ,sections of ,grand ,canyon #ce ,the ,grand ,canyon #cf ,zion ,canyon #cg ,chart of ,san ,francisco ,mountains #ci ,san ,francisco ,mountain--,past and ,present 7,sketch7 #dj ,map of ,san ,francisco ,mountain ,volcanic ,field #dj ,san ,francisco ,mountain #da ,elephant and ,camel ,remains #db ,ancient ,indian ,petroglyphs1 ,head of ,bright ,angel ,trail1 ,grand ,canyon #dc ,,introduction ,probably no place in the world of similar area has recorded a more complete or a more interesting resume of the earth's history than has the high plateau country of northern ,arizona and southern ,utah4 ,although many great events and some long intervals of time are not represented by the formations of this region1 yet of the five major chapters or eras into which all of time has been divided by geologists1 at least some parts of each have left their traces in this area4 ,whether on the brink of the mighty ,grand ,canyon1 among beautiful logs of the ,petrified ,forest1 or beneath the lofty walls of ,zion--the 8,rainbow of the ,desert0--one looks upon rocks which are not alone curious or colorful1 but which are also records of the past inscribed and illustrated in an intensely interesting manner4 ,in one place is seen the sand of ancient dunes1 in another the border of an early sea1 or perhaps the floodplain of mighty rivers1 and in all of these remain the unmistakable evidences of life--plants and animals preserved to make a reality of the living1 moving past4 ,everywhere are found the evidences of those great processes of nature--erosion of the high country1 land formation in the low country1 and mighty crustal movements slowly raising or lowering the land in both4 ,from the rim of ,grand ,canyon one not only looks down through tremendous space1 but also through time1 glimpsing the record of vast ages1 measurable not in centuries but in millions and even hundreds of millions of years4 ,there in the bottom of that mighty chasm are found rocks formed during the first and oldest era--rocks in which the original structure has been entirely modified by great heat and pressure and in which no evidence of life has been found4 ,there in the ,grand ,canyon are also seen two other great series of rocks1 those of the second era which are partially altered and which contain earliest traces of plants1 and those of the succeeding era in which are preserved primitive animals of many types4 ,illustration3 ,,north-,,south ,,cross-,,section ,,of ,,the ,,grand ,,canyon ,,region2 ,,east-,,west ,,cross-,,section ,,of ,,the ,,grand ,,canyon ,,region ,rocks of the fourth great era--the age of dinosaurs--lend color to the ,painted ,desert1 and to the sheer walls of ,zion ,canyon4 ,beautiful little ,bryce ,canyon to the north boasts of some of the most recently formed rocks in the region--those of the fifth and last era1 the age of mammals4 ,the great volcanic mountains and the marvelous features of erosion1 such as the canyons and the desert cliffs1 are also developments of this most recent chapter4 ,in brief1 the ,grand ,canyon region affords some wonderfully interesting glimpses of ancient landscapes during many different parts of the earth's history1 and these make the past a moving1 living thing4 ,,chapter ,i ,,the ,,archean ,,era ,illustration3 ,,rocks ,,of ,,first ,,era4 ,,inner ,,gorge ,,of ,,grand ,,canyon ,,the ,,earth',s ,,oldest ,,rocks 7,,the ,,archean ,,era7 ,looking into the depths of ,grand ,canyon from any point within the ,bright ,angel section1 one is immediately impressed by the narrow ,v-shaped gorge cut in the black rocks at the bottom4 ,this is popularly termed the ,granite or ,inner ,gorge4 ,within its walls one is in another world1 both scenically and geologically4 ,their steep1 bare sides1 whose surfaces are chaotic in the extreme1 have a history--long and complex4 ,the rocks of which they are formed--some of the oldest known today on the surface of the earth--partially tell the story of the first great era in geologic history4 ,other rocks of this1 the ,archean age1 are found in the ,rockies1 in the ,adirondacks of ,new ,york1 and to a very great extent in eastern ,canada4 ,in the last named place they contain valuable deposits of iron1 nickel1 cobalt1 and copper4 ,rocks which probably also correspond in age occur in ,scandinavia1 ,brazil1 ,china1 ,india1 and central ,africa4 ,at the ,grand ,canyon1 although we are impressed by the depth of the dark ,archean rocks1 beneath the plateau surface approximately a mile1 yet we marvel even more when we contemplate their great age and the important series of events whose history they partially record4 ,built up originally as great horizontal deposits of sand and mud1 they were bent by mighty crustal movements until high mountains1 probably comparable to the present ,alps1 were formed4 ,pressures from the northwest and southeast apparently folded them4 ,the rocks themselves were greatly compressed and heated1 with the result that complete recrystallization and the development of a banded structure were brought about4 ,the present vertical attitude of these ancient beds1 together with their dense crystalline character1 is evidence of the great depth at which they were formed and of the extreme pressures to which they were subjected4 ,in brief1 the rocks that we see today in the ,canyon bottom represent merely the roots of once lofty mountains1 and the flat surface cut on these rocks is an old plain that resulted from the wearing down of high country in this region4 ,illustration3 ,,block ,,diagrams ,,of ,,events ,,of ,,first ,,era #a ,sands and ,muds accumulated to form rock strata4 #b ,the strata were folded into high mountains4 ,heat and pressure changed both structure and composition of the lower rocks during the folding4 #c ,molten masses were forced up into cracks from below4 ,upon cooling they formed lavas on the surface and granites beneath4 #d ,during a tremendously long period of time the rivers and rains slowly widened the valleys and wore down the ancient mountains to a great plain near sea level4 ,as yet no definite traces of either plant or animal life have been found in rocks of the ,archean age in ,grand ,canyon4 ,though various forms of life may have existed then1 and may have been preserved in the original rocks1 their record has since been entirely removed by those extreme pressures which altered even the composition and structure of the rocks themselves4 ,,granite ,,in ,,grand ,,canyon 7,,the ,,archean ,,era7 ,within the black1 crystalline rocks of the ,inner ,gorge may be seen many large streaks1 bands or irregular masses of a lighter color4 ,from the ,canyon rim these appear white1 but from nearby they are usually pink4 ,these light colored rocks are granites with a coarse crystalline texture4 ,granites derive their name from their granular texture4 ,they are formed by the slow cooling of molten masses that have been forced into older rocks from the earth's interior4 ,from a similar source are formed lavas and volcanic ash1 but these flow out or are ejected on the surface of the earth where they cool so rapidly that no crystals form4 ,exceptionally fast cooling or chilling of molten masses1 moreover1 forms volcanic glass or obsidian4 ,it is by the application of this same principle that crystal forming is prevented in the manufacture of common glass4 ,the large size of the crystals forming the granite that fills cracks and fissures of the ,inner ,gorge at ,grand ,canyon indicates the considerable depth at which it was formed and is further evidence of the great mountains that existed in this region during the first era in geologic history4 ,,chapter ,,ii ,,the ,,algonkian ,,era ,illustration3 ,,tilted ,,rocks ,,of ,,the ,,second ,,era4 ,,grand ,,canyon ,rocks formed during the second great era of the earth's history are distinctive in several respects4 ,they are not highly altered or completely changed in form and structure as are those of the oldest era1 but are largely free from such changes and1 for the most part1 similar to rocks which are seen in the process of formation today4 ,furthermore1 they are known to contain definite traces of plant life1 though no certain forms of animal life have yet been found in them4 ,they represent a period probably as great as all of subsequent time4 ,,algonkian ,,rocks ,,in ,,grand ,,canyon ,along ,bright ,angel ,canyon and in several other places in the ,grand ,canyon1 rocks of ,algonkian age1 representing accumulations of sediments several thousand feet in thickness1 are found4 ,below and to the north of ,desert ,view 7southeast of ,cape ,royal on the ,north ,rim7 they form the open floor of the ,canyon4 ,everywhere the most conspicuous layer of this series is a mud rock of brilliant vermilion color4 ,however1 the rocks also include a conglomerate or pebble layer1 a dark limestone formed principally by plants1 and a purple quartzite made by the consolidation of the grains of a sandstone4 ,,formation ,,of ,,mountains 7,,the ,,algonkian ,,era7 ,the ,algonkian rocks of the ,grand ,canyon region were bent and broken into mountains at an early date4 ,in many places sloping layers showing the steep angle at which they were tilted are easily visible1 even from the ,canyon rim4 ,folded areas and strata which have been shattered are also conspicuous features here and there4 ,the mountains which they formed1 however1 are now missing for they were worn away in large measure by slow erosion4 ,today only remnants--small hills on a general level surface--remain in the lower parts of ,grand ,canyon to tell the story4 ,,early ,,climates 7,,the ,,algonkian ,,era7 ,the rocks of ,algonkian age are roughly estimated to be at least six or seven hundred million years old1 yet from all indications they were formed under conditions of climate