\ 
 
 J4J 
 
ENGINEER DEPARTMENT, U. S. ARMY. 
 
 REPORT 
 
 OF THE 
 
 EXPLORING EXPEDITION 
 
 FROM SANTA FE, NEW MEXICO, TO THE JUNCTION OF THE GRAND AND 
 GREEN RIVERS OF THE GREAT COLORADO OF THE WEST, 
 
 1859, 
 
 UNDER THE COMMAND OF 
 
 CAPT. J. N. MACOMB, 
 CORPS OF TOPOGRAPHICAL ENGINEERS 
 
 (NOW COLONEL OF ENGINEERS); 
 
 GEOLOGICAL REPORT 
 
 PROF. J. S. NEWBERRY, 
 
 GEOLOGIST OF THE EXPEDITION. 
 
 WASHINGTON: 
 
 GOVERNMENT PRINTING OFFICE, 
 1876. 
 
OFFICE OF THE CHIEF OF ENGINEERS, 
 
 Washington, D. C., June 28, 1875. 
 
 SIR: When Major Macomb, of the Topographical Engineers (now colonel of 
 engineers), made his report of an important exploration in New Mexico, in 1859, he 
 was unable to furnish the report on the geology of that region, owing to the fact that 
 Dr. J. S. Newberry, the geologist who accompanied him, was then actively employed 
 in his duties on the Sanitary Commission in the West. 
 
 Colonel Macomb has recently transmitted to this Office Dr. Newberry's report