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 PRELIMINARY REPOR/T 
 
 OF THE 
 
 FIELD-WORK OF THE UNITED STATES GEOLOGICAL AND GEO- 
 GRAPHICAL SURVEY OF THE TERRITORIES, 
 
 UNDER THE DIRECTION OF PROF. F. V. HAYDEN, 
 
 FOR THE SEASON OF 1877. 
 
 OFFICE OF THE UNITED STATES GEOLOGICAL AND 
 
 GEOGRAPHICAL SURVEY OF THE TERRITORIES, 
 
 Washington, D. 0., December 1, 1877. 
 
 SIR: I have the honor to submit the following preliminary report on 
 the operations in the field of the Survey under my charge during the 
 season of 1877. 
 
 On the completion of the survey of Colorado last year, it was deter- 
 -^ mined that the work of the United States Geological and Geographical 
 Survey of the Territories under my direction should continue north- 
 ward into Wyoming and Idaho. The belt of country including the 
 Pacific Railroad having been explored and mapped in detail by the 
 Survey of the Fortieth Parallel, under Clarence King, esq., it was deemed 
 best to commence at the northern line of that work, and continue north- 
 ward and westward, taking for the season of 1877 the country from Fort 
 Steele, Wyoming Territory, to Ogden, Utah, or, more exactly, from longi- 
 tude 107 to 112, and northward to the Yellowstone Park. 
 
 The primary-triangulation party, in charge of Mr. A. D. \Vilsou, 
 
 Chief Topographer of the Survey, took the field from Rawlins Springs, 
 
 Wyo. Near this point a base line was measured with great accuracy, 
 
 Q from which a net- work of triangles was extended over the country to 
 
 O the north and west, locating, at intervals of from twenty to thirty miles, 
 
 some prominent peaks, upon which stone monuments were built, in order 
 
 ^ that the topographers could recognize the points thus fixed for them. 
 
 : Upon these points was based the system of secondary triangulation. 
 
 From the base at Rawlins, the work was carried northward to the 
 ui Sweet-water Mountains, and thence to the Wind River Range. Upon 
 ^5 some of the more prominent peaks of the latter range, such as Fremont's 
 *" Peak, the stations were made with much difficulty, owing to the great 
 masses of snow found there during the mouth of June, when the party 
 was working. From this range the work was carried across the Green 
 River Basin to the mountains on the west and north, where several 
 stations were made. The work was resumed to the west as far as 
 i^ort Hall, Idaho, and thence south to the vicinity of Bear Lake, where 
 another base, or base of verification, was measured ; thence south as far 
 as Ogden and Evanston, connecting with the triaugulatiou of the Forti- 
 eth Parallel Survey at these points. From Evanston the party marched 
 eastward, making some stations north of the railroad, thus bringing the f 
 work back to the point of beginning, Rawlins Springs, where the party v. 
 
 
 was disbanded for the season. The system of triangulation employed 
 
756 REPORT OF THE SECRETARY OF THE INTERIOR. 
 
 during the past season was essentially tbe same as that carried over 
 Colorado. , 
 
 The n humiliation is all-important, as the topographical work depends 
 entirely upon it, and the geologist can do but little without an accurate 
 map. 'Tnns the topographical as well as the geological maps are de- 
 piMidtMit upon a good system of primary triangulation. 
 
 In addition to the primary-triangulation party already referred to, 
 there were three fully equipped divisions for topographical and geolog- 
 ical work, and another, under the direction of Dr. 0. A. White, tor crit- 
 ical paheoutological work. 
 
 The area assigned to the Green Kiver division, under the direction of 
 31 r. Henry Gannett, was rectangle No. 56, which is limited on the east 
 and west by the meridiausof 109 30' and 112 and on the north and south 
 by the parallels of 43 and 41 45'. This is an area of about 11,000 square 
 miles, lying in parts of Wyoming, Utah, and Idaho. The party took the 
 Held at Green River City, Wyo., on June 1. They first surveyed 
 the drainage of Green Eiver Basin. For this purpose they traveled up 
 the Big Sandy, a large eastern branch of the Green, to the foot of the 
 Wind Kiver Mountains ; thence crossing the head of the basin, fording 
 the large and rapidly rising streams which make up the New Fork of the 
 Green, they reached" the main Green, and traveled down its western 
 bank, going in to Granger, Wyo., on the Union Pacific Kailroad, for 
 supplies on June 23. 
 
 The Green Kiver Basin is a broad, flat, almost unbroken expanse, 
 covered mainly with sage, among which considerable grass is scattered. 
 Its greatest width in this district is about 50 miles, and its length reaches 
 nearly a hundred. Its area within the district is not far from 3,000 
 square miles. 
 
 The river-bottoms of the Green and its branches, excepting the Big 
 Sandy, are everywhere broad and beautiful, well covered with grasses, 
 and shaded by magnificent groves of cottonwood. For agricultural 
 purposes these bottom-lands are very valuable, while the limitless ex- 
 panse of bunch-laud would afford grazing to enormous herds of cattle. 
 The Big Sandy is in low canon through most of its course. 
 
 Leaving Granger, the party next surveyed the broken, hilly country 
 lying between the basin and the upper course of Bear River, north of 
 Ilariis's Fork. Following this belt northward, these hills develop into 
 mountains of considerable importance about those large branches of the 
 Snake known as John Day's and Salt Rivers. The party surveyed this 
 belt northward to the north line, whence, turning westward, they mapped 
 the basin ol the Blackfoot and the valleys of the Portneuf; thence going 
 in to Fort Hall, early in August, for further supplies of provisions. 
 Taking up this section of the district in the order in which it was worked, 
 it will be noud that the valley of Harris's Fork is fine agricultural land; 
 that the hills about its head, separating it from the Bear, are rounded 
 and gia>s covered, affording a magnificent stock-range. As the hills in- 
 crease in si/e and assume the dignity of mountains, the grass gives 
 j lace to heavy pine and spruce timber of fine quality. John Day's Kiver 
 tlows in a canon valley, heavily timbered. The valley of Salt Kiver is 
 nearly ten miles in width and of the finest quality of land. West of 
 this valley are high, broken hills, separating Salt Kiver from the Black 
 loot. The latter stream pursues a devious course in a great plain of 
 basalt, diversified by buttesand extinct craters. Along the river are fine 
 meadows, alternating with large swamps. The whole basin is covered 
 with the best of grass. 
 
GEOLOGICAL SURVEY OF THE TERRITORIES. 757 
 
 West of this basin the Black foot is separated from tbe Portneuf, here 
 flowing south, by a range of low, grass-covered hills. The valley of the 
 Upper Portneuf is at least eight miles broad, and is valuable for agri- 
 culture or grazing. West of it is a high range of mountains, through 
 which, lower down, the Portneuf cuts its way into another broad valley, 
 in which it flows to the north. This valley is floored with basalt, and 
 is almost valueless. 
 
 From Fort Hall the party proceeded to survey the country drained by 
 the Bear and its tributaries, proceeding generally from the east west- 
 ward. The country is a succession of parallel valleys, separated by 
 ranges of bare, grass-covered hills or timbered mountains. The most 
 eastern of these valleys is on the upper waters of the Bear. It is nearly 
 ten miles wide, of good soil, and easily irrigated. The only drawback to 
 agricultural pursuits is the elevation, 6,000 to 6,500 feet, which, in this 
 latitude, indicates severe winters. 
 
 Kext westward is Bear Lake Valley. Here the cultivable area is at 
 the head and foot of the lake, besides a narrow strip on its west border. 
 Below the lake, the valley extends on to the northward for many miles 
 down the Bear, and is very broad and fertile. The elevation of this val- 
 ley is 5,500 to 6,000 feet. 
 
 Further westward we encounter the Bear River Range, a broad belt 
 of mountains reaching nearly to 10,000 feet in height, and heavily tim- 
 bered. Beyond is Cache Valley, one of the finest arens of farming-land 
 west of the Missouri. The elevation is 4,500 to 5,000 feet. Besides 
 grain, nearly all garden-vegetables and many fruits are raised in this 
 valley. 
 
 A broken range of mountains separates this valley from that of the 
 Malade. The latter has about the same elevation as Cache Valley, and 
 is almost equally fine. Beyond it is a range of grass-covered hills, sep- 
 arating it from Blue Creek Valley. 
 
 The valleys of the Bear are peopled mainly by Mormons; very few 
 Gentiles indeed are to be found there. Mormon settlements, of greater 
 or less extent, are to be found all along the Bear, from its mouth nearly to 
 Randolph. Malade Valley is but sparsely settled as yet. Cache Valley 
 contains several good-sized towns ; the eastern part of the valley is quite 
 closely settled. The valley of Bear Lake contains several good-sized 
 towns, but above that settlements are scarce. 
 
 The party left the field at Ogden, Utah, on September 30, having been 
 in the field just four months. The area surveyed was between 12,000 
 and 13,000 square miles ; 347 stations and locations were made ; 53 of 
 the stations, being important ones, were marked with stone monuments 
 for future reference. 
 
 The geological work of Dr. A. C. Peale in the Green River district con- 
 nected directly with the eastern edge of the Sweetwater district. 
 
 With the exception of a small area of granite along the southwestern 
 side of the Wind River Mountains, and some basaltic flows in the north- 
 western portion of the district, the rocks are sedimentary, including the 
 rocks from the Carboniferous to very late Tertiary age. 
 
 The first month of the season was occupied mainly with the survey of 
 the Green River Basin. Leaving Green River City, the river was fol- 
 lowed to the mouth of the Big Sandy, a shallow, muddy stream, rising 
 in the southwestern slopes of the Wind River Mountains. Both on Green 
 River and the Big Sandy the prevailing formation is the Green River 
 Tertiary group, consisting of clays, marls, and calcareous sandstones, 
 forming blufls on the rivers. These [strata continue uninterruptedly 
 
758 REPORT OF THE SECRETARY OF THE INTERIOR. 
 
 westward, inclining eastward from the bills west of Green River. To- 
 \\anl tin- southern part of the district remains of the Bridger clays are 
 n, t -.rniing Imttes on the Green River beds. They are the outlines 
 of 'tiii' extensive Bridger areas that extend southward. On the south- 
 west slopes of the Wind River Mountains there are abundant evidences 
 of comparatively recent glacial action. 
 
 The next area taken up was that lying between Green River and the 
 Hear, \vith a strip along the northern edge of the district, reaching west- 
 ward beyond Fort Hall. 
 
 The mountains west of Green River are composed mainly of Carbonif- 
 erous limestones. Toward the north they form two beautiful ranges on 
 John Day's River and Salt River, separated by a valley in which rocks 
 of Jurassic and Cretaceous age outcrop. Between the mountains and 
 the Green River Basin is a range of hills of Jurassic and Cretaceous 
 a.ue. On the east of these is the Wasatch group of Tertiary, resting 
 tineon tonnably on the Jurassic hills. Farther north the Wasatch beds 
 cover the Jurassic and Lower Cretaceous strata, extending partly over 
 the Laramie Cretaceous, with which it is u neon form able. Carbonifer- 
 ous fossils were obtained from limestone bowlders in a conglomerate at, 
 the base of the Wasatch. These were derived, without doubt, from the 
 Carboniferous mountains to the westward, which formed the shore-line 
 of the ancient lakes in which these beds were deposited. An arm of 
 this lake extended up Harris's Fork of Green River. The Green River 
 and Wasatch beds here are horizontal, the former containing abundant 
 remains of insects and fish. Good collections were obtained at several 
 localities. 
 
 The region of the Blackfoot River, in the northern portion of the dis- 
 trict, is covered in the lowest portions with flows of basalt. These had 
 their origin between the Blackfoot, Bear, and Portneuf Rivers. A 
 number of the craters still remain. One of these, south of the Black- 
 foot, is very distinct, rising 200 feet above the general level. It is 
 about 130 yards in diameter, and has a circular depression on the sum- 
 mit. The pouring out of this basalt must have occurred either during 
 or immediately prior to our present period, as there has been little if 
 any change in the surface since the eruption. 
 
 The Blackfoot, Portneuf, and Bear all have the basalt in their val- 
 leys. Cu the Portneuf it extends almost to the Snake River plain, 
 showing as a narrow belt. Its surface slopes, but not so much as the 
 present bed of the stream. In some places the volcanic rock appears to 
 have pushed the river to the western side of the valley. The lower val- 
 ley of the Portneuf is interesting from the fact that it is the probable 
 ancient outlet of the great lake that once filled the Salt Lake Basin. At 
 the head of Marsh Creek, which occupies the valley, continuing directly 
 south from that of the Lower Portueuf, is the lowest pass between the 
 Great Basin and the drainage of the Columbia. In fact, so low and 
 flat is it that a marsh directly connects the two streams, one flowing to 
 the Bear and the other to the Portneuf and Snake Rivers. 
 
 The bend of Bear River at Soda Springs is one of the most remarkable 
 features of the whole district. Rising in the Uintah Mountains, Bear 
 Kiver Hows northward for over two hundred miles, and at Soda Springs 
 bends abruptly and flows southward toward Salt Lake. After it emerges 
 from the <;a|, west of Soda Springs, it flows out into a wide valley which 
 opens directly into that of the Upper Portuenf. In this valley the divide 
 between the two rivers is only a basalt plain, and in the eruption of 
 tins lava we may look for the clew to the extraordinary course of Bear 
 River. 
 
GEOLOGICAL SURVEY OF THE TERRITORIES. 759 
 
 Forth of the bend of Bear River the mountains consist of isolated 
 masses of Jurassic and Carboniferous rocks, the general strike of the rocks 
 being northwest and southeast. There are several interesting folds in 
 the rocks of this region. 
 
 The interesting springs at Soda Springs were carefully examined. 
 
 The latter half of the season was devoted to Bear River, Bear Lake, 
 and Cache and Malade Valleys. 
 
 The Upper Bear River Valley has a wide drift-covered bottom. The 
 hills on the east side soon develop into mountains as we go north. Forma- 
 tions from the Carboniferous up to the Wasatch Tertiary are represented, 
 the latter resting on the upturned edges of the older rocks. On the west 
 the same unconformability is seen, the area of Wasatch extending 
 farther north. The beds consist of variegated sandstones and conglom- 
 erates. Bear Lake Valley has a range of low hills on the east, at the 
 foot of which the lake leaves but a narrow margin. The waters of the 
 lake occupy an area that is probably underlaid by several folds. 
 
 The Bear River Mountains are composed of Silurian and Carbonifer- 
 ous rocks, limestones, and quartzites. The edges of the strata face the 
 east, but as \ve go west we soon cross a synclinal fold, the western side 
 of which rises into high peaks on the east side of Cache Valley. The 
 base of the range facing Cache Valley is Silurian. It is abrupt, and the 
 basset edges of the strata give it extreme raggedness. In the canons 
 of the streams coming from the range, saw-mills have been erected, and 
 now supply the flourishing towns of the valley. Numerous lime-kilns 
 also furnish them with a good quality of lime, the limestone being derived 
 from the adjacent rocks. 
 
 There is but little doubt that the waters which once filled the Salt Lake 
 Basin covered also the broad Cache Valley. The modern Tertiary deposits 
 are found jutting against the mountains, and seem to pass gradually into 
 the more recent deposits found in the central portion of the valley. The 
 clays, sands, and marls of these modern beds are beautifully exposed 
 along Bear River, which cuts its way across the northwestern part of 
 the valley. On the west the mountains are broken or isolated ranges, 
 which seem to have risen above the waters of the old lake as islands. 
 The terraces are well marked on their sides, connecting with the Salt 
 Lake Valley through the gap of Bear River. 
 
 West of this gap, and extending northward, is the Malade Valley. It 
 is broid and filled with modern lake deposits. Silurian rocks outcrop 
 on the east and Carboniferous on the west. At the divide between the 
 Malade and Marsh Creek is another of the old outlets of the ancient Salt 
 Lake when its waters were at the highest level. Although the area sur- 
 veyed was large, (13,000 square miles,) good collections of fossils were 
 made and data obtained for the elucidation of many interesting prob- 
 lems in relation to the age of the mountains. The entire district is 
 of great interest to the geologist. Coal-outcrops were noted at a num- 
 ber of places on the Upper Bear River and its tributaries, and on some 
 of the branches of Green River. 
 
 At one locality between Twin Creek, a branch of the Bear, and Harris's 
 Fork, a tributary of Green River, there are some twenty-nine coal beds, 
 separated by sandstones and clays, the aggregate thickness being 315 
 feet. The beds of coal are from 1 foot to 48 feet thick. This locality 
 has been called the " Mammoth Vein." 
 
 The area allotted for examination to the Sweetwater division, under 
 the direction of Mr. G. B. Chittenden, covering atlas-sheet No. 57, ,is 
 bounded on the east by the meridian 107, and on the west by that of 
 
7 GO REPORT OF THE SECRETARY OF THE INTERIOR. 
 
 1000 30' of west longitude, and on tbe north by the parallel of 41 45', 
 iiiul on the south by that of 43 of north latitude, embracing a district 
 of ;il)out 10.SUO square miles. 
 
 In working this area, 171 principal topographical stations were made, 
 U-xuirs sonic twenty auxiliary ones not numbereJ in the regular series. 
 Between eighty and ninety stone monuments were erected on these 
 stations to mark them permanently, while the peculiar topographical 
 features of a great many others mark them with equal distinctness. 
 While many of these, owing to the extremely desolated character of the 
 country surveyed, are not likely ever to be used as initial points for the 
 rectilinear surveys, there still will be many others which will be of very 
 great value in giving starting-points for isolated pieces of rectilinear 
 work, where fertile valleys and oases in this desert country are rapidly 
 coming into demand by the settler. The most important of these fertile 
 tracts are on the great southern drainage of the Wind River; the whole 
 of the Sweetwater, with its southern tributaries; Sand Creek: the 
 drainage of the old Seminole mining-district, and a series of lakes and 
 springs south of the Sweetwater, near the latitude of Saint Mary's 
 Station. 
 
 Into the first two of these districts (or a portion of them) a rectilinear 
 survey was pushed this season by the measuring of a guide-meridian 
 from the railroad, north, and the establishment of base-lines within 
 the district. The guide-meridian had to be measured over about seven- 
 ty-five miles of broken desert country, where water was extremely scarce 
 and found only at long intervals. In the vicinity of all these fertile dis- 
 tricts, particular pains were taken to give permanent markings to the 
 topographical stations, and connections were made on two of the guide- 
 meridian stakes, distant some forty miles from each other. 
 
 In continuance of the summer's work, the party took the field from 
 Salt Wells Station, on the Union Pacific Railroad, on the 1st day of 
 June, and completed tbe topographical work on the 25th day of Septem- 
 ber, in the vicinity of Fort Steele. Owing to orders, received at the 
 beginning of the season, to complete the field-work by the 1st of Octo- 
 ber, and the very doubtful safety of a tract of low country in the north- 
 eastern portion of the district, an area of about 800 square miles was 
 necessarily left unworked in that portion of the district. The total 
 area worked by the party, as nearly as can be estimated before the final 
 plat is made, was 10,000 square miles. Careful notes were made on the 
 grazing facilities, timber, and irrigability of the whole district, which 
 will be more, fully given in a later report. Taken in masses, an estimate 
 of this area shows five-eighths to be desert country, two-eighths mount- 
 ainous, and the remaining eighth valuable laud. "Giving these figures 
 before the plat is made, they are of course merely estimates, but will 
 afford an idea of the general characteristics of the country. 
 
 The weather throughout the entire season was much colder than that 
 experienced at thesame altitudes in Colorado, buttheparty suffered much 
 less from rain, and in the four months of field-work did not lose one 
 single day from bad weather, or indeed from any cause. 
 
 Dr. F. M. Endlich, Geologist of the Sweetwater division, states that 
 within the area described above he found a well diversified country. 
 
 A portion of the Wind River Mountains, in the northwest coruer'-'the 
 Sweetwater and Seminole Hills, toward the eastward, in ad litiou to the 
 lower bluff-country in the southern portion, furnished material at once 
 lull ot interest to the student and to the surveyor. 
 
 After having surveyed fhat portion of the Green River drainage which 
 
 
GEOLOGICAL SURVEY OF THE TERRITORIES. 761 
 
 lies immediately outside of the mountains, the first halt was made at 
 Camp Stambaugh. The party until then had passed through a region 
 containing none but Tertiary formations. But little variation was 
 found in the arrangement of strata, as well as in the distribution of fossil 
 remains. Isolated volcanic eruptions of small dimensions produced 
 prominent bluffs, far visible. These formed excellent landmarks, and 
 were duly utilized as such. From Stambaugh, the party turned its 
 course southward toward the Union Pacific Railroad. Here, too, the 
 regular succession of Tertiary strata prevailed. The readily-disintegrat- 
 ing sandstones of the region have given rise to the formation of very 
 extensive sand dunes. It may be observed that westerly winds are 
 prevalent throughout that section of country, and, as the result thereof, 
 we find them driving the sand to leeward and depositing it wherever 
 the configuration of the country presents any obstacle to its farther prog- 
 ress. In this manner a "belt" of sand-dunes, about ten miles wide and 
 fifty miles long, has been formed. Some difficulty was here experienced, 
 occasioned by the sparing distribution of water. Only in springs and 
 small alkaline lakes could it be obtained. 
 
 lied Desert Siation, on the Union Pacific Railroad, was the point 
 reached June 18. From there the party moved northward again toward 
 Stambaugh, which place was reached July 3. Stambaugh is located 
 within the area of the oldest metamorphic rocks of the district. In these 
 metamorphics gold has been found during the last ten years in varying 
 quantities, and the region was at one time the scene of considerable 
 mining excitement. At present the mines have been to a great extent 
 abandoned, and but little activity is noticeable. 
 
 Snow still covered a large portion of the Wind River Mountains, and 
 it was deemed advisable, therefore, to carry on the explorations in some 
 lower country until, late in the season, the mountains should be more 
 accessible. 
 
 On July 5 the party left Stambaugh and marched toward the low 
 valleys belonging to the Wind River drainage. The difference in ele- 
 vation amounted to about 3,000 feet, and the temperature of the atmos- 
 phere was consequently much higher. While all the surroundings of 
 the post were totally useless for agricultural purposes, the valleys of the 
 Popo-Agies and their tributaries contained excellent farming land. In 
 spite ot continually threatened raids by the Indians, a large number of 
 settlers have taken advantage of the good soil and mild climate. With 
 the change of elevation the geological formations change, instead of 
 the youngest beds resting directly upon the metamorphics, we now find 
 a full series of the sedimentary formations, beginning with the Silurian. 
 Numerous interesting stratigraphical phenomena were observed and 
 studied with a view to determine their relations to the main mountain- 
 chain. An ample amount of evidence has been obtained, more particu- 
 larly by this means, to speak positively respecting the geological age of 
 the Wind River Mountains. These latter, in this region, furm the main 
 Rocky Mountain chain, and the determination of their age will neces- 
 sarily throw much light upon the same question arising in other por- 
 tions ot the same range. It will be possible to speak with a certain 
 degree of precision of either the local, varying (as to time) elevation 
 of the mountains or to refer it to one particular epoch for the distance 
 of many hundreds of miles. 
 
 Camp Brown is located in the valley of the Little Wind River, which 
 there is of considerable breadth. The famous hot springs there were 
 examined. As the main peaks of the Wind River Mountains were 
 mostly inaccessible from the east side, it was deemed advisable to make 
 
762 REPORT OF THE SECRETARY OF THE INTERIOR. 
 
 the ascents of the highest from the west. Therefore the party traveled 
 along tin* eastern foot hills, through a very ragged country, until Stam- 
 baugh was reached. 
 
 July 22 the party again left Stambaugh and marched along the head- 
 water's first of Sweetwater River and then of the eastern tributaries of 
 Green Kiver. Several of the highest peaks were ascended, and the 
 greatest altitude reached found to be about 13,700 feet. This latter was 
 iin what the settlers generally designate as Fremont's Peak. From 
 careful comparison of Fremont's report with the observations made by 
 the party, it is evident that a misapplication of the name has been 
 made, and that the peak in question is not the one ascended by that 
 intrepid explorer of an "early day." 
 
 Having reached the northern limit of the district, the route was re- 
 versed and the western foot-hills of the main ranges examined. Here, as 
 well as in the mountains proper, were noticed the remains of enormous 
 ancient glaciers. Moraines, covering many square miles, often a thou- 
 sand feet in thickness, extend downward through narrow valleys, now 
 containing rushing streams. Striation, grooving, and mirror-like polish 
 of rock in- situ denote the course taken by the moving ice-fields that 
 have left these marks of their former existence. From all appearance 
 the cessation of glacial activity must have occurred within a compara- 
 tively recent time. Scarcely any vegetation has sprung up on the light 
 glacial soil, and the characteristic distribution of erratic material bears 
 every evidence of u freshness. 7 ' Considering the enormous amount of 
 snow and ice that was observed by the party exploring, (latter part of 
 July and beginning of August,) the view was expressed by the geolo- 
 gist that the discovery of still active glaciers in that range would by 
 110 means be surprising. 
 
 Returning for the last time to Stambaugh, the route was taken in an 
 easterly direction along the Sweetwater and its drainage. First, the 
 adjacent drainage of the Wind River was surveyed, and the divide be- 
 tween the two streams crossed. All along the Sweetwater the charac- 
 teristic " Sweetwater group " of Tertiary age was found to occur. It 
 has been named and described in my former publications. This con- 
 tinued uninterruptedly until a series of hills north of the river, oppo- 
 site Seminole Pass, was reached. These consist merely in projections 
 of granite that during the Tertiary epoch, and probably long before 
 that, had remained as islands above a widely-extended sea. Apart 
 from their singularly unique character in this respect, the granite it- 
 self possesses a peculiarity that renders it at once conspicuous. Ow- 
 ing to the distribution of component minerals, this granite is in a high 
 degree subject to exfoliation. Probably the main cause of this may 
 be found in the action of freezing water. The result is striking. In- 
 stead of the rugged outlines usually presented by isolated granitic out- 
 crops, we lind a series of rounded, smooth, almost totally barren hills. 
 To such an extent is this feature developed that many of them offer 
 serious obstacles to ascent. A locality where the celebrated moss-agates 
 occurred in great quantities was found in that region, and the geognostic 
 horizon of these interesting quartz varieties was established. Marching 
 southward, the party crossed the Sweetwater, and in the Seminole Hills 
 once more encountered older sedimentary formations. Disturbances 
 <>t enormous dimensions have here taken place, and render the study 
 of the range one of extreme interest. 
 
 On AuguM _M) Uawlins was reached and the provisions for the folio w- 
 ng month taken. From there the course lav northward, through low 
 dry country, where several alkali-lakes furnished water. Between two 
 
 
GEOLOGICAL SURVEY OF THE TERRITORIES. 763 
 
 
 
 of these, a short distance apart only, a rare occurrence was observed. 
 Mud-springs, analogous to the mud-puffs of the famous Geyser region, 
 covered about two square miles. Some of them were extinct, but 
 most of them were still in action. By some force, which will not be 
 here discussed, the water is caused to enter cylindrical orifices of vary- 
 ing dimensions. Inasmuch as th,is water contains in solution a large 
 amount of mineral substances, and there is suspended in it a very large 
 quantity of tine clay, evaporation produces a deposition of these mate- 
 rials. In this manner a cone is gradually raised, consisting of slightly 
 arenaceous clay. So long as the force acting upon the water is more 
 than adequate to the height of the cone, there will remain a circular 
 opening at the top of the latter. When, however, this ceases, the result 
 is simply a mound. About four hundred of these curious springs were 
 found and examined. Great care was requisite, as the soil is very 
 treacherous, and a mud-bath inevitable in case of breaking through. 
 
 The Sweetwater and Seminole Hills were examined during this trip 
 and found to afford ample material for study. Stratigraphically consid- 
 ered, they may be regarded as being among the most interesting portions 1 
 of the district. A satisfactory distribution of fossils in the various 
 formations permitted all difficulties to be readily interpreted. 
 
 September 17, Dr. Endlich left the party and proceeded to examine 
 the coal-bearing series and the mines near Evanston, Wyo. This 
 was done with a view to present at an early date a report upon a sub- 
 ject which now has become one of vast importance. 
 
 On September 22 the party reached Fort Steele, and, having completed 
 the work of the season, disbanded. Its members returned to Washing- 
 ton, there to prepare the maps and reports of the summer's work during 
 the coming winter. Over 10,000 square miles were surveyed topograph- 
 ically and geologically during the time occupied in the field. Notes 
 were obtained upon the geology, for the preparation of a geological 
 map, and upon the agricultural and mineral resources of the district 
 explored. A collection of Coleoptera and Diptera was made as com- 
 plete as time would permit. 
 
 The district assigned to the Teton division, directed by Mr. G. E. 
 Bechler, was situated between the parallels 43 and 44 15' of north 
 latitude and the meridians 109 and 112 of west longitude. This area 
 is drained by the branches of Shoshone or Snake River. The first por- 
 tion surveyed by this division lies along the Blackfoot River and its 
 tributaries. There are also some branches of Snake River, as Salt, 
 McCoy, John Gray's, Fall, Antelope, Big Sandy, and Willow Creeks. 
 Along the north side, and parallel to the Blackfoot River, is the Black- 
 foot range of mountains, with its higher portions toward the west, front- 
 ing the great plain of Snake River. In its southeastern continuation, 
 near Gray's Lake, this range is reduced to a height of not more than 
 700 feet above the general level, so that it forms a low plateau divide ; 
 but south of Gra.y's Lake it rises until it attains a height of about 
 8,000 feet, about the sources of the Salt and Blackfoot Rivers. 
 