not unlike those of far later periods of history4 ,in several parts of the world traces of great ice sheets--glaciers which scratched and eroded the surface--are found preserved in ,algonkian rocks4 ,in other places1 including the ,grand ,canyon1 ancient flows of lava are found where they gushed out upon the surface of an old land mass4 ,among the rocks below ,desert ,view 7,navajo7 ,point and bordering on the ,colorado ,river may readily be seen several black cliffs formed by the volcanic activity of this early age4 ,the brilliant red shales of ,algonkian age found in the lower parts of the ,grand ,canyon were formed as muds1 accumulated probably by large rivers4 ,in these muds are found preserved great quantities of ripple marks1 indications of changing currents1 also the moulds of salt crystals1 and large shrinkage cracks resulting from a very hot sun4 ,in brief1 these criteria point toward a hot and probably arid climate in this region during that chapter of history4 ,,oldest ,,known ,,life 7,,the ,,algonkian ,,era7 ,the oldest forms of life represented in rocks of ,grand ,canyon are found in strata of the ,second1 or ,algonkian1 ,era4 ,certain layers of limestone showing peculiar structural patterns on their surfaces are interpreted as being the reefs built up through the activities of primitive one-celled plants known as algae4 ,similar structures are being formed today by plants of this type4 ,near ,harper's ,ferry1 ,west ,virginia1 for example1 algae are building up limestone layers almost identical to the fossil ones found in the ,algonkian rocks of ,grand ,canyon4 ,in this connection1 it is interesting to note that because of this similarity of the present to the past1 the reality of the ancient plant structures was recognized a few years ago4 ,they were discovered at a place in the ,grand ,canyon just west of the mouth of ,bright ,angel ,creek4 ,illustration3 ,rocks of the ,third ,era in the ,grand ,canyon ,rocks of the ,fourth ,era 7,red ,butte7 ,rim of ,grand ,canyon a ,sandy limestone formed beneath the sea4 ,in it are found corals1 sponges1 sharks' teeth and many sea shells4 ,kaibab ,formation #cjj ft4 ,permian ,age b ,red sandstone and gray limestone4 ,formed at bottom of a shallow sea4 ,toroweap ,formation #bej ft4 ,permian ,age c ,wind-blown sand which was piled in dunes4 ,contains the tracks of many kinds of primitive reptiles or amphibians4 ,coconino ,sandstone #cjj ft4 ,permian ,age d ,river mud in which are preserved many impressions of ferns and cone-bearing plants1 insect wings1 raindrop pits and tracks of salamander-like animals4 ,hermit ,shale #cjj ft4 ,permian ,age e ,ancient flood-plain deposits of sand and mud containing impressions of fern-like plants and tracks of land animals4 ,supai ,formation #hjj ft4 ,permian ,age f ,sea deposits containing remains of shells1 fish1 sea-lillies and related forms of life4 ,redwall ,limestone #eej ft4 ,mississippian ,age g ,accumulations of sandy lime in which are preserved the remains of some of the earliest fish4 ,temple ,butte ,limestone ,devonian ,age h ,sand1 muds1 and limes representing ancient beach which was gradually covered with water until finally the sediments were at a considerable depth beneath the sea4 ,the earliest definite traces of animal life in the canyon found here4 ,tonto ,rocks ,cambrian ,age i and j rocks of the ,first and ,second ,era ,,chapter ,,iii ,,the ,,paleozoic ,,era ,it was during the third or middle chapter in the earth's history that all of the apparently horizontal1 upper layers in the ,grand ,canyon walls were formed4 ,as will be seen in the succeeding pages1 some of these rocks are sandstones formed from the sands of early beaches or sand dune areas1 others are shales--the hardened muds of ancient river deltas--and still others are limestones built up by accumulations of plant and animal remains on sea bottoms4 ,all are rocks formed by the deposition of sediments by wind and water during vast intervals of time4 ,in them have been hidden and preserved many forms of life4 ,seashells1 footprints1 fern impressions1 and various other traces of early plants and animals remain to tell the story of these ancient times4 ,it is of special interest to note that in rocks formed during the earliest part of this chapter are found the first definite traces of animal life1 that in other rocks of this chapter have been found evidences of primitive fish1 and that in the most recent rocks of this group occur the traces of early reptiles1 insects1 ferns1 and cone-bearing plants4 ,in the walls of ,grand ,canyon examples of all of these fossils have been found1 and these will be described in detail in the succeeding pages4 ,,first ,,animal ,,life--,,the ,,tonto ,,rocks 7,,cambrian ,,period7 ,great highlands which were formed in the ,grand ,canyon region during the ,second ,era of history were afterwards gradually worn away by erosion until near the start of the next era a flat1 almost featureless plain existed4 ,here and there1 however1 isolated hills of dark1 crystalline rocks of the ,first ,era stood above the general surface1 as seen opposite ,yaki point4 ,in other places1 such as to the west of where ,bright ,angel ,creek now flows1 small mountains of red ,algonkian rocks 7,second ,era7 remained4 ,around and against these1 sediments were then deposited4 ,pebbles and sands accumulated1 forming a thick layer which today appears as the brown sandstone rim of the ,inner ,gorge4 ,these represent the first deposits of the ,third ,era4 ,but the sea was encroaching upon the land during this period1 and gradually the sand deposited near shore was covered by mud and this in turn by lime far out from the beach4 ,today this series of sand1 mud and lime is found represented in the rocks of the ,tonto ,platform in ,grand ,canyon4 ,illustration3 ,,scene ,,on ,,cambrian ,,sea ,,floor ,,in ,,grand ,,canyon ,,region 7,,reconstruction4 ,,museum ,,northern ,,arizona7 ,along the ,tonto ,trail a few hundred yards east of ,indian ,gardens numerous primitive sea animals have been found buried and preserved in layers of thin shale4 ,many of these are creatures with rounded shells smaller than the nail of a person's little finger1 others are animals related to the snail1 and still others are crab-like creatures known as trilobites4 ,the trilobites undoubtedly were the rulers of that age for they excelled not only in numbers but in size4 ,some specimens from ,grand ,canyon have measured over three inches in length4 ,despite this size1 however1 the trilobites and their associates from the ,tonto ,platform represent some of the earliest known forms of animal life4 ,illustration3 ,,trilobites ,,preserved ,,in ,,green ,,shale ,,of ,,grand ,,canyon ,,walls 7,,one-,,eighth ,,natural ,,size7 ,,the ,,missing ,,periods ,,of ,,the ,,third ,,era 7,,ordovician ,,and ,,silurian ,,periods7 ,the geologist has found that two long periods of history are lacking in the great succession of ages represented by the strata in the ,grand ,canyon walls4 ,these missing periods which belong to the ,third ,era are known as the ,ordovician1 the time when fish first appeared in the seas1 and the ,silurian1 the time when millipeds and scorpions became our first air breathers4 ,these ages immediately followed the ,cambrian and involved millions of years4 ,the absence of the first of them is explained by some geologists as the result of its rocks having been completely worn away at a later time4 ,it seems more probable1 however1 that the ,grand ,canyon region was above sea level during these two ages so that no sediments were accumulated and consequently no rocks formed4 ,,the ,,age ,,of ,,fish 7,,devonian ,,period7 ,illustration3 ,a ,,fresh ,,water ,,fish ,,of ,,devonian ,,age ,during that period of geologic time commonly known as the 8age of fish10 sands and limes were accumulated on the surface of the ,grand ,canyon region filling in old river channels and burying the bodies of fish and other animals4 ,the deposits formed at this time were later eroded to a large extent4 ,the surface of the land was worn and washed away until finally only isolated patches or pockets of limestone and sandstone remained4 ,these we find today exposed in the walls of the ,grand ,canyon occurring just at the base of the great ,redwall cliff in about fifteen different localities4 ,although fish were rulers of the age during ,devonian times1 they were of primitive types and apparently depended for defense upon bony skin armour rather than upon speed4 ,the plates and scales of fresh-water fish have been found preserved in the lavender rocks of this age in the ,grand ,canyon4 ,,sea ,,life ,,from ,,the ,,north--,,the ,,redwall ,,limestone 7,,mississippian ,,or ,,lower ,,carboniferous ,,period7 ,illustration3 ,,redwall ,,fossils 7,,natural ,,size7 ,one of the most prominent and conspicuous features of the ,grand ,canyon is the great red cliff of limestone about midway in its walls4 ,this cliff is the highest in the ,canyon--averaging about #eej feet in the area of ,bright ,angel ,canyon4 ,in most places it is almost vertical1 and in some it even overhangs to such an extent that a visitor once aptly said1 8,the ,washington ,monument might be placed beneath it and kept out of the rain40 ,to the prospector this formation is known as the ,blue ,lime2 to the geologist it is the ,redwall ,limestone4 ,both are correct4 ,actually the rock is a rather pure limestone of a grey or bluish color1 but in most places where seen1 its surface has been stained a bright red by iron oxides from above4 ,it appears throughout the ,grand ,canyon as a wide band or ribbon of red4 ,illustration3 ,,havasu ,,falls ,,in ,,redwall ,,limestone4 ,,grand ,,canyon ,large amphitheaters1 many curving alcoves1 caves1 and solution tunnels are all characteristic features of the great ,redwall4 ,it is composed of relatively pure lime so rain and other waters have a chemical action upon it--they leach and dissolve it4 ,waters all tend to drain toward curving centers1 and so increase this curving4 ,everywhere the rounding off of corners takes place4 ,the origin of the ,redwall ,limestone is as interesting as its form4 ,the purity of the lime indicates that it was built up in a relatively wide and quiet sea4 ,its composition represents a vast accumulation of the skeletons of ancient plants and animals4 ,seashells are found in great numbers1 some of them preserved in delicate detail4 ,these and other forms of ocean life clearly indicate that a great sea connection then existed between this region and that of western ,canada to the north4 ,,tracks ,,in ,,the ,,supai ,,sandstone 7,,permian ,,period7 ,during that period in geological history known as the ,permian1 when some of the beds of soft coal in eastern ,america were being formed1 a large area in northern ,arizona was receiving red sediments from the east1 probably carried by rivers from the granitic highlands of that region4 ,today these sediments appear in the ,grand ,canyon walls as alternating layers of red sandstone and shale immediately above the great ,redwall4 ,they are almost a thousand feet in thickness4 ,illustration3 ,,tracks ,,of ,,short-,,legged ,,prehistoric ,,animal4 ,,supai ,,formation4 ,,grand ,,canyon ,when the red beds were accumulating in this region1 the climate probably was more or less arid2 the vegetation consisted principally of ferns and other lowly plants2 and the animal life included a group of large but primitive four-footed creatures4 ,numerous tracks of the latter1 preserved in the walls of ,grand ,canyon1 have provided one of the most interesting discoveries of recent years4 ,some of these footprints are several inches in length1 and the number of toes varies between three and five4 ,they show no close relationship to the tracks of other localities1 and apparently represent a fauna new to ,north ,america4 ,,landscapes ,,of ,,the ,,hermit ,,shale 7,,permian ,,period7 ,illustration3 ,,landscape ,,at ,,time ,,hermit ,,shale ,,was ,,forming 7,,reconstruction4 ,,museum ,,northern ,,arizona7 ,illustration3 ,,fossil ,,fern ,,from ,,the ,,hermit ,,shale 7,,reduced7 ,concerning the conditions under which the topmost red formation of the ,grand ,canyon 7the ,hermit ,shale7 was developed1 and the nature of its origin1 we have today a rather definite and interesting picture4 ,a wealth of fossil plants and a number of tracks of animals have been found excellently preserved in its muddy layers1 and by means of these and other indications the following conclusions have been drawn4 ,the ,hermit ,shale represents accumulations of mud and fine sandy material deposited probably by streams flowing from the northeast4 ,here and there are found evidences of pools and arroyos with wavy ripple marks on their borders and a thin film of shiny slime covering the surface4 ,the trails of worms1 the footprints of small salamander-like animals1 and the fronds of ferns1 mostly mascerated or wilted1 are found delicately preserved in this slime4 ,raindrop impressions1 the molds of salt crystals and numerous sun-cracks also add to the picture4 ,this region has been described by ,dr4 ,david ,white as 8the scene of showers1 burning sun1 hailstorms1 occasional torrents and periods of drought and drying up of pools0 during ,hermit times4 ,thirty-five species of plants are at present known from the ,hermit ,shale of ,grand ,canyon4 ,many of these have not been found elsewhere in the world1 though some were representatives of ,european plants1 and others had their closest relations in central ,asia1 ,india1 ,australia1 ,africa1 and ,south ,america4 ,this fossil flora consists principally of ferns and small cone-bearing plants1 all of which were relatively dwarfed in size and appear less dense than those of corresponding age found in eastern ,america4 ,they apparently indicate a semi-arid climate with long dry seasons1 for the absence of moist-climate and swamp-loving types is noticeable4 ,several insect wings have been found in the ,hermit ,shale1 one of which was four inches in length4 ,numerous footprints of vertebrate animals have also been found1 and undoubtedly represent an interesting fauna4 ,,wind-,,blown ,,sand--,,the ,,coconino 7,,permian ,,period7 ,the light-colored formation which appears as a conspicuous ribbon-like band around the upper part of the ,grand ,canyon has long presented a puzzle concerning its origin4 ,the grains of white sand of which it is composed apparently were deposited at steep angles1 for the many and varied slopes which were formed may be readily seen today on the surface of the rock4 ,these slopes were probably once the lee sides of sand dunes deposited by winds in an area bordering the sea4 ,we find the only traces of life in this formation represented by the trails of ancient worms and insects1 and by the foot-prints of early lizard1 or salamander-like creatures4 ,already the tracks of some #bg species of animals have been discovered in this sandstone within the ,grand ,canyon1 though strangely enough no bones have yet been located4 ,illustration3 ,,wind-,,blown ,,sand4 ,,coconino ,,formation4 ,,grand ,,canyon ,illustration3 ,,tracks ,,of ,,primitive ,,four-,,footed ,,animals1 ,,coconino ,,sandstone4 ,,grand ,,canyon ,,photo ,,by ,e4 ,w4 ,,ensor ,,warm ,,seas ,,from ,,the ,,west--,,the ,,toroweap ,,and ,,kaibab ,,formations 7,,permian ,,period7 ,illustration3 ,,seashells ,,from ,,kaibab ,,limestone 7,,reduced7 ,along both sides of ,grand ,canyon at the top1 two buff and gray layers of limestone stand out as massive cliffs separated by a tree-covered slope4 ,the upper of these limestones forms the plateau surface and may be seen for a great distance in every direction4 ,both layers were formed as the result of vast accumulations of organic and sandy materials on sea bottoms1 and in places are composed largely of the remains of marine life--shells1 corals and sponges4 ,the teeth of sharks have also been found in the upper limestone4 ,,sea ,,lily ,,or ,,crinoid 7,,reduced7 ,,horn ,,coral 7,,natural ,,size7 ,during the early stages of the period when these marine animals lived and multiplied in the region1 a great body of salt water extended over its surface from far to the west1 remained briefly1 then retreated from the area4 ,soon1 however1 marine waters advanced once more and another sea was formed with its shoreline extending eastward even beyond the region in which we now find ,grand ,canyon4 ,evidences of the second and larger sea are found beyond ,flagstaff to the south1 in the ,painted ,desert to the east1 and almost to ,zion ,canyon to the north4 ,the presence of corals and sharks' teeth not only indicates that this region was covered on more than one occasion by marine waters1 but also suggests that these seas were warm and shallow4 ,this is estimated to have been some #bjj million years ago4 ,,fossil ,,shark',s ,,tooth 7,,natural ,,size7 ,illustration3 ,,rocks ,,of ,,the ,,fourth ,,era ,the ,painted ,desert and ,zion ,canyon ,region ,,chapter ,,iv ,,the ,,mesozoic ,,era ,the ,fourth ,chapter of the earth's history is commonly known as 8the age of dinosaurs40 ,large reptiles were the dominating forms of life all over the world during this age4 ,landscapes and types of climate varied considerably1 and in the ,grand ,canyon region they changed completely several times4 ,during some periods ocean bodies covered the country2 at others desert winds piled up dunes on the surface4 ,again this region was the flood plain of rivers1 where pebbles1 mud and great logs of pine were washed in and deposited4 ,at still other times coal was formed in some quantity4 ,all of these interesting features of the ,fourth ,chapter will be briefly treated in the pages following4 ,their records as found at ,zion ,canyon to the north1 in the ,painted ,desert to the east1 and at the ,petrified ,forest to the south are such that a visitor to the region can scarcely help but marvel and wonder at their meaning4 ,,remnants ,,of ,,younger ,,strata--,,red ,,butte ,,and ,,cedar ,,mountain 7,,moenkopi ,,formation3 ,,triassic ,,period7 ,two isolated hills of unusual interest rise above the plateau surface near ,grand ,canyon4 ,looking east from ,desert ,view 7,navajo7 ,point one of these1 a flat-topped mesa called ,cedar ,mountain1 may be seen4 ,the other1 known as ,red ,butte1 is a rounded hill about fifteen miles to the south of ,grand ,canyon village4 ,the most interesting feature of these hills is found in the fact that they are composed for the most part of red sandstones and shales which once formed a continuous layer over this entire plateau region4 ,these same rocks are found throughout southern ,utah to the north1 and in the ,painted ,desert to the east4 ,except at ,red ,butte and ,cedar ,mountain they have been completely stripped off and eroded away from the vicinity of ,grand ,canyon4 ,the time involved in this erosion was tremendous and the consequences widespread4 ,as a result the present flat plateau surface was formed--a great plain high above sea level4 ,the persistence of ,red ,butte and ,cedar ,mountain against time and the elements is easily explained1 moreover1 by the hard lava cap of the former and the protecting layer of pebble-rock on top of the latter4 ,illustration3 ,,cedar ,,mountain ,illustration3 ,,red ,,butte ,the red sandstones and shales found in ,red ,butte and ,cedar ,mountain were formed from sands and muds accumulated during the early part of the ,triassic ,age--the beginning of the fourth great era of history4 ,near ,flagstaff at the southernmost limit of the formation