 Along the southwestern border of Shoshone or Snake River stretches 
 another mountain ridge, reaching its highest point to the eastward, near 
 Salt River, but diminishing in height as it follows along the lower canon 
 of Snake River, until it assumes more the character of a plateau, and 
 finally terminates, near the Crater Butte bend, in a flat, terraced country. 
 
 Within this district Mr. Bechler made thirty topographical stations, 
 over an area of about 10,000 square miles. There is in this district 
 
764 REPORT OF THE SECRETARY OF THE INTERIOR. 
 
 a considerable amount of timber, mostly pine and poplar, (quaking 
 aspen,) with a fair average of arable and grass land. The streams con 
 tain running water, even in the driest portions of the year. 
 is especially adapted to stock-ranches, and must soon be occupied by 
 herds ot cattle. 
 
 After having completed the area described above, Mr. Bechler re- 
 turned to Fort Hall for supplies, and then passed u t ) Henry's Fork to 
 the northern portion of the Teton Mountains, where he spent several 
 weeks investigating this snow-covered range; then, crossing Pierre's 
 P.asin, surveyed the lofty group to which in 1872 he gave the name of 
 Pierre's Hole Mountains. These ranges are characterized by as great 
 and inaccessibility as any other mountains in the North- 
 
 \vest. 
 
 During the past season the waters of Snake Kiver and its tributaries 
 were extraordinarily hiyh, owing to an unusual amount of snow in the 
 mountains, so that the party experienced much difficulty and loss of 
 time in crossing the various streams. The fording of Snake Kiver has 
 always been difficult at all seasons of the year. The Snake and Gros- 
 ventre Rivers flow through a broad and beautiful basin or valley, which 
 separates the Teton from the Grosventre Range. The trend of the latter 
 is southeast, and northwest, nearly at right angles with the Teton group. 
 The Grosventre Range, with the other parallel ranges to the south, of 
 which Salt RiverRange is one, forms the dividing barrier between the 
 waters ot the Columbia and Green Rivers. 
 
 Fronting the Grosventre Range on the north rises another mountain 
 cluster, separated from the former by the Grosventre River. This range 
 forms the divide between the latter river and the Buffalo Fork of the 
 Snake. It connects with the main Rocky Mountains near the sources 
 of Wind and Grosventre Rivers and the Buffalo Fork of the Snake, 
 and culminates near its western end in Mount Leidy. Mr. Bechler occu- 
 pied two weeks in a careful survey of a part of the Grosventre Range, 
 the entire Mount Leidy group, with the Upper Snake River Valley and 
 its numerous interesting features. 
 
 o^orth of the Buffalo Fork of the Snake, his observations extended 
 into that densely wooded mountain region which connects to the north 
 with the Mount Sheridan group, near the Yellowstone, Lewis, and Sho- 
 shone Lakes. 
 
 About the 1st of September he left the waters of Snake River, and 
 marched along the rugged and densely timbered mountain spurs toward 
 the Upper Wind River Pass, and, after crossing the latter, entered 
 Wind River Valley, having the Owl Mountains on the left and the 
 Wind River Range on the right. As he was about to cross over the 
 Warm Spring Pass of the Wind River Mountains into the Green River 
 Valley, to survey the southern ends of the Grosventre and Salt River 
 Ranges, he received a notice, through Indian scouts, from the com- 
 mander of the military post at Camp Brown, to leave the country, on 
 account of the danger of hostile Indians. On this account nearly a 
 mouth of valuable time was lost, abridging somewhat the results of the 
 M-ason's work. Notwithstanding the various difficulties which this 
 party encountered, they surveyed an area of about 6,000 square miles of 
 t lie most rugged mountain country in the Northwest, and made one hun- 
 dred and ten reliable observations with the mercurial barometer. Mr. 
 Bechler, throughout his district, personally observed 7,340 horizontal 
 angles and f>,700 angles of elevation and depression; and as they re- 
 ported backward and forward, and were checked by good barometric 
 
GEOLOGICAL SURVEY OF THE TERRITORIES. 765 
 
 * 
 
 readings, they must give satisfactory results as to the altitude of that 
 extremely mountainous country. 
 
 The following is a summary of the results of the geological investi- 
 gations of Mr. Orestes St. John, geologist of the Teton division: 
 
 Commencing with the area assigned to the Teton division of the sur- 
 vey at its southwestern corner, the first five weeks were devoted to the 
 examination of the region lying in the great northern bend of the Snake 
 River, and which includes an area of 1,700 to 2,000 square miles. 
 
 This section consists, topographically, of a series of more or less paral- 
 lel low mountain ranges, of which the three principal ones are, the Mount 
 Putnam Range, on the southwest, and which extends southward into the 
 adjacent district: the Blackfoot Mountains, in the central portion; and 
 the Caribou Range, which embraces a rather wide belt of broken hill 
 country and low mountains along the eastern border, and which culmi- 
 nates in Mount Baiubridge. These ranges have a general direction west 
 of north and east of south, and are separated by broad, shallow depres- 
 sions, in the rnidst of which occur other lesser parallel ridges. To the 
 north these low ranges die away in the great plains of the Snake Basin, 
 which comprise about one-third the area of the section here referred to. 
 
 The Snake plains are everywhere floored with basaltic rocks, which 
 were met with in the extreme southwest portion of the district, along 
 Ross Fork, at the western foot of Mount Putnam. To the northward, 
 in the debouchure of Blackfoot River, these rocks rise high up on the 
 flanks of the hills bordering the plains, where they attain elevations of 
 GOO to 800 feet or more above the level of the plains, toward which they 
 incline in great benches orforelaud slopes. Similar occurrences of basalt 
 are found at various points along the northern border of the hill country ; 
 the northern termini of the Blackfoot and Caribou Ranges exhibiting 
 similar benches, inclining in long, gentle slopes to the general level of 
 the Snake plains. These basalties penetrate all the principal valley 
 depressions opening to the southward, forming extensive inlets which 
 occupy ancient valleys of erosion in the sedimentaries. The Blackfoot 
 Valley and the valley depressions between the Blackfoot Mountains and 
 the Caribou Range are floored with basaltics in every way similar to the 
 deposits occurring in the Snake plains, and which extend up these val- 
 leys to the southern boundary of the district, flooring wide, basin-like 
 expanses into which these depressions open out toward their sources. 
 In this manner the Blackfoot Mountains are surrounded, as it were, 
 rising in the midst of a basaltic sea, as also is the case with other sedi- 
 mentary ridges in this region. 
 
 The vertical extent of these basaltic flows, which doubtless represent 
 several distinct epochs of eruption, it is impossible to decide with any 
 degree of accuracy, though they are here seen to reach a thickness of 
 several hundred feet. The extent to which they have suffered erosion 
 is enormous, for it is undoubtedly true that they once in many places 
 reached high up on the flanks of the insular mountain ridges, but where 
 to-day not a trace remains to show their former presence. Yet there 
 are a host of phenomena bearing on the present occurrence and extent 
 of these deposits which require thorough examination into before we 
 can present even a general statement of the facts which may finally lead 
 to the elucidation of the history of this member of the volcanic series 
 in this region. 
 
 These basalts extend up the valley of the Snake as far as the lower 
 basin, where they are succeeded by other volcanics. These latter, 
 mainly trachytic materials, are far less conspicuous in the area of their 
 50 I 
 
766 REPORT OF THE SECRETARY OF THE INTERIOR. 
 
 exposed occurrence than the basalts, and are usually met high up on 
 tin- sides, and even crowning some of the highest mountain crests. 
 They are al\va>s observed to incline at greater or less angles, and when 
 seeii in the ridges along the northern border of this region, they dip m 
 the dim-lion ofthe Snake plains. They appear to be more ancient than 
 the basalts, their connection with which cannot now be clearly deter- 
 mined. Toward the northern terminus of the Caribou Range, in some ot 
 the hi-hest erests in that quarter, these deposits are seen to be under- 
 laid 1>\ a heavy mass of water- worn bowlders and pebbles, cemented 
 with a line paste. This deposit is not clearly stratified. And again, 
 within the lower basin of the Snake, (that marked " prairie-bottom -' m 
 1872 map,) similar pebble deposit is imbedded with alternations of 
 laminated trachytics and compact lava-basalt, which together make up 
 a thickness of several hundred feet, gently inclining toward the center 
 of the valley, forming a sort of low foreland along the base of the 
 mountain, against which the volcanics abruptly impinge. In the valley 
 of the Blackfoot, where the party met with isolated areas of trachyte, a 
 heavy mass of conglomerate of a similar appearance occurs, associated 
 with sand, and dipping in the east side ofthe valley at a moderate 
 angle toward the Blackfoot Mountains. It differs, however, from the 
 before-mentioned bowlder-bed in being made up of a greater variety of 
 more or less abraded material, including pebbles of trachyte and lava- 
 basalt, indicating its more recent origin. 
 
 lih^ olitic and other volcanic products were found at a few localities in 
 the region. In one instance the eruptive matter appears as a dike in 
 the crest of a low, short ridge (station 17) between the Blackfoot and 
 Caribou Ranges, its eruption having tilted the sedimentary deposits into 
 an anticlinal ridge. Again, in Mount Baiubridge, (station 28,) very 
 interesting phenomena w:ere observed in connection with these rocks. 
 The mountain is a monoclinal ridge, made up of sedimentaries, between 
 whose strata the igneous matter is intruded, appearing like veritable 
 beds of deposition, seen from a distance, while the bulk of the west 
 poition of the mountain appears to consist of an enormous mass of 
 eruptive matter thrust up from below. Mount Bain bridge would seem 
 to be another instance of local outburst of volcanic material similar to 
 those brouj- n't to light by the survey in Western Colorado. In the course 
 of the prosecution of the examinations in the volcanic rocks of the 
 district as complete suites were secured of the various kinds of these 
 rocks as it w y as practicable to transport, and which, together with the 
 notes, will afford the materials for an interesting chapter on this subject. 
 
 The Mount Putnam Range proper is a monoclinal ridge, made up 
 of ancient quartzites and slaty schists, followed by Quebec and Carbo- 
 niferous limestones, dipping generally to the eastward. The angle of in- 
 clination is very variable, as is also the strike of the strata. In the 
 high peak on which station 1 was located the mass of the strata is 
 qnartzite, which in places stands vertical or even overturned and dip- 
 ping westerly at a steep angle. These rocks, together with the schistose 
 beds, constitute the exposed ledges occurring in the western side of this 
 mountain, while to the east, doubtless, the Silurian and Carboniferous 
 beds successively appear in the lower declivities. But in the low ridge 
 which forms the northern extension of the Putnam Range proper these 
 ancient quartzites gradually pass out into the plains, where they are 
 eroded and concealed beneath detrital accumulations and late volcanic 
 Tertiary, (the latter described by Bradley;) while the ridge itself, as its 
 trend curves more and more round into the northeast, is crested, first, 
 by the Quebec lim intone, and then by Carboniferous limestones, fol- 
 
GEOLOGICAL SURVEY OF THE TERRITORIES. 767 
 
 lowed by obscure exhibitions of the Trias sic, and finally the Jurassic 
 deposits. All these deposits in this quarter succeed each other with 
 apparent regularity, with dips generally varying" from 25 to 45, but 
 the strike gradually passes more and more to the west of north as we 
 pass along this ridge in that direction, and which, together with evi- 
 dences of extraordinary local disturbance, is still more manifest in the 
 low range of hills next east and lying between Lincoln Valley and 
 Blackfoot Eiver. 
 
 This latter region embraces a belt of low hills and ridges which cul- 
 minate to the north in Higham's Peak. Its northern extremity is covered 
 by the upraised volcanic, through which the Blackfoot has cut a deep 
 canon, in which these latter deposits are finely displayed. As it will 
 have inferred from the foregoing brief notice of the distribution of the 
 volcanics, the basalts occur all along the eastern flank of these hills, as 
 far south as the bend in the Blacklbot. The southern portion of this 
 belt of hills is connected with Mount Putnam by a series of interpolated 
 ridges, defining the water-shed between the Portneuf and Ross Fork 
 drainages. 
 
 This belt is made up of Carboniferous limestones and siliceous de- 
 posits. Triassic sandstones, and Jurassic limestones and shales. In the 
 southern portion of the belt these deposits occur in a rather shallow 
 synclinal, defined on the east and west by the Carboniferous beds. But 
 in the middle and northern portions these strata are complicated by dis- 
 placements and foldings to such an extent as to render their study an 
 exceedingly difficult undertaking. Here the geologist encounters the 
 most conflicting manifestations of disturbance in the constant variation 
 of dip and strike exhibited by the beds, and which, even in short dis- 
 tances, change from moderate inclination in one direction to vertical and 
 inverted position; while the strike exhibits in the flexures of the strata 
 all those irregularities which may be attributable to violent upheaval. 
 None of the later members of the Cretaceous were identified in this 
 region; but in the low border hills to the north of Fort Hall occur ex- 
 tensive deposits of yellowish and light-red sandstone, which may prove 
 to belong to the earliest epoch of this period, though no certain evidence 
 on this point was gained, more than that on the slopes outlying High- 
 am's Peak on the west these beds overlie Jurassic limestones. 
 
 To the southeast, in the region of the southern bend of the Blackfoot 
 River, to the west, but somewhat isolated from the above range of hills, 
 in low isolated hills, and apparently also making up the bulk of low 
 ridges intervening between the Blackfoot and a shallow basin next east 
 of Lyucoln Valley, an extensive deposit of light-colored calcareous ma- 
 terial was found, indurated layers of which contain great numbers of 
 molds of gasteropoda, identical with those occurring in -similar deposits 
 iu the region of the debouchure of Bear River, and which have been 
 referred to fresh-water forms of the Pliocene. These beds dip 25 east 
 ot north, aud are overlaid by trachyte, also inclining northeast at an 
 angle of 15 to 20. Station 30 was located on one of these volcanic- 
 capped Tertiary buttes. To the west of these Tertiary hills occur the 
 conglomeratic deposits, dipping from northerly east, aud finally south- 
 east 10 to 20, whose components show it to have been formed subse- 
 quent to the eruption of the volcanics, although these coarse materials 
 are included in a fine paste which may be of volcanic origin. In this 
 place mention should not be omitted of the existence of a low anticlinal 
 axis or fold in the volcanics which occupy the Blackfoot Valley. From 
 all a hasty trip reveals, it seems certain that this region has been sub- 
 jected to intense volcanic action in comparatively recent times. 
 
7G8 REPORT OF THE SECRETARY OF THE INTERIOR. 
 
 The Blackfoot Mountains are mainly composed of Carboniferous strata, 
 which occur in a well-defined monoclinal ridge, but which really forms 
 the remnant of an anticlinal fold, the axis of which lies about the mid- 
 dle of the range, the strike bending in and out but always crossing the 
 raii-e obliquely; to the north the beds dip off to the southwest, and to 
 the south inclining northeasterly. Blackfoot Peak is a high culminating 
 point on a sort of spur to the northeast of the main range, beyond which 
 occur areas or belts of variegated early Mesozoic deposits. In the south- 
 ern portion of the range, on the southwest flank, a considerable thick- 
 ness of brown arenaceous and limestone deposits comes to view from 
 beneath the Carboniferous beds, where they are seen to form the axis 
 of the anticlinal fold. These deposits contain a meager fauna, which 
 appear to be referable to Silurian .forms. The Carboniferous mainly 
 represents the earlier period, whose epochs are indicated by similar 
 pahumtological peculiarities which distinguish the Lower Carboniferous 
 formations in the Mississippi Basin, and which more extended research 
 will doubtless reveal in this distant region. But one of the most inter- 
 esting discoveries in this connection was the presence of fish-remains, 
 representing several forms identical with or closely allied to Keokuk 
 species of the genera Cladodus, Petalodus, Antkiodus, Helodus. 
 
 Between the Blackfoot Mountains and the Blackfoot Eiver, and occu- 
 pying the angle in the southern bend of the Blackfoot, an isolated area 
 of hills exhibits a series of strata, including the Upper Carboniferous on 
 the north to the Jurassic on the south. The middle portion of this sec- 
 tion is much disturbed and the exposures unsatisfactory. The former 
 beds incline steeply southward, while in the Jurassic ledges on the 
 south a marked anticlinal fold is observed, the strata inclining to the 
 north and south either side of the axis. Stations 12 and 13 were located 
 on ridges on the north side of this fold. The beds in this group of hills 
 have veered round so as to have nearly east and west strike. 
 
 To the southeast of the Blackfoot Mountains, from which they are 
 separated by a wide basin-plain floored with basalt, rise a couple of low 
 parallel ridges, lying between John Gray's Lake and the upper basin 
 of the Blackfoot River. The northeastern flank of the eastern ridge 
 shows red sandstones, probably Triassic beds, and similar deposits oc- 
 cur on the opposite flank of the western ridge. Their present condition 
 is that of mouoclinal ridges, the strata of which show northeasterly and 
 southwesterly dips, respectively. The eastern ridge shows the basalt 
 reclining high up on its southwest flank, resting on the Carboniferous 
 limestone near the crest of a sag in the ridge. Both ridges are, how- 
 ever, principally composed of Carboniferous limestone and siliceous beds. 
 
 East of the Blackfoot Mountains, the first low mountain eminence 
 encountered appears to be a bulging up of the volcanics, the basalts 
 rising up on the flanks of the ridge, whose summit is composed of sco- 
 riaceous lava. To the southeast the basalt has been denuded, leaving 
 several low buttes of this rock, which seems to be connected with the 
 deposit which fills the broad valley separating this from the Blackfoot 
 Mountains. (Station 4.)' But to the northward, beneath the basalt, the 
 nucleus of the ridge displays a series of soft gray sandstones and harder 
 red, coarse sandstones, with variegated shales, underlaid by drab-gray 
 limestone containing great numbers of a small gasteropod, and which is 
 in turn underlaid by hard light-red sandstones. These beds incline 
 southwesterly, and together they represent a great thickness of strata. 
 The ridge on the north is capped by trachyte, which dips at a steep angle 
 into the Snake plains. The upper sandstones contain obscure vegeta- 
 ble remains, from which circumstance their Cretaceous age may be in 
 
GEOLOGICAL SURVEY OF THE TERRITORIES. 769 
 
 ferred. The limestones and sandstones are again exposed to view in a 
 low anticlinal ridge next east, which was thrust up by a rhyolitic (?) 
 dike, on which station 17 was established. The limestone is also here 
 charged with the same little gasteropod, and underlies the sandstone, 
 which latter shows obscure plant-remains. The dips at the latter local- 
 ity are southwest and northeast. 
 
 To the southeast of the above locality, in the vicinity of Gray's Lake, 
 obscure outcrops of reddish and gray sandstone may be seen in a cluster 
 of low hills just to the south of the lake. These beds dip at moderate 
 angles to the south west ward, and on the westernmost low ridge among 
 the debris an obscure Ammonites was found preserved in a fragment of 
 graj T limestone. It is uncertain whether these beds should be referred 
 to the Cretaceous or Jurassic; but the fossils obtained will doubtless 
 readily establish their age. To the west these beds are doubtless sud- 
 denly and sharply folded, as the Carboniferous appear in the before- 
 mentioned pair of ridges just west of Gray's Lake and but a few miles 
 from the above-mentioned exposures with Ammonites. 
 
 The Caribou Eange occupies by far the largest area of any range in this 
 region, and in its geological aspects it is also the most varied. Along 
 the northeastern border at intervals, or near the northern extremity 
 and again between the lower and upper basins in the Snake Valley, the 
 range is flanked by heavy deposits of quartzites which resemble the an- 
 cient quartzites in Mount Putnam. Ihis is succeeded by the Carbonif- 
 erous, consisting of limestones and hard quartzitic sandstones, in the 
 upper portion of which occurs a horizon charged with a peculiar lamelli- 
 branch fauna, which strongly recalls the Permian. This latter probably 
 represents the equivalent of the Perrno Carboniferous in this region. 
 Next in order of superposition is a thickness of several hundred feet of 
 u red- beds," which is in turn overlaid by the peculiar light drab, indu- 
 rated, calcareous shales and limestones of the Jurassic. Along the 
 western border of the range, to the north, occurs a heavy series of red- 
 dish and soft, gray sandstone, imbedded witli variegated shales, which 
 contain vestiges of a flora represented by obscure impressions of woody 
 stems "and dicotyledonous leaves, (between stations 19 and 20.) Higher 
 in the mountain slope these deposits are overlaid by gray and drab 
 limestones, which afford a few small ostreas and the pentagonal disks of 
 crinoid columns. The former deposits can hardly be referred to a more 
 ancient period than the Cretaceous, while the latter as probably belong 
 to the Jurassic ; the relative position of the beds indicating a fold which 
 overturned or inverted the strata. These or very similar gray sand- 
 stones were met on the eastern flank of Mount Bainbridge, where they 
 are followed above by dark shales, here much changed by contact with 
 the intruded volcanics and the limestone cap of the mountain, which 
 latter afforded traces of a little gasteropod, apparently similar to those 
 occurring in before mentioned limestones found elsewhere in connection 
 with these gray and reddish sandstones. The general strike of these 
 strata is northwesterly and southeasterly, though subject to great varia- 
 tion even along the same line of exposure in crossing the series ; while 
 they are much folded, which greatly complicates their study, rendering 
 accurate measurements impracticable in the hurried examinations made. 
 There are three or four conspicuous folds, one of which is a sort of 
 double fold, which at one point shows an abrupt flexure in the strata 
 involved which may at other points have completely severed the bed, 
 resulting in a fault. As already intimated, the region is further compli- 
 cated by inverted beds, and in certain parts there are found the most 
 contradictory dips, indicating a chaotic condition, the result of intense 
 
770 REPORT OF THE SECRETARY OF THE INTERIOR. 
 
 local disturbance. Tlio vertical displacement is very great, and the 
 amount of material which has been removed by erosion, and this, too, 
 within a comparatively not remote date, is almost inconceivably great. 
 
 Allusion has already been made to the Mount Bainbndge volcanies, 
 when- these igneous products are so intruded in the limestones and 
 shales as to present the appearance of regularly-bedded deposits. As- 
 sociated with the eruptive rocks at this locality are auriferous lodes ot 
 some richness, which have given a fair supply of gold to the placers, 
 thou-h as yet little has been done toward developing the lodes them,- 
 Strive*. H 'is presumable that all the placer diggings in the Caribou 
 district received their gold irom the lodes intersecting Mount Bain- 
 bridge. The intrusion of this great ma^s of eruptive rock does not ap- 
 pear to have greatly disturbed the sedimentaries, since the southwest- 
 erly inclinations observed in ascending the eastern slope of the mount- 
 ain are continued down the opposite slope and as far as Gray's Lake 
 Basin, the only change of note being the gradual flattening of the angle 
 of inclination 'as we recede from the range westerly. While the Car- 
 boniferous deposits appear to be mainly, if not wholly, restricted to the 
 northeastern border of the range, the Jura-Trias composes the bulk of 
 the central portion, with belts of the variegated shales and sandstones of 
 later date in the southwest; all of which share equally in the effects of 
 upheaval, which has folded and warped these deposits in a remarkable 
 manner. 
 
 There remains to be noticed the occurrence, in the upper basin of the 
 Snake Valley, extending up to the debouchure of the grand canon, of a 
 peculiar deposit of variegated clays and partially indurated sands, which 
 fill this part of the valley. These beds are extensively exposed in the 
 right bank of the Snake River below the confluence of Salt liiver, and 
 also may be seen in the opposite side, that along which the party 
 traveled, and where their tilted edges are planed off to various terrace- 
 levels, marking the work of the river erosion, and the whole overlaid by 
 the coarse materials out of which the more modern terraces were formed. 
 These beds incline quite uniformly obliquely up stream, or in an east- 
 erly direction, at angles of 35 to 40. Their tilting it is difficult to ac- 
 count for, since they areunconformable to the older formations in either 
 the east or west side ranges bordering the Snake Valley; and yet it 
 seems almost certain that they owe their present position to disturbances 
 lying to the westward, in which case it may enable the determination 
 with a good degree of accuracy the precise age of at least (if there be 
 more than one such) the latest upheavals which have taken place in the 
 Caribou Range. I take it these valley deposits are of late origin, proba- 
 bly Tertiary lacustrine beds. 
 
 Below the month of Salt River occur extensive deposits of calcareous 
 tufa, jutting out into the valley in low platforms, in the neighborhood 
 of which saline springs are flowing feebly to-day. Again, in the little 
 basin-valley east of Lyncoln Valley, quite, extensive calcareous deposits 
 floor the valley, in the midst of which are vestiges of the now extinct 
 springs from whose flow this material was precipitated. The little 
 i ms which rise in the Blackfoot Mountains also contain much lime, 
 which isdeposiied on stones and sticks in the beaver-darns in their lower 
 courses. But none of these accumulations are comparable to the enor- 
 mous spring-deposits met with in the northeastern foot of the Wind 
 River Mountains, in the upper portion of the Wind River Valley which 
 wen- hastily examined later in the season. 
 
 Reference has been made in the foregoing pages to the evidence bear- 
 ing on the age of some of the disturbances which have taken place iu 
 
GEOLOGICAL SURVEY OF THE TERRITORIES. 771 
 
 the Caribou Range, and which would appear to have taken place at a 
 comparatively modern date, or subsequent to the deposition of the 
 Tertiary lake-beds. In the valley of the Blackfoot are found a set of 
 loose sand and conglomerate deposits, which are apparently of later 
 date than the period of basaltic effusions, and which were tilted by forces 
 lying to the westward, the beds dipping toward the Blackfoot Range. 
 Hence, it is reasonable to infer that these deposits, together with the 
 Pliocene shell-beds in the same quarter, were tilted at the time of the 
 disturbances winch folded and complicated the strata in the belt of hills 
 lying between the Blackfoot and Lyncoln Valley, and which does not 
 appear to have affected the Blackfoot Mountains, whose elevation is 
 probably referable to an earlier date, or late Mesozoic time. 
 
 In conclusion, it may not be out of place to mention the beautiful 
 scenery of this region, its grassy hills and plains, and its many tracts of 
 arable land adjacent to the numerous little streams of pure water which 
 drain the region. For the purposes of stock-growing the country offers 
 many inducements. Save in the plains bordering the Snake River, 
 where excellent crops of small grain and vegetables are grown, we have 
 not the aid of experiment to guide to positive information respecting 
 the agricultural capability of the tracts of fertile valley-soil everywhere 
 found, and which can be easily irrigated. But even in the high basin, 
 or mountain valley, in the Caribou district, oats and the hardier vege- 
 tables are grown. There is a scarcity of wood, and the largest forest 
 tracts are generally in the most inaccessible localities. 
 
 That portion of the district next visited comprises ground which was 
 partially explored by the expedition of 1872. Hence, during the limited 
 time the present party spent in this region, it was principally the geolo- 
 gist's aim to visit those quarters which had not previously been examined. 
 This region embraces all that portion of the district lying in the great 
 southern bend of the Snake River, extending northward to the northern 
 boundary, and in area more than a third greater than the previously 
 noticed region lying to the southwest. The whole northern portion is 
 occupied by the plains of the Snake Basin, which in the west and north- 
 west are interrupted by a cluster of low volcanic cones, surrounded by 
 sand-hills. On the east the plains rise into the broad ridge which slopes 
 off from the northern end of the Teton Range, and which merges into 
 the low, densely-wooded water-shed separating the Henry's Fork drain- 
 age on the west from the upper waters of the main Snake River on the 
 east. The entire extent of the plains region, including the before- 
 mentioned low water-shed, is immediately underlaid by volcanic rocks. 
 A vast sheet of lava-basalt is spread over the extensive lower levels of 
 the plain. In the sloping upland border region to the south, these 
 basaltic rocks are succeeded by a laminated variety, associated with 
 trachytic material, which gently rise upon the flanks of the highlands 
 to the southward, precisely in the manner observed in connection with 
 the volcanics in the southwestern portion of the district. Pierre's 
 Basin, which lies- between the Teton Range and the northern portion of 
 the Snake River or Pierre Mountains, forms a sort of estuary, opening 
 out north into the Snake plains, up which the laminated and trachy- 
 tic volcanics extend on the east side as far as the mouth of Teton 
 Pass, and on the west side about half the distance toward the head of 
 the basin. Formerly, doubtless, the entire area of this basin was 
 floored with these rocks; but to day they are only observed in isolated 
 patches, reclining on the foot of the surrounding mountains, while in 
 the valley they are covered by Post Tertiary deposits of water-worn 
 gravel and bowlders and the silted washings from the surrounding 
 
772 REPORT OF THE SECRETARY OF THE INTERIOR. 
 
 slopes. To the north of West Teton Creek, however, the volcanics con- 
 stitute a prominent feature in both the basin plain and in the foot of the 
 mountains. They are here seen to rise up on the flank of the range to 
 an elevation of 2, 000 t>eefc above the basin, forming a wide, heavily- 
 timbered foreland, lying between the mountains and the plain. lu this 
 border region the streams are deeply cauoned. 
 
 In Pierre's Basin, as also in the bottoms along Henry's Fork and its 
 tributaries, accumulations of water worn drift materials are prevalent, 
 mainly consisting of quartzite bowlders, with more rarely limestone, 
 granitic, and volcanic bowlders; the three former varieties derived from 
 ledges in the Teton Range and the mountains to the south and west. 
 These drift materials were also occasionally observed in the uplands, 
 where they are weathered out in the slopes immediately bordering the 
 canoned courses of the streams; showing their general distribution over 
 the entire area of the volcauics. as well upon the sloping upland as in 
 the river-bottoms. Indeed, on some of the high crests in the northern 
 part of the Teton Range, quartzite and gueissose bowlders are sparsely 
 present in situations where their presence cannot be accounted for satis- 
 factorily without the intervention of glacial transporting agencies. 
 
 A march of eight days' duration from Fort Hall brought the party to the 
 Teton Mountains, near the northern end of which, on the west side, the 
 first ascent was made. This range, in its present condition, may be 
 described as a gigantic mouoclinal ridge, with a metamorphic and 
 granitic nucleus which forms a lofty, exceedingly rugged, jagged crest, 
 extending in a north and south direction three-fourths the length of the 
 range, and which culminates in Mount Hayden. The eastern face is 
 suddenly broken down in precipitous walls and steep slopes, which de- 
 scend into Jackson's Basin. The western slope throughout its extent is 
 covered by the sedimentaries, dipping to the westward at comparatively 
 moderate angle of inclination. About midway between West Teton 
 Canon and the northern terminus of the range, the continuity of this 
 sedimentary foreland is suddenly interrupted by a rugged spur of 
 Archaean rocks, thrown oft' from the main range to the east, and which 
 separates the sedimentary area into two portions. The northwest ter- 
 minus of this spur reaches quite across the belt of lofty summits outly- 
 ing on the west the Archa3au belt, the volcanic ledges lapping up on 
 its loot, and beneath which the sedimentaries are concealed. The struc- 
 tural features of the range, so far as relates to the sedimeutaries, are 
 comparatively simple. To the north, where the volcanics reach high 
 up on the western flank, in one of the canoned sources of the North 
 Fork of Pierre's River, the lowest ledges in situ consist of a consider- 
 able thickness of thin-bedded drab limestone, which I take to be Quebec. 
 Above this occurs a heavy ledge of buff magnesian limestone, showing 
 a thickness of 100 feet or more, and which contains obscure corals re- 
 sembling Xiagan forms: Above the latter, to the summit of the high 
 ridge on which station 32 was made, occurs a thickness of 1,500 feet of 
 ( 'arboniferous deposits. At this point these deposits show a gentle in- 
 clination northwesterly ; but to the north, at the base of the same mount- 
 ain, the northeasterly dip of these strata indicates a synclinal depres- 
 sion at this point. Beyond, in the same directiod, and near the terminus 
 of the range, the strata are steeply tilted or upturned, with sharp west- 
 erly dips, as though the result of the upheaval of the Archa3an ridge which 
 ics just to the east. From such observations as Mr. St. John was able 
 to make, it appears that the sedimentaries which may once have folded 
 continuously round the north extremity of the range, were extensively 
 denuded prior to the eruption of the volcanics, which overlap alike the 
 
GEOLOGICAL SURVEY OF THE TERRITORIES. 773 
 
 sedimentary outlying deposits and the Archaean areas, wherever the 
 latter reach, the western and northern borders of the range. To the south 
 of the above mentioned ArchaBan spur, the same series of sedimentaries 
 recur, and which extend high up on the more elevated portions of the 
 range, sloping thence to the westward in the direction of Pierre's Basin. 
 But to the south, of the West Teton Creek Canon, a series of deep red 
 arenaceous shales and sandstones are superimposed on the Carboniferous, 
 the capping of intensely hard siliceous roclv or quartzite forming an 
 effectual protection to the foreland, which here sweeps down in long, 
 comparatively regular slopes into the valley. These latter deposits here 
 show a thickness of 300 to 500 feet. On the lower slopes of the foreland, 
 apparently overlying these red-beds, obscure traces of drab limestone, not 
 unlike Jurassic deposits found elsewhere in the district, occur. Though 
 no fossils were observed in these beds, it will at once occur to you that 
 they are probably Triassic. These red-beds form a conspicuous feature 
 in the magnificent escarpments thence southward nearly to Teton Pass 
 Creek, where they have been denuded, the Carboniferous beds again ap- 
 pearing in the base of the mountains. In passing southward along the 
 west flank of the range, the inclination of the sedimeutaries is observed 
 to gradually change from a north of west to west and southwest direc- 
 tion. In the vicinity of Teton Pass, to the southwest, are evidences of 
 unusual disturbance, the Carboniferous beds being suddenly upturned, 
 forming what appears to be a short, sharp fold, with steep easterly dip 
 and more gentle westerly inclination. The pass itself is eroded out of 
 the "red-beds" and siliceous upper deposits of the Carboniferous. While 
 obscure exposures of brownish gray limestone containing a small ostrea- 
 like shells and soft gray sandstone indicate the presence of the Jurassic, 
 and probably the Cretaceous, which seem to occupy a synclinal depres- 
 sion whose axis deviates ncore to the east of south from the prevalent 
 strike of the sedimentaries in the Teton Range, and in this respect cor- 
 responding intimately with the folds afterward observed in the mount- 
 ains on the west side of Pierre's Basin. 
 
 The Tetou Range terminates rather suddenly in lofty peaks sculptured 
 out of the sedimentaries, to the south and southwest of which a much 
 lower but very broken mountain tract extends to the grand caiion of the 
 Snake River. This tract is crossed by broad belts of " Red Beds," drab 
 and buff beds, corresponding to the Triassic, Jurassic, and, possibly, 
 Cretaceous, and which are limited in the distance by rugged crests com- 
 posed of gray ledges, which may prove to be the Carboniferous basin 
 bounding the Snake River. The high peaks which rise immediately to 
 the north of Teton Pass summit are made up of Carboniferous strata, 
 dipping a little north of west at angles of 10 to 45 ; to the west, how- 
 ever, the same deposits incline at much steeper angle, as noticeable in the 
 acclivities on the north side of Teton Pass Creek. These ledges sweep 
 up over the summit of the range, forming lofty ridges which break 
 down abruptly on the east in a succession of escarpments and steep de- 
 bris covered slopes. East of the summit of Teton Pass, in descending 
 to Jackson's Basin, the granitic nucleus cannot lie far beneath the bed 
 of the caiion, since the short northern tributary canons have brought 
 down much granitic debris; but below this still, in a bulky outlying 
 ridge at the debouchure of East Pass Creek, the Carboniferous again ap- 
 pears, also dipping north of west at a moderate angle. Farther north, 
 in these east-lacing sedimentary escarpments, where the whole series of 
 Palleozoics occurring in this region is revealed in magnificent exposures, 
 a fold or undulation in the strata is observed by which the Carboniferous 
 beds are carried down along the east slope to a level far below the lofty sum - 
 
774 REPORT OF THE SECRETARY OF THE INTERIOR. 
 
 mits which the beds crown along the crest of the range ; a similar fold 
 would explain the occurrence of the low-lying exposures in th,e debouch- 
 ure of East Pass Creek, above noticed. Beneath the sedimeutaries at 
 this point the Archaoan rocks are exposed, and which descend in steep, 
 rugged slopes to the level of the valley. To the north still, the Archasau 
 nucleus rises higher and higher, carrying up with it tlje sedimentaries, 
 which gradually disappear, one formation after another, until only Que- 
 bec is seen, forming a coping ot dark limestone to some of the high ridges 
 south of Mount Haydeu, and where they are finally crowded back, occu- 
 pying subordinate ridges west of the main crest. The east face of the 
 range from the vicinity of the-Tetons to its northern extremity shows 
 onlv the Archraan rocks. It is very probable that the sediineutaries 
 were profoundly faulted along the east side of the range, along which 
 side, it would appear, the greatest force was expended in the upheaval. 
 But toward the extremities of the range, where these forces were less 
 violent, the sedimentaries may have been merely crumpled or folded in 
 the manner apparent in the southern extremity of the range. 
 
 Subsequent erosion has greatly changed the surface contour, and ob- 
 scured many details, but the general features are still manifest. 
 
 A brief visit to the Pierre Mountains, on the west side of Pierre's 
 Basin, afforded opportunity for the study of the structural features of 
 the eastern half of the range. This range intersects the Teton Range 
 at a sharp angle, its general direction being northwest and southeast, 
 and forming an exceedingly broken mountainous belt between Pierre's 
 Basin and the Snake River. In its geological structure it is inti- 
 mately related to the Caribou Range on the opposite, west, side of the 
 Snake River. The range exhibits a series of folds, whose axes extend in 
 a general direction northwesterly and southeasterly, and in which are 
 exposed typical exhibitions of the Carboniferous, Ti lassie, and Jurassic, 
 and probably the Cretaceous formations. Along the eastern border, to- 
 ward the northern extremity of the range, in a section 'much compli- 
 cated and broken up by the forces which folded the beds, occur a series 
 of gray sandstones and shales which closely resemble deposits found in 
 the Caribou Range, which have been referred to the Cretaceous. These 
 beds appear in low ridges, upon which lap the volcanics in long, gentle 
 ascents from the canon-scored plain of Pierre's River to the northeast 
 and north. To the southwest a wide belt of Carboniferous is met, show- 
 ing the entire thickness of the formation, which is made up of lime- 
 stones and heavy siliceous deposits. On the southwest side of the anti- 
 clinal in which these limestones are exposed, a heavy series of deep red 
 gritty shales and sandstones, reaching a thickness of 1,500 feet or moie, 
 occur, which represent the Triassic. Succeeding the latter, occur a sec 
 of beds made up of limestones and drab indurated calcareous layers, 
 with Jurassic fossils, representing a thickness of a thousand feet or 
 more. These are followed by a series of heavy deposits of hard sand- 
 
 _. .1 _;.___ i . i i j 
 
 similar deposits are here and there indicated, bounded in the distance 
 by the more uniform and even loftier mountain wall along the northeast 
 margin of the Snake Valley, which appears to consist of Carboniferous 
 strata. These several folds, so far as I was able to determine, are pretty 
 constant for long distances. Although the middle part of the rano-e 
 has been much eroded, so as to cause the Carboniferous to flank the 
 mountains between Horse Creek and the head of Pierre's Basin the 
 outer belt of Cretaceous near the northern end of the range probably 
 
GEOLOGICAL SURVEY OF THE TERRITORIES. 775 
 
 belongs to the same fold which lies just to the southwest of Teton Pass ; 
 while the inner folds above alluded to correspond to those observed in 
 the southeastern half of the range to the southwest of Teton Pass. The 
 condition of the sedimentaries in the interval embraced to-day in Pierre's 
 Basin, of course remains conjectural, these rocks being hidden from ob- 
 servation beneath the volcanic sheet which at a later date flooded the 
 valley. From the relative age of the folding of the strata which make up 
 this range, compared with other neighboring ranges, it seems probable 
 that the date of its upheaval is referable to a time antecedent to that dur- 
 ing which the disturbances took place which resulted in the folding of 
 the Caribou Range, and probably subsequent to the upheaval of the Teton 
 Range. This latter forms a unique as it is one of the grandest ranges 
 in the West. In many particulars it bears a more striking resemblance 
 to the Wind River Mountains than it does to the low but much more 
 complicated ranges which* it dominates. 
 
 That which forcibly strikes the observer on entering Jackson's Basin, 
 which lies at the east base of the Teton Range, is the vast accumulation 
 of drift materials with which the valley is filled. Along the west side 
 of the basin extensive morainic accumulations in irregular, wooded ridgos, 
 outlying the debouchures of the canons which penetrate the range; while 
 the stream itself, in various stages, has fashioned these materials into 
 beautiful terrace formations. Scarcely anything could offer greater con- 
 trast than that presented by the mountain environments of this basin. 
 The Teton Range forms a rugged, almost precipitous barrier on the west, 
 which rises 4,000 to 7,000 feet above the valley. To the east the country 
 rises in gentle, wooded ascents, culminating in clusters of low mountain 
 elevations which are connected by high mountain plateaus with the con- 
 tinental water-shed. To the southeast of the Teton range, and running 
 up into the angle formed by the confluence of the Snake and Grosventre 
 Rivers, lies a rather lofty and very rugged range of mountains which 
 occupies a considerable area between the Grosventre and the headwaters 
 of Green River, and which forms a sort of transverse belt connecting the 
 Teton Range with the WindRiver Mountains to the east. This range 
 is known as the Grosventre or Wyoming Mountains. ^The geologist's 
 examinations wer/e confined to the western portion of the range. Here 
 he meets with an Archasan (gueissic) nucleus, which in places penetrates 
 through the heavy mantle of sedimentaries in sharp peaks which but 
 for the presence of the colossal Tetons would elicit admiration for their 
 real grandeur and perfect mountain contour. In many respects the 
 range presents marked resemblance to the Teton Range, and probably 
 its relationship to the Wind River Mountains is even more intimate. 
 The sediuieutaries have been uplifted bodily upon portions of the range, 
 though they exhibit evidences of great disturbance and of .the unequal 
 distribution of the elevatory forces, which have in places sharply folded 
 the strata. One of these Archa3an peaks sends down a sharp spur to the 
 westward, which terminates ratherabruptly in the valley at a point about 
 opposite the Lower Grosventre buttes. Between the latter and the 
 foot of the spur, a little stream has excavated a widish valley, in the 
 west side of which, in a line of bluffs, dark weathered ledges appear, 
 gently dipping westerly, and which are probably Quebec. In the north- 
 ern butte, Professor Bradley mentions having observed volcanic ledges 
 (" porphyriiic breccias," ) and to the south limestones in horizontal posi- 
 tion, which are referred to the Carboniferous. The volcanic capping 
 gradually rises to the southeast, and finally disappears. A similar rem- 
 nant occurs on Elkhorn Creek, near the edge of the basin, where ifc rests 
 upon Tertiary deposits. To the north of the above-mentioned spur, in 
 
776 REPORT OF THE SECRETARY OF THE INTERIOR. 
 
 the foot of the foreland, outcrop ledges of thin-bedded drab limestone, 
 dipping northwesterly, which are undistinguishable from the Quebec 
 limestones occurring in the Teton Range. Ascending this foreland, east- 
 ward, the same limestones are exposed at frequent intervals, showing 
 the same dip, and iu places overlaid by remnants of the buff magnesian 
 limestone referred to the Niagara. These deposits finally give way to 
 densely wooded debris slopes, which reach up to the Archaean peak of 
 station 44, like gigantic moraines. From this point an excellent oppor- 
 tunity is had for the study of the rugged and almost inaccessible mount- 
 ain highlands which make up the broad northern summit of the Gros- 
 ventre Range. It is a region of lofty ridges and profound amphitheaters, 
 whose precipitous walls exhibit the complete sedimentary series from 
 quartzites to the Carboniferous, and off to the east heavy deposits of the 
 Triussic u red beds " cap high ridges. The region strongly recalls the 
 Teton Range, but the sedimentaiies are much* more disturbed, and, as a 
 consequence, this highland is more uneven than that along the west 
 summit of the latter range. A few miles to the northward, the foreland 
 which rises into station 46 from the debouchure of the Grosventre, ex- 
 hibits the Carboniferous dipping northerly, and which extends to the 
 summit of this lofty peak. These beds pass beneath the Triassic, which 
 appears in line of vermillion bluffs along the north side of Grosventre 
 Canon, beyond which the hills gradually rise into a high conical peak 
 which forms the culminating point of the highlands between the Gros- 
 ventre and Buffalo Fork, and which is known as Mount Leidy. Over- 
 lying the Triassic red beds, a broad belt shows light drab deposits 
 which also dip norther-ly, and which hold the position and have the ap- 
 pearance of the Jurassic, though no fossils were observed in the lime- 
 stones, which in part make up these latter deposits, by which their age 
 could be determined. The space intervening between the latter depos- 
 its and Mount Leid> is more broken, and apparently consists of an ex- 
 tensive accumulation of softer deposits. The lower portion of these are 
 found to consist of light and yellowish soft sandstones and clays, capped 
 by light-brownish beds, which are finely displayed in Mount Leidy, 
 whose steep slopes the elements have beautifully sculptured. Iu the 
 northern foot of Mount Leidy, the lower or middle beds of this series 
 exhibit an exposure of one or two hundred feet in canon-bluffs of Elk- 
 horn Creek, in the base of which a thin bed of rotten lignite was found. 
 He failed to detect any traces of organic remains in these beds, and am, 
 in consequence, unable to refer them to their place in geological time, 
 though I believe they belong to the Tertiary. The northerly inclination 
 of these beds at a gentle angle continues across the low upland to the 
 Buffalo Fork, and in the hills which rise on the north of this stream simi- 
 lar beds of clays and buff sandstone outcrop, where they attain eleva- 
 tion of above 2,000 feet above the valley. Th-se bills 'are, capped by 
 bed of partially cemented bowlders and pebbles, the degradation of 
 which has strewn the slopes with drift debris. The above-mentioned 
 Tertiary deposits were met in the gradually-ascending upland to the 
 east as high up as the debouchure of the Buffalo Fork, though they 
 were not observed to extend up on the mountain sides iu this quarter. 
 From the Buffalo Fork the route led up Black Rock Creek, through 
 the To-owo-tu Pass, across the continental divide into the Wind River 
 Valley. Just wiihin the western entrance to the pass, on the north 
 side, ii group of high mountains occupies the interval between Black 
 Rock Creek and Buffalo Fork, of which Buffalo Fork Peak forms the 
 culmination. The bases of these mountains, together with the corre- 
 sponding heights on the opposite side of Buffalo Fork, and which together 
 
GEOLOGICAL SURVEY OF THE TERRITORIES. 777 
 
 form the gateway to the upper mountain valley of this stream, are com- 
 posed of Archaean (gneissose) rocks, which constitute a thousand or more 
 feet of the lower portion of fche canon-walls. Upon these rests a thickness 
 of one hundred feet or more of quartzite, and upon the latter a heavy ledge 
 Of the lower Quebec limestone occurs, forming the summit of Buffalo Fork 
 Peak. This mountain is connected with the lower peak, station 40, to 
 the southwest, by a long spur, in which this limestone forms the coping 
 and dips in the same direction. It is overlaid by the thin-bedded upper 
 ledge, with a considerable thickness of intervening clays and indurated 
 fine-grit layers, in all of which Trilobites and other Silurian fossils were 
 found. These beds are in turn overlaid, without apparent unconfor- 
 mability, by several hundred feet of Carboniferous, which latter crowns 
 the summit of station 49. The southern slopes of these mountains 
 steeply descend over heavy ledges of limestone and grayish buff and 
 reddish hard sandstone into the valley of Black Rock Creek, where the 
 deep red sandy shales and sandstone of the Triassic outcrop, and the 
 presence of which in the adjacent slopes is plainly hinted by the rank her- 
 baceous vegetation its soil supports. The same deposits are also seen to 
 the east or southeast, reclining on the southeasterly declivities of these 
 mountains, in the gap which separates them from the volcanic escarp- 
 ments of the main water-shed. This group of mountains appears to owe 
 its origin to a local bulging of the crest, since to the north th<* sedimen- 
 taries which it bears on its crest are seen to dip off in that direction, as 
 they do in the opposite direction on their western and southern flanks, 
 overlooking the lower valley of the Buffalo Fork and the upper course 
 of Black Rock Creek in the approach to To-owo-tu Pass. The latter 
 valley, like the Teton Pass, (and for that matter, so many of the passes 
 in the mountains of this region,) is excavated in the Triassic red-beds. 
 To the southwest of the Black Rock indications of the presence of the 
 Jurassic are obscurely revealed here and there, but soon concealed in 
 the long, wooded slopes, which are continuous with the Tertiary ridges 
 of the Mount Leidy region. 
 
 In the valley of Black Rock Creek are encountered heavy masses ot 
 volcanics consisting largely of a sort of conglomerate breccia. These 
 continue to the summit of To-owo-tu Pass, where they are seen in inti- 
 mate association with some of the most remarkable volcanic accumula- 
 tions. The latter rise into lofty horizontally-bedded mountains whose 
 sides are sculptured in colossal architectural forms, and which form a 
 grand portal to the pass across the continental divide. The heights 
 command Jackson's Valley and the Teton to the westward, while to the 
 eastward lies the low country of the Wind River Valley, diversified by 
 the peculiar variegated formations which occupy a great basin bounded 
 on the north by the continuation of the volcanic cliffs. These latter 
 offer on close examination the most varied appearance, being made up 
 of volcanic ash, sands, breccias, and conglomerate, which are partly of 
 aqueous origin, as shown by their bedderl coudition. These strata are 
 practically horizontal, although they incline slightly in various direc- 
 tions, but appear not to have been affected by disturbances such as ele- 
 vated the Buffalo Fork Mountains, and hence the more recent date of 
 their formation is inferred. 
 
 To the east, north, and northwest, these deposits are spread over an 
 immense area of elevated mountain country, themselves constituting 
 some of the highest elevations in the region. Their debris effectually 
 conceals the older rocks in the To-owo-tu Pass, to the south of which 
 the same great escarpments are continued for a short distance, when 
 they give way to lower levels of long, wooded mountain summits. In 
 
778 REPORT OF THE SECRETARY OF THE INTERIOR. 
 
 the latter appear heavy exposures of dark, compact, and scoriaceous 
 lavas, with trachytic domes. These extend along the summit of the 
 water-shed several miles in a southerly direction, and may reach to the 
 near vicinity of Union Pass. 
 
 Descending into the Wind River Valley, a few miles below the summit 
 of the pass, the bluff banks along the stream show a hundred feet or so 
 of cream-colored and bnff sandstone and gritty clays. These deposits 
 gradually increase in vertical exposure as we descend the valley, the 
 beds gentl? inclining in the same direction, or southeasterly. At a point 
 where the stream opens out into the intervale-bordered valley these beds 
 are seen to be overlaid by a series of variegated, red, greenish, and buff 
 or ash colored clays, and indurated arenaceous beds, which make up a 
 thickness ot several hundred feet in a rather high plateau or terrace 
 outlying the high volcanic ridges which hem the basin on the north. 
 These deposits continue down the valley several miles farther, lower 
 beds coining to view as we descend. Above De Noir Creek, in a low 
 bluff on the north side ot Wind River, a thin seam of lignite occurs in 
 connection with bluish-drab and chocolate-colored clays and rusty, soft 
 sandstone. In the neighborhood of Warm Water Creek we first met the 
 older sidimentaries, which appear in a mass of reddish and light colored 
 sandstones reclining on the toot of the Wind River Mountains, (lipping 
 20 to 30 northeasterly. The sandstones are underlaid by older for- 
 mations, which rise successively higher and higher upon the northeast- 
 ern face of the range. 
 
 In the same neighborhood, on the northeast side of the river, a series 
 of beautifully exposed deposits, consisting of variegated, light-red, and 
 drab clays, and bands of 'ferruginous sandstone, capped by yellowish 
 sandstone, appear, and which seem to underlie conformably the before- 
 mentioned horizontal deposits. These variegated beds continue thence 
 far down the valley; but above Crow Heart Butte they are crowded in- 
 land, the terraces which bound the stream showing buff' sandstones, and 
 which, together with brownish clays, make up the rock exposed in the 
 above-named butte. In the vicinity of the confluence of North Fork 
 the variegated beds exhibit their greatest development, as shown at 
 any one point observed. Here they are seen to rest upon brown clays, 
 recalling the clays interbedded with the sandstones in Crow Heart 
 Butte, and all of which rest unconformably upon the more steeply- 
 inclined Jurassic limestone and Triassic sandstone, which here form a 
 wide belt of exposures in the foot of the mountain. The variegated 
 beds are also slightly inclined northeasterly. 
 
 Below Bull Creek we soon enter a region where the Mesozoics extend 
 several miles out into the plains, which here intervene between the river 
 and the foot of the mountains; a section where they exhibit much dis- 
 placement, which contrasts with the grand simplicity which uniformly 
 characterizes the position of the Mesozoic and Paleozoic formations in 
 the great foreland slopes of the range between the Warm Water and 
 Little Wind Rivers. 
 
 Thence, on their return, the party passed through Mr. Chittenden's 
 district, which was visited by Dr. Endlich. 
 
 The necessity of a careful examination of the various geological for- 
 mations in the field, and a review by a practical paleontologist of the 
 various districts that have from year to year been surveyed by the dif- 
 ferent geologists of this and other surveys, has been long felt. Such a 
 work, indeed, was imperatively necessary before a consistent and com- 
 prehensive classification of the formations could be established. This 
 
GEOLOGICAL SURVEY OF THE TERRITORIES. 779 
 
 duty was assigned to Dr. 0. A. White, the palaeontologist of this Survey, 
 and he took the field at the beginning of the past season and continued 
 his labors until its close. The special duty with which he was charged 
 was to pursue such lines of travel as would enable him to make critical 
 exam i nation of the geological formations in succession as they are exposed 
 to view on both sides of the Rocky Mountain chain, and also on both 
 sides of the Uintah chain ; to collect and study the fossils of these forma- 
 tions in such detail as to settle, as far as possible, the questions of the 
 natural and proper vertical limits of the formations, their geographical 
 range, their correlation with each other, and to define the paleontologi- 
 es! 1 characteristics of each. 
 
 He has pursued his researches with such success during the past sea- 
 son as to demonstrate the necessity of continuing this class of investi- 
 gations by various lines of travel across what is generally known as the 
 great Rocky Mountain region, especially those portions of it that have 
 been surveyed, as well as those in which surveys are in progress. 
 
 Among other important results, he has shown the identity of the lig- 
 nitic series of strata east of the Rocky Mountains in Colorado with the 
 Fort -Union group of the Upper Missouri River, and also its identity 
 with the great Laramie group of the Green Riwr Basin and other 
 portions of the region west of the Rocky Mountains. He also finds 
 the planes of demarkation between any of the Mesozoic and Cenozoic 
 groups, from the Dakota to the Bridger inclusive, to be either very ob- 
 scure or indefinable; showing that whatever catastrophal or secular 
 changes took place elsewhere during all that time, sedimentation was 
 probably continuous in what is now that part of the continent from the 
 earliest to the latest of the epochs just named. Other results and further 
 details of the season's work will appear in the following paragraphs. 
 
 The general course of travel pursued by Dr. White during the season 
 was as follows, not including the numerous detours, meanderings, and 
 side trips which the work necessitated : Outfittingat Cheyenne, he jour- 
 neyed southward, traversing in various directions a portion of the great 
 plains which lie immediately adjacent to the eastern base of the Rocky 
 Mountains in Colorado. The most easterly point thus reached was some 
 sixty miles east of the base of the mountains and the most southerly 
 point about twenty-five miles south of Denver. Returning to Denver to 
 renew his outfit, he crossed the Rocky Mountains by way of Boulder 
 Pass, through Middle Park. After making certain comparative exam- 
 inations of the Mesozoic and Ceuozoic formations in. Middle Park he 
 proceeded westward to the headwaters of the Yam pa River, following 
 that stream down to the western foot-hills of the Park Range of mount- 
 ains. 
 
 Here resuming his comparative examinations of the Mesozoic and 
 Cenozoic strata, he passed down the valley of the Yampa as far as Yam pa 
 Mountain, one of those peculiar and remarkable up-thrustsof Paleozoic 
 rocks through Mesozoic strata. In all this area, as well as that between 
 the Yampa and White Rivers, the Laramie group reaches a very great 
 and characteristic development, and it received careful investigation, 
 yielding some of the most important results of the season's work. 
 Crossing the ground between the two rivers named to W T hite River Indian 
 agency, thence down White River Valley about one hundred miles; 
 thenc'e to Green River, crossing it at the southern base of the Uintah 
 Mountains, making many detours on the way, he reviewed the geology 
 of the region which he had surveyed during the previous season. This 
 review brought out not only the important paleontological facts before 
 referred to, but it also added materially to the elucidation of the geological 
 
780 REPORT OF THE SECRETARY OF THE INTERIOR. 
 
 structure of the region which lies.between the eastern end of the Uintah 
 Mountain Range on the west and the Park Range on the east, 
 
 Hrvond Green River he pursued his travels westward, studying the 
 Mesozoic and Cenozoic strata that flank the Uintah Range upon its south 
 side, and making comparisons of both their lithological and paleonto- 
 logical characteristics. 
 
 In this \v;iy he traversed the whole length of the Uintah Range, cross- 
 ing at its junction with the Wasatch Range over into the valley of Great 
 Salt Lake. Recrossing the Wasatch to the north side of the Uintah 
 Range he continued his examinations of the Cretaceous and Tertiary 
 strata into and entirely across the great Green River Basin, leaving the 
 field at the close of the season at Rawlius Station, on the Union Pacific 
 Railroad. 
 
 A general statement of the results of the season's work has been 
 given in a previous paragraph, but the following additional summary 
 will make the statement somewhat clearer, being made after the route 
 of the season's travel has been indicated. The formations of later 
 Mesozoic and earlier Cenozoic ages, especially those to which Dr.White, 
 in former publications, has applied the provisional designation of "Post- 
 Cretaceous," have received particular attention. The extensive explora- 
 tions of Dr. Hayden in former years, and the paleoutological investi- 
 gations of the late Mr. Meek, pointed strongly to the equivalency of the 
 Fort Union beds of the Upper Missouri River withXhe lignitic formation 
 as it exists along the base of the Rocky Mountains in Colorado, and 
 also to the equivalency of the latter with the Bitter Creek series west 
 of the Rocky Mountains. The investigations of this year have fully 
 continued these views by the discovery not merely of one or two doubt- 
 ful species common to the strata ot each of these regions, but by an 
 identical molluscan fauna ranging through the whole series in each of 
 the regions named. 
 