have been found many tracks and trails left by small crawling animals which indicate a shore environment in that section4 ,in the same formation found in ,utah and other places to the north are many seashells of various types4 ,gypsum1 an indication of arid climate1 is also found to a large extent in the rocks of this group4 ,,the ,,petrified ,,forest 7,,shinarump ,,and ,,chinle ,,formations2 ,,triassic ,,period7 ,the ,petrified ,forests of northern ,arizona and southern ,utah were formed from trees which grew during a period known as the ,triassic4 ,the type of environment in the ,painted ,desert region during that period makes a very interesting speculation4 ,the landscape of this ancient country1 as interpreted from the present rock formations found there1 was that of a low1 flat area1 perhaps a floodplain1 where rivers and streams meandered back and forth1 depositing first large pebbles and sand1 and later a great thickness of finer material consisting of sand and much mud4 ,it was by these streams that a great quantity of logs of evergreen trees was carried down probably from mountains to the south or southwest4 ,many of the tree trunks were worn and battered on the way1 and in this region 7from southern ,utah to the vicinity of ,adamana and ,holbrook7 they were buried in great numbers among the depositing sediments4 ,all four of the ,petrified ,forests south of ,adamana originated in this manner--and probably represent old log-jams4 ,nine miles north of ,adamana1 however1 is the ,north ,sigillaria ,forest where the trees are found standing as they grew4 ,illustration3 ,,petrified ,,forest4 ,,arizona ,illustration3 ,,petrified ,,logs ,,of ,,triassic ,,age ,a large majority of the fossil trees in ,petrified ,forest ,national ,monument represent a pine-like species belonging to a group now extinct in the northern hemisphere4 ,some individuals of this type have diameters as great as ten feet and heights of more than #bjj feet4 ,four or five other varieties of tree occur but they are less common and rather inconspicuous4 ,the process by which these trees were changed to stone took place a very long time after they were buried beneath sands and silts4 ,at a time probably millions of years later1 waters bearing in solution the mineral silica passed through the rocks of this region4 ,particle by particle wood was decayed1 and almost simultaneously it was replaced by silica4 ,the brilliant colors found in much of it are due to small quantities of iron and manganese which were introduced in a similar manner4 ,the wicked-looking upper jaw of a phytosaur--relative of the crocodile--has been discovered buried in one of the colorful mounds of mud out in the ,petrified ,forest4 ,in nearby deposits are found still other fossils including ferns preserved in delicate detail and clamlike shells4 ,these1 together with the petrified logs of evergreen trees1 make the picture very much alive and real to one whose imagination allows him to review these fascinating early pages in history4 ,,dinosaur ,,tracks 7,,wingate-,,kayenta2 ,,jurassic ,,period7 ,dinosaur means 8terrible lizard40 ,everyone has heard this name and attaches to it at least a vague conception of a creature of peculiar shape and tremendous size4 ,in the dim far-away past these giant reptiles lived1 developed and died in many parts of this country1 but to most of us1 they are only fantastic creatures in literature--not live or moving animals4 ,illustration3 ,,dinosaur ,,tracks4 ,,painted ,,desert ,the reality of the dinosaur should become apparent to those who travel through the ,painted ,desert region of ,arizona4 ,in that country the grey and red hills of clay1 the cliffs of sand and the many brightly colored layers of hardened mud represent a part of the ancient landscape in which lived the 8terrible lizards40 ,furthermore1 life definitely inserts itself into this picture when a person sees in the rocks the very three-toed tracks left by the dinosaur4 ,who can deny the story of life when he can place his fingers in the foot impressions and measure the strides of these animals--many of them--both large and small8 ,such is the privilege of those who visit the ,painted ,desert just south of ,tuba ,city4 ,the tracks of the dinosaurs are found in rocks which apparently were formed from river deposits of sands and muds4 ,in other rocks closely associated have been found the bones of dinosaurs1 other reptiles1 and animals related to the frog or toad4 ,some of these creatures apparently were 8largely if not entirely terrestrial in habit0 while others probably lived in either fresh water streams or swamps4 ,illustration3 ,,the ,,painted ,,desert ,,the ,,rocks ,,of ,,zion ,,canyon ,,and ,,rainbow ,,natural ,,bridge 7,,navajo ,,sandstone2 ,,jurassic ,,period7 ,the lure of a desert with its drifting sands1 its scattered oases1 and its broad extent has ever been great4 ,today in the ,southwest1 cut off from the moist ocean breezes of the west by the lofty ,sierra ,nevadas and further isolated by the ,rocky ,mountains to the east1 is ,america's great desert region4 ,here the winds and the rains are constantly at work tearing down and sculpturing the great land masses1 while in places the wind is piling up the sand and debris to form dunes and new lands4 ,far back in history1 probably in what is known as the ,jurassic ,period1 southwestern ,united ,states witnessed conditions of climate and environment which were perhaps somewhat comparable though probably far more desert-like than those which exist today4 ,the land which had been raised in the preceding period to form a great flood-plain remained above sea level4 ,lofty mountains were formed to the west and like the ,sierras of today1 they robbed the east-travelling winds of their moisture4 ,these mountains were very high and furnished a vast supply of sediment which was carried down into the arid basin to the east1 worked and reworked by the wind1 and finally deposited as a great layer of sand4 ,illustration3 ,,zion ,,canyon4 ,,navajo ,,sandstone ,illustration3 ,,rainbow ,,natural ,,bridge4 ,,navajo ,,sandstone ,the beautiful ,vermilion ,cliffs and the ,white ,cliffs of southern ,utah which together form the walls of ,zion ,canyon1 the red sandstone out of which is carved ,rainbow ,natural ,bridge1 and the jagged ,echo ,cliffs seen to the northeast of ,desert ,view 7,navajo7 ,point at ,grand ,canyon are all monuments of the ,jurassic ,age4 ,these high walls are of sandstone--formed from sand steeply piled at varying angles4 ,they have been aptly called 8cliffs of fossil sand dunes40 ,while desert winds and a burning sun were playing a prominent part in the ,grand ,canyon region1 during the ,jurassic ,age1 other sections of the country were favored with a moist climate and luxuriant vegetation4 ,dinosaurs and other reptiles waded about in swamps and developed to tremendous sizes4 ,the country teemed with life1 very different from that of today1 yet none the less interesting4 ,,from ,,seashells ,,to ,,coal ,,beds 7,,dakota4 ,,mancos1 ,,mesa ,,verde2 ,,cretaceous ,,period7 ,illustration3 ,,cretaceous ,,shells ,,from ,,southern ,,utah ,during the last part of the 8,age of ,dinosaurs10 in that period of history known as the ,cretaceous1 much of northeastern ,arizona1 southern ,utah1 and northwestern ,new ,mexico apparently was submerged beneath a sea4 ,mollusks abounded1 and various other types of water animals swam or crawled in this region4 ,their shells were buried and preserved among the muds and limes which were accumulating1 and today many of them are found in the rocks of this age4 ,as time went on1 the ,cretaceous seas were expelled from their basins in the ,southwest4 ,low-lying coastal plains--two hundred and more miles wide--with luxuriant vegetation and perhaps swamps1 replaced them1 and these new conditions were the means of much coal formation4 ,great accumulations of vegetable matter1 buried beneath sediments brought down by streams1 eventually formed the many layers of coal which today are found in various places in ,utah1 ,arizona1 and ,new ,mexico4 ,in the last named state some extensive and valuable coal beds are found in rocks of this age near ,gallup4 ,impressions of leaves and pieces of fossil wood are also numerous among these rocks and they indicate that there was a warm1 moist climate during that period in which they grew4 ,the ,cretaceous ,period ended with a general change of conditions or a revolution1 the world over4 ,many of the seas were changed into lands1 new mountains were formed and the dinosaurs and giant reptiles were largely replaced by mammals and other modern varieties of life4 ,illustration3 ,,coal ,,canyon4 ,,painted ,,desert ,,country ,,aerial ,,photo ,,copyright ,,fred ,,harvey ,,chapter ,v ,,the ,,cenozoic ,,era ,although chapter five is the most recent in the earth's history and lasts up to the present day1 evidences of its life and its happenings are extremely meager in the ,grand ,canyon region4 ,with the exceptions of the fresh water deposits formed during the very early part 7,bryce ,canyon formations7 and of the many volcanoes built in the later stages1 no rocks were formed here during that chapter4 ,this region was then above sea level and erosion was working continuously4 ,the great level plain which today forms the plateau surface at ,grand ,canyon was created by the wearing away of overlying rocks4 ,the ,grand ,canyon itself and also ,zion and ,bryce ,canyons were sculptured4 ,in fact1 all of the features of erosion which today make this desert region so picturesque and fanciful owe their origin to the various agents of erosion which have been at work during this most recent chapter of the world's history4 ,the 8,age of ,mammals0 is a name often applied to the last era4 ,creatures not unlike some of the most advanced forms of life found today lived even in the early parts of this age4 ,as the era progressed1 nevertheless1 a development was noticeable until finally in the very last part man himself appeared4 ,though few remains of this interesting and comparatively recent life have been found in northern ,arizona and southern ,utah1 still a few elephant tusks1 some camel teeth and the more recent remains of early cliff and pueblo dwellers give evidence of a thrilling history during parts of this era4 ,in the following pages will be found brief sketches of some of these interesting features represented in the ,grand ,canyon region4 ,the many activities of erosion such as canyon-forming1 the eruption of volcanoes1 influences of the great ice sheets of the north1 crustal movements1 fragmentary evidences of early mammals1 and lastly early man himself are all introduced4 ,,bryce ,,canyon ,,formation 7,,wasatch3 ,,eocene ,,epoch7 ,the formation found at ,bryce ,canyon and at ,cedar ,breaks in southern ,utah has the distinction of being composed of the most recently formed sedimentary rocks in this plateau region4 ,it was during the early part of the last great chapter of history that lime and some sand were accumulating here in fresh water4 ,they are believed by most geologists to represent the deposits of ancient lakes and in them are found freshwater mollusks4 ,rivers and other agents of deposition probably also took a part in the forming of these strata as is indicated by the great irregularity and variety of sand and other sediments4 ,truly the origin of these rocks presents an interesting problem4 ,illustration3 ,,bryce ,,canyon ,,aerial ,,photo ,,copyright ,,fred ,,harvey ,illustration3 ,,map ,,of ,,the ,,colorado ,,river ,the delicate and beautiful colors of ,bryce are due to the white limestone which in many places retains its creamy color1 but in others has been stained a vivid pink by the drainage from upland washes4 ,the ,canyon itself is almost entirely the result of running water which has carved and etched its pattern during geologically recent times4 ,just as the ,grand ,canyon and ,zion ,canyon were made possible by a great elevation of the land in this region1 so also was ,bryce affected4 ,the small streams of the ,paunsagunt ,plateau were given power to cut into the sandstones and limestones which form the ,pink ,cliffs1 and due to the peculiar nature of these rocks the many spires1 promontories1 and pinnacles were formed as remnants of erosion in the valleys4 ,a ,,great ,,erosion ,,surface 7,,cenozoic ,,age7 ,the level1 flat and almost featureless skyline of ,grand ,canyon is an outstanding characteristic of the plateau of northern ,arizona4 ,this surface is fascinating to some2 monotonous to others4 ,to all1 it is one of the most striking features of the region4 ,the history which it represents1 moreover1 is of extreme interest and impressive length4 ,here on the top of the great plateau is seen the result of vast erosion4 ,long periods of work by water1 wind1 and other elements have gradually worn away strata that were once above4 ,just as erosion is forming the ,grand ,canyon today1 so it has accomplished this much greater task4 ,several thousand feet of materials have been removed from the surface over much of this entire region4 ,illustration3 ,a ,,great ,,erosion ,,surface ,,national ,,park ,,service ,south of ,grand ,canyon1 at ,red ,butte1 east in the ,painted ,desert1 and north in ,utah are found remnants of those rocks which once formed a continuous layer over the present plateau4 ,red sandstones and shales representing former sands and muds of shallow water and beach1 pebble-rocks and marls deposited by rivers and containing the remains of cone-bearing trees1 crocodiles1 and dinosaurs--all these rocks and probably others once gave color to this area just as today they lend brilliance to the ,painted ,desert and to southern ,utah4 ,in those places high cliffs mark the lines of recession--the stages of the constant retreat of the rocks from the ,grand ,canyon region before ever-working forces of erosion4 ,red ,butte to the south of ,grand ,canyon1 on the other hand1 has been preserved as an isolated remnant of the same rocks by its hard1 resistant cap of lava4 ,thus we have mute evidence of a tremendously large and wonderful story of former lands1 and of their later wearing away to leave the great plain which now forms the surface of the plateau about ,grand ,canyon4 ,,crustal ,,movement ,,at ,,grand ,,canyon 7,,cenozoic ,,age7 ,many visitors to the ,grand ,canyon are distinctly surprised when they find numerous seashells1 corals1 and sponges1 beautifully preserved in the limestone layer upon which they are standing4 ,the idea immediately occurs that this region was once beneath the sea4 ,obviously then either the land has risen or the ocean has receded4 ,a careful study of the region shows that the rock strata which form the great plateau of northern ,arizona have been bent into a huge arch or dome4 ,the ,santa ,fe railway travels steadily up grade to the south rim of ,grand ,canyon which is #g1jjj feet above sea level4 ,the north rim is a thousand feet higher1 while fifteen miles farther north a high point of #i1jjj feet is attained4 ,in southern ,utah the limestone layer which forms the top of ,grand ,canyon passes beneath the surface at #d1jjj feet4 ,why crustal movements occur is not definitely known though many theories have been advanced to explain them4 ,it is significant1 nevertheless1 that such movements have gone on in all parts of the world many times in history1 and that in many regions they are taking place today4 ,parts of the ,california coast are known to be rising1 while some other parts of the country are sinking slowly4 ,the question of whether or not the ,grand ,canyon region is still rising today cannot be answered with assuredness1 but certain it is that it has been both above and below sea level at many different times in history4 ,it is the slow sinking of the region which has made possible great accumulations of sediments and the building up of rock layers4 ,it is the rising of the land which has brought about great cycles of erosion such as apparently have occurred several times in the history of the ,southwest4 ,since today this region is high above sea level1 erosion is rapid4 ,not only does this elevation give the ,colorado ,river and its tributaries speed and power to erode downward1 but also it gives them unusual depth through which to cut and to carve the canyons which are their valleys4 ,without the rising of this plateau region1 the colossal gorges1 the weird1 sculptured forms of erosion1 all of the fascinating and picturesque features of this region could not be4 ,,cutting ,,the ,,grand ,,canyon 7,,pliocene ,,and ,,pleistocene ,,epochs7 8,,what ,,force ,,has ,,formed ,,this ,,masterpiece ,,of ,,awe8 ,,what ,,hands ,,have ,,wrought ,,these ,,wonders ,,in ,,the ,,waste8 ,o ,,river1 ,,gleaming ,,in ,,the ,,narrow ,,rift ,,of ,,gloom ,,that ,,cleaves ,,the ,,valley',s ,,nether ,,deep1 ,,fierce ,,colorado1 ,,prisoned ,,by ,,thy ,,toil1 ,,and ,,blindly ,,toiling ,,still ,,to ,,reach ,,the ,,sea4 ,,thy ,,waters1 ,,gathered ,,from ,,the ,,snows ,,and ,,springs ,,amid ,,the ,,utah ,,hills1 ,,have ,,carved ,,this ,,road ,,of ,,glory ,,to ,,the ,,california ,,gulf40 --,,henry ,,van ,,dyke ,very difficult is it for the average human fully to realize1 to comprehend the tremendous power of running water4 ,one does not question the origin of a wayside gulch cut out by recent storms1 nor is it hard to visualize the formation of some steep-walled glen where a fast-rushing stream is found at work in its bottom4 ,the vast ,grand ,canyon1 however1 an extreme example of erosion1 seems a bit too large--too wide and deep--to be attributed alone to the power of any river such as exists today4 ,but the ,grand ,canyon--the greatest of chasms--is nothing more than the result of the work of running water over a long period of history4 ,illustration3 ,,cross ,,sections ,,of ,,grand ,,canyon ,,near ,,the ,,western ,,end ,,of ,,national ,,park4 ,,rocks ,,of ,,the ,,third ,,era ,,alone ,,here ,,form ,,the ,,canyon ,,walls4 ,,those ,,of ,,the ,,first ,,era ,,are ,,probably ,,not ,,far ,,below ,,the ,,river ,,bed4 ,,central ,,or ,,bright ,,angel ,,area4 ,,the ,,inner ,,gorge ,,is ,,cut ,,in ,,hard ,,vertical ,,rocks ,,of ,,the ,,first ,,era 7,,archean74 ,,the ,,upper ,,canyon ,,walls ,,are ,,formed ,,of ,,horizontal ,,rocks ,,of ,,the ,,third ,,era4 ,,the ,,tilted ,,strata ,,of ,,the ,,second ,,era ,,were ,,here ,,worn ,,away ,,except ,,to ,,the ,,left ,,of ,,the ,,gorge4 ,,eastern ,,end 7,,desert ,,view1 ,,cape ,,royal74 ,,the ,,floor ,,of ,,the ,,canyon ,,is ,,here ,,formed ,,of ,,tilted ,,rocks ,,of ,,the ,,second ,,era4 ,,the ,,upper ,,walls ,,are ,,of ,,comparatively ,,horizontal ,,rocks ,,of ,,the ,,third ,,era4 ,illustration3 ,,the ,,grand ,,canyon ,those who have been to the rocky shores of the ,colorado ,river in ,grand ,canyon1 who have heard its wild roar1 and seen its mad waves rush along their course1 need no further introduction to the power of this stream4 ,it is a mighty river6 ,in the open stretch above the mouth of ,bright ,angel ,creek its speed varies between two and a half and ten miles an hour4 ,its width at the same place is over one hundred yards and its depth between twelve and forty-five feet4 ,but the ,colorado ,river alone would have made but little progress were it not for the many rocks--boulders1 pebbles1 and sand grains--all of which act as tools and are constantly gouging and cutting as they move4 ,just as sandpaper rubbing over the same place continuously leaves its groove1 so this combination of power and tools is ever