 This shows that the strata just referred to all belong to one well- 
 marked period of geological time, to the strata of which Mr. King has 
 applied the, name of " Laramie group," (Point of Rocks group of 
 Powell.) His investigations also show that the strata, which in former 
 reports by himself and Professor Powell have been referred to the base 
 of the Wasatch group, also belong to the Laramie group, and not to 
 the Wasatch. He has reached this later conclusion not merely because 
 there is a similarity of type in the fossils obtained from the various strata 
 of the Laramie group with those that were before in question, but by 
 the specific identity of many fossils that range from the base of the 
 Laramie group up into and through the strata that were formerly re- 
 ferred to the base of the Wasatch. Furthermore, some of these species 
 are found in the Laramie strata on both sides of the Rocky Mountains. 
 Thus the vertical range of some of these species is no less than three 
 thousand feet, and their present known geographical range more than a 
 thousand miles. 
 
 Besides the recognition of the unity of the widely-distributed mem- 
 bers of the formation of this great geological period, bounded by those 
 of undoubted Cretaceous age below and those of equally undoubted 
 Tertiary age above, his further observations have left comparatively little 
 doubt that the < Lake Beds" of Dr. Hayden, as seen in Middle Park 
 the " Brown's Park group " of Professor Powell, and the " Uintah group" 
 of Mr. King, all belong to one and the same epoch, later than and 
 distinctly separte from the Bridger group. 
 
 In that portion of the region which lies adjacent to the southern base 
 of the Uintah Mountain Range, and which is traversed by Lake Fork 
 
GEOLOGICAL SURVEY OF THE TERRITORIES. 781 
 
 and the Du Chesne River, not only the Uintah group, but both the 
 Green River and Bridger groups also, are well developed, each possess- 
 ing all its peculiar and usual characteristics as seen at the typical local- 
 ities in the great Green River Basin, north of the Unitah Mountains. 
 This, added to the known existence of Bridger strata in White River 
 Valley, and the extensive area occupied by the Green River group be- 
 tween White and Grand Rivers, has added very largely to our knowledge 
 of the southward extension of those formations. 
 
 In all the comparative examinations of the formations or groups of 
 strata that have just been indicated, he has paid especial attention to 
 their boundaries,or planes of demarkation, crossig and recrossing them 
 wherever opportunity offered, noting carefully every change of both 
 lithological and paleontological characters. While he has been able to 
 recognize with satisfactory clearness the ihree principal groups of Cre- 
 taceous strata, namely, the Dakota, Colorado, and Fox Hills, on both 
 sides of the Rocky and Uintah Mountains, respectively, they evidently 
 constitute an unbroken series, so far as their origin by continuous sedi- 
 mentation is concerned. While each of the groups possesses its own 
 peculiar paleontological characteristics, it is also true that certain spe- 
 cies pass beyond the recognized boundaries of each within the series. 
 
 The strati graphical plane of demarkation between the Fox Hills, the 
 uppermost of the undoubted Cretaceous groups, and the Laramie group, 
 the so-called Post Cretaceous, is equally obscure ; but the two groups are 
 paleontologically very distinct, inasmuch as the former is of marine origin, 
 while the latter, so far as is now known, contains only brackish-water and 
 fresh-water invertebrate forms. He reports a similar obscurity, or ab- 
 sence of a stratigraphical plane of demarkatiou, between the Laramie 
 and Wasatch groups, although it is there that the final change from 
 brackish to entirely fresh water took place over that great region. Fur- 
 thermore, he finds that while the three principal groups of the fresh- 
 water Tertiary series west of the Rocky Mountains, namely, the Wasatch, 
 Green River, and Bridger groups, have each peculiar characteristics, 
 and are recognizable with satisfactory distinctness as general divisions, 
 they really constitute a continuous series of strata, not separated by 
 sharply-defined planes of demarkation, either stratigraphical or paleou- 
 tologicat. 
 
 During the progress of the field-work, as above indicated, large and 
 very valuable collections of fossils have been made, all of which will 
 constitute standards of reference in the future progress of the work, 
 and quite a large number of the species are new to science. These are 
 now being investigated, and will be published in the usual paleontological 
 reports of the survey. 
 
 Messrs. S. H. Scudder, of Cambridge, and F. C. Bowditch, of Boston 
 spent two months in Colorado, Wyoming, and Utah, in explorations for 
 fossil insects, and in collecting recent Coleoptera and Or th opt era, espe- 
 cially in the higher regions. They made large collections of recent 
 insects at different points along the railways from Pueblo to Cheyenne 
 and from Cheyenne to Salt Lake, as well as at Lakiu, Kaiis., Garland, 
 and Georgetown, Colo., and in various parts of the South Park and sur- 
 rounding region. 
 
 For want of time, they were obliged to forego an anticipated trip to 
 White River, to explore the beds of fossil insects known to exist there. 
 Ten days were spent at Green River and vicinity in examining the Ter- 
 tiary strata for fossil insects, with but poor results; the Tertiary beds of 
 the South Park yielded but a single determinable insect, but near Flo- 
 51 i 
 
782 REPORT OF THE SECRETARY OF THE INTERIOR. 
 
 rissant the Tertiary basin, described by Mr. Peale in one of the annual 
 reports of the survey, was found to be exceedingly rich in insects and 
 plants. 
 
 In company with Kev. Mr. Lakes, of Golden, Mr. Scudder spent several 
 days in a careful survey of this basin and estimates the insect-bearing 
 shales to have an extent at least fifty times as great as those of the 
 famous locality at (Eningen in Southern Bavaria. From six to seven 
 thousand insects and two or three thousand plants have already been 
 received from Florissant, and as many more will be received before the 
 close of the year. 
 
 Mr. Scudder was also able to make arrangements in person with par- 
 tics who have found a new and very interesting locality of Tertiary strata 
 in Wyoming, to send him all the specimens they work oat, and he con- 
 fidently anticipates receiving several thousand insects from them in the 
 course of the coming winter. The specimens from this locality are re- 
 markable for their beauty. There is, therefore, every reason to believe 
 the Tertiary strata of the Eocky Mountain region are richer in remains 
 of fossil insects than any other country in the world, and that within a 
 few months the material at hand for the elaboration of the work on fossil 
 insects, which Mr. Scudder has in preparation for the survey, will be 
 much larger than was ever before subject to the investigation of a single 
 naturalist. 
 
 Prof. Joseph Leidy, the eminent comparative anatomist and micro- 
 scopist, made his second visit to the West the past season, under the 
 auspices of the survey. He made a careful exploration of the country 
 about Fort Bridger, Uintah Mountains, and the Salt Lake Basin, in 
 search of rhizopods. He has been engaged for a long time on a memoir 
 on this subject, which will eventually form one of the series of the quarto 
 Keports of the Survey. 
 
 The rhizopods are the lowest and simplest forms of animals, mostly 
 minute, and requiring high power of the microscope to distinguish their 
 structure. While most of them construct shells of great beauty and 
 variety, their soft part consists of a jelly-like substance. This the ani- 
 mal has the power of extending in threads or finger-like processes, which 
 are used as organs of commotion and prehension, often branching. 
 From the appearance of their temporary organs, resembling roots, the 
 class of animals has received its name of rhizopoda, meaning literally 
 root footed. 
 
 In compensation for the sraallness of these creatures, they make up 
 in numbers, and it is questionable whether any other class of animals 
 exceed them in importance in the economy of nature. Geological evi- 
 dence shows that they were the starting-point of animal life in time, and 
 their agency in rock making has not been exceeded by later higher and 
 more visible forms. 
 
 With the marine kind, known as foraminifera, we have been longest 
 familiar. The beautiful many-chambered shells of these for the most 
 part just visible to the naked eye form a large portion of the ocean- 
 iniid and the sands of the ocean-shore. Shells of foraminifera likewise 
 form the basis of miles of strata of limestone, such as the chalk of England 
 and the limestones of which Paris and the pyramids of Egypt are built. 
 
 Fresh-water rhizopods, though not so abundant as marine forms are 
 nevertheless very numerous. They mainly inhabit our lakes, ponds, and 
 standing waters, but they also swarm in sphagnous swamps and ever 
 live in newest earth. Professor Leidy has devoted several years of 
 study to the fresh-water rhizopods of the eastern portion of our country 
 aud his especial object in the past expedition was to investigate those 
 which are to be found in the elevated regions of the Rocky Mountains 
 
GEOLOGICAL SURVEY OF THE TERRITORIES. 783 
 
 The botany of the Survey was represented the past season by the two 
 great masters of that department, Sir Joseph D. Hooker, director of the 
 Gardens of Kew, England, and president of the Royal Society of Lon- 
 don ; and Prof. Asa Gray, of Cambridge, Mass. Their examinations ex- 
 tended over a great portion of Colorado, Wyoming, Utah, Nevada, and 
 California. Their investigation into the alpine floras and tree vegeta- 
 tion of the Rocky Mountains and Sierra Nevada enabled them to give a 
 clear idea of the relations and influence of the climatic conditions on 
 both sides of the great mountain-ranges. 
 
 Sir Joseph Hooker, whose botanical researches embrace the greater 
 part of Europe ; the Indies, from the bay of Bengal across the Hima- 
 laya's to Thibet; the Antarctic regions and the southern part of South 
 America, New Zealand, Australia, South Africa, Morocco and Asia 
 Minor, presents in the English periodical "Nature" for October 25 an 
 outline of his studies during the season, and this outline when tilled out 
 wi'lform a most important report for the eleventh annual Report of the 
 Survey. It will be seen at a glance that the report will be of the most 
 comprehensive character, and cannot fail to be of the highest interest 
 to our people. The tree vegetation, and especially the conifer&e, were 
 made special objects of study, and many obscure points were cleared up. 
 
 Ufa section of the Rocky Mountains comprising Colorado, Wyoming, 
 and Utah, Dr. Hooker says: 
 
 Such a section of the Rocky Mountains must hence contain representatives of three 
 very distinct American floras, each characteristic of immense areas of the continent. 
 There are two temperate arid two cold or mountain floras, viz: (1) a prairie flora 
 derived from the eastward; (2) a so-called desert and saline flora derived from the 
 west; (3) a snbalpine ; and (4) an alpine flora; the two latter of widely different origin, 
 and in one sense proper to the Rocky Mountain ranges. 
 
 The principal American regions with which the comparison will have first to be in- 
 stituted are four. Two of these are in a broad sense humid ; one, that of the Atlantic 
 coast, and which extends thence west to the Mississippi River, including tbe forested 
 shores of that river's western affluents ; the other, that of the Pacific side, from the 
 Sierra Nevada to the western ocean ; and two inland, that of toe northern part of the 
 continent extending to the Polar regions, and that of the southern part extending 
 through New Mexico to the Cordillera of Mexico proper. 
 
 The first and second (Atlantic plus Mississippi and the Pacific) regions are traversed 
 by meridional chains of mountains approximately parallel to the Rocky Mountains, 
 namely, on the Atlantic side by the various systems often included under ti>e general 
 term appalachian, which extend from Maine to Georgia, and on the Pacific side by the 
 Sierra Nevada, which bound California on the east. The third and fourth of tbe 
 regions present a continuation of the Rocky Mountains of Colorado and Utah, flanked 
 for a certain distance by an eastern prairie flora extending from the British Possessions 
 to Texas, and a western desert or saline flora, extending from the Snake River to Ari- 
 zona and Mexico. Thus the Colorado and Utah floras might be expected to contain. 
 representatives of all the various vegetations of North America, except the small trop- 
 ical region of Florida, which is confined to the extreme southeast of the continent. 
 
 The nxost singular botanical feature of North America is unquestionably the marked 
 contrast between its two humid floras, namely, those of the Atlantic plus Mississippi, 
 and the Pacific one; this has been ably illustrated and discussed by Dr. Gray in various 
 communications to che American Academy of Sciences, and elsewhere, and he has further 
 largely traced the peculiarities of each to their source, thus laying the foundations for 
 all future researches into the botanical geography of North America ; but the relations 
 of the dry intermediate region either to these or to the floras of other countries had not 
 been similarly treated, and this we hope that we have now materials for discussing. 
 
 Dr. Hooker sums up the results of the joint investigations of Dr. Gray 
 and himself, aided by Dr. Gray's previously intimate knowledge of the 
 elements of the American flora, from the Mississippi to the Pacific coast : 
 
 That the vegetation of the middle latitudes of the continent resolves itself into three 
 principal meridional floras, incomparably more diverse than those presented by any 
 similar meridians in the Old World, being, in fact, as far as the trees, shrubs, and many 
 genera of herbaceous plants are concerned, absolutely distinct. These are the two 
 humid and the dry intermediate regions above indicated. 
 
784 REPORT OF THE SECRETARY OF THE INTERIOR, 
 
 li of these, again, is subdivisible into three, as follows: 
 
 1. Tin- Atlantic slope ]lns Mississippi region, subdivisible into (a) an Atlantic, (,J) 
 a Mississippi Valley, and (;) an interposed mountain region with a temperate and sub- 
 alpiiM- lloia. 
 
 J. 'I !: Pacific slope, subdivisible into (a) a very humid, cool, forest-clad coast range; 
 . .ir. hot. <lr er Californian valley formed by the San Juan River flowing to 
 Tin- north and the Sacramento River flowing to the south, both into the Bay of San 
 rran.-isro: and (v) thr Sierra Nevada flora, temperate, subalpine, and alpine. 
 
 ::. The Rocky Mountain region, (in its wildest sense extending from the Mississippi 
 beyond its forest, region to the Sierra Nevada,) subdivisible into (a) a prairie flora, 
 , desert or saline flora, (y) a Rocky Mountain proper flora, temperate, subalpine, 
 and alpine. 
 
 Aft above^tnted. the difference between the floras of the first and second of these re- 
 gii ns is .sp.-i'ilirally, and to a great extent geuerically, absolute; not a pine or oak, 
 maple, elm, plane "or birch of Eastern America extends to Western, and genera of 
 thirty 10 iifry species are confined to each. The Rocky Mountain region again, though 
 abundantly distinct from both, has a few elements of theeastern region and still more 
 of the western. 
 
 Many interesting facts connected with the origin and distribution of American plants, 
 and the introduction of various types into the three regions, presented themselves to 
 our observation or our minds during our wanderings. Many of these are suggestive of 
 comparative study with the admirable results of Heer's and Lesquereux's investiga- 
 tions into the Pliocene and Miocene plants of the north temperate and frigid zones, 
 arid which had already engaged Dr. Gray's attention, as may be found in his various 
 publications. No less interesting are the traces of the influence of a glacial and a 
 warmer period in directing the course of migration of Arctic forms Kouthward, and 
 Mexican forms northward in the continent, and of the effects of the great body of 
 water that occupied the whole saline region during (as it would appear) a glacial 
 period. 
 
 Lastly, curious information was obtained respecting the a<res of not only the big 
 trei s of California, but of equally aged pines and junipers, which are proofs of that 
 duration of existing conditions of climate for which evidence has hitherto been sought 
 raiher among fossil than among living organisms. 
 
 Up to the year 1874 rumor had been telling many marvelous stories 
 of strange and interesting habitations of a forgotten people, who once 
 occupied the country about the headwaters of the Kio San Juan, but 
 these narrations were so interwoven with romance that but few people 
 placed much reliance upon them. To those well versed in archaeology, 
 ruins of an extensive and interesting character were known to exist 
 throughout New Mexico and Arizona, and the various reports of Abert, 
 Johnson, Sit greaves, Simpson, Whipple, Newberry, and others form our 
 most- interesting chapter in ancient American history; but their re- 
 st-arches, aside from the meager accounts published by .New berry, throw- 
 no light on the marvelous cliff dwellings and towns north of the San 
 Juan. In 187-1 the photographic division of the United States Geological 
 Survey was instructed, in connection with its regular work, to visit and 
 report upon these ruins, and in pursuance of tLis object made a hasty 
 tour of the region about the Mesa Verde and the toierra el Late, in 
 Southwestern Colorado, the results of which trip, as expressed by Ban- 
 croft, in the Native Eaces of the -Pacific Coast, "although made known, 
 to the world only through a three or four days 7 exploration by a party 
 of three men, are of the greatest importance.'' A report was made and 
 published, with fourteen illustrations, in the Bulletin of the United 
 States Geological and Geographical Survey of the Territories, second 
 series, No. 1. 
 
 The following year the same region was visited by Mr. W. H Holmes, 
 one of the geologists of the Survey, and a careful investigation made of 
 all the i uins. Mr. Jackson, who had made the report the previous year, 
 also revisited this locality, but extended his explorations down the San 
 Jaail to the mouth of the De Chelly, and thence to the Moqui villages 
 in Northeastern Arizona. Returning, the country between the Sierra 
 Abajo and La Sal and the La Plata was tiaversed, and an immense nuin- 
 
GEOLOGICAL SURVEY OF THE TERRITORIES. 785 
 
 ber of very interesting ruins were first brought to the attention of the 
 outside world by the report which was published the following winter 
 by Messrs. Holmes and Jackson, in the Bulletin of the Survey, Vol. II, 
 No. 1. 
 
 The occasion of the centennial exhibition at Philadelphia led to the 
 idea of preparing models of these ruins for the clearer illustration of 
 their peculiarities, four of which were completed in season for the open- 
 ing of the exhibition. Since that time not only the number of these 
 interesting models has been increased, but they have been perfected in 
 execution and faithful delineation of these mysterious remains of an 
 extinct race who once lived within the borders of our western domain. 
 
 A visit to the rooms of Mr. Jackson, photographer of the Survey, 
 enables one to inspect in miniature size the dwellings of the Moqui, and 
 in full size a large collection of the ceramics and implements of those 
 ancient and extinct people of our continent. A study of the models will 
 give a very excellent idea of the ruined dwellings themselves. The first 
 of these models, executed by Mr. Holmes, with whom the idea originated, 
 represents the cliff house of the Mancos Gallon, the exterior dimensions 
 of which are 28 inches in breadth by 40 inches in height, and on a scale 
 of 1.24, or two feet to the inch. This is a two-story building, constructed 
 of stone, occupying a narrow ledge in the vertical face of the bluff 700 
 feet above the valley, and 200 feet from the top. It is 24 feet in length 
 and 14 feet in depth, and divided into four rooms on the ground-floor. 
 The beams supporting the second floor are all destroyed. The doorways, 
 serving also as windows, were quite small, only one small aperture in the 
 outer wall facing the valley. The exposed walls were lightly plastered 
 over with clay, and so closely resembled the general surface of the bluff 
 that it becomes exceedingly difficult to distinguish them at a little dis- 
 tance from their surroundings. 
 
 The second model of this series was constructed by Mr. Jackson, and 
 represents the large "cave town," in the valley of the Kio de Chelly 
 near its junction with the San Juan. This town is located upon a nar- 
 row bench, occurring about 80 feet above the base of a perpendicular 
 bluff some 300 feet in height. It is 545 feet in length, about 40 feet at 
 its greatest depth, and shows about 75 apartments on its ground-plan. 
 The left-hand third of the town, as we face it, is overhung some distance 
 by the bluff, protecting the buildings beneath much more perfectly than 
 the others. This is the portion represented by the model. A three- 
 story tower forms the central feature; upon either side are rows of 
 lesser buildings, built one above another upon the sloping floor of rock. 
 Nearly all these buildings are in a fair state of preservation. This model 
 is 37 by 47 inches, outside measurements, and the scale 1.72, or 6 feet to 
 the inch. A "restoration" of the above forms the third in the series, of 
 the seme s.ize and scale, and is intended, as its name implies, to repre- 
 sent as nearly as possible the original condition of the ruin. In this we 
 see that the approaches were made by ladders and steps hewn in the 
 rock, and that the roofs of one tier of rooms served as a terrace for those 
 back of them, showing a similarity, at least, in their construction to the 
 works of the Pueblos in New Mexico and Arizona. Scattered about 
 over the buildings are miniature representations of the people at their 
 various occupations, with pottery and other domestic utensils. 
 
 The u triple- walled tower,' 7 at the head of the McElmo, is the subject 
 of the fourth model. It was constructed by Mr. Holmes, and represents, 
 as indicated by its title, a triple-walled tower, situated in the midst of 
 a considerable extent of lesser ruins, probably of dwellings, occupying 
 
786 REPORT OF THE SECRETARY OF THE INTERIOR. 
 
 a low bench bordering the dry wash of the McElmo. The tower is 42 
 feet in diameter, the wall 2 feet thick, and now standing some 12 feet 
 hi>h. The two outer walls inclose a space of about li feet in width, 
 which is divided into 14 equally-sized rooms, communicating with one 
 another by smal window-like doorways. The next is a "cliff-house" m 
 the valley of the Kio <!e Chelly. It is about 20 miles above the cave 
 town Mhv'ady spoken of. This is a two-story house, about 20 feet square, 
 occupying a' ledge some 75 feet above the valley, and overhung by the 
 bluff. * The approach from the valley is by a series of steps hewn m the 
 steep luce of the rock; and this method was the one most used by 
 the occupants, although there is .- way out to the top of the bluff. 
 '1 his model is 42 inches in height by 24 broad, and is built upon a scale 
 of 1 .30. 
 
 Te*wa, one of the seven Moqui towns in Northeastern Arizona, is a 
 very interesting and instructive model, representing, as it does, one of 
 the' most ancient and best authenticated of the dwellings of a people 
 who Hie supposed to be the descendants of the cliff dwellers. Tewa is 
 the first of The seven villages forming the province as we approach 
 them Irom the east, and occupies the summit of a narrow mesa some 
 COO feet in height and 1,200 yards in length, upon which are also two 
 other somewhat similar villages. The approach is by a circuitous road- 
 way hewn in the perpendicular face of the bluff, which surrounds the 
 mesa upon all sides. Jt is the only approach accessible for animals to 
 the three villages. Other ladder-like stairways are cut in the rock, 
 which are used principally by the water carriers, for all their springs 
 and reservoirs are at the bottom of the mesn. This village is represented 
 upon a scale of 1 inch to 8 feet, or 1.96. The dimensions of the model 
 are ,'50 inches in length, 29 inches in width, and 14 inches in height. 
 
 Jn the spring of 1877, Mr. Jackson made a tour over much of the 
 northern part of New Mexico, and westward to the Moqui towns in 
 Arizona, mid secured materials for a number of very interesting models, 
 illustrating the methods of the Pueblos or town-builders in the con- 
 struction of their dwellings. Two villages have been selected for imme- 
 diate construction, as showing the most ancient and best known exam- 
 ples of their peculiar architecture, viz, Taos and Acoma ; the one of 
 many-storied, terraced houses, and the other built high up on an impregna- 
 ble rock. The model of Taos is now completed, the dimensions of which 
 are 42 by 39 inches, and the scale one inch to twenty feet, 1 : 240. 
 
 Of this town Davis says: 
 
 It is the best, sample of the ancient mode of building. Here are two large houses 
 lint e or four hundred feet in length, and about one hundred and fifty feet wide at the 
 b;ise. They are situated upon opposite sides of a small creek, and in ancient times 
 juv said to have been connected with a bridge. They are five and six stories high, 
 each story receding from tbeoi.e below it, and thus forming a structure terraced from 
 t<>p to bottom. Each story isdivided into numerous little compartments, the outer tier 
 of rooms being lighted by small windows in the sides, while those in the interior of the 
 bnihl ing are dark, and are principally used as storerooms. * * * The only means 
 of entrance is tlnough a trap-door in the roof, and you ascend from story to story by 
 means of ladders ou the outside, which are drawn up at night. 
 
 Their contact with Europeans has modified somewhat their ancient 
 style of buildings, principally in substituting doorways in the walls of 
 iheir houses for those in the roof. Their modern buildings are rarely 
 over two stories in height, and are not distinguishable from those of 
 their Mexican neighbors. The village is surrounded by an adobe wall, 
 which is first included within the limits of the modelj and incloses an 
 area of eleven or twelve acres in extent. Within this limit are four of 
 their estufas, or secret council-houses. These are circular underground 
 
GEOLOGICAL SURVEY OF THE TERRITORIES. 787 
 
 apartments, with a narrow opening in the roof, surrounded by a pali- 
 sade, ladders being used to go in and out. 
 
 These models are first carefully built up in clay, in which material all 
 the detail is readily secured, and are then cast in plaster, a mold being 
 secured by which they are readily multiplied to any extent. They are 
 then put in the hands of the artists and carefully colored in solid oil 
 paints to accurately resemble their appearance in nature, and, in the 
 case of restorations or modern buildings, all the little additions are made 
 which will give them the appearance of occupation. The survey is in 
 possession of the data for the construction of many more models, and 
 they will be brought out as opportunity is given. They have also, in 
 connection with the views, multiplied many of the curious pieces of pot- 
 tery which have been brought back from that region by the various 
 parties connected with the survey. 
 
 During the season of 1877 it was found impracticable to place a sepa- 
 rate party in the field for zoological work, as Dr. Elliott Coues, the 
 naturalist of the Survey, was fully occupied during the summer at the 
 Washington office in the care of the numerous publications of the Sur- 
 vey which have appeared during the present year. 
 Very respectfully, your obedient servant, 
 
 Y. V. HAYDEN, 
 
 United States Geologist. 
 Hon. CARL SCHUKZ, 
 
 ^'Secretary of the Interior, Washington, D. C. 
 
PRELIMINARY REPORT 
 
 OF THE 
 
 FIELD WORK OF THE UNITED STATES GEOLOGICAL AND GEO- 
 GRAPHICAL SURVEY OF THE TERRITORIES FOR THE SEASON 
 
 OF 1878. 
 
 BvF. V. HAYDEX. 
 
 OFFICE GEOLOGICAL AND GEOGRAPHICAL 
 
 SURVEY OF THE TERRITORIES, 
 
 Washington, I). C., December 1, 1878. 
 
 SIR : I have the honor to present for your consideration a brief sum- 
 mary of the field work of the United States Geological and Geographical 
 Survey under my charge, for the season of 1878. 
 
 Owing to the length of the session, Congress did not pass the usual 
 appropriation for the work of the survey until July, and consequently 
 the field labor was of comparatively short duration. " 
 
 The headquarters of the survey was at Cheyenne, Wyo., the same as 
 the preceding season. Four parties were organized, butni such a manner 
 that in case of necessity they could be divided for special duty. All our 
 outfit and animals Avere transported from Cheyenne to Point of Rocks 
 and Green River Stations, on the Union Pacific Railroad, and from thence 
 the parties pursued their way northward to their respective fields of 
 labor. 
 
 To the first division, in .charge of A. D. Wilson, was confided the pri- 
 mary triangulatioii of the entire area to be surveyed. Eight of the 
 most important peaks were employed as stations, with some minor 
 points. Among the more important stations were Wind River, Fre- 
 mont's, Gxand Teton, and SawteUe ? s Peaks (near Henry's Lake); 
 also several of the most conspicuous points in the Yellowstone Park. 
 This division was robbed, near Sawtelle's Peak, of all its animals and a 
 portion of its outfit, so that at least half of the most valuable time for 
 work during the season, was lost. Had it not been for this misfortune 
 at least double the work would have been accomplished. The Yellow- 
 stone Park at this time forms the most extensive unoccupied area in the 
 West, and, surrounded by great ranges of mountains, becomes a resor 
 for hostile bands of Indians when pursued by the troops. 
 
 To the division of the survey in charge of Mr. Henry Gannett was in- 
 trusted the work of making a specially-detailed geological and geograph- 
 ical survey of the Yellowstone National Park. The party was divided 
 into two sections for the prosecution of this work ; one section, consist- 
 ing essentially of Mr. Gannett, topographer, and Mr. W. H. Holmes, 
 geologist, made the general survey of the park, while the other, consist- 
 ing of Dr. A. C. Peale and Mr. J. E. Mushbach, were occupied in mak- 
 ing detailed studies and maps of the geyser and hot-spring localities, a 
 work of the greatest interest and value to the scientific world. 
 
 Material was secured for a detailed map, on a scale of one mile to an 
 inch, of the Yellowstone Park, an area of 3,500 square miles ; and for 
 maps on a large scale of all the principal geyser and hot-spring locali- 
 
952 REPORT OF THE SECRETARY OF THE INTERIOR. 
 
 tics. In the survey of the park, forty-seven important stations were 
 oreupied tor secondary triangtdation and topography, besides a large 
 numU'i -oriesser importance; On all the principal stations, stone monu- 
 ments were erected tor future reference. Several groups ot geysers and 
 hoi >piin-s. not heretofore known, were discovered. 
 
 Tin- area of the Yellowstone Park is, in round numbers, 3,aOO square 
 miles. Its surface is in large part level or rolling, with several groups 
 and short ranges of mountains diversifying it. In the eastern part, 
 extending its whole length and forming the Avater-shed between the 
 Yellowstone and the Bighorn, stand the rugged volcanic peaks of the 
 Yellowstone Raime. Nearly all of the park is covered with a dense 
 month of magnificent pine timber; indeed, west of the one hundredth 
 meridian there is no area so densely timbered with the exception of Wash- 
 ington Territory. The mean elevation of the park above sea-level is be- 
 tween 7,000 and 8,000 feet, which implies too cold a climate to admit of 
 agriculture, except in certain very limited localities. It is safe to say 
 that not more than one per cent, of this area can, by any possibility, be 
 used for agricultural purposes. Except along the northern border, 
 grazing land exists only in small patches of a lew acres each. There 
 are not, so far as is known, any mines or mineral deposits within the 
 park. 
 
 The only occupied buildings within the park are at the White Mount- 
 ain Hot Springs, where Mr. J. C. McCartney has made some improve- 
 ments. A good wagon-road extends from Bozeniau, Mont., to this point. 
 From these spring*; which form the usual point of departure for excur- 
 sionists, there are excellent trails to all points of interest within this 
 region ; to Amethyst Mountain, Yellowstone Falls and Lake, the Mud 
 (leysers, and other objects of interest on Yellowstone Eiver and the 
 Geyser Basins. It is unnecessary to specify these trails, as they traverse 
 the country in all directions. In his campaign against the Nez Perees, 
 in 1S77, General Howard constructed an excellent wagon-road up the 
 Madison to the Lower Geyser Basin, and thence across to the Yellow- 
 stone. His road up the YelloAvstone is impassable at present for wagons. 
 
 Mr. W. H. Holmes acted as geologist to the second division. The 
 first month of the season he was wiih the fourth division, which pro- 
 ceeded from Point of Rocks Station northward, along the west side of 
 the Wind Eiver Mountains, and up the Snake Eiver Valley to the Yel- 
 lowstone Park, where he joined the second division. In the mean time 
 he was engaged in making sketches, panoramic views, and geological 
 sections of the intermediate country, all of which will prove of the 
 highest importance in illustrating the geological structure of this most 
 interesting and complicated region. 
 
 The latter part of the summer was spent in making detailed geological 
 examinations in the district that includes the National Park. The greater 
 portion of the park was found to be covered with somewhat uniform 
 flows of the ordinary volcanic rocks. Features of more than ordinary 
 geologic interest occur, however, along the northern border of the park 
 district. Here a small belt, not more than 15 by 30 miles in extent, con- 
 tains a fair epitome of the geology of the Eocky Mountain region. The 
 whole series of formations from the earliest to the most recent are almost 
 typically developed. The only marked irregularity in the succession of 
 geologic events occurred during the great mountain-building period of 
 t he M iddle Tertiary. After that followed a number of inferior oscillations 
 of the sin-face, during which an extensive series of recent Tertiary and 
 volcanic rocks were deposited. Connecting this period with the present 
 are the deposits of a number of great lakes, which at the present time 
 
GEOLOGICAL SURVEY OF THE TERRITORIES. 953 
 
 have their chief representative in Yellowstone Lake. Detailed investi- 
 gations were made at many points of interest, and a fine mineralogical 
 collection was made. 
 
 In the mean time Mr. Holmes sketched every square mile of the park, 
 an area of 3,500 square miles. In such minute detail was the work done 
 that the economic resources, as well as all the minor features of the geol- 
 ogy, can be laid down on a map on a scale of one mile to an inch Avith 
 the greatest care and minuteness. The great variety of forms which 
 the mountains in and around the park assume can be presented to the 
 eye by panoramic views with wonderful distinctness. 
 
 The third division, under Mr. E. A. Clark, surveyed the Wind River 
 Mountains, a portion of the Wyoming Range, the Gros Ventres Range, 
 with a large area in the Snake River Valley. Mr. Clark made 31 gradi- 
 enter stations and 15 compass stations. The area lies between latitude 
 43 and 44 and longitude 109 15' and 111. This includes the upper 
 portion of the Wind River Mountains, Avith portions of the Wyoming 
 n ling Range, the Gros Ventres Range, and portions of the Shoshone 
 Mountains and the Owl Creek Range ; also the sources of Green River, 
 Hoback Basin, and upper Avaters of Wind River. Mr. St. John acted as 
 geologist and Mr. N. W. Perry as mineralogist to this party. Their 
 reports w r ill prove of general interest. Mines of gold, silver, iron, and 
 vast beds of gypsum, as Avell as many other minerals, Avere found. 
 
 In the prosecution of the field- work of the survey during the past 
 season a photographic division was again put in operation, after an 
 interval of two years, under the leadership of Mr. W. II. Jackson, who 
 has been connected with the survey as its photographer during the past 
 nine years. 
 
 Leaving Point of Rocks, on the Union Pacific Railroad, on July 24, 
 the first points of interest Avere reached on the western flank of the 
 Wind RiA T er Mountains. Two side trips, undertaken in connection with 
 Mr. Wilson, in charge of the primary triangulation, AA~ere made to the 
 crest of the range, and some grand views of that remarkable region 
 were obtained. From the summit of Fremont's Peak A r ieAA r s Avere made 
 of an immense glacier IIOAV occupying its eastern slope. Fine views 
 were also obtained of the great glaciated plateau lying between the 
 plains and the crest of the range. 
 
 Proceeding next to the vicinity of the Grand Tetons, lying to the east 
 of the headAvaters of the Snake RiA^er, seA 7 eral magnificent AdeAvs of the 
 remarkable range in Avhich they occur AA r ere made from the neighborhood 
 of Jackson's Lake. 
 
 Reaching Shoshone Lake the 18th of August, the entire month folloAV- 
 ing AA r as deA r oted exclusively to the careful photography of all the remark- 
 able phenomena connected Avith the hot springs and geysers of the various 
 basins Avithiii the Park. Especial attention was paid to the almost un- 
 known but exceedingly interesting features of the new Shoshoue and 
 Red Mountain Basins. The u Fire Hole" and ''Mammoth Hot Spring" 
 Basins Avere again gone over, and the experience derived from the work 
 done here in former years shoAvs its benefits in the remarkably eifectiA r e 
 A T iews obtained this season. At this latter basin many detailed as Aveli 
 as general A T ieAvs were ma"de with especial reference to the future pro- 
 duction of an exact model in plaster of the whole group. 
 
 On the homeward route, AA'hich was by the way of the Upper Yellow- 
 stone, across the headwaters of the Snake to the Wind River and thence 
 A'ia Camp Brown to the railroad, a number of A 7 ery effective views were 
 made, particularly about the Grand Falls and the canon of the Yellow- 
 stone. At the Yellowstone Lake some very fine vieAvs Avere made, but 
 
954 REPORT OF THE SECRETARY OF THE INTERIOR. 
 
 that region was left somewhat incomplete in consequence of a prolonged 
 snow-storm. , , . ^ ,.,, 
 
 As the To-wotee Pass some characteristic views were obtained ot tne 
 remarkable breccia mountains, whose castellated forms adorn that por- 
 tion ofthe continental divide, and also some of the curious bad lands 
 ini t her down on Wind River. The season's work closed at Camp Brown, 
 ^ here some excellent portraits and groups were made of the Bannock 
 prisoners in confinement at that post. 
 
 V brief summing up of the season's operations of three months, much 
 Of which time was characterized by extremely inclement weather, shows 
 an increase to the already very extensive collection of the survey, ot 4o 
 negatives 11 by 14 inches in size, and 110 of smaller ones, 5 by 8. The 
 number was purposely kept small that a better quality might prevail 111 
 
 The geologist in charge accompanied the photographic division, and 
 the route pursued gave him an opportunity to secure a very accurate 
 general knowledge of the geological structure of a large area. The 
 Wind River Range proved one of remarkable interest. It has a trend 
 about northwest and southeast, with a length of about 100 miles. On 
 the west side all the sedimentary belts have been swept away, down to 
 the Arcluean, older than the Wahsatch, and the latter formation rests on 
 the Archaean rocks all along the base of the range, seldom inclining more 
 than 5 to 10. On the east side of the range the seams of sedimentary 
 formations usually known to occur in the northwest are exposed from 
 the Potsdam sandstone, which rests upon the Archsean rocks, to the Cre- 
 taceous inclusive. 
 
 Along the northwestern portion of the range the Wahsatch Group only 
 is seen for some distance, but as we proceed down the Wind River 
 Valley the formations appear one after the other, until at the lower end 
 the entire series is exposed. The Wind River Range may be regarded 
 as originally a vast anticlinal, of which one side has been entirely 
 denuded of the sedimentary, except the Middle Tertiary. On the same 
 side of the range the moraiiial deposits and glaciated rocks are shown 
 on a scale such as we have not known in any other portion of the West. 
 Three genuine glaciers were discovered on the east base of Wind River 
 and Fremont Peaks, the first known to exist east of the Pacific coast. 
 
 The moraiiial deposits are also found on a grand scale in the Snake 
 River Valley, on the east side of the Teton Range. The numerous lakes 
 have been the beds of glaciers, and the shores of the lakes are walled 
 with morainal ridges. ^North of the Teton Mountains the prevailing 
 rocks are of modern volcanic origin, and in the Yellowstone Park the, 
 hot springs and geysers are the later manifestations of the intense vol- 
 canic activity that once existed. All these interesting features were 
 studied with care, and the results Avill be elaborated for the twelfth an- 
 nual report of the survey. 
 
 1 1 was with great pleasure that the geologist in charge reviewed the 
 ground passed over in I860, over eighteen years previously. In the 
 years is.V.J and 1860 he acted as geologist to the exploring expedition 
 under the command of Col. William F. Raynolds, now of the Engineer 
 ( 'orps, IT. S. A. A portion of the geological "report made on that expe- 
 dition will be reprinted in the llth annual report.* A geological map 
 accompanies this report, which embraces Dakota and Montana, with 
 portions of Idaho, Wyoming, and Colorado. 
 
 <; ( -olooi(. a l Report of the Exploration of the Yellowstone and Missouri Rivers, 
 under tin- direction of dipt, (now Lieut. Col. and Brevet Bri" 1 . Gen ) W F Ravnolds 
 Corps of Engineers, 1859-1860. By F. V. Hayden. 
 
GEOLOGICAL SURVEY OF THE TERRITORIES. 955 
 
 The publications of the survey during the past year have been numer- 
 ous and important. The atlas of Colorado, in twenty sheets, has received 
 the most unqualified praise for its accuracy and beauty, both in this 
 country and in Europe. The following analysis of the atlas was written 
 for the London periodical "Nature," of September 12, by Prof. Archi- 
 bald Geikie, director of the geological survey of Scotland and professor 
 of geology in the University of Edinburgh, and one of the ablest geol- 
 ogists in Europe : 
 
 In the magnificent atlas just issued by the Department of the Interior we have the 
 consummation and crown of all the labors which Dr. Haydeii and his staff have carried 
 on so triumphantly for the last five years, and of which they have already given us so 
 much interesting and important information in a series of annual reports. Before ex- 
 amining the work from a scientific point of view, no reader can refrain from expressing 
 his admiration of the style in which the atlas has been produced by the United States 
 Government. As a specimen of cartography, typography, and lithography it is alto- 
 gether worthy of the highest praise. For beauty and, indeed, sumptuousness of exe- 
 cution, it may be classed with those livres tie luxe which from time to time have been 
 issued from the National Imprimerie of France. 
 
 The atlas consists of two series of maps, the one of a general, the other of a detailed 
 kind. The first series, on the scale of twelve miles to one inch, comprises four sheets, 
 each embracing the whole State of Colorado and part of the neighboring territory. 
 The first of these illustrates the system of triaiigulation adopted in the survey ; the 
 second shows the drainage system of the area ; the third, by a simple and clear arrange- 
 ment of colors, exhibits at a glance the economic features of the whole region the ag- 
 ricultural land, pasturage, forests and woodlands, sage and bad lands, mineral tracts, 
 and the portions rising above the limit of timber-growth; the fourth contains a con- 
 densed and generalized geological map of the same territory. Nothing can surpass the 
 lucidity of expression and artistic finish of these maps. 
 
 The second series twelve in number is on the scale of four miles to one inch, and 
 consists of six topographical sheets and six identical sheets, colored geologically. The, 
 topographical details, though numerous, are so selected as not to neutralize each other 
 or mar the broad, clear picture which the maps were designed to be. By means of 
 contour-lines of %00 feet vertical distance, the surface-configuration of the whole region 
 is depicted as in a model. We can follow the lines of the broad valleys, of the deep, 
 narrow canons, and of the hundreds of minor tributaries which have scarped out their 
 courses on either side. Here we look down upon a vast table-land, deeply trenched by 
 stream-channels; there upon a succession of bold escarpments or mesas, which bound 
 the table-laud and hem in the neighboring valley. Huge mountain-ranges rising out 
 of the plateaus are so vividly drawn that they seem to stand out of the paper; yet 
 no shading is employed. All the effects of inequality are produced by contour lines, 
 so faithfully set down that a single line may be tracked in its sinuous course along the 
 whole of a mountain front until it comes out upon the table-land beyond. When will 
 our map-makers learn to use this, the only true method for expressing the surface of a 
 country ? The best of our atlases are disfigured by strips of shading running across the 
 map, like so many caterpillars, to represent mountain ranges. Even our ordnance 
 maps, so admirable in most respects, are sometimes so loaded with shading that a steep 
 hillside, only a few hundred feet high, is made as black as our highest mountains, and 
 the topographical names can hardly be read, even with a magnify ing-glass. 
 
 But, above all, welcome are these six geological maps. In the previously published 
 maps and charts accompanying the annual reports only small detached areas were 
 represented, and even from the careful descriptions of the various geologists of the 
 staff, it was hardly possible to frame a satisfactory conception of the geology of Col- 
 orado as a whole. Ever since the marvels of its deep gorges and vividly painted cliffs 
 were made known, that region has possessed a high interest to the geologist. He has 
 now the means of gratifying his desire for further knowledge. With the help of these 
 maps and the two accompanying sheets of sections, he can realize most satisfactorily 
 every great feature of Colorado geology. The ancient Archaean ridge the nucleus or 
 backbone of the American Continent may be traced running north and south nearly 
 along the present hydrographical axis of the country. Flanking that ridge comes a 
 series of Palsezoic deposits, the oldest of which have been identified paheontologically 
 with Silurian formations. Rocks regarded as of Devonian age overlap the Silurian 
 beds, and repose against the ancient crystalline ridge on the southwest side of the 
 San Juan Mountains. They are soon buried under later accumulations, and they 
 seem to be of but local development, since in most places where the rocks are found 
 in juxtaposition, the Silurian are directly succeeded by Carboniferous strata. These 
 last-named rocks cover largo tracts of country, running as bands round the Archaean 
 area, and lying in basins across it. Far to the west, where the Grand River has so 
 deeply trenched the Utah plateau, the flat Carboniferous beds appear from under the 
 
956 REPORT OF THE SECRETARY OF THE INTERIOR. 
 
 brilliant iv. 1 Triassir strata. The difficulty of drawing any line between Triassic and 
 Jurassic formations in thai region is again acknowledged on these maps, the lower 
 ivd aeriea l.eiug doubtfully assigned to the older, and the upper variegated deposits to 
 the latter system. 
 
 CreUoeous rocks arc abundantly developed, and cover a vast extent of territory. 
 In particular, they spread over tlie wide plateaux between the San Juan and Guimison 
 Ki\eis. and form 'the platform on which the enormous volcanic outbursts have been 
 piled up from the West Elk Mountains southward into New Mexico. It is more easy 
 t.. n.iee on these maps, too, the area respectively occupied by the Laraniie, Wa- 
 sateh. (Jiveu River, I'.ridger, and T'intali formations which represent Post Cretaceous 
 and Tertiary times. Glacier moraines, lake deposits, drifts, sand-dunes, and recent 
 alluvia, all iind adequate expression on the maps. Especial care, too, seems to have 
 been bestowed upon the eruptive rocks which form so important and interesting a 
 feature of Colorado geology. The more characteristic varieties are represented by 
 distiuet shades of crimson or orange, and they have been mapped in such a way as to 
 eonvey at a glance, and even without the aid of sections, a tolerable clear notion of 
 the volcanic phenomena of the region. On the one hand we see the great lava-sheets 
 capping the mesas and spreading far over- the plateaux; on the other, we notice the 
 meat centres of volcanic activity, with their abundant flows, dikes, and breccias. 
 
 1 \\ o sheets of sections, drawn across all the more interesting and important portions 
 of the geology, complete the vast fund of information given by the maps; while, that 
 nothing may he wanting to enable readers to realize what has been done by the sur- 
 \ey. and the conditions under which it has been accomplished, two large sheets of 
 sketches are given, which most vividly represent the forms of the mountains, plateaux, 
 mesas, and river channels as seen from various commanding heights. 
 
 Dr. Hayden, with whose personal supervision this great work has been accomplished, 
 has increased tenfold the obligations under which he has laid geologists all over the 
 world for Ihe number and value of his contributions to geology. He now furnishes us 
 with new light whereby to read his former researches and those of his able colleagues. 
 M ay we venture to hope that he may find leisure to confer yet one further benefit before 
 t he progress of his survey plunges him into a new whirl of work ? If he could be pre- 
 vailed upon to sketch out a plan for digesting the materials of his published annual 
 reports, he could doubtless find among his staff some competent writer who, under his 
 guidance, could produce a well-arranged systematic guide-book or text-book to com- 
 plete the value of the work of his survey. Such a book of reference's would give a 
 leader who has never had access to the annual reports a clear and comprehensive view 
 of ( 'olorado geology would be of great service. 
 
 These remarks may be fitly closed with an expression of the warmest admiration of 
 the liberal spirit in which the United States Government has conducted these surveys 
 of the Territories and has published their results. This costly atlas has been distrib- 
 uted gratuitously all over Europe. That this is a wise policy cannot be doubted. 
 Whether actuated or not by a desire to diffuse scientific information, the authorities 
 at Washington do well to make as widely known as possible the geological structure 
 and economic resources of their country. They cast their bread upon the waters and 
 the harvest comes to them in the form of eager, active emigrants from all parts of 
 Europe, 
 
 Tin- Bulletin of the Survey Las now reached the close of the fourth 
 volume, which contains 37 articles and about 900 octavo pages. The 
 tenth annual report embraces 550 closely printed pages, octavo, with 80 
 pint cs, maps, sections, &c. About 50 of the plates illustrate the remark- 
 ;ihh' cliff-dwellings which were found by the members of the Survey along 
 tin- canons of the streams of Southern Colorado and New Mexico. 
 Volume IV, quarto, on the Miocene and Pliocene vertebrates of the 
 \\Vst, by E. D. Cope, and Volume XII, by Dr. Joseph Leidy, on the 
 IMii/opods, are far advanced, and will be ready for distribution in the 
 spring, The eleventh annual report is in press ; about 300 pages already 
 in type. This volume will be issued early in the spring. 
 
 Tlic members of the Survey are now all in the office from their field- 
 work, and busily engaged in elaborating their field-notes. The materials 
 for4he twelfth annual are very ample and of great interest. 
 Very respectfully, your obedient servant, 
 
 F. V. HAYDEN, 
 
 United States Geologist. 
 Hon. CARL SCIIURZ, 
 
 Secretary of the Interior. 
 
APPENDIX. 
 
 The following articles on the geology of the Rocky Mountain region were published 
 in the American Journal of Science, New Haven, Conn., several years ago, and are 
 now entirely out of print. Inasmuch as they contain some views that have either 
 been absorbed or overlooked by modern geologists, they are reprinted in this connec- 
 tion. There are some views that, if written at this time, might be restricted or modi- 
 fied, but in the main they are correct. The articles are reprinted \vithout any altera- 
 tion. 
 
 SOME REMARKS IN REGARD TO THE PERIOD OF ELEVATION OF 
 THOSE RANGES OF THE ROCKY MOUNTAINS NEAR THE SOURCES 
 OF THE MISSOURI RIVER AND ITS TRIBUTARIES. 
 
 BY DR. F. V. HAYDENV 
 
 [From the American Journal of Science, vol. xxxiii, May. 1862.] 
 
 The object of the present article is to show r , as nearly as can be done from known 
 geological data, the period of the elevation of a portion of the Rocky Mountains. My 
 observations have been more especially confined to the ranges from which the Missouri 
 and Yellowstone Rivers, with their numerous tributaries, take their rise, though I feel 
 confident that principles which will apply to mountains occupying so large an area, 
 will also be applicable to the whole Rocky Mountain district. It will be impossible, 
 at this time, to mention in detail all the facts in support of my statements, and there- 
 fore I shall assume that the reader has examined the previous papers of my associate, 
 Mr. Meek, and myself. During the coming year I hope to prepare a series of articles 
 for this journal which will have a more or less direct bearing on the physical geog- 
 raphy of this region and the influences which gave to it its present configuration. 
 Some erroneous statements, growing out of our limited knowledge of the structure of 
 these mountain chains, may be made, but these, when known, will be corrected. 
 (icology is a progressive science, and even our best eiforts are but approximations to 
 truth rather than the truth itself. 
 
 The evidence seems tome to be clear that the great subterranean forces that elevated 
 the western portion of our continent were called into operation toward the close of 
 the Cretaceous epoch, and that the gradual quiet rising continued, without a general 
 bursting of the earth's crust, until after the accumulation of the Tertiary lignite de- 
 posits, or at least the greater part of them ; also, that after the fracture of the surface, 
 commenced and those great crust movements began to display themselves, the whole, 
 country continued rising, or at least, though there may have been periods of subsidence 
 or repose, there was a general upward tendency, which has continued even up to our 
 present period. I hope hereafter to illustrate the correctness of these statements by 
 all the facts that have been obtained in my past explorations as well as by those I may 
 secure in the future. 
 
 Let us, in the first place, examine some of the barometrical profiles across the country 
 from the Mississippi River to the Pacific coast, constructed under the direction of the 
 War Department. Previously, however, to this examination we may make the state- 
 ment that west of longitude 98 the surface of the country may be separated into two 
 divisions, mountain and plain, and that a combination of the two compose the Rocky 
 
 * For most important information I would direct attention to second series of this 
 journal, articles xiii, xxxix, vol. iii, 1847, article xxxiv, vol. xii, 1849, and articles xxiv, 
 xxv, vol. xxii, 1856, by Prof. J. D. Dana, in which, it seems to me, Avill be found the, 
 most profound, far-reaching generalizations in regard to the physical geography and 
 geology of the West and other portions of our country which have ever been given to 
 the public. The origin and character of those subterranean forces which have pro- 
 duced such important results in the West are fully discussed in those papers. 
 
958 BEPORT OF THE SECRETARY OF THE INTERIOR. 
 
 M..,mt .'.in district. After leaving the Mississippi the intervening country westward to 
 tin- upheaved riders is an apparently level or undulating plain, with no disturbance 
 of the strata of the underlying formations until we come in close proximity to some 
 of the mountain elevations. Reaching the base of the elevated ridges which form the 
 mountain crests, we at ouee commence a rugged and abrupt ascent. 
 
 If we look at the profile constructed by Governor Stevens, from Saint Paul, Minn., 
 1-ititude 44 ">*' and longitude 92 58', to the Pacific coast, we shall find that the start- 
 in^ point is s->-' f.-et above the ocean-level. Near Fort Union, at the junction of the 
 Wfttcrs of the Yellowstone and Missouri, 670 miles westward, the height above the 
 ocean-level has increased to 2,010 feet, or 1,182 feet higher than Saint Paul. We thus 
 sec that the average ascent of the country between these two points is not quite two 
 Vert to the mile. From Fort Union to the valley of Dearborn River, just under the 
 base of the elevated ridges of the principal eastern range, we find the distance to be 
 44S miles and the height above the ocean 2,081 feet greater then that at Fort Union, 
 or the average rate (if ascent increased to nearly five feet per mile. Over this vast 
 extent of country extends an almost limitless prairie, apparently level, with no forests 
 or groves, with no timber except that which skirts the streams. There is in this great 
 distance a gradual increase in the inclination of the strata proportioned to the increase 
 of the ascent, but no marked disturbance of the beds until we arrive in close proximity 
 to the mountain elevations. There are a few local fractures of the earth's crust caused 
 by the elevation of the Bear's Paw, Little Rocky Mountain, &c., around which the sedi- 
 mentary rocks are more or less disturbed, but 'all these lesser mountains are more or 
 less remotely connected with the main chain. After passing the highest point of the 
 principal range, along this line, which is near Cadotte's Pass, we commence our descent 
 toward the Pacific very much as we ascended the eastern slope, but over a much more 
 rugged route. We find a continued series of more or less parallel ridges of elevation 
 ninTl we approach the coast for a distance of from 400 to 600 miles. From Fort Walla 
 Walla to the ocean, however, the average descent is a little less than one foot to the 
 mile. 
 
 Again, if we e'xamine the profile constructed by Fremont, commencing at the mouth 
 of the Kansas River, we find that the initial point is 690 feet above the ocean. Pro- 
 ceeding westward, the average grade for the first 300 miles is between 4 and 5 feet per 
 mile. Thence to Fort Laramie the ascent, as stated by Fremont, is 8 feet to the mile, 
 and from Fort Laramie to Hot Spring Gate, although still passing over prairie coun- 
 try, tint average grade of ascent is given by the same explorer as 45 feet per mile. 
 Over this entire route, however, loaded wagons have been transported with ease: 
 When we reach the foot of the mountains in this direction, the lofty elevated ridges 
 seem to rise abruptly out of the prairie, averaging from 1,000 to 6,000 feet in height 
 above the surrounding country. From thence to the Pacific coast we pass over a con- 
 t i n ued series of elevations which taken in the aggregate seem to trend nearly northwest 
 and southeast, but which, when examined in detail, often present no definite direction 
 or continuous line of fracture. This mountain region is composed of a series of these, 
 ridges forming a belt or zone 400 to 800 miles in width from east to west, interspersed 
 with beautiful valleys through which wind streams of clear water. So numerous are 
 the profiles which have now been made across the continent by different explorers 
 that it is hardly necessary to describe each one, since what we have already said in- 
 dicates the object in view. 
 
 \\V have said that the western portion of our continent, especially if we look only 
 ;it the easterly slope, may very properly be divided into mountain and prairie. It is 
 true that in Kansas and Iowa, groves of timber of considerable size are seen, but they 
 form rat her the exception than the rule. Along the eastern slope there is a belt of 
 country :'><><) to (500 miles in width, where, for the most part, the only timber to be seen 
 is a thin fringe bordering the streams. Even in the eastern portion of the main 
 range the timber is not luxuriant, like that so common along the coast of Oregon and 
 California. The pine trees are seldom more than 3 feet in diameter. 
 
 A-nin, we may divide the mountains or elevated ridges which form the different 
 ranges into two kinds, viz, those with long extended lines of fracture, with a granitic 
 nucleus and a comparatively regular outline, and those which appear to be composed 
 
 illust rat ions of t he second class. From all the information within our reach we have 
 inferred that alter passing the eastern slope the mountain ranges of eruptive origin 
 are far the most numerous. We also know from personal observation that the main 
 range of the Rocky Mountains and the subordinate ridges on either side near the 
 headwaters of the two principal branches, the Yellowstone and Missouri, are of sim- 
 ilar Origin and present similar rugged features. 
 We may now return to the Cretaceous period. In a previous paper in this journal, * 
 
 *Vol. xxxi, March, 1861. 
 
GEOLOGICAL SURVEY OF THE TERRITORIES. 959 
 
 we remarked that there were no indications in the geological formations of that por- 
 tion of the West over which we have traversed of long-continued deep-water deposits 
 mitil we pass up into the Cretaceous epoch. The lower portion of No. 1, or the Da- 
 kota Group, which ushered in the Cretaceous epoch in this portion of the West, is 
 composed of coarse sand, pebbles, &c., with ripple marks, oblique laminae, and with 
 other indications of shallow water and change of currents. The same characters are 
 seen throughout the formation wherever it is exhibited. We also know from the nu- 
 merous impressions of leaves, and some beds of impure lignite, that dry land could not 
 have been far distant. But as we pass up through Nos. 2, 3, and 4, whatever changes 
 of land may have occurred in the mean time, we think there were periods at least 
 when the sea was of considerable depth and suffered a quiet deposition to go on. We 
 infer this from the fine and homogeneous character of the sediments. Throughout 
 No. 4 we have a fine plastic clay which continues up into No. 5, when a gradual change 1 
 takes place from the introduction of yellowish ferruginous matter, and a slow increase 
 of sandy sediments. Toward the middle of No. 5 the sand begins to predominate 
 until the upper part becomes a coarse ferruginous sandstone, with all the indications 
 of shallow-water deposits. We know, also, from fragments of wood and impressions 
 of leaves which have been found quite widely distributed in the upper part of No. 5, 
 that dry land could not have been far away. We also infer from the character of the 
 molluscan remains that the great Cretaceous sea which had so long spread its vast wa- 
 ters over this region was becoming shallow, and that a new epoch was approaching. 
 As we arise in No. 4, and pass up into No. 5, there is an evident increase in the num- 
 ber of gasteropoda, indicating shoal waters. We have already remarked their peculiar 
 Tertiary aspect, which seemed to point directly to that epoch, showing that it was 
 not far distant. We may now ask the cause of this apparent approach to land, as 
 foreshadowed by the lithological as well as the paleontological characters of the Up- 
 per Cretaceous formation No. 5. We think that the facts indicate that during the 
 deposition of this formation the western portion of the continent was slowly rising 
 above the ocean level, the waters on the one side receding toward the Pacific, and on 
 the other toward the Atlantic, introducing the great Tertiary epoch which had already 
 been foretold in the Cretaceous. At the commencement of the Tertiary period, 
 throughout the central portions of the continent, lakes, estuaries, &c., more or less 
 salt, at length becoming brackish, and finally fresh water, existed, and a new flora 
 and fauna were introduced. The subterranean expansive power which was quietly 
 lifting up the country still continued, although no bursting of the earth's crust had 
 commenced. These brackish water-deposits, which appear to mark the dawn of the 
 Tertiary period in the West, are distributed quite widely over the central portions of 
 the Rocky Mountain district, and then, by a general subsidence or a vast increase of 
 fresh water, the true lignite deposits spread themselves over large areas and probably 
 covered much of the country now occupied by the mountain ranges, and were doubt- 
 less more or less intimately connected with the Tertiary beds on the Pacific coast. 
 What barriers separated them from the Tertiary formations along the Pacific it is im- 
 possible from our present limited knowledge of the geology of the intermediate region 
 to determine. 
 