carving its course4 ,the ,colorado ,river during a vast period has cut almost a mile vertically through all of the great rock layers now exposed in the walls of ,grand ,canyon4 ,the width of the ,grand ,canyon1 an average of about ten miles1 has been brought about by the wearing and washing-in of its sides by natural processes of erosion4 ,rain1 wind1 frost1 temperature changes and plant action have all combined to break down the ,canyon walls4 ,the soft rocks on the slopes are continually being broken and removed2 the more resistant ones in the cliffs are undermined so in time fall down4 ,while the river has been cutting deeper1 the ,canyon's sides have been steadily receding4 ,the ,grand ,canyon itself is the valley of the ,colorado1 and its narrowness rather than its width is the remarkable feature when compared with the valleys of other rivers4 ,this present canyon profile has been brought about as the combined effects of an arid climate and a rapidly downward cutting river4 ,even a distant view of the ,colorado ,river in the ,grand ,canyon bottom is sufficient to convince one of the tremendous transporting power of this stream4 ,thus it not only does the work of cutting downward1 but also carries off the vast load of sand and silt which is continually emptied into its waters4 ,it has been aptly described as being 8too thick to drink but too thin to plow40 ,in this region the river known at its headwaters as the 8,silvery ,colorado0 bears even a higher percentage of sediment than does the muddy ,mississippi-,missouri4 ,it has been found from carefully made tests by the ,united ,states ,geological ,survey that the ,colorado ,river carries past any given point in the ,grand ,canyon an average of nearly a million tons of sand and silt every day4 ,thus has the ,grand ,canyon been excavated6 ,,the ,,forming ,,of ,,zion ,,canyon 7,,pliocene ,,and ,,pleistocene ,,epochs7 8,a ,yosemite ,valley in colors0 is a very apt description which has often been applied to ,zion ,canyon in southern ,utah4 ,sheer-walled with a beautiful flat valley floor1 this canyon is not unlike ,california's glacier-carved fairyland in general size and shape1 but in formation it has a very different history4 ,illustration3 ,,zion ,,canyon ,the brilliant ,vermilion ,cliffs which form the bottom two thousand feet of ,zion's walls and the contrasting ,white ,cliffs which rise an additional thousand feet are hard1 resistant sandstones4 ,wherever these rocks are found1 they form conspicuous perpendicular cliffs because of their hardness1 yet even they show the results of the constant attacks of weather and erosion over long periods4 ,from once continuous layers1 they have in many places gradually been cut and dissected by running water until now numerous canyons expose their secrets4 ,it was relatively late in the last chapter of the earth's history 7,cenozoic ,era7 that the cutting of ,zion and associated canyons was made possible by gradual though tremendous crustal movements in the region4 ,the then broad1 low-lying country was raised several thousand feet to about its present altitude4 ,this was the means of giving power to the streams1 including the masterstream--the ,virgin ,river4 ,steadily and relentlessly these active agents of erosion1 heavy-laden with their tools1 the muds1 sands1 and pebbles1 have been cutting notches and then canyons4 ,zion ,creek itself1 which is one of the largest tributaries of the ,virgin ,river1 has cut downward through all of the layers now exposed in the walls of its canyon1 and the rock fragments derived from these have been the means of grinding and gouging4 ,as the stream has struggled in its course1 these sides have slowly but surely receded through the combined efforts of rain1 wind1 frost and plants4 ,they have been undermined and otherwise attacked1 but as yet represent comparatively little progress in widening4 ,beautiful ,zion ,canyon1 therefore1 has been created as the result of crustal movements bringing into action the effective cutting power of running water1 assisted by all the ever-working forces of disintegration and decay4 ,,glaciers 7,,pleistocene ,,epoch7 8,what part did glaciers play in cutting the ,grand ,canyon80 ,this is a question asked almost daily on the rim of that great chasm4 ,everyone has heard of the mighty ice sheets which somewhere back in geologic history covered a large part of eastern and midwestern ,united ,states4 ,many people have seen beautiful ,yosemite ,valley in the far west1 and have been told how it was carved by the action of glaciers4 ,it is not altogether strange1 therefore1 that visitors to the ,grand ,canyon should associate the cutting power of ice with that tremendous gash in the earth's surface4 ,but geologists agree that the glaciers of the ,ice ,ages had no direct part in the story of ,grand ,canyon4 ,no scratches or gouges made by ice are to be found on the canyon walls1 no great rock piles formed at a glacier's front are in evidence1 and lastly1 the very ,v-shape of the canyon itself is vastly different from the usual flat-bottomed valley scooped out by moving ice4 ,during the last epoch of geologic history1 climatic conditions the world over altered very materially4 ,upon five different occasions snow accumulated in the north to form extensive ice sheets which advanced steadily toward the equator and then retreated with a later change in conditions4 ,these were not the only ice ages in history1 but they were of such a comparatively recent date that their influence is strongly felt today in many parts of the world4 ,at the time of greatest expansion the glaciers reached ,new ,york in the east1 ,missouri in the mid west1 and ,washington in the far west4 ,contemporaneous with these main ice sheets1 furthermore1 were large glaciers throughout the ,rocky ,mountains and the ,sierra ,nevadas4 ,in the mountains of ,utah and even in the ,san ,francisco ,peaks1 just south of the ,grand ,canyon1 are found evidences of glaciers of this period4 ,evidently then1 climatic conditions in the ,southwest as elsewhere were greatly different from those of today4 ,it is believed that there was much more rainfall and less evaporation1 as shown by the extensive lakes which existed in this region at that time4 ,furthermore1 the later melting of the glaciers must have supplied a vast quantity of water to the ,colorado ,river causing it to be far larger and more powerful than today4 ,,san ,,francisco ,,mountain ,,volcanic ,,field 7,,pliocene ,,and ,,pleistocene ,,epochs7 ,illustration3 ,,view ,,of ,,volcanoes ,,from ,,north ,over a large part of the great plateau of northern ,arizona are found sheets of hard lava and cone-shaped craters4 ,the center of this volcanic activity is located in the ,san ,francisco ,peaks just north of the town of ,flagstaff1 but lavas and cones are found westward beyond ,williams and to a considerable extent in every other direction4 ,looking south from ,grand ,canyon these peaks may be seen to rise high above the plateau and are a very beautiful sight4 ,from ,flagstaff and ,williams not only the mountains but also great sheets of lava resting on the limestone surface are conspicuous4 ,illustration3 ,,san ,,francisco ,,mountain--,,past ,,and ,,present ,it was during the last great era in geological history1 and for the most part after the ,colorado ,river had already started to cut the ,grand ,canyon1 that molten masses broke through and flowed out on the northern ,arizona plateau4 ,three great periods of such volcanic activity are represented by the rocks of this region and they range in age from probably at least a million to relatively recent years4 ,the first general period of eruption in the ,san ,francisco ,volcanic ,field was characterized by a predominance of lava flows which formed a black rock known as basalt4 ,these flows had an average thickness of about #ej feet and covered an area of #c1jjj square miles4 ,accompanying them was the formation of about a hundred small cinder cones4 ,illustration3 ,san ,francisco ,mountain ,volcanic ,field ,it was during the second period of volcanism that six isolated cones of large size and a somewhat greater number of small cones were formed by the eruption of lavas widely ranging in composition4 ,san ,francisco ,peak1 the largest of these cones and a dominant feature of the region reaches an elevation of #ab1faa feet above sea level1 or about #e1jjj feet above the plateau surface4 ,it is composed of five different types1 of lava--mostly red or light colored--which represent a corresponding number of distinct stages in eruption4 ,since the termination of its building-up1 the crest of this cone has been eroded and worn away to the extent of #c1jjj feet as estimated from restored cross-sections4 ,other large volcanic craters of this period are ,bill ,williams 7#i1jij feet71 ,kendrick 7#aj1dah feet71 ,o',leary 7#h1ibe feet7 and ,sitgreaves 7#i1bdj feet74 ,two hundred small cones and about twenty cubic miles of lava were produced in this same general region during a third and relatively recent period of volcanic activity4 ,much of this material overlies that of the two preceding periods4 ,probably the most interesting feature of these cones and flows is their age1 at least one cone being so recent that ash from it buried numerous pithouses built by ,pueblo ,indians during the eleventh century1 ,a4 ,d4 ,illustration3 ,,san ,,francisco ,,mountain ,,elephants ,,and ,,camels 7,,pleistocene ,,epoch7 ,it was during the fifth and last great era in the earth's history that mammals developed and that man made his appearance on earth4 ,in many places in the world the remains of animals that lived during various parts of this age have been preserved4 ,in the famous asphalt pits of ,california literally hundreds of the