 We have remarked that the probable period of the bursting of the earth's crust 
 which resulted in the formation of those abrupt mountain crests or ridges, occurred 
 somewhere near the close of the accumulation of the true lignite deposits. We believe 
 this for the following reasons : Whenever we observe the lignite beds in the vicinity 
 of tin; mountain ranges we find them more or less inclined in the same direction with 
 the older fossiliferous rocks, though, as a general rule, dipping at a smaller angle, 
 because more remote from the axis of the disturbing power. Of course, as the land 
 was slowly elevated toward the surface of the waters, the newer Tertiary beds would 
 be subjected to the erosive action of water first, and thus continuing downward, as 
 the mass was slowly rising, until the granitic nucleus was exposed. The Tertiary 
 rocks, being composed for the most part of loose, yielding material, sands, clays and 
 lignites, would be worn away from the surface for some distance from the axis of ele- 
 vation. Although the lignite Tertiary beds are developed in full force all along the 
 base of the larger ranges of mountains, it is not unlikely that some of these ridges 
 formed barriers or lofty shores to these great Tertiary lakes. It would seem as if this 
 country during the Tertiary period was not unlike the Undine region of the north, so 
 called by the geographer Nicollet on account of the great number of fresh-water lakes 
 distributed over that district. 
 
 Near the Black Hills these beds are worn away from the immediate base of the 
 mountains, and it is doubtful from any proofs that we can now obtain whether the Ter- 
 tiary lake extended over the country at that time occupied by the Black Hills. West 
 of this range, the lignite Tertiary beds incline from the western slope 5 to 10 degrees. 
 All along the Bighorn Mountains, the same features, only more strongly marked, are 
 seen. These beds often lie quite high upon the slopes of the mountains, conforming to 
 the Cretaceous rocks and sometimes inclining at a high angle. Between the western 
 extremity of the Bighorn Range and the Sweet Water Mountains on the North Plat to 
 
)60 REPORT OF THE SECRETARY OF THE INTERIOR. 
 
 Thev are more disturbed than sit any other locality. The lignite Tertiary strata are 
 nearlv vertical and the hard layers of sandstone or limestone extend in long project- 
 inirlh.rsjirn.ssih.' ro.n.try, while the intermediate yielding beds of clay, sand and 
 li-nite an- sinootl.rd and leveled by atmospheric agencies and clothed with a thick 
 turf of "rass. Ml along the Larainie Range, from the Red Buttes to Deer Creek, until 
 tin- lignite l>rds air concealed by the White River Group, the same features are seen, 
 though the strata incline less, being more remote from the anticlinal crest. On both 
 rides of the Wind River .Mountains the same phenomena occur, and other examples 
 init'ht br ritrd pointingto the same conclusions, but enough has been said to show that 
 it is probable that the lignite Tertiary beds partook of the same movements that have 
 elevated ihr older fossiliferous rocks. We therefore infer that the fracture of the 
 earth's crust in (his portion of the West, by Avhich the nucleus of the mountains was 
 revealed, oceurred near the time of the accumulation of the lignite deposits or at the 
 close <>t' that epoch. 
 
 Again, although there is not a strict iinconforniability between the true lignite beds 
 andlhe Wind River Group, the latter incline in the same direction, only at a much 
 smaller angle. Near the source of Wind River the Wind River Group rests directly 
 npon Cretaceous formation No. 2. At this point the Cretaceous rocks incline from 10 
 to -J.V, while the Wind River beds dip from 1 to 5. As we ascend the valley of 
 Wind River towards its source, we pass, for a long distance, the steeply inclined Cre- 
 taceous and Jurassic rocks, along the margins of the mountains on our left hand, 
 while on our right, but a few hundred yards distant, the naked, almost vertical walls 
 of the lower portion of the Wind River Group* are seen, the strata, however, seldom 
 inclining more than one degree. 
 
 The same examples may be observed on the west side of the Wind River Mountains, 
 where the Wind River beds lie high upon the sides of the w ester n slope in a very 
 slightly inclined position and in some localities covering the very summit, showing 
 clearly that even the dividing crest of the mountains was beneath the waters during 
 the deposition of this group. Along the margins of both the Wind River and the Big- 
 horn Mountains these beds seem to have risen in an undisturbed or in a nearly horizonta 1 
 condition. We have already expressed the opinion in a previous paper, t that the 
 Wind River Group was intermediate in age between the lignite Tertiary and the White 
 River l>eds, and in point of time filled up a chronological chasm. W T e have inferred 
 this from t lie fact that these beds seem to possess paleontological and lithological 
 characters intermediate between the two. They contain casts of a species of Vivipam 
 which is undistinguishable from V. trocliiformis, and fragments of a Trionyx apparently 
 the same with that occurring in the lignite beds, also fragments of a Testndo which, 
 so far as we can determine, is identical with the T. Xebrascensis of the White River 
 beds. If we look also at the composition of the Wind River beds, we find that their 
 light color, indurated arenaceous and argillaceous character, and their general appear- 
 ance after erosion, favor the correctness of the inference in regard to their interme- 
 diate position. From the facts before us in regard to this group, we conclude that 
 even after the crust broke, the country continued slowly rising while the Wind River 
 deposits were accumulating, and that the upper portions when not eroded away were 
 elevated high upon the sides of the mountains in a nearly horizontal position. 
 
 Again, the White River beds hold a similar position with reference to the lignite 
 formations as the Wind River Group. They are seldom disturbed, and only in a few 
 instances do they incline as much as 5. They, however, occur high up on the mount- 
 ain slopes along both sides of the Laramie Range, showing that they partook of the 
 gradual elevation of the country, after the crust was broken and the mountain district 
 began to approach its present configuration. On the west side of the Black Hills, 
 where t he White River beds probably began their origin, we find only the lower strata 
 of this group, usually reposing directly upon Cretaceous rocks, though in a few locali- 
 ties upon lignite formations. But as we descend south and southwestward, these 
 lower beds disappear and more recent ones take their place, until they pass into the 
 Pliocene sands of the Loup River Group, and then, in turn, still farther southward, 
 an- lost in the Loess or yellow marl deposits. We can only account for these phenom- 
 ena on the supposition that this great Tertiary fresh-water lake had its commence- 
 ment in the White River Valley, and as the Black Hills, and of course the whole Rocky 
 Mountain district, arose slowly toward its present elevation, the waters gradually re- 
 ceded southward and sonthwestward, and then more recent beds continued to be ac- 
 cumulated, until this formation spread itself over the vast area which it now occu- 
 pies. We thus think that, by means of these Cretaceous and Tertiary deposits of the 
 \\cNt. weean yet trace step by step the progress of that grand development which 
 has given the present geographical conformation to the West, and originated the 
 fountains from which flow those mighty rivers which may well be called the commer- 
 cial arteries of the American continent. 
 
 Another illustration of the, gradual and long-continued rise of the country niav be 
 tonnd in the immense chasms or canons which have been formed by the streams along 
 
 " Same as the Wahsatch Group, 1878. 
 
 t ISee this Journal, vol. xxxi, March, 1861. 
 
GEOLOGICAL SURVEY OF THE TERRITORIES. 961 
 
 the mountain sides. We can only account for them on the supposition that as the an- 
 ticlinal crest was slowly emerging from the sea, the myriad sources of our great rivers 
 were seeking their natural channels, and that these branches or tributaries began this 
 erosive action long before the great thoroughfares, the valleys of the Mississippi and 
 the Missouri, were marked out. The erosion would go on as the mountains continued 
 slowly rising at an almost imperceptible rate, and in process of time the stupendous 
 channels which everywhere meet us along the immediate sides of the mountains would 
 be formed. If we examine the barometrical profiles, already referred to, we see at a 
 glance that in traversing the country from the Mississippi to the foot of the mount- 
 ains the ascent is very gradual, but increases as we approach the upheaved ridges. In 
 an equal proportion will the rapidity and consequently the erosive power of the streams 
 be increased so that we may readily account for those grand displays of the erosive 
 action of water which occur so frequently along the mountain sides. Eastward from 
 the mountains, beyond this immediate influence, the descent is so gradual that the 
 Missouri flows quietly along over its yielding alluvial bed, transporting its sediments 
 to the Gulf of Mexico. 
 
 That the progressive elevation of the country continued up to our present period, or 
 at least until near the time of the deposition of the most recent superficial deposits, 
 we think we have evidence derived from the terraces, which are seen all along the 
 streams. The elevation of these terraces increases as we approach the sources of the 
 rivers, averaging from a few feet to 150 or 200 feet in height. This subject will be dis- 
 cussed more fully in a future article. 
 
 We conclude, therefore, that the barometrical profiles, constructed from explora- 
 tions across our continent, and geological data, indicate a long-continued quiet expan- 
 sion of the earth's crust, commencing toward the close of the Cretaceous epoch and 
 extending even to our present period ; that near the close of the accumulation of the 
 Tertiary lignite deposits, the crust of the earth had reached its utmost tension, the 
 long lines of fractures had commenced, and the anticlinal crests of the mountain 
 ranges were marked out. In a previous paper in this Journal, we remarked that there 
 is no unconformability in any of the fossiliferous sedimentary strata in the Northwest, 
 from the Potsdam sandstone to the summits of the true lignite Tertiary. We believe, 
 therefore, that the elevated ridges which form the nuclei of the mountain ranges 
 began to emerge above the surface of the surrounding country near the close of the 
 Eocene period. We think also that the evidence is clear that there were periods of 
 subsidence and repose ; but the thought which we wish to illustrate is, that there was 
 a slow, long-continued, quiet, upward tendency which began near the close of the Cre- 
 taceous epoch and culminated in the present configuration of the western portion of 
 our continent near the commencement of our present period. 
 WASHINGTON, D. C., January 1, 1862. 
 
 ART. XXXIV. -REMARKS ON THE GEOLOGICAL FORMATIONS 
 ALONG THE EASTERN MARGINS OF THE ROCKY MOUNTAINS.* 
 
 BY F. V. HAYDEN. 
 
 [From the American Journal of Science, May, 1868.] 
 
 On several former occasions I have described the different geological periods repre- 
 sented by the rocks uplifted along the margins of the Rocky Mountains and especially 
 along the eastern slope. Examinations over a great extent of country in considerable 
 detail, from latitude 49 south nearly to the Arkansas River, have shown me that 
 quite marked lithological and paleontological changes occur in them all as we proceed 
 from the north southward. It is the purpose of this article to note this fact some- 
 what more in detail than hitherto. Beginning with the nucleus of the Rocky Mount- 
 ains at any point along the eastern range, we find it composed of massive granite 
 rocks, mostly red feldspathic, but not unfrequently gray or other shades of color ; then 
 a series of metamorphic rocks (as they are usually called, though no doubt all the 
 granites should be included with them), syenites, diorites, clay, mica, and hornblende 
 slates, and igneous rocks of various kinds here and there. 
 
 Proceeding outward, we find the Silurian period represented by the Potsdam sand- 
 stone , Devonian wanting, then Carboniferous, Red Beds (Triassic ?), Jurassic, Creta- 
 
 * This article refers only to the eastern ranges of the Rocky Mountains, extending 
 south to the Arkansas. The same remarks may or may not apply to other portions. 
 61 1 
 
962 REPORT OF THE SECRETARY OF THE INTERIOR. 
 
 ceons, and Tertiary, all connected together in the regular order of sequence, and all 
 l.nt I!M- most recent Tertiary in strict conformity. The Tertiary deposits do not ex- 
 liil.it :mv marked change either in their mineral or fossil contents from the northern 
 i.ori ion of our domain to the Arkansas, but the Cretaceous beds present several quite 
 marked rliaii"rs. Ns.* ."> and 4 maintain their peculiar characters as shown on the 
 I'jmcr Missouri, wherever they are exposed all along the eastern slope, except that 
 tli.-y contain comparatively few fossils, yet a few characteristic species are found 
 win-revel- these beds are seen, which identify them. On the Missouri River, No. 3 at- 
 tains M -Teat thickness, 400 to 600 feet, presenting massive escarpments of yellow 
 chalk and it can hi; traced all the way across the prairie country lying between 98 
 and KID- lon"ii ude. At Forts Hayes and Wallace on the Union Pacific Railway, East- 
 ern Division, there are massive beds of this chalk which is sawed into building blocks 
 with a common saw, and in many instances it is nearly as white as our chalk of com- 
 merce and might be used for the same purposes. 
 
 The two characteristic species of fossils of this division are found everywhere, 
 Osti-ea congesta and Inoceramus problematic^. All along the slope of the mountains 
 No. 3 still retains its chalky nature, but becomes quite shaly, none of the layers 
 ever becoming more than oiie or two inches in thickness. This is the case at the' 
 sources of the Missouri along the Bighorn and Wind River Mountains also, from the 
 South Pass to Pike's Peak, and on the western slope wherever this bed is exposed. 
 Near Denver, at Marshall's coal-mine, No. 3 has been changed by heat into a grayish 
 mm pact limestone, quite hard and brittle in its fracture, which makes an excellent 
 flux in smelting ores. But this change is local, for 16 miles north of this point it pre- 
 sents the same laminated character. It seems that No. 3 loses its massive chalky 
 character, by which it first attracted attention on the Missouri River, in its westward 
 extension, so that along the margins of the mountains, except in one locality, it can- 
 not prove of any economical value, while between 98 and 100 longitude it becomes 
 very useful not only for lime, but also for building purposes. No. 2, like Nos. 4 and 5, 
 retains its dark plastic clay character everywhere that it has been observed, but, like 
 the others, it is not nearly as well developed in Colorado as on the Upper Missouri. 
 Near Fort Benton it attains a thickness of 200 to 400 feet, while in Colorado it is not 
 more than 50 to 150 feet. Between longitude 96 and 99 No. 1 retains its deep rust- 
 red sandy characters with dicotyledonous leaves from the Missouri River to the Ar- 
 ka nsus, but nowhere along the margins of the mountains from latitude 49 to Pike's 
 Peak have I ever seen any well-defined palseontological proof of its existence. Near 
 Fort Benton are a series of Cretaceous beds containing some seams of impure lignite 
 and numerous species of fossils, not one of which is identical with those so abundant 
 in Nos. 4 and 5 lower down on the Missouri. 'These beds have been placed provision- 
 ally in the general section as a portion of No. 1, but the region about Fort Beuton 
 needs a more careful examination before any positive conclusions can be arrived at. 
 Around the Black Hills is a bed of massive siliceous rocks, some layers forming a pud- 
 ding stone, which in some localities takes the name of fortification rocks. These hold 
 a position between No. 2 Cretaceous and the Jurassic marls. The same are seen along 
 the margin of the Bighorn Mountains, in which I observed a bed of impure lignite, an 
 abundance of silicified wood, and some uncharacteristic Saurian bones. From the 
 Wind River Mountains to Pike's Peak these same siliceous and pebble cemented rocks 
 occur holding the same geological position, -forming, as it were, beds of transition be- 
 tween the Cretaceous and the Jurassic periods. I have carefully examined these rocks 
 for hundreds of miles and have never yet detected any organic remains, animal or 
 vegetable, in them. 
 
 The Jurassic beds, as revealed along the mountains, possess peculiar and marked 
 lithological characters, so that having identified them by the fossils in one locality we 
 can trace them over great areas. They were first shown to exist in the West in the 
 form of a zone engirdling the Black Hills. They here attain a thickness from 200 to 
 
 )0 feet at least, and from the beds in this locality alone have fossils enough been col- 
 lected of such unmistakable Jurassic types as to prove their existence beyond a doubt. 
 But these beds have also been shown, since they were first made known in the Black 
 Hills, to l)e exposed along the margins of the Bighorn and Wind River Mountains 
 near Red Buttes, on North Platte, and in numerous localities in the Laramie Plains, 
 and west ward to Fort Bridger. So numerous are the species now known from the West 
 and so close are the affinities of most of them to well-known Jurassic tvpes that it 
 is not necessary for me in this place to detail the evidence in support of that state- 
 ment. 
 
 It is sufficient to remark that the Jurassic system is quite plainly represented along' 
 the mar-ins of the different ranges of mountains north of latitude 42. but proceeding 
 southward from Deer Creek on the North Platte, the Jurassic beds diminish in force 
 tear Cache la Poudre it becomes doubtful whether they are represented at all' 
 
 * The different divisions of the Cretaceous period, as shown on the Missouri River, 
 have received geographical names, as Fort Benton Group, &c., but I use the old divis- 
 ions by figures for brevity. 
 
GEOLOGICAL SURVEY OF THE TERRITORIES. 963 
 
 At tliis point there is a thin bed, perhaps 20 to 50 feet in thickness, of greenish-gray 
 arenaceous marl overlying the Red Beds, which seem to occupy the place of the Juras- 
 sic. This seems to thin out more and more as we proceed southward toward the Ar- 
 kansas. From Deer Creek 100 miles north of Fort Laramie to Denver, a distance of 
 400 miles, I have searched in vain for any organic remains in the rocks which appear 
 to represent the Jurassic period of the Black Hills, Bighorn and Wind River Moun- 
 tains. In the Red Beds or supposed Triassic no organic remains have been found north 
 of the Arkansas, and they do not differ much lithologically in their southward exten- 
 sion, except that they seem to be much thicker and more, gypsiferous northward. In 
 the far north the Carboniferous rocks are in many localities 500 to 1,500 feet in thick- 
 ness, and even as far south as the Red Buttes the massive beds of limestone, with true 
 Carboniferous fossils, are exposed 500 to 1,000 feet thick, and are quite distinct from 
 the red or variegated beds. But as we proceed southward from this point the Carbon- 
 iferous limestones seem to lose their usual lithological characters and the Red Beds 
 prevail. At the head of Pole Creek on the eastern margin and in the Laramie Plains 
 west, the Carboniferous rocks are mostly of a red arenaceous character, with a few lay- 
 ers 2 to 10 feet in thickness of whitish or yellowish limestone. From these limestones 
 I collected Productus Prattenianus, Atliyris suMUta, and other well-known Carbonifer- 
 ous forms. 
 
 Above these Red Beds, which contain intercalated layers of limestone, is a considerable 
 thickness of purely red arenaceous beds, but in studying all these rocks with some 
 care from Pole Creek nearly to Pike's Peak, I could not separate the Red Beds from the 
 Carboniferous by any break in continuity, and I was rather inclined to the opinion 
 that inasmuch as a large portion of the gypsiferous or variegated beds could be shown 
 to be Carboniferous, they might possibly all be included in that period. TLe Potsdam 
 sandstone, the only portion of the Silurian era ever detected along the eastern slope 
 of the Rocky Mountains north of the Arkansas, seems to fade out entirely south of the 
 Red Buttes on the North Platte. It is well denned around the Black Hills, Bighorn, 
 and Wind River Mountains. Near the Red Buttes there is a bed of siliceous pudding 
 stone resting on the metamorphic rocks which may be the Potsdam in its southern 
 extension, but south of Fort Laramie to Pike's Peak it is somewhat doubtful whether 
 any trace of it exists. If it occurs at all it a very thin layer, for the most part con- 
 cealed. So far as I could determine, the Carboniferous rocks rest directly (though not 
 conforming) upon the metamorphic rocks. There is also some change in the nuclei 
 of the mountain ranges southward. At the north the feldspathic and the gray gran- 
 ites prevail, but southward the syenites and igneous rocks form the central portions 
 of the mountains almost entirely. It is rare to see true granite. 
 
 The above remarks, founded, on observations that have been made over a very great 
 extent of country through a period of many years, lead me to the following conclu- 
 sions : 
 
 1st. That all the formations of the West undergo more or less change both in their 
 mineral and fossil contents in their extension toward the west and south. They all 
 seem to reach^ their culmination not far from the central portion of the great area 
 drained by the Missouri, and lose to a great extent their distinctive characters beyond 
 its limits. 
 
 2d. The Potsdam sandstone and the Jurassic beds present more remarkable changes 
 than any of the others. While north both these formations are well marked, both 
 lithologically and paloeontologically in their southward extension they gradually fade 
 out, so that south of Fort Laramie to Pike's Peak it becomes a matter of doubt whether 
 they exist at all. The inference therefore is that these groups of rocks are not well 
 defined, if they occur at all south of the Arkansas. In support of this statement is the 
 fact that although this southern region has been traversed in every direction by mul- 
 titudes of explorers for thirty years past, among whom have been geologists of high 
 reputation, yet south of latitude 40 not a single animal fo.ssil has ever 'been detected 
 with Jurassic affinities, and it is quite doubtful whether any have been found with 
 Triassic or Permian relations;* even the few plants that have been found are doubtful 
 in their affinities and are regarded as probably Cretaceous or Permian. I have made 
 these remarks from the fact that all the observations that have been made by explorers 
 in the West during the past will, ere many years, be put to the rigid test of a most 
 careful scrutiny, and an error by whomsoever made, though sustained by the highest 
 authority in the land, will fall to the ground before the light of true science as the 
 dead bark from a tree. The ease with which the Rocky Mountain region can soon 
 be reached, in a few years, when our great national highways are completed to the Pa- 
 cific, will induce the best geologists in this country and in Europe to visit them, and 
 the many intricate problems of Rocky Mountain geology must be solved. 
 
 * I do not wish to be understood as saying that the Jurassic rocks do not occur, south 
 of the Arkansas, as well as the Permian and Triassic, for there is ample room for their 
 fullest development, but no evidence has ever yet been obtained of its (Jurassic) exist- 
 ence, although the country has been so long traversed by explorers. The evidence, so 
 far as it goes, would seem to be against its occurrence at all. 
 
964 REPORT OF THE SECRETARY OF THE INTERIOR. 
 
 Tho school of mines which will no doubt be soon established in the heart of 
 
 thl mhn is Its of the Rocky Mountains, must gather around it able men who 
 will 1'IZ^us.Mh' onvj.ct the observations of other investigators who have exam- 
 iiinl tlu- coiiniry under less favorable auspices. 
 
 THE PRIMORDIAL SANDSTONE OF THE ROCKY MOUNTAINS IN THE 
 NORTHWESTERN TERRITORIES ON THE UNITED STATES. 
 
 BY DR. F. V. HAYDEN. 
 
 [From the American Journal of Science and Arts, vol. xxxiii, Jan., 1862.] 
 
 We have attempted in this paper to present as clear and connected an account as 
 the known facts will permit, of the Primordial rocks west of the Mississippi, more 
 especially those of the northwest, west of longitude 96. The Potsdam sandstone of 
 the New York series is the division of the Primordial zone of Barrande, mainly repre- 
 sented in the Rocky Mountain district, and is that part alluded to unless otherwise 
 mentioned. 
 
 In speaking of the geographical distribution of the Potsdam sandstone reterence 
 will lie made to localities to the eastward where it has furnished most abundant and 
 sat isf'actory testimony in regard to its age. We will, in the first place, present more 
 in detail such facts as Ave have been able to obtain by personal observation in the 
 field, and by the aid of these and the statements of reliable explorers we hope to give 
 some idea of the geographical extension of this wide-spread formation in the West. 
 
 Our first knowledge of Primordial rocks west of the Missouri River was obtained 
 in the summer of 1857, during the exploration of the Black Hills of Nebraska, by an 
 expedition under the command of Lieut. G. K. Warren, Topographical Engineers. The 
 more important facts, with the determination of the fossils, were published by Mr. 
 Meek and the writer in March, 1858.* 
 
 By reference to the general map of the country west of the Mississippi, recentlv 
 published under the auspices of the War Department, we find that the Black Hills lie 
 between the 43d and 45th degrees of latitude, and the 103d and 104th degrees of longi- 
 tude, and occupy an area about 80 miles in length, and from 30 to 50 in width. Ac- 
 cording to Lieutenant Warren the shape of the mass is elliptical and the major axis 
 trends about 20 west of north. The base of these hills is about 2,500 to 3,000 feet, and 
 the highest peaks 6,700 feet above the ocean. The entire range is clasped, as it were, 
 by the North and South Branches of the Shyenne River, the most inportaut stream in 
 this region. The North Branch passes along the north side of the range, receiving 
 most of its waters from it, but taking its rise far to the westward near the sources of 
 Powder River, in the "divide," between the waters of the Yellowstone and those of 
 the Missouri. The South Branch also rises in the same " divide," flows along the south- 
 ern base of this range, receiving the waters of numerous tributaries which have their 
 sources in it. 
 
 Again, by referring to the map above alluded to, we ascertain that the Black Hills 
 form the most eastern outlier of the great Rocky Mountain Range as well as the first 
 point where rocks older than the Carboniferous are exposed to the eye after leaving the 
 Missouri westward. These hills would seein to constitute an independent elevation, 
 so far are they removed from other ranges, were it not for a low anticlinal which may 
 be traced across the plain country southward, connecting them with the Laramie 
 Mountains near Laramie Peak. The central portion is composed of red feldspathic 
 granite and stratified Azoic rocks, and resting unconformably upon, and forming a 
 zone or belt around the ellipsoidal nucleus, are a series of variable, reddish ferrugi- 
 nciiis sandstones, which by their organic remains furnish the most reliable evidence 
 that tlu-y belong to the Potsdam period. 
 
 As observed in and around the Black Hills, the Potsdam sandstone presents a great 
 varn-t v of lithological characters. In many localities it is composed of a conglomer- 
 ate of more or less water-worn pebbles, mostly whitish crystalline quartz, but repre- 
 senting to a greater or less extent the different varieties of the changed rocks beneath. 
 Tin- pelililrs vary in wize from an eighth of an inch to four inches in diameter cemented 
 toi;rtln r with a si li co-calcareous paste. Some of the pebbles are scarcely worn while 
 t 1 HTM are quite smooth. At the locality where the following section was taken, the 
 sandstone is of a gray color tinged with red at the base, but ascending it becomes more 
 
 * Proceedings of the Academy Nat. Sci., Pa., March, 1858. 
 
GEOLOGICAL SURVEY OF THE TERRITORIES. 965 
 
 ferruginous until its color is a dark dull red, and its texture a coarse-grained friable 
 sandstone with many quartzose and micaceous particles and some calcareous matter. 
 Seams two to four inches in thickness are very nearly composed of shells of the gen- 
 era Lingula, Obolella, &c., which, though quite fragile in their nature, are so well 
 preserved as to be easily identified. The following section taken near the central por- 
 tion of the Black Hills exhibits Carboniferous rocks and the Potsdam sandstone con- 
 forming to each other, but the latter resting discordantly upon the Azoic stratified 
 and granitic rocks. 
 
 Feet. 
 
 1. A hard, compact, fine-grained yellowish limestone of an excellent quality, 
 passing down into a yellow calcareous sandstone, quite friable. Fossils: Spi- 
 rifer fiockymontana, Marcou; an Athyris, like A. subtilita, Cyploceras, &c 50 
 
 2. Loose layers of very hard yellow arenaceous limestone with a reddish tinge, 
 underlaid by a bed, six to eight feet in thickness, of very hard blue limestone ; 
 the whole contains great quantities of broken crinoidal remains with cya- 
 thophylloid corals and several species of brachiopoda 40 
 
 3. Variegated sandstone, of a gray and ferruginous red color, composed chiefly 
 of grains of quartz and particles of mica cemented with calcareous matter. 
 Some portions of the bed are very hard, compact, siliceous ; others a coarse 
 friable grit; others a conglomerate. Fossils : Lingula pj-ima, L. antiqua, Obo- 
 lella nana, and fragments of a trilobite, Arionellus f Oweni 50 to 80 
 
 4. Stratified Azoic rocks standing in a vertical position for the most part. 
 
 Leaving the Black Hills in a direction a little west of south, we follow an anticlinal 
 valley to the Laramie Mountains with which the Black Hills seem thus obscurely con- 
 nected. The evidence, so far as it goes, appears to indicate that the same force which 
 elevated the one raised the other, and that the events were synchronous. We do not 
 observe the lower rocks after leaving the Black Hills until we reach the source of the 
 Niobrara River, where we find a series of horizontal strata resting upon the vertical 
 edges of Azoic clay slates and schists, which from their lithological characters and 
 position doubtless belong to the age of the Potsdam sandstone, though no organic 
 remains could be found. The following section shows the descending order of the 
 beds. 
 
 Feet. 
 
 1. Quartzose sandstone, some parts filled with pebbles 22 
 
 2. Red argillaceous slate 1 5 
 
 3. Sandstone, dull reddish ferruginous, like bed 1, above 37 
 
 4. A series of strata more or less inclined, composed of gneiss with silvery rnica 
 in large plates, micaceous and talcose slates, white quartz, &c. 
 
 We have no doubt that the Potsdam sandstone occurs in the form of an outcropping 
 belt all along the Laramie range of mountains, though, after a thorough search we 
 were unable to discover any organic remains. Having once fixed the position and 
 age of a formation, as the Potsdam sandstone is established in the Black Hills, we 
 may rely with considerable confidence upon the physical characters and stratigraph- 
 ical position to determine the age of rocks in the same district of country. We have 
 on these grounds regarded certain rocks along the Laramie Range as of this age. In 
 the first ridge of elevation west of the trading post on La Prele Creek, about 60 miles 
 northwest of Fort Laramie, is a series of rocky layers 50 feet in thickness, reposing 
 unconformably upon red feldspathic granites, mica schists, and clay slates. The lower 
 portion is a fine-grained subcrystalliiie quarfczose rock, partially metamorphosed, pass- 
 ing up into a friable sandstone arranged in thin layers, with the laminae quite oblique, 
 overlaid by a considerable thickness of conglomerate. The dip is about 20 east. Rest- 
 ing upon these supposed Potsdam rocks at this point and inclining at about the same 
 angle are layers of limestone, containing numerous fossils which prove them to belong 
 to the Carboniferous age. 
 
 Again, further southward along the same range, near the source of the Chugwater 
 River we find the same limestones well developed, containing some Carboniferous 
 fossils, and underneath them and inclining in the same direction is a group of strata 
 of a brick-red color, more or less changed by heat, holding the position of the Pots- 
 dam sandstone in other localities. In some places these rocks are so metamorphosed 
 by heat from beneath as to appear like a red feldspathic granite, and in others, like 
 a reddened granular sandstone containing numerous unchanged masses of quartz. 
 
 At the Shyeime Pass, we observed the well-known Carboniferous rocks, inclining 
 about 13. Beneath them is a considerable thickness of red marls and laminated 
 sandstone, and still farther down and inclining 26 is a quartzose sandstone, full of 
 water-worn pebbles, passing down into layers which at a distance look like indurated 
 clay, but which, 011 closer examination, proved to be an aggregation of quartz and 
 feldspar crystals cemented with a calcareous paste. At another locality we have the 
 following characters : (1) a grayish quartzose sandstone, 12 inches; then descending, 
 (2) laminated granitoid rock, 2 feet; (3) compact reddish ferruginous granitoid mate- 
 
966 REPORT OF THE SECRETARY OF THE INTERIOR. 
 
 rial, 8 feet ; (4) a considerable thickness, perhaps 50 feet, of feldspar crystals cemented, 
 with a calcareous paste, inclining 13. Though we could find no organic remains in 
 thes.e supposed Potsdam rocks along the Laramie range of mountains, yet their strati- 
 graphical position and physical characters leave very little room for doubt as to their 
 age. 
 
 Although we think that the known facts justify the inference that the Potsdam 
 sandstone is revealed in an outcropping belt all along the margins of the Bighorn 
 Range, resting uncoiiformably upon the Azoic rocks beneath, yet we were unable to 
 make a careful examination except in. a few localities. We could see, however, in 
 the loose material scattered along the foot of the mountains, washed down by the 
 streams, masses of sandstone closely resembling. the rock under consideration. Near 
 the source of Powder River we penetrated to the nucleus of the mountains and found 
 a series of sandstones underlying the Carboniferous limestone and resting uuconform- 
 ably upon the schistose and clay slates of the Azoic series, in very nearly the same 
 manner as in the Black Hills before described.. The Potsdam sandstone in this region 
 is quite well developed, attaining a thickness of 200 feet, and exhibiting its usual 
 variable lithological characters. Near the base, the rock is of a reddish flesh-color, 
 very compact, composed of an aggregation of quartz pebbles, varying in size from a 
 minute grain of quartz to masses half an inch in diameter, cemented with siliceous 
 matter. Portions of the rock contain many pebbles of jasper which appear to have 
 been slightly worn before being inclosed in the calcareous paste. Passing up we find 
 the rock to be arranged in thin ferruginous layers, slightly calcareous but mostly 
 siliceous, with many small particles of mica. These thin layers are also charged with 
 fossils, as Lingula antiqua, Obolella nana, Theca greyarea, and Arionellus f OwenL Many 
 of the slabs were covered with fucoidal markings and what appear to be tracks or 
 trails of worms. The upper part of 'this formation as seen in the Bighorn Mountains 
 is a rust-color granular sandstone, the small siliceous grains being held together by a 
 calcareous cement which causes the rock to effervesce briskly on the application of an 
 acid. In tracing the different fossiliferous rocks, at this locality, from the nucleus 
 outward, we can see a good illustration of the strict conformability of all the forma- 
 tions from the Potsdam sandstone to the summit of the Lignite Tertiary. We see here 
 the evidences of only two great periods of disturbance, the one occurring prior to the 
 deposition of the Primordial sandstones which inclined the Azoic rocks, and the other 
 at the close of the accumulation of the true Lignite Tertiary deposits when the mount- 
 ain nuclei began their elevation above the surrounding country. 
 
 Along the Wind River Mountains, which extend far northward and form the dividing 
 crest of the great Rocky Range, the Potsdam sandstone is quite thinly represented and 
 yielded no organic remains to a somewhat hasty examination. Near the junction of 
 the three forks of the Missouri, alternate strata of clay, limestone, and compact sili- 
 ceous rock occur beneath well-marked Carboniferous beds. These rocks are evidently 
 of ancient date, and were deposited in quite shallow water, as is shown by numerous 
 thin layers of rock covered with trails of worms and fucoidal plants. These facts 
 thus enumerated would seem to indicate with considerable certainty that this rock 
 once spread over the area occupied by the central range of the Rocky Mountains, 
 doubtless extending far north beyond the limits of the territories of the United States. 
 The predominance of eruptive rocks as we pass northward along the main range of 
 the Rocky Mountains greatly increases the difficulty in tracing out the lower fossili- 
 ferous beds. 
 
 We have now described this member of the Primordial zone as far as it has occurred 
 within the limits of our own observations. It now becomes an interesting point to 
 determine its geographical extension in the West, and for that purpose we propose to 
 summon all the evidence at our command. The proof will not, however, be as satis- 
 factory as could be desired, owing to the general absence of organic remains. 
 
 If we now extend our examinations far north into the Hudson's Bay territory, we find 
 that much interesting information has been obtained in regard to the Silurian rocks of 
 that region, but not accompanied by the evidence which gives to the knowledge ac- 
 quired that definiteness which is desirable. It is probable, however, that when not 
 eroded away or concealed by more recent deposits, the Potsdam sandstone and, per- 
 haps, rocks of more recent Silurian age occur all along the margins of the Rocky 
 Mountains to the Arctic Sea. To what extent still more recent or Upper Silurian occur 
 over this vast region our present knowledge will not enable us to determine, but the 
 few fossils which have been collected indicate that the great Silurian Sea extended over 
 much of the Northwest. Sir John Richardson mentions the existence of conglomerates 
 and sandstones to which succeed limestones and clay slates, probably of Silurian age, 
 and granite. We know that in many localities in the mountains, about the sources of 
 the Missouri, the rocks of the Potsdam period are composed of sandstones and more or 
 less coarse conglomerates. Underneath are clay slates and very hard limestones of 
 Azoic age, and to these succeed granite. As we proceed northward the evidence 'of 
 true Lower Silurian rocks gives place to those of Upper Silurian age, which have fur- 
 nished a good supply of organic remains. According to Mr. Isbister, these rocks are 
 
GEOLOGICAL SURVEY OF THE TERRITORIES. 967 
 
 well developed around Hudson's Bay, Great Slave Lake and River, Lake Winnipeg, 
 &c. He cites numerous fossils as belonging to Silurian types, but the species are too 
 numerous to mention here. We may simply state that, so far as our knowledge extends, 
 there is no evidence which renders it certain that any portion of the Primordial zone of 
 of Barande occurs north of latitude 49, though it is quite probable that when care- 
 fully sought after it will be found revealed along the margins of the mountain eleva- 
 tions to the Arctic Sea. 
 
 As we proceed southward along the line of the mountain ranges toward New Mexico, 
 though no fossils have been found, we feel safe, acting upon our previous knowledge, 
 in regarding the evidence as quite clear that this sandstone occurs in numerous local- 
 ities. In our investigations of the geology of the West, we have relied on three tests 
 of evidence, viz : 
 
 First. Paheontological evidence, which is the most important and in most instances 
 the only conclusive proof. 
 
 Second. Stratigraphical position. 
 
 Third. Lithological resemblance. 
 
 The last two tests are all we have to rely upon to determine the extension of the 
 Lower Silurian rocks as we proceed southward from the Black Hills. Having traced 
 rocks which we regard of this age south to a point on a parallel with the Salt Lake 
 district, we present the following resemblances in Iithol6gical characters as probable 
 evidence of their existence in Utah Territory : 
 
 Professor Hall, in Stansbury's report, in several places describes a bed of sandstone 
 corresponding in its lithological characters and geological position to the Potsdam 
 sandstone in the Black Hills. Stansbury Island (Great Salt Lake), the summit of which 
 is 3,000 feet in height, is capped with Carboniferous limestones, which rest upon a 
 coarse sandstone or conglomerate. Again, north of Great Salt Lake City the limestone 
 overlies a coarse sandstone or conglomerate, which almost invariably accompanies it* 
 In several localities, as at Promontory Point and near Mud Island, the metamorphic 
 strata appear to be overlaid by a coarse conglomerate or coarse sandstone, which is 
 partially altered and assumes the character of a quartz rock. Marcou, in the [third 
 volume of Pacific Railroad reports, page 156, mentions a formation occurring near the 
 Aztec Mountains. He says: "We traveled seven miles upon the granite, then a bed 
 of red sandstone ; above this the beds of limestone and gray sandstone belonging to the 
 mountain limestone." The following day " we traveled three miles on the granite, the re- 
 mainder on the Old Red Sandstone." An excellent diagram, illustrating a section of the 
 rocks near the mountains above alluded to, accompanies Mr. Maroon's remarks, which 
 would apply equally well to similar beds in the Black Hills. The great uniformity in 
 the physical characters of the different formations over large areas, which have been 
 examined with care and definite knowledge obtained, leads us to place some degree of 
 confidence in the above statements. From latitude 49 to 40 south, and east of the 
 dividing crest, we have the Potsdam sandstone, then, immediately above it, with re- 
 markable uniformity, a series of beds of limestones containing true Carboniferous fos- 
 sils. We infer, therefore, that both northward and southward the same uniformity of 
 geological structure continued, unless we have evidence to the contrary. 
 
 The observations of Dr. J. S. Newberry render it quite probable that rocks of Lower 
 Silurian age occur along the valley of the Colorado. The following paragraphs from 
 a letter addressed to the writer by Dr. Newberry are extracted by permission : 
 
 "I have never collected any unmistakable Silurian fossils in^the far West, 
 perfectly satisfied that the lower stratified rocks of the Colorado section are Silurian, 
 but the only fossils they contain are too much changed to be satisfactorily identified. 
 
 " The lower rocks above the granite are coarse, red sandstones, lithologically and 
 stratigraphically corresponding to your Potsdam of the Black Hills; above these a 
 great thickness,' over 300 feet, of shales, limestones, and sandstones, and then the first 
 Carboniferous fossils. 
 
 "Just above the Potsdam (?) is a limestone filled with corals, apparently Ckatoto 
 lycoperdon, or rather the same with that so common in the Trenton, with DTftE 
 stems, formerly included in C. lycoperdon, but evidently distinct, On the mount:. ins 
 bounding the Colorado basin the Carboniferous rocks rest directly upon the granite. 
 
 We have now considered the Potsdam sandstone in its geographical extension over 
 the West as far as we are acquainted with its existence, and have pointed out the lo- 
 calities where it is revealed. Along the Mississippi Valley and eastward most in 
 portant discoveries are made annually, which show it to be developed ev<-rywli 
 when the conditions are favorable for its exhibition. It is true that m some looalit 
 beds of more recent age repose directly upon Azoic rocks, but m those rases IM:;Y not 
 the Primordial sandstones lie concealed or be eroded away! Die researches ol Dr. i. 
 F. Shumard in Texas have shown that the Primordial zone attains aconsideraW 
 thickness in the Southwest, and is charged with an interesting group I its peculiar 
 fossil forms. The examination of others proved its existence all along ilu- 
 coast extending westward from Canada to Wisconsin, Iowa, ami Mmn-sota. 
 a great period in the world's geological history, formerly supposed to possess b 
 
968 REPORT OF THE SECRETARY OF THE INTERIOR. 
 
 meager fauna, the first representatives of life on our globe, has already yielded very 
 abundant and varied forms. The following is a summary of the principal facts and 
 conclusions from our knowledge of the Potsdam sandstone in the far West : 
 
 1. We have the most undoubted evidence of the existence of that division of the 
 Primordial zone, which is the equivalent of the Potsdam sandstone of the New York 
 series in two important ranges of mountains, outliers of the great Rocky Mountain 
 chain. All the fossils are well known Primordial types, and at least two species are 
 identical with forms occurring at the typical localities of this period in the Eastern 
 States. The others are forms closely allied to species found in the equivalent rocks 
 both in this country and in Europe. 
 
 2. This division of the Primordial zone, as a rule, appears as an underlying forma- 
 tion, when the conditions are such as to expose it to view, from the Atlantic coast to 
 the crest of the Rocky Mountains, and probably farther. Localities doubtless do occur 
 where rocks of more recent age than the Potsdam sandstone rest directly upon the 
 Azoic or granitic rocks below ; but these facts to not militate against the general rule. 
 Having proved its existence in two important ranges of mountains from, its organic 
 remains, by means of lithological resemblance and stratigraphical position, we have 
 with considerable confidence traced it by personal observations throughout the mount- 
 ainous district comprised within latitude 40 and 49 and longitude 103 and 112. From 
 these facts and the observations of reliable explorers in different parts of the West, we 
 we think we are warranted in the belief that this rock is exposed all along the margins of 
 the Rocky Mountain Range when not eroded away or concealed by overlying formations. 
 How far westward of the dividing crest of the Rocky Mountains it extended we have no 
 data for determining, nor can we hope to have, where eruptive rocks seem to predomi- 
 nate. As yet we have not known the Potsdam sandstone to be exposed, except along 
 mountains with a true granite nucleus. 
 
 3. Wherever this rock occurs, we are struck not only with the peculiarity of the 
 organic remains, but also with the remarkable uniformity in the nature of the sedi- 
 ments and the general lithological appearance, compared with its equivalents in more 
 eastern localities. We do not believe this to be due to currents of water bearing the 
 materials from far eastern lands, but that the sediments were obtained from the vicinity, 
 and that the uniformity in their character arises from the nature of the underlying 
 rocks from which they were derived. 
 
 The Potsdam sandstone is everywhere composed of calcareous and silicious matter, 
 granular quartz, ferruginous material in great quantities, also pebbles of various kinds 
 worn and unworn, with now and then seams and layers of argillaceous material. We find 
 in the Azoic rocks below an abundance of limestone, clay slates, mica schists, seams of 
 white quartz, granite composed largely of feldspar, and we can readily detect the source 
 of the fragmentary masses which form the conglomerates. We also know that while 
 nuclei of certain mountain ranges on the eastern slope are composed of a massive 
 feldspathic granite, a great thickness of more recent or overlying rock, forming the 
 lower and smaller ridges, are composed of a kind of "rotten granite," which is so full of 
 the hydrated oxide of iron that it readily decomposes on exposure to the atmosphere. 
 We therefore believe that the source of all the sediments composing the Primordial 
 rocks in the West can be traced to the underlying rocks in the vicinity. 
 
 4. There are no indications of long-continued deep water in the Primordial sea, so 
 far as the West is concerned. If we examine the lower part of the Potsdam sandstone, 
 we find that the physical conditions which ushered in this period were quite violent, 
 as is shown by the conglomerate character of the rock. Passing upward, this conglome- 
 rate graduates into a rock composed of granules of quartz and small plates of mica 
 cemented with calcareous matter, and about midway in the formation we have a fine, 
 very ferruginous calcareous sandstone, in thin layers, filled with fossils in a very good 
 state of preservation. The condition of the organic remains, the fineness of the sedi- 
 ment, and the perfect horizontality of the laminae of deposition indicate a short period 
 at least of quiet water. As we continue upward the rocks begin to show the shifting 
 nature of the currents, shallow water and perhaps a proximity to land, by oblique 
 laminae of deposit, ripple markings, and fucoidal remains. The upper portion of this 
 rock contains no fossils, nor w r ere the physical conditions such as to have preserved 
 them even if they had existed. 
 
 5. There seem to be evidences of a gradual thnining out of the Primordial sandstone 
 in its far western extension, as also of all the Palaeozoic formations. According to 
 Dr. Owen, the Protozoic sandstones in Minnesota are at least 500 to 600 feet in thick- 
 ness, and in Iowa Professor Whitney estimates them at from 250 to 400 feet. In Ten- 
 nessee Professor Saiford finds several thousand feet of rocks, which he refers to this 
 age ; and in Texas, where they seem to be quite well exhibited and to yield a large 
 number of fossils, Dr. Shumard gives them as only about 500 feet. In the Rocky 
 Mountain district they are seldom more than 80 feet and never over 200 feet. Indeed, 
 all the Primary fossiliferous rocks are but thinly represented there, while the lower 
 Secondary formations begin gradually to increase in force until all along the eastern 
 
GEOLOGICAL SURVEY OF THE TERRITORIES. 969 
 
 slope we have an enormous development of the Upper Secondary and Tertiary, with an 
 aggregate thickness of from 8,000 to 10,000 feet. 
 
 6. So far as we yet know, there is no unconformability in any of the fossiliferous 
 sedimentary rocks of the Northwest from the Potsdam sandstone to the summit s <r i In- 
 true Lignite Tertiary. There are proofs of two great periods of disturbance which 
 had a marked influence upon the physical geography of the West. The one occurred 
 prior to the deposition of the Potsdam sandstone, when the Azoic or granitic rocks 
 were elevated into a more or less inclined position, and the other and most important 
 period took place at the close of the accumulation of the great Lignite Tertiary de- 
 posits, when the great lines of fracture were produced and the massive nuclei of the 
 mountain ranges wefe raised above the surrounding country. 
 
 7. What changes took place in the physical geography of the West during the long 
 period which must have elapsed after the deposition of the Potsdam sandstone until 
 the commencement of the Carboniferous age, we have very few data to determine. 
 We are inclined to think that this portion of the West at least was elevated above the 
 water level during the greater part of that period ; the numerous indications of shal- 
 low water during the accumulation of the Potsdam sandstone and the almost entire 
 absence of rocks of intermediate age over so large an area further strengthens that 
 opinion. It is true that in the far Northwest we have proofs that the hiatus is partially 
 filled, but in the South and Southwest the evidence is still more meager. Near the 
 Humboldt Mountains, in Utah, Messrs. Meek and Engelmann have detected proofs of 
 Devonian rocks, but they are not known to be largely developed, and on the western 
 declivity of the El Paso Mountains Dr. G. Shuniard found "well-marked strata of the 
 inferior Silurian system corresponding in age to the Blue Limestone of Cincinnati and 
 the Hudson River Group of the New York series."* But so far as our present knowl- 
 edge extends, rocks of intermediate ages do not form a prominent feature in the 
 geology of the West. 
 
 WASHINGTON, November, 1861. 
 
 SKETCH OF THE GEOLOGY OF THE COUNTRY ABOUT THE HEAD- 
 WATERS OF THE MISSOURI AND YELLOWSTONE RIVERS 
 
 By Dr. F. V. HAYDEN. 
 
 [From the American Journal of Science and Arts, vol. xxxi, March, 1861.] 
 
 The observations made during the recent expedition to the headwaters of the Mis- 
 souri and Yellowstone Rivers, under the command of Capt, William F. Rayuolds, To- 
 poo-raphical Engineers, have served to extend quite largely our knowledge of the geo- 
 graphical area of the different geological formations already indicated as existing m 
 the far West. I propose in the following paper to present a brief abstract ot the Lead- 
 ing facts ascertained with a view to their bearing upon the physical geology of the 
 mountain chains. I know that it will be impossible within the limits of a single paper 
 to make every point as clear as could be desired, or to use terms in all cases in thru- 
 usually restricted sense. Much of the country passed over, west ot thy 1 
 had never before been explored by scientific men, no maps existed NY!... ln-\ 
 topoo-raphy with any pretensions to accuracy, and the mount;.. n ran^s xvh.rh wen 
 known to e^ist in that region from information given by traders and ,,, ,,,,, -s w,-,v , 
 always laid down in thei?true geographical localities or with their pio,,, . 
 not until the forthcoming report of Captain Raynolds now iiy-ours,- ,.l ,,1,-, . 
 appears can these deficients be supplied. Moreover, the wild an. hro k,- , ,. . 
 of the surface of the country examined, uninhabited ^&""bg ' ' 
 Indians, precluded the possibility of perfect accuracy in all Hu'.nn no d t 
 can only hope that we have obtained a general idea ot tin- l>nnr. 1 , 
 tures of the vast area explored. The rocks observed belong to the clil. 
 periods in the following order : 
 
 I. Granite, stratified Azoic, and eruptive rocks.T 
 
 -Transactions of the Academy of Sciences, Saint Louis, 
 
 ,is BsS*St?aa 
 
 ...... ' ....... " 
 
 tion, at various periods. 
 
970 REPORT OF THE SECRETARY OF THE INTERIOR. 
 
 II. Potsdam sandstone (Silurian). 
 
 III. Carboniferous rocks (including Permian?). 
 
 IV. Red arenaceous deposits. 
 V. Jurassic beds. 
 
 VI. Cretaceous, with its divisions. 
 VII. Tertiary deposits. 
 
 I. GRANITE, STRATIFIED AZOIC, AXD ERUPTIVE ROCKS. 
 
 Under the first division of my subject I will take up the mountain elevations as they 
 appeared in their- detached portions along our route. It is now well known that the 
 term "Rocky Mountains" is quite general in its application, including a vast number 
 of more or less important ranges of mountains, which, when examined in detail, seem 
 to have been elevated with very little regularity and in many instances to be but 
 slightly connected, but when viewed in the aggregate to present a trend nearly north- 
 west and southeast. Before reaching the main range we find along the eastern slope 
 many detached minor elevations showing the wide geographical area under which the 
 elevating forces acted. 
 
 I allude in the first place to the Black Hills, the northern portion of which we ex- 
 amined on our route from Fort Pierre, on the Missouri, to the Yellowstone River. These 
 hills form the most eastern outlier of the Rocky Mountains, and would seem to be an 
 independent elevation were it not for a low anticlinal which extends across the plain 
 country southward, connecting it with the Laramie Mountains. The central portion is 
 composed of a coarse flesh-colored feldspathic granite, with a series of metainorphic 
 slates and schists superimposed, and thence, upon each side of the axis of elevation, 
 the various fossiliferous formations of this region follow in their order to the summits 
 of the Cretaceous, the whole being more or less inclined against the granitic rocks. 
 The distance across the granitoid nucleus is from 15 to 30 miles, and on each side of 
 the crest or axis of elevation we find the corresponding portions of the fossiliferous 
 beds from the Silurian to the summit of the Cretaceous. The evidence therefore is 
 conclusive that all the unchanged sedimentary strata at a period of comparatively 
 recent date extended continuously over the whole area occupied by the Black Hills. 
 The eruptive rocks reveal themselves at various localities, as at Bear Peak, Inyankara 
 Peak, &c. Bear Peak is a protrusion of very compact igneous rocks, almost isolated 
 from the main range of the Black Hills, and Inyankara Peak is for the most part 
 composed of pentagonal basaltic columns arranged in a vertical position. There is no 
 evidence, however, that they were formed by any force independent of that which 
 elevated the entire range of mountains. 
 
 The next range that we examined was the Big Horn, which is perhaps the most im- 
 portant detached outlier on the eastern side of the main crest of the continent. This 
 seems to trend nearly northwest and southeast, extending into the valley of the Yel- 
 lowstone. The nucleus of these mountains is also composed of red feldspathic granite, 
 with a series of stratified Azoic rocks ; and the unchanged sedimentary strata to the 
 summit of the Cretaceous and including a portion of the Lignite Tertiary can be seen 
 in regular sequence outward inclining at greater or less angles. From the observations 
 of Dr. C. M. Hines, who acted -as geologist to the exploring division under Lieutenant 
 Maynadier, we know that the corresponding formations occur on the opposite side of 
 the axis of elevation, and, as we remarked of the Black Hills, we may infer from this 
 fact that the unchanged sedimentary beds once extended continuously over the whole 
 area occupied by the Big Horn Mountains, in a nearly horizontal position, some time 
 during the Tertiary period. As we pass along the northeastern base of the Big Horn 
 Mountains southwestward, the ridges of upheaval seem to be presented en echelon, the 
 range gradually making a flexure around to the westward. Toward the headwaters 
 of Wind River this range, as it attaches itself to the main chain of the mountains, 
 changes its lithological characters, no true ancient granitic rocks being seen, but in- 
 stead, lofty peaks composed of eruptive rocks, presenting every variety of structure, 
 from compact basalt to porous lava-like masses. 
 
 The Laramie Mountains, by which we mean the whole range from the Red Buttes to 
 the Arkansas, were examined with some care* from Red Buttes southward nearly to 
 Pike's Peak. There is a remarkable similarity in the general geological features of 
 all the mountains on the eastern slope. The more lofty elevations, as Long's and Pike's 
 Peaks, with other ridges and peaks scarcely less lofty than those just mentioned, are 
 composed of the same coarse feldspathic granite before alluded to, but the lower ridges 
 are formed to a great extent of a ferruginous feldspathic granite which easily yields 
 to atmospheric agencies, and the surface of the country is paved with crystals of feld- 
 spar in consequence of its decomposition. All along" the base, and often extending up 
 to the crest of the mountains, we see the outcropping edges of the fossiliferous rocks 
 inclining at greater or less angles, and on crossing over into the Laramie Plains we 
 find the corresponding strata leaning from the opposite side. The granitoid nucleus 
 varies from 8 to 20 miles in width. No indications of true eruptive rocks were observed 
 
GEOLOGICAL SURVEY OF THE TERRITORIES. 971 
 
 in tliis range. The Medicine Bow and Sweet Water Mountains appear to be of the 
 same character for the most part, but 011 the east side of the Sweet Water River the 
 evidence of igneons action is shown on a large scale. The ancient volcanic material 
 would seem to have been elevated to a great height in but a partially fluid condition 
 and then to have gradually cooled, affecting to a greater or less extent the fossilifer- 
 ous strata in contact. 
 
 Near the junction of the Popo Agie with Wind River we came in full view of the 
 Wind River Mountains, which form the dividing crest of the continent, the streams on 
 the one side flowing into the Atlantic and those on the other into the Pacific. This 
 range is also composed to a large extent of red and gray feldspathic granite, with the 
 fossiliferous rocks inclining high upon its sides. After passing the sources of Wind 
 River the mountains appear to be composed entirely of eruptive rocks. Even the ' 
 Three Tetons, which raise their summits 11,000 feet above the ocean level, are formed 
 of very compact basaltic rock.* The Wasatch and Green River Ranges, where we ob- 
 served them, have the same igneous origin, and the mountains all along the sources 
 of the different branches of the Columbia exhibit these rocks in their full force. In 
 Pierre's Hole, Jackson's Hole, and other valleys surrounded by upheaved ridges, these 
 ancient volcanic rocks seem to have been poured out over the country and to have 
 cooled in layers, giving to vast thicknesses of the rocks the appearance of stratified beds. 
 
 The mountains about the sources of the Missouri and Yellowstone Rivers are of erup- 
 tive origin, and in the valley of the Madison Fork of the Missouri are vertical walls of 
 these ancient volcanic rocks 1,000 to 1,500 feet in height, exhibiting the appearance 
 of regularly stratified deposits, dipping at a considerable angle. As we pass down the 
 Madison we find some beds of feldspathic rocks and mica and clay slates beneath the 
 eruptive layers, dipping at the same angle. After passing the divide below the three 
 forks of the Missouri we see a number of partially detached ranges which appear to be 
 of the same igneous character. In the Belt and Highwood Mountains, and indeed all 
 along the eastern slope in this region, we find continual evidence of the outpouring of 
 the fluid material in the form of surface beds, or in layers thrust between the fossilif- 
 erous strata. These igneous beds thin out rapidly as we recede from the point of effu- 
 sion. A large number of these centers of protrusion may be seen along the slope of 
 the mountains west of the Judith Range. The erupted material sometimes presents 
 a vertical wall 300 feet high, then suddenly thins out and disappears. The Judith, 
 Bear's Paw, and Little Rocky Mountains seemed to be composed for the most part of 
 granite and other rocks, with igneous protrusions here and there. I have in a former 
 paper expressed the opinion that the central portions of our mountain ranges are com- 
 posed of feldspathic granite, and to a certain extent this is true in regard to the more 
 eastern outliers, but more recent observations have convinced me that these rocks 
 which I have defined by the term " eruptive" compose by far the greater portion 01 
 the mountain masses of the West. 
 
 -ROFT 
 
 II. POTSDAM SANDSTONE (SILURIAN). ,/ w ; 
 
 The discovery of this formation in its western extension has already been announced 
 in a former paper.t It was first made known as occurring in the Black Hills and rest- 
 ing upon the upturned or nearly vertical edges of the schists, clay slates, and granit- 
 oid rocks, and the inference was drawn that the same rocks would be found forming an 
 outcropping belt along the eastern slope of the Rocky Mountains. After leaving the 
 Black Hills we next observed it along the margins of the Big Horn Range near the 
 summit, holding the same relative position and exhibiting the same lithological char- 
 acters. A few thin layers of fine calcareous sandstone were observed filled with fossils 
 characteristic of this period. At the head of La Boiite Creek, in the Laramie Range, I 
 noticed a bed resting discordantly upon Azoic slates, 50 to 100 feet in thickness, hold- 
 ing the same position and possessing the same lithological characters which it reveals 
 at other localities. I could discover no fossils in it at this point, but I am confident 
 that this bed represents the Potsdam sandstone. The same bed seems to occur a 
 along the mountains from Laramie Peak to Cache la Poudre Creek, underlying the well- 
 known Carboniferous strata, and resting upon the decomposing granitoid rocks wlm-h 
 form the nucleus of the first ridge. This rock (the Potsdam) is more or less changed 
 by heat from beneath, but I was able to trace it continuously from the source of the 
 Chuo-water Creek to the source of Cache la Poudre. a distance of over II 
 was also seen along the eastern slope of the Wind River Mountains, but did not con- 
 tain any organic remains. 
 
 The above facts show very clearly that in its western extension, the primordial zoi 
 of Barrande is represented only by a thin bed of sandstone never exceeding 150 feet 
 thickness, and that it is seen only in a very narrow outcropping belt near the margins 
 of the mountain crests. The stratified Azoic rocks upon which it rests discort lai 1 1 1 \ . s, i 
 far as my observations have extended, never reach a very great thickness 
 
 *This is an error. The Tetons are composed mostly of gneissic granite. 1878. 
 
 tAm. Jour. Sci. and Arts, vol. xxvi, 276. 
 
972 REPORT OF THE SECRETARY OF THE INTERIOR. 
 
 III. CARBONIFEROUS ROCKS (INCLUDING PERMIAN ?). 
 
 f On both sides of the divide of the Rocky Mountains, so far as our explorations have 
 extended, a series of calcareous, areno-calcareous, and arenaceous beds are seen, which 
 we have referred to the Carboniferous epoch. They vary in thickness at different 
 points. Without specifying localities it will be sufficient to remark that all along the 
 margins of any of the mountain elevations in the far West, these rocks are seen in a 
 more or less inclined position. 
 
 Sometimes they are not visible for a short distance (as between the Laramie and 
 Platte Rivers, 20 or 30 miles), but it is plain that they have either been removed by 
 erosion or concealed by more recent deposits. Along the Big Horn Mountains there 
 are alternate layers of sandstone, arenaceous, andmaguesian limestones, many of which 
 show oblique laminae and other indications that their deposition took place in shallow 
 and perhaps turbulent waters. They are here developed to a thickness of 1,000 to 
 1,500 feet, and incline high upon the sides of the mountains at an angle of 50 to 70. 
 They contain few fossils, but these indicate rocks of the same age as those in the Black 
 Hills. Along the Laramie Mountains, from the Red Buttes to Pike's Peak, apparently 
 the same limestones are see"n inclining against the sides of the elevated ridges at greater 
 or less angles, and on the opposite side of the axis, sloping down to the Laramie Plains, 
 the corresponding strata are seen, though leaning at much smaller angles, usually 
 from 9 to 15. Along the Sweet Water and Wind River Mountains these rocks are 
 highly developed and incline against the sides of the ridges of elevation, as heretofore 
 described. The corresponding portions are also seen on the west slope of the main 
 range at the sources of Green and Snake Rivers, but not as conspicuously developed, 
 the eruptive rocks predominating. Crossing back over the dividing crest near the 
 sources of the Madison, Jefferson, and Gallatin Forks of the Missouri, we find similar 
 limestones largely developed and covering a considerable area on the eastern slope. 
 Near the junction of the three forks and along Smith's or Kainas River we find them 
 reaching a thickness of 800 to 1,000 feet, often partially changed by contact with igne- 
 ous rocks beneath. They were also observed around the Judith Mountains, and also 
 about the Bear's Paw and Little Rocky Mountains. 
 
 Nowhere in the Rocky Mountain Range, so far as my observations have extended, do 
 the Carboniferous rocks seem to abound in organic remains, and the few usually seen 
 are generally found in a bad state of preservation and comprise a limited number of 
 species. The precise period to which these rocks belong which are so persistent in all 
 disturbed regions is not positively known, the evidence from organic remains pointing 
 to the age of the Coal Measures and sometimes to that of the Lower Carboniferous pe- 
 riod; probably both members of the system occur there. 
 
 At the foot of the Big Horn Mountains, near the head of Powder River, I observed 
 at one locality a series of beds which indicated the presence of Permian rocks. These 
 beds, which are composed of cherty magnesian limestone, are very much like those 
 already described in Northeastern Kansas, and contain in great abundance some of 
 the same species of fossils as Myalina perattenuata and others. I have also seen similar 
 limestones in other localities, out no fossils were detected, and though having a Per- 
 mian appearance they may belong to the upper portion of the Carboniferous. 
 
 The evidence is clear in many localities that prior to the deposition of the Red Marls 
 succeeding the supposed Permian a very great erosion of the surface of the Carbonif- 
 erous rocks took place. We find, for example, in many localities only a thin repre- 
 sentation of the Carboniferous rocks, and again a full development, 1,000 to 1,500 feet 
 in thickness. 
 
 IV. RED ARENACEOUS DEPOSITS. 
 
 Overlying the Carboniferous rocks, and equally persistent with them, is a series of 
 red arenaceous marl beds or gypsum-bearing marls, which are coextensive with the 
 upheaved sedimentary formations along the Rocky Mountains. The largest develop- 
 ment of these beds which I have observed occurs on the northeastern side of the Big 
 Horn Mountains and on the west slope of the Wind River Mountains, near the source 
 of the Gros Ventres Fork of Snake River. From the Red Buttes, on the North Platte, 
 to Pike's Peak these beds are often removed by erosion or concealed by superficial de- 
 posits, but their appearance in numerous places shoAvs very clearly that beneath the 
 surface they occupy a considerable area throughout the country bordering the mount- 
 ain ranges, possibly extending entirely over the eastern slope. Passing over into the 
 Laramie Plains we find that the red marls constitute the surface formation of the plain 
 country. It has also been shown from Mr. H. Engelinann's explorations that these 
 beds are revealed along the Wasatch Mountains, even south of Lake Utah, furnishing 
 undoubted evidence that they belong to the same great deposit. The fact also that 
 1,000 to 1,500 feet of red arenaceous beds are seen near the sources of Green River, 
 leads to the inference that they continue southward far down the Green River Valley 
 to that portion which takes the name of Colorado, and are in fact a continuation of 
 the extensive red deposits described by various explorers in New Mexico. 
 
GEOLOGICAL SURVEY OF THE TERRITORIES. 973 
 
 These red beds are also seen under similar circumstances highly developed alone the 
 mountains at the sources of the Missouri. There seems to be a change in the Htho- 
 logical characters below the Gate of the mountains, the peculiar red deposits disap- 
 pearing for the most part, and a series of irregular' layers of siliceous limestone with a 
 reddish tinge, and with oblique laminse, ripple-mark and other indications of shallow- 
 water deposition. It is through these layers of rock that the Missouri River cuts its 
 way from the foot of the mountains to the mouth of High Wood Creek, about 10 miles 
 below the falls. They are also distinctly revealed around the Judith Mountains 
 Along the Big Horn Mountains thick layers of gypsum occur, but the gypsum beds 
 are by no means coextensive with the red deposits, and indeed are present in but few 
 localities. Near the head of Powder River the aggregate thickness of the ypsum 
 strata is about 100 feet, while near the source of Snake River there is a thickness from 
 50 to 80 feet. It also occurs to a considerable extent at the foot of the mountains on 
 La Bonte Creek, a branch of the North Platte. 
 
 V. JURASSIC ROCKS. 
 
 These rocks are everywhere revealed, overlying the red deposits just mentioned and 
 possessing an equal geographical extension. Their fullest development and most fos- 
 siliferous condition seems to be along the margins of the Black Hills, where they have 
 furnished the most satisfactory evidence of their age. Along the northeastern slope 
 of the Big Horn Mountains this group of rocks presents its usual appearance of gray 
 and whitish calcareous and arenaceous layers, with indurated, somewhat variegated 
 beds of more or less laminated marls, containing in great abundance Belemnites densus, 
 Pentavrlnus asteriscus, a new species of Ostrea, Pecten, &c. 
 
 At Red Buttes we find a fair development of these beds with the same fossils, but as 
 we proceed southward toward Long's Peak, the intercalated laminated marls disap- 
 pear and the whole formation seems to be reduced to a thickness of 50 to 100 feet, with 
 very few fossils. Along the southwest side of the Big Horn Mountains and the north- 
 east side of the Wind River Mountains we have a thickness of Jurassic rocks from 800 
 to 1,000 feet containing organic remains in the greatest abundance. Crossing the Wind 
 River Mountains we observed the strata corresponding to those upon the eastern side, 
 with B. densus, Ostrea, &c. Returning to the eastern slope at the sources of the Mis- 
 souri, we see occasional indications of their existence, but not so conspicuous as to be 
 readily identified. The age of this group of rocks may be now considered as thoroughly 
 established, so great a number of fossils which appear to be of undoubted Jurassic 
 forms having been obtained. 
 
 I have remarked that the older fossiliferous beds doubtless pass beneath the more re- 
 cent Cretaceous and Tertiary deposits, and occupy a greater or less area underneath 
 the prairie country east of the "divide" of the Rocky Mountains. I have made this 
 inference from the fact that where any elevations occur the complete series of fossilif- 
 erous beds are exposed around the axis of upheaval. That I may not be misunderstood 
 by those geologists who have colored large areas Triassic and Jurassic on geological 
 maps of the West, I would say that I liave never seen any of the older fossiliferous 
 rocks, from the Potsdam to the Jurassic, inclusive, exposed except in narrow outcrop- 
 ping belts around the margins of the mountain elevations. The Carboniferous rocks 
 occupy a belt from one to two miles wide, and the red arenaceous deposits are exposed 
 over about the same area, while the Jurassic form a zone never more than one-fourth 
 of a mile to three miles in width. 
 
 VI. CRETACEOUS ROCKS WITH SUBDIVISIONS.* 
 
 The various subdivisions of the Cretaceous Group in the West were observed at nu- 
 merous localities. The strata in many places occupy large geographical areas, holding 
 a horizontal position, in others forming a belt or zone of greater or less width around 
 the mountain elevations. No. 1 is a well-marked and distinct division along the Mis- 
 souri River from De Soto to a point above the mouth of the Big Sioux River in the 
 eastern portions of Kansas and Nebraska and in the South and Southwest. But when 
 we come into the vicinity of the mountain ranges in the Northwest its typical form is 
 wanting, and apparently an increased development of No. 2 only is seen. Along the 
 Big Horn Mountains, No. 2 is 800 to 1,000 feet in thickness, composed of black, plastic 
 clay with several layers of gray and yellowish calcareous sandstones 10 to 50 feet in 
 thickness. Along the Laramie and Wind River Mountains the same characters are 
 shown. After leaving the Missouri, near the mouth of the Niobrara River, No. 3 is 
 never seen presenting its typical marly character. In the vicinity of the Black Hills 
 we saw a series of beds composed of alternate thin layers of arenaceous and argilla- 
 
 * The Cretaceous rocks of the West have been divided into five formations, num- 
 bered 1, 2, 3, &c. A more careful study of No. 1 ? may render it necessary to make 
 other divisions. 
 
974 REPORT OF THE SECRETARY OF THE INTERIOR. 
 
 ceous sediments with Ostrea congesta and Inoceramus problematicns which may possibly 
 represent No. 3. Along the Big Horn Mountains and from Red Biittes to Cache la 
 Poudre Creek the same fossils were pften found and some other indications of its ex- 
 istence, but no well-marked typical beds were seen. It is now well known that O. 
 congesta and I. problematicus range down into No. 2, so that No. 3 in the West and 
 Southwest may give place to an increased development of No. 2. Nos. 4 and 5 are 
 largely developed everywhere, when not concealed by the overlying Tertiary deposits, 
 especially along the Laramie Mountains and in the valley of Cache la Poudre. In the 
 valley of Wind River all the Cretaceous rocks down to No. 2 appear to have been re- 
 moved by erosion prior to the deposition of the Tertiary beds, and the characteristic 
 fossils of No. 2 are quite abundant. As we pass over the mountains, we have, inclining 
 from the western slope, 600 to 800 feet of alternations of black plastic clays, arenace- 
 ous marls, and beds of sandstones and limestones, with a few seams of carbonaceous 
 matter passing up into calcareous and arenaceous compact rocks. In some arenace- 
 ous limestones near the middle of the series, and extending upward, quite abundant 
 fossils were observed, among them a large Inoceramus, two species of Oslrea, a large 
 Pinna, four inches in length, a Cardium, and a number of undetermined species, 
 with fragments of silicified wood. The general dip of these rocks is about 20. 
 These well-marked Cretaceous beds pass up quite imperceptibly into an enormous 
 thickness of Lignite Tertiary. Passing over the dividing crest to the headwaters 
 of the Missouri, we did not observe any indications of Cretaceous rocks until we had 
 descended below the three forks, where we find traces left after erosion. They do not 
 reveal themselves conspicuously until we arrive within twenty or thirty miles of Fort 
 Benton, where the black, plastic clay begins to overlap the Jurassic rocks, with its 
 characteristic fossils, and on reaching Fort Benton the plastic clay is quite homogeneous, 
 and is developed to a thickness of 800 feet. As we proceed toward the mouth of 
 the Judith River and near the Judith Mountains, we find quite thick beds of concre- 
 tionary sandstone which form the " Stone Walls," "Citadel," &c. It is from these 
 beds that we have obtained a group of fossils which 'we have referred provisionally to 
 No. 1, but which seem to be specifically distinct from all others in the West. It may 
 be that when this group of beds now referred to Nos. 1 and 2, comprising a thickness 
 of 1,500 to 2,000 feet in this region, are more carefully studied, that several subdivisions 
 will be made, having equal importance with the others. During the past season our 
 route led us along the "divide" between the Missouri and Yellowstone rivers, south of 
 the Judith Mountains, so that we passed outside of any good exposures of No. 1, as well 
 as beyond the limits of the estuary beds at the mouth of the Judith. We must await a 
 more thorough and detailed exploration of this region before we can state with entire 
 confidence the succession of the beds. 
 
 VII. TERTIARY DEPOSITS. 
 
 In speaking of the Tertiary deposits of the Northwest, so far as known at; the present 
 time, I propose to separate them into four divisions, which will be sufficient for our 
 immediate purposes : 1st. Estuary deposits. 2d. True Lignite beds. 3d. Wind River 
 Valley deposits. 4th. White River Tertiary deposits. 
 
 The estuary deposits, of which the Judith Basin may be regarded as the type, are 
 quite remarkable and of a most interesting character. ' Opinions of a somewhat con- 
 flicting nature have been entertained in regard to them, owing to the peculiar character 
 of the organic remains ; but recent observations have convinced me that they are all 
 of Tertiary age, and that they are quite widely distributed throughout the for West. 
 The lithological characters of the Judith deposit have already been sufficiently de- 
 scribed, and it has yielded many important fossils. A thin series of beds is also found 
 near the sources of the Moreau, Grand, and Cannon Ball Rivers; and at the mouth of 
 the Big Horn River we have a group of beds 800 to 1,000 feet in thickness, with fossils 
 of the same character as those occurring at the mouth of the Judith. The researches 
 of Mr. H. Engelrnann, in Utah, have also established the existence of an estuary de- 
 posit in the country bordering upon Green River, scarcely less interesting than that of 
 the Judith. These deposits pass up into the true lignite beds without any perceptible 
 line of separation, gradually losing their estuary character and ever after containing 
 only land and fresh-water shells. The lignite strata are chiefly remarkable for yielding 
 in the greatest abundance finely preserved vegetable remains. A few fragments of 
 leaves of Dicotyledonous trees and silicified wood, with very impure lignite beds, are 
 formed in some of the estuary deposits, but no groups to indicate the great luxuriance 
 of vegetation which must have existed during the accumulation of the lignite strata. 
 
 The geographical extension of the lignite deposits of the West is now a matter of the 
 highest interest, and, from what is already known, I am convinced that they will yet 
 be found to cover a greater or less area on both sides of the main "divide" of the Rocky 
 Mountains, from the Arctic Sea to the Isthmus of Darien. The estuary and lignite 
 beds seem also to have partaken equally with the older fossiliferous rocks of the influ- 
 ence which elevated the mountain chains. Along the Laramie Mountains and from 
 
GEOLOGICAL SURVEY OF THE TERRITORIES. 975 
 
 the Red Buttes to the "divide" between Platte and Wind Rivers, along the Big Horn 
 Mountains, the strata incline at very high angles, 40 to 80, and in some instances are 
 very nearly vertical. The true lignite strata seem to conform to the older fossiliferous 
 rocks and to have been disturbed by the same influences that elevated the mountain 
 ranges in the vicinity. These Tertiary beds extended over all the plain country to the 
 north, and east of the Laramie Mountains, far to the northward, beyond the limits of 
 our explorations. Crossing the Wind River Mountains, we find them largely developed 
 high upon the western slope, dipping at a high angle, from the Wind River Range on 
 the one side and the Wasatch and Green River Mountains on the other. 
 
 Throughout the Wind River Valley is a series of beds, of great thickness, which seem 
 to be intermediate in their character between the true lignite beds and the White 
 River Tertiary deposits. We first observed them gently inclined near Willow Springs 
 on the North Platte, and thence westward toward the Sweet Water Mountains and 
 near the "divide" between the North Platte and Wind River they reach a thickness of 
 400 feet. From this "divide" throughout the Wind River Valley they occupy the 
 greater portion of the country, and, though inclining in the same direction with the 
 older strata, the beds do not dip more than 1 to 5. They diifer from the other de- 
 posits in the great predominance of arenaceous sediments and in the absence of vege- 
 table remains, but they contain fragments of turtles and numerous fresh-water and 
 land shells of the genera Helix, PlanorMs, Vivipara, &c. The entire thickness of these 
 deposits may be estimated at from 1,500 to 2,000 feet. From the fact that these de- 
 posits do not conform to the true lignite beds and that detached portions are seen 
 lying upon the sides of the mountains but slightly inclined, while the corresponding 
 beds are shown in the valley below, we infer that they were accumulated long before 
 the mountains were raised to their present height, or perhaps during the gradual pro- 
 cess of elevation. This is especially shown at the upper end of the Wind River Valley. 
 Passing over the Wind River Mountains we again see them holding the same position 
 on the western slope, and possessing the same lithological characters. While the lig- 
 nite beds on the west side of the ''divide" incline at a large angle, the more recent 
 beds, although in some places occupying the very crest of the mountains, seldom in- 
 cline more than 3 to 5. 
 
 The most interesting additional facts which we have obtained in regard to the 
 White River Tertiary beds, are their geographical extension and the evidence of their 
 age in relation to the lignite deposits. We can now show beyond a doubt that the 
 former must have been accumulated long since the latter. We have ascertained that 
 they extend southward along the Laramie Mountains to Willow Springs within 10 
 miles of Cache la Poudre ; that they also extend up the North Platte to the Box Elder 
 Creek, and even beyond are small outliers, showing that much has been removed by 
 erosion. Passing over into the Laramie Plains we find at the source of the Box Elder 
 and extending over to the head of Bates Fork a large development of this Tertiary, 
 and it also reaches far westward to the Medicine Bow Mountains. We also know 
 from the observations of Dr. Hiues that it occupies a considerable area among the 
 Sweet Water Mountains, extending over into the Green River Valley. We have along 
 the North Platte the overlapping of the White River beds upon the lignite strata, thus 
 affording the evidence of ' superposition for their relative age. The same fact was no- 
 ticed between the North Fork of the Cheyenne and the head of Cherry Creek, where 
 beds of marl and limestone containing PlanorMs, Limnea, &c., the same as are seen in 
 the Bad Lands proper, repose upon true lignite Tertiary strata. Again, while the 
 White River beds hold for the the most part a horizontal position, those of the lignite 
 Tertiary are often much disturbed. Near the Black Hills the former seem to have been 
 elevated to a considerable height by 'the upheaval of the mountains, but they do not 
 in any case incline more than 1, while north of the Black Hills the lignite beds dip 
 5 to 10. Alono- the Platte I have seen the former inclining 5, especially on La 
 Bonte Creek and about 15 miles east of the mouth of that creek. Often the beds seem 
 to have been raised up several hundred feet above their original position, without 
 inclination, resting upon the upturned edges of the lignite beds which we have before 
 observed, partook -equally of the disturbing influences which have given so gn-at :m 
 inclination to the older fossiliferous rocks. Along the Big Horn Mountains and tin- 
 North Platte the lignite beds sometimes incline from the foot of the mountains 80- .and 
 often the influence of the elevatory power has affected them far out into 
 
 C In the above accounts of the Tertiary deposits of the West we have shown that the 
 older members are clearly separated into four divisions exclusive bf the Pliocene de- 
 posits of the Niobrara. Let us examine the evidence in regard to the age of the* 
 deposits. If we study the upper portions of Cretaceous ionnnti on >. 5 when not 
 removed by the erosive power of water to any great extent, w.' il..-i. oWrvr t,,m 
 time we pass from No. 4 to No. 5 a gradual change in the sedn.H-n is and ml.,. Ladiea- 
 tions of a slow approach to shallow water; arenaceous sediments begin 
 place of argillaceous, so that we have alternate thin layers 01 sand ** 
 continuing to increase until the upper part becomes a yellow im-n^mous, 
 
976 REPORT OF THE SECRETARY OF THE INTERIOR. 
 
 stone, with most conspicuous examples of ripple-mark and oblique laminae. As the 
 waters of the Cretaceous sea were gradually receding, toward the Atlantic, on the one 
 side, and toward the Pacific on the other, remnants were left in the form of lakes, estu- 
 aries, &c., which now afford us the last indications of marine and brackish water 
 deposits in the central portions of the West. In these deposits we have first a ming- 
 ling of brackish and fresh water forms, gradually passing up to pure fresh water and 
 terrestrial species, with no return to the marine condition again. 
 
 In the upper part of the Cretaceous formation No. 5, on the Moreau, we find the 
 Ostrea suUrigonalis, and in the Judith deposits a form occurs in the greatest abundance, 
 which is undistiuguishable from it. 
 
 'We have also mentioned the fact that the fossils of upper part of No. 5 seem to have 
 existed upon the verge of the Tertiary period, that they sometimes present peculiar 
 forms more closely allied to Tertiary types than Cretaceous, and were it not for the 
 presence of the genera Baculites, Ammonites, Inoceramus, &c., which are everywhere 
 supposed to have become extinct at the close of the Cretaceous epoch, we would be in 
 doubt whether to pronounce them Tertiary or Cretaceous. These facts would seem to 
 indicate a foreshadowing of the Tertiary era, and that the transition from one great 
 period to the other Avas gradual and quiet, the change in the physical conditions being 
 ultimately sufficient to destroy the Cretaceous fauna, and bring into existence that of 
 the Tertiary. Again, in numerous localities where No. 5 is fully developed and a large 
 thickness of Tertiary deposits is superimposed, so that near some of the mountain 
 elevations I have found it difficult to draw the line of separation, no apparent physical 
 break occuring in the sediments. 
 
 Will not these statements go far to show that the estuary deposits ushered in the 
 dawn of the Tertiary epoch and induce the belief that they belong to the first part or 
 Eocene period ? This point is an important one to establish, on account of its bearing 
 upon the history of the physical development of our western continent. 
 
 The estuary deposits soon lose their marine and brackish character and gradually 
 pass up into the true lignite strata, of purely fresh-water origin, thence by a slight 
 discordancy into the Wind River Valley beds, which give evidence of an intermediate 
 deposit between the true lignite and White River Tertiary beds. Then come the White 
 River bone beds, which pass up into the Pliocene of the Niobrara by a slight physical 
 break, and the latter are lost in the Yellow Marl or Loess deposits. I have estimated 
 the entire thickness of Tertiary rocks in the Northwest at from 5,000 to 6,000 feet, and 
 their interest will be appreciated when I venture to suggest that by thorough investi- 
 gation they will doubtless reveal in a most remarkably clear manner the history of the 
 physical growth and development, step by step, of the central portion of this continent. 
 I shall treat this subject more fully in a future paper, and would refer to the forth- 
 coming report of Captain Raynolds for the details of the facts sustaining my opinions. 
 
 We have no evidence, so far as I know, of long continued deep-water deposits in the 
 West, until far up in the Cretaceous period. If we examine the Potsdam sandstone 
 we shall find that where it reaches its greatest force the lower portion is composed of 
 an aggregation of quartz pebbles cemented with siliceous matter, and as we pass up- 
 ward, we find it arranged in thin layers quite compact with fucoidal markings, ripple- 
 mark, &c. Everywhere are most abundant examples of oblique laminae of deposition 
 and ripple and wave markings evidences of shallow waters. 
 
 During the long period that elapsed between the deposition of the earliest part of 
 the Silurian epoch and the commencement of the Carboniferous we have reason to be- 
 lieve that dry land prevailed over a large portion of the West. The Carboniferous 
 epoch commences with thin layers of arenaceous deposits, gradually passing up into 
 homogeneous siliceous and calcareous beds. The latter are never more than from 
 20 to 50 feet in thickness, and then the arenaceous sediments begin again to predomi- 
 nate, and all the proofs of shallow as well as turbulent waters are shown. We then 
 pass up through the red arenaceous deposits and Jurassic beds, and find no rocks that 
 indicate deep water deposition. Cretaceous formation No. 1 commences in many places 
 with a considerable thickness of an aggregation of water-worn pebbles passing up into 
 thin alternate layers of arenaceous and argillaceous sediments with thick beds of sand- 
 stone with ripple markings and oblique laminae, then gradually ceases in No. 2, and 
 through Nos. 2, 3, and 4, the sediments indicate that they were accumulated in com- 
 paratively deep and quiet waters. No. 2 is a black plastic clay, No. 3, gray marl, and 
 No. 4, a dark indurated, sometimes laminated, clay, with many calcareous concretions. 
 In No. 5 we gradually approach indications of shallow Avater until dry land appears, as 
 already stated. 
 
 It will not be possible at this time to mention in detail all the oscillations of surface 
 and other physical changes to which Ave have reason for supposing the country Avas. 
 subjected during all these periods. It is sufficient for our present purpose to show 
 that, except during the Middle Cretaceous epoch, no long-continued periods of quiet 
 water prevailed in these ancient western seas. 
 
 The evidence appears to me to point to the conclusion that a much milder climate 
 prevailed throughout the Avestern portions of our continent, during a greater part of 
 
GEOLOGICAL SURVEY OF THE TERRITORIES. 977 
 
 the Tertiary period, than that which exists iii the same latitudes at the present time. 
 The organic remains appear to indicate a subtropical climate, or one similar to that of 
 our Gulf States. Near the close of the Cretaceous epoch the waters of the great Creta- 
 ceous sea receded toward the present position of the Atlantic 011 the one side, and to- 
 ward that of the Pacific on the other, leaving large areas in the central portions of the 
 West, dry land. These areas were of course in close proximity to the sea, and com- 
 paratively but slightly elevated above the ocean waters. In regard to the mollusca 
 which have been found quite abundantly entombed in the lignite-bearing strata, it is 
 an interesting fact that the most nearly allied living representatives of many of these 
 species are now found inhabiting the streams of Southern Africa, Asia, China, and 
 Siam, apparently indicating the existence of a tropical climate in these latitudes at 
 as late a period as the Tertiary epoch.* 
 
 Again, the luxuriance of the flora which has been so perfectly preserved in the lig- 
 nite strata of the West point to the same conclusion. It is true that until recently no 
 species have been found which belong exclusively to a tropical vegetation, but during 
 our last expedition we obtained a species of true fan-palm, very closely allied to Sabal 
 lamonis, figured by Dr. Heer in his " Flora Tertiaria Helvetia." " The most northern 
 limit of palms is that of Chamcerops palmetto, in North America, in latitude 34-36, and 
 of Chamcerops humilis in Europe, near Nice, in 43-44 N. latitude."t The true palms 
 of our present day are considered as having their native laud within the tropics. That 
 this or a similar condition of climate continued throughout the accumulation of the 
 Wind River Valley deposits may be inferred from their molluscau remains, which are 
 more nearly allied to tropical forms. 
 
 Again, we have in this region, as before mentioned, an extensive area occupied by the 
 lignite-bearing strata. There are from 30 to 50 beds of lignite, varying in thickness 
 from 1 inch to 7 feet. Over all this great area there are at the present time no large 
 forests, no timber except that which skirts the streams. We now know that during the 
 Tertiary period vast forests of timber must have covered many portions of the far West 
 from the abundance and variety of the vegetable remains preserved in the rocks. Silici- 
 fied trunks of trees, 50 to 100 feet in length and 2 to 4 feet in diameter, and stumps which 
 indicate gigantic forest trees occur abundantly over hundreds of square miles along 
 the Missouri and Yellowstone Rivers. Professor Henry and other meteorologists have 
 arrived at the conclusion, from a vast number of well-authenticated facts, that the ab- 
 sence of forest trees on the great prairies of the far West is due to the want of moisture, 
 which is well known to prevail all along the eastern slope of the Rocky Mountains. 
 The prevailing winds are now known to come from the west and northwest, and, as 
 the currents of air laden with moisture from the Pacific ascend the western slope of 
 the mountains, become condensed and deposit their burdens for the most part before 
 reaching the eastern slope. 
 
 Professor Henry, in his paper on Climatology, contributed to the Patent Office Re- 
 port for 1856, says: "The return westerly current, sweeping over the Pacific Ocean, 
 and consequently charged with moisture, will impinge on the Coast Range of moun- 
 tains of Oregon and California, and, in ascending its slopes, deposit moisture on Tli<> 
 western declivity, giving fertility and a healthful climate to a narrow strip of country 
 bordering on the ocean, and sterility to the eastern slope. All the moisture, however, 
 will not be deposited in the passage over the first range, but a portion will be pre- 
 cipitated on the western side of the next, until it reaches the eastern elevated ridge ot 
 the Rocky Mountain system, when, we think, it will be nearly, if not quite, ex- 
 hausted." We are now supposing that the climatic conditions winds, currents of air, 
 &c., did not differ to any great extent during the Tertiary epoch from those which 
 prevail in the same latitudes at the present day. We therefore venture the suggestion 
 that up to the time of the accumulation of the Middle Tertiary deposits the lofty 
 barrier of the Rocky Mountains did not exist. 
 
 WASHINGTON, D. C., January 20, 1861. 
 
 * See Memoir by F. B. Meek and F. V. Hayden in Proc. Phila. Acad., June, 1856. 
 tLindley's Vegetable Kingdom, p. 136. 
 62 I