bones of large mammals--tigers1 mastodons1 wolves and many others--have been brought to light4 ,in the receding ice of northern ,siberia1 large mammoths--elephant-like animals representative of the last era1 but unknown today--have come to the surface with even their skin and flesh preserved4 ,but in the ,grand ,canyon region few fossils of the more recent times remain to tell the story of the life that then roamed over this surface4 ,for long ages this region has been above the level of the sea1 erosion has been continuous1 so sediments have not accumulated and consequently few records of life have been made4 ,recently near the western ,navajo ,indian agency at ,tuba ,city1 ,arizona1 however1 the remains of several extinct animals were discovered4 ,in a spring1 hidden in a sandstone crevice1 were found the tusks of a mammoth and some teeth which belonged to camels and bison4 ,these were creatures native to this country not far back in history4 ,they give but a very fragmentary insight into the more recent geologic history of the region1 but they open up a field for interesting speculation to the imaginative person4 ,illustration3 ,,elephant ,,and ,,camel ,,remains ,,advent ,,of ,,man ,,in ,,the ,,southwest 7,,pleistocene ,,historic7 ,after reviewing the chapters of the earth's history and witnessing the procession and the slow but steady development of life through the ages1 it is very natural that one should wonder when man came upon the scene4 ,compared with the hundreds of millions of years which have elapsed since the time of the first plants1 or the millions of years following the first appearance of vertebrate animals1 the age of man is as nothing4 ,in the ,old ,world there is evidence that humans existed before the last great ,ice ,ages1 more than a million years ago1 but in the ,americas human occupation is measured in terms of thousands of years only4 ,numerous recent discoveries in widely scattered parts of the ,southwest indicate that man first occupied this region at a time when it was still inhabited by such animals as the ground sloth1 the mammoth and the camel4 ,artifacts of stone and bone have been found associated with the remains of these animals4 ,early man's camp sites are located along the margins of former extensive water bodies that existed throughout this region at a time when the climate was far more humid than now4 ,little is known about the nature or habits of these men1 but it is supposed that they were hunters with no knowledge of agriculture4 ,in the ,grand ,canyon region1 the earliest human history with a clear1 detailed record goes back only to about #cjj ,a4 ,d4 ,from that time up to the present1 however1 the story of a flourishing and rapidly changing civilization is well recorded4 ,although no written documents have been left1 abundant reliable information is available as a result of archeological excavations4 ,even the dates of many important events have been accurately determined through an ingenious method of calculating years on the basis of growth rings in the trees used for house construction4 ,illustration3 ,,ancient ,,indian ,,petroglyphs1 ,,head ,,of ,,bright ,,angel ,,trail1 ,,grand ,,canyon ,two distinct cultures are represented in the people who have inhabited the ,grand ,canyon region for the past #a1fjj years4 ,the earlier and more primitive was that of a long-headed type of man known as the ,basketmaker4 ,this culture was replaced at about #gjj ,a4 ,d4 by another1 probably the result of new people entering the area1 mixing with the older inhabitants and introducing new ideas4 ,a broad-headed type of man who lived in pueblos and made pottery was the result4 ,in the earliest stages he built only small one-roomed houses and made relatively crude pottery1 but by #a1bjj ,a4 ,d4 his architecture and crafts had developed to a very high stage as witnessed in the largest cliff-dwellings and pueblos of the region4 ,since then the culture has declined4 ,the ,hopi ,indians of today who live near the ,painted ,desert ,country to the east of ,grand ,canyon are considered to be modern representatives of this group4 ,in numerous localities throughout southern ,utah burials of the early ,farmer ,basketmaker period and also pithouses of the later ,potter ,basketmaker period have been found4 ,one of the latter has also been discovered near ,clear ,creek in ,grand ,canyon4 ,the remains of cliff-dwellings and surface houses built by the later ,pueblo ,indians are common everywhere throughout the region and show all stages of development4 ,those at and in the ,grand ,canyon are typical of the intermediate periods and1 judging from pottery fragments in them1 were made by the ancestors of the modern ,hopi4 ,,geological ,,bibliography ,,of ,,grand ,,canyon ,,region ,including ,zion1 ,bryce1 ,painted ,desert1 and ,petrified ,forest ,allen1 ,v4 ,t41 ,triassic ,bentonite of the ,painted ,desert3 ,am4 ,jour4 ,sci41 vol4 xix1 ,april1 #aicj4 ,baker1 ,a4 ,a4 and others1 ,notes on the ,stratigraphy of the ,moab ,region1 ,utah2 ,bull4 ,am4 ,assoc4 ,petrol4 ,geol41 vol4 #aa1 #aibg4 ---- and ,reeside1 ,j4 ,b41 ,correlation of the ,permian of southern ,utah1 northern ,arizona1 northwestern ,new ,mexico1 and southwestern ,colorado3 ,bull4 ,am4 ,assoc4 ,petrol4 ,geol41 vol4 #ac1 no4 #aa1 ,nov41 #aibi4 ----1 ,dane1 ,c4 ,h41 and ,reeside1 ,j4 ,b4 ,jr41 ,correlation of the ,jurassic ,formations of ,parts of ,utah1 ,arizona1 ,new ,mexico and ,colorado3 ,u4 ,s4 ,geol4 ,survey ,prof4 ,paper #ahc1 #aicf4 ----1 ,geology of the ,monument ,valley--,navajo ,mountain ,region1 ,san ,juan ,county1 ,utah3 ,u4 ,s4 ,geol4 ,survey ,bull4 #hfe1 #aicf4 ,brady1 ,l4 ,f41 ,preliminary ,note on the ,occurrence of a ,primitive ,theropod in the ,navajo3 ,amer4 ,jour4 ,sci41 vol4 #cj1 #aice4 ,branson1 ,e4 ,b41 and ,mehl1 ,m4 ,g41 ,triassic ,amphibians from the ,rocky ,mountain ,region3 ,univ4 ,mo4 ,studies1 vol4 #d1 no4 #b1 #aibi4 ,butler1 ,b4 ,s41 ,the ,ore ,deposits of ,utah3 ,u4 ,s4 ,geol4 ,survey ,prof4 ,paper #aaa1 pp4 #fai-fbj1 #aibj4 ,bryan1 ,kirk1 ,discussion of rock-fill dam1 ,lees ,ferry1 ,arizona3 ,am4 ,soc4 ,civ4 ,eng41 ,proc41 vol4 #dh1 pp4 #afae-afbg4 ----1 ,wind ,erosion near ,lees ,ferry1 ,arizona3 ,am4 ,jour4 ,sci41 vol4 #f1 p4 #bia1 #aibc4 ,camp1 ,charles ,l41 ,a ,study of the ,phytosaurs3 ,memoirs1 ,univ4 ,calif41 vol4 #aj1 ,univ4 ,calif4 ,press1 #aicj4 ---- and ,vander,hoof1 ,v4 ,l41 ,small ,bipedal ,dinosaur from the ,jurassic of ,northern ,arizona3 ,proc4 ,geol4 ,soc4 ,amer41 abstract1 pp4 #chd-e1 #aicd4 ,campbell1 ,ian1 and ,maxson1 ,j4 ,h41 ,some ,observations on the ,archean ,metamorphics of the ,grand ,canyon3 ,proc4 ,nat4 ,acad4 ,sci41 vol4 #ai1 no4 #i1 pp4 #hjf-hji1 #aicc4 ,campbell1 ,m4 ,r41 and ,gregory1 ,h4 ,e41 ,the ,black ,mesa coal field1 ,arizona3 ,u4 ,s4 ,geol4 ,survey ,bull4 #dca1 pt4 #b1 #aiji4 ,carpenter1 ,frank ,m41 ,a ,fossil ,insect from the ,lower ,permian of the ,grand ,canyon3 ,u4 ,s4 ,national ,museum ,proc4 ,no4 #bfie1 #aibg4 ,colton1 ,harold ,s41 ,sunset ,crater--,the ,effect of a ,volcanic ,eruption on an ,ancient ,pueblo ,people3 ,geogr4 ,review1 vol4 #bb1 no4 #d1 #aicb4 ---- ,basaltic ,cinder ,cones and ,lava ,flows of the ,san ,francisco ,mountain ,volcanic ,field3 ,mus4 ,northern ,arizona1 ,bull4 #aj1 #aicg4 ,cross and ,howe1 ,redbeds of southwestern ,colorado and their correlation3 ,geol4 ,soc4 ,am4 ,bull41 vol4 #af1 pp4 #dhf-dhg1 #aije4 ,dake1 ,c4 ,l41 ,the pre-,moencopi unconformity of the ,colorado ,plateau3 ,jour4 ,geology1 vol4 #bh1 pp4 #fa-gd1 #aibj4 ,darton1 ,n4 ,h41 ,reconnaissance of parts of northwestern ,new ,mexico and northern ,arizona3 ,u4 ,s4 ,geol4 ,survey1 ,bull4 #dce1 #hd pp41 #ag pls41 #aiaj4 ---- ,guidebook of the western ,united ,states3 ,part ,c1 the ,santa ,fe ,route with a side trip to the ,grand ,canyon of the ,colorado3 ,u4 ,s4 ,geol4 ,survey ,bull4 #fae1 pp4 #abc-aca1 #aiae4 ---- ,a ,reconnaissance of parts of northwestern ,new ,mexico and northern ,arizona3 ,u4 ,s4 ,geol4 ,surv4 ,prof4 ,paper #aca1 #aibb4 ---- ,resume of ,arizona geology3 ,arizona ,bu4 of ,mines1 ,bull4 #aai1 #aibe4 ,daugherty1 ,lyman ,h41 ,new ,fossil ,plants from the ,petrified ,forest3 ,proc4 ,geol4 ,soc4 ,amer41 abstract1 p4 #chi1 #aicd4 ,davis1 ,w4 ,m41 ,notes on the ,colorado ,canyon district3 ,am4 ,jour4 ,sci41 #dth ser41 vol4 #aj1 pp4 #bea-bei1 #aijj4 ---- ,an excursion to the ,grand ,canyon of the ,colorado3 ,harvard ,coll4 ,mus4 ,comp4 ,zool41 vol4 #ch1 pp4 #ajg-bja1 #aija4 ---- ,the lessons of the ,colorado ,canyon3 ,bull4 ,am4 ,geogr4 ,soc41 vol4 #da1 #aiji4 ,diller1 ,j4 ,s41 ,asbestos in #aiag3 ,u4 ,s4 ,geol4 ,survey ,mineral ,resources of ,u4 ,s4 #aiag1 ,pt4 #b1 pp4 #aih-aii1 #aiah4 ,dutton1 ,e4 ,c41 ,the physical history of the ,grand ,canyon ,district3 ,u4 ,s4 ,geol4 ,survey ,second ,ann4 ,rept41 pp4 #dg-aff1 pls4 ,x-,,xxv1 and map1 #ahhb4 ---- ,tertiary history of the ,grand ,canyon ,district3 ,u4 ,s4 ,geol4 ,survey ,mon4 #b1 #bfd pp41 folio atlas1 #ahhb4 ,frech1 ,f41 ,section in ,congress ,canyon opposite ,point ,sublime3 ,compt4 rend4 #eth ,sess4 ,cong4 geol4 internat41 pp4 #dgf-ha1 #ahic4 ,gilbert1 ,g4 ,k41 ,report on the geology of portions of ,nevada1 ,utah1 ,california1 and ,arizona1 examined in the years #ahga1 #ahgb1 and #ahgc1 ,report ,u4 ,s4 ,geog4 ,surveys ,w4 #ajjth ,mer4 vol4 #c1 pp4 #ag-ahg1 #ejc-efg1 #ahge4 ,gilmore1 ,charles ,w41 ,fossil ,footprints from the ,grand ,canyon3 ,smithsonian ,misc4 ,collections #gg ,no4 #i1 #hj ,no4 #c1 #hj ,no4 #h1 #aibf-g-h4 ,gregory1 ,h4 ,e41 ,geology of the ,navajo ,country3 ,u4 ,s4 ,geol4 ,survey ,prof4 ,paper #ic1 #afa pp41 map1 #aiag4 ---- ,the ,shinarump conglomerate3 ,am4 ,jour4 ,sci41 vol4 #ce1 pp4 #dbd-dch1 #aiac4 ---- ,reconnaissance of a portion of the ,little ,colorado ,valley3 ,am4 ,jour4 ,sci41 #dth ser41 vol4 #ch1 pp4 #dia-eja4 ---- ,igneous origin of the glacial deposits of the ,navajo ,reservation3 ,am4 ,jour4 ,sci41 #dth ser41 vol4 #dj1 pp4 #ig-aae4 ---- ,the ,navajo ,country3 ,u4 ,s4 ,geol4 ,survey ,water-,supply ,paper #chj1 #bai pp41 map1 #aiaf4 ---- and ,moore1 ,r4 ,c41 ,the ,kaiparowits ,region3 ,u4 ,s4 ,geol4 ,surv4 ,prof4 ,paper #afd1 #afa pp4 #ca pls41 #aica4 ----1 ,colorado ,plateau ,region1 xvi ,international ,geological ,congress1 ,guidebook #ah1 ,excursions ,c-#a1 ,c-#b1 #aicc4 ,hager1 ,dorsey1 ,stratigraphy--northeast ,arizona--southeast ,utah3 ,mining and ,oil ,bull41 vol4 #aj1 pp4 #afg1 #dbc1 #aibd4 ,hesse1 ,curtis ,j41 ,semionotus cf41 gigas1 from the ,triassic of ,zion ,park1 ,utah3 ,amer4 ,jour4 ,sci41 vol4 #bi1 #aice4 ,hinds1 ,norman ,e4 ,a41 ,ep-,archean and ,ep-,algonkian ,intervals in ,western ,north ,america3 ,carnegie ,inst4 ,washington1 ,publ4 ,no4 #dfc1 pp4 #a-eb1 #aice4 ---- ,uncompahgran and ,beltian ,deposits in ,western ,north ,america3 ,carnegie ,inst4 ,washington1 ,publ4 ,no4 #dfc1 pp4 #ec-acf1 #aicf4 ,huntington1 ,ellsworth and ,goldthwait1 ,j4 ,w41 ,the ,hurricane ,fault in the ,toquerville district1 ,utah3 ,harvard ,coll4 ,mus4 ,comp4 ,zool4 ,bull41 vol4 #db1 #aijd4 ,iddings1 ,j4 ,p41 ,pre-,cambrian igneous rocks of the ,unkar terrane1 ,grand ,canyon of the ,colorado1 ,ariz41 by ,c4 ,d4 ,walcott1 with notes on the petrographic character of the lavas by ,iddings ,u4 ,s4 ,geol4 ,survey ,fourteenth ,ann4 ,report1 ,part #b1 pp4 #ebj-bd1 #ahie4 ,johnson1 ,d4 ,w41 ,a geological excursion in the ,grand ,canyon district3 ,proc4 ,boston ,soc4 ,nat4 ,hist41 vol4 #cd1 pp4 #ace-afa1 pls4 #ag-bb1 #aiji4 ,knowlton1 ,f4 ,h41 ,the ,fossil ,forests of ,arizona3 ,amer4 ,for41 vol4 #i1 #aiac4 ---- ,a ,catalogue of the ,mesozoic and ,cenozoic plants of ,north ,america3 ,u4 ,s4 ,geol4 ,survey ,bull4 #fif1 #aiai4 ,lee1 ,w4 ,t41 ,geologic reconnaissance of a part of western ,arizona3 ,u4 ,s4 ,geol4 ,survey ,bull4 #ceb1 #if pp41 #aa pls4 #aijh4 ---- ,stories in ,stone4 ,c4 ,van ,nostrand ,co41 #aibf4 ---- ,the ,canyons and ,painted ,cliffs of ,zion ,national ,park and the ,story of their ,origin1 ,national ,park ,service4 ,longwell1 ,c4 ,r41 ,geology of the ,muddy ,mountains1 ,nev41 with a section to the ,grand ,wash ,cliffs1 in western ,arizona3 ,am4 ,jour4 ,sci41 #dth ser41 vol4 #ej1 pp4 #eb-ed1 #aiba4 ---- and others1 ,rock formations in the ,colorado ,plateau of southeastern ,utah and northern ,arizona3 ,u4 ,s4 ,geol4 ,survey ,prof4 ,paper #acb1 pp4 #a-bc1 #aibc4 ----1 ,the pre-,triassic unconformity in southern ,nevada3 ,am4 ,jour4 ,sci41 #eth ser41 vol4 #aj1 pp4 #ic-ajf1 #aibe4 ---- ,structural studies in southern ,nevada and western ,arizona3 ,geol4 ,soc4 ,am4 ,bull41 vol4 #cg1 pp4 #eea-ehd1 pls4 #ag-bj1 #aibf4 ----1 ,geology of the ,muddy ,mountains1 ,nevada1 with a section through the ,virgin ,range to the ,grand ,wash ,cliffs1 ,arizona3 ,u4 ,s4 ,geol4 ,survey ,bull4 #gih1 #aibh4 ----1 ,geology of the ,boulder ,reservoir ,floor3 ,bull4 ,geol4 ,soc4 ,amer41 vol4 #dg1 pp4 #acic-adgf1 #aicf4 ,lucas1 ,f4 ,a41 ,vertebrates from the ,trias of ,arizona3 ,science1 new ser41 vol4 #ad1 p4 #cgf1 #aija4 ---- ,a ,new ,batrachian and a new reptile from the ,trias of ,arizona3 ,u4 ,s4 ,nat4 ,mus4 ,proc41 vol4 #bg1 pp4 #aic1 #aie1 #aijd4 ,lull1 ,r4 ,s41 ,fossil ,footprints from the ,grand ,canyon of the ,colorado3 ,amer4 ,jour4 ,sci41 vol4 #de1 #aiah4 ,marcou1 ,jules1 ,resume and field notes3 ,u4 ,s4 ,pacific ,railroad ,expl4 vol4 #c1 pt4 #d4 ,geological ,report1 #ahef4 ,matthes1 ,f4 ,e41 ,bright ,angel ,quadrangle4 ,u4 ,s4 ,geol4 ,survey topo4 map text4 ,marvine1 ,a4 ,r41 ,report on the geology of the route from ,st4 ,george ,utah1 to ,gila ,river1 ,arizona1 examined in #ahga3 ,u4 ,s4 ,geog4 ,survey ,w4 of #ajjth ,mer41 vol4 #c1 #ahge1 pp4 #ahi-bbe1 maps4 ,maxson1 ,j4 ,h41 and ,campbell1 ,ian1 ,archean ,ripple ,mark in the ,grand ,canyon3 ,amer4 ,jour4 ,sci41 vol4 #bh1 #aicd4 ,mc,kee1 ,edwin ,d41 ,climates of the ,age of ,mammals in the ,grand ,canyon ,region3 ,museum ,notes1 ,museum of ,northern ,arizona1 ,flagstaff1 #aicb4 ----1 ,arizona ,through the ,ages3 ,scientific ,monthly1 #aicb4 ---- ,the ,coconino ,sandstone--,its ,history and ,origin3 ,carnegie ,institution ,publ4 #ddj1 vii1 #aicd4 ---- ,a ,study of the ,light-colored1 ,cross-bedded ,sandstones of ,canyon de ,chelly1 ,arizona3 ,am4 ,jour4 ,sci41 #eth ,ser41 vol4 #bh1 pp4 #bai-bcc1 #aicd4 ----1 ,occurrence of ,triassic ,sediments on the ,rim of ,grand ,canyon3 ,jour4 ,wash4 ,acad4 ,sci41 vol4 #be1 no4 #d1 #aice4 ----1 ,a ,conularia from the ,permian of ,arizona3 ,jour4 ,paleontology1 vol4 #i1 no4 #e1 #aice4 ----1 ,triassic ,pebbles in ,northern ,arizona ,containing ,invertebrate ,fossils3 ,amer4 ,jour4 ,sci41 vol4 #cc1 #aicg4 ----1 ,the ,environment and ,history of the ,toroweap and ,kaibab formations of ,northern ,arizona and ,southern ,utah3 ,carnegie ,inst4 ,washington1 ,publ4 #dib1 #aich4 ,merriam1 ,john ,c41 ,the ,living ,past1 ,charles ,scribner's ,sons1 #aicj4 ,miller1 ,w4 ,j41 ,zion ,canyon ,national ,park1 ,utah3 ,journal of ,geography1 ,may1 #aibc4 ,moore1 ,r4 ,c41 ,on the ,stratigraphy of ,northeastern ,arizona3 ,am4 ,assoc4 ,petrol4 ,geol4 ,bull41 vol4 #f1 no4 #a1 pp4 #dg-di1 #aibb4 ,newberry1 ,j4 ,s41 ,report upon the ,colorado ,river of the ,west1 explored in #aheg-eh by ,lieut4 ,j4 ,c4 ,ives3 ,govt4 ,printing ,office1 pt4 #c1 ,geological ,report1 #ahfa4 ,noble1 ,l4 ,f41 ,the geology of the ,shinumo area3 ,am4 ,jour4 ,sci41 #dth ser41 vol4 #bi1 pp4 #cfi-chf1 #dig-ebh1 #aiaj4 ----1 ,the ,shinumo ,quadrangle1 ,grand ,canyon district1 ,arizona3 ,u4 ,s4 ,geol4 ,survey ,bull4 #edi1 #ajj pp41 #ah pls41 #aiad4 ---- ,a ,section of the ,paleozoic formations of the ,grand ,canyon on the ,bass ,trail3 ,u4 ,s4 ,geol4 ,survey ,prof4 ,paper #aca1 pp4 #bc-gc1 #aibb4 ---- and ,hunter1 ,j4 ,f41 ,a reconnaissance of the ,archean complex of the ,granite ,gorge1 ,grand ,canyon1 ,arizona3 ,u4 ,s4 ,geol4 ,survey ,prof4 ,paper #ih1 pp4 #ie-aac1 #aiaf4 ---- ,a ,section of ,kaibab ,limestone in ,kaibab ,gulch1 ,utah3 ,u4 ,s4 ,geol4 ,survey1 ,prof4 ,paper #aej1 #aibh4 ,powell1 ,j4 ,w41 ,exploration of the ,colorado ,river of the ,west and its tributaries explored in #ahfi-ahgb3 ,smithsonian ,inst41 #bia pp41 #ahgc4 ,ransome1 ,f4 ,l41 ,pre-,cambrian in ,grand ,canyon3 ,science1 vol4 #bg1 pp4 #ffg-ffh1 #aijh4 ---- ,some ,paleozoic sections in ,arizona and their correlations3 ,u4 ,s4 ,geol4 ,survey ,prof4 ,paper #ih1 pp4 #acc-aff1 #aiaf4 ,reagan1 ,albert ,b41 ,some ,geological ,notes on the ,upper ,cretaceous of ,black ,mesa1 ,arizona1 ,transactions of the ,kansas ,academy of ,science1 vol4 #ce1 pp4 #bcb-beb1 #aicb4 ---- ,the ,tertiary--,pleistocene of the ,navajo ,country in ,arizona1 with a description of some of its included fossils3 ,transactions of the ,kansas ,academy of ,science1 vol4 #ce1 pp4 #bec-bei1 #aicb4 ,reeside1 ,j4 ,b41 and ,bassler1 ,harvey1 ,stratigraphic sections in southwestern ,utah and northwestern ,arizona3 ,u4 ,s4 ,geol4 ,sur4 ,prof4 ,paper1 #abi-;,d1 #aibb4 ,robinson1 ,h4 ,h41 ,the ,san ,franciscan volcanic field1 ,arizona3 ,u4 ,s4 ,geol4 ,survey ,prof4 ,paper #gf1 #bac pp41 #ad pls41 #aiac4 ,schuchert1 ,charles1 ,on the ,carboniferous of the ,grand ,canyon--,the ,cambrian of the ,grand ,canyon3 ,am4 ,jour4 ,sci41 #dth ser41 vol4 #de1 pp4 #cdg-cfi1 #aiah4 ,shimer1 ,h4 ,w41 ,permo-,triassic of northwestern ,arizona3 ,geol4 ,soc4 ,am4 ,bull41 vol4 #cj1 #aiai4 ,stoyanow1 ,a4 ,a41 ,notes on recent stratigraphic work in ,arizona3 ,am4 ,jour4 ,sci41 vol4 #ab1 pp4 #caa-cbd1 #aibf4 ----1 ,correlation of ,arizona ,paleozoic ,formations3 ,bull4 ,geol4 ,soc4 ,amer41 vol4 #dg1 pp4 #dei-edj1 #aicf4 ,vander ,hoof1 ,v4 ,l41 ,the ,chinle ,formation3 ,museum ,notes1 ,mus4 ,northern ,arizona1 vol4 #f1 no4 #g1 #aicd4 ,walcott1 ,c4 ,d41 ,the ,permian and other ,paleozoic groups of the ,kanab ,valley1 ,arizona3 ,am4 ,jour4 ,sci41 #crd ser41 vol4 #bj1 pp4 #bba-bbe1 #ahhj4 ---- ,pre-,carboniferous strata in the ,grand ,canyon of the ,colorado1 ,ariz43 ,am4 ,jour4 ,sci41 #crd ser41 vol4 #bf1 pp4 #dcg1 #ddb1 #dhd1 #ahhc2 ,u4 ,s4 ,geol4 ,survey ,fourth ,ann4 ,rept41 p4 #dg1 #ahhd4 ---- ,study of a line of displacement in the ,grand ,canyon in northeast ,arizona3 ,bull4 ,geol4 ,soc4 ,america1 vol4 #a1 pp4 #di-fd1 #ahij4 ---- ,pre-,cambrian igneous rocks of the ,unkar terrane1 ,grand ,canyon of the ,colorado1 ,ariz41 with notes on the petrographic character of the ,lavas1 by ,j4 ,p4 ,iddings3 ,u4 ,s4 ,geol4 ,survey ,fourteenth ,ann4 ,rept4 ,pt4 #b1 pp4 #dig-ebd1 #ahid4 ---- ,algonkian rocks of the ,grand ,canyon of the ,colorado3 ,jour4 ,geology1 vol4 #c1 pp4 #cab-ccj1 pls4 #f1 #ahie4 ---- ,pre-,cambrian fossiliferous formations3 ,bull4 ,geol4 ,soc4 ,america1 vol4 #aj1 pp4 #aii-bdd1 #ahii4 ---- ,cambrian geology and paleontology3 ,smithsonian ,misc4 ,coll41 vol4 #fd1 no4 #e1 pp4 #cgc1 #cgd1 #aiaf4 ----1 ,geology of the ,little ,colorado ,valley3 ,am4 ,jour4 ,sci41 #dth ser41 vol4 #ab1 pp4 #dja-dac1 #aija4 ,ward1 ,l4 ,f41 ,report on the ,petrified ,forest of ,arizona3 ,twentieth ,ann4 ,rept41 ,u4 ,s4 ,geol4 ,survey1 ,pt4 ,,ii1 pp4 #cbd-ccb1 #aijj4 ---- ,the ,petrified ,forest of ,arizona3 ,smith ,rept4 for #ahii1 ,wash41 pp4 #bhi-cjg1 #aija4 ,white1 ,david1 ,study of the fossil floras in the ,grand ,canyon3 ,carnegie ,inst4 ,year-,book #bf1 pp4 #cff-cfi1 #aibg4 ---- ,flora of the ,hermit ,shale1 ,grand ,canyon1 ,ariz41 ,publication ,no4 #dje ,carnegie ,institution1 #aibi4 ,williams1 ,howell1 ,pliocene ,volcanoes of the ,navajo-,hopi ,country3 ,bull4 ,geol4 ,soc4 ,amer41 vol4 #dg1 pp4 #aaa-agb1 #aicf4 99 99 99 99 99 99 ,transcriber's note3 --,obvious typographical errors were corrected without comment4 --,non-standard spellings and dialect were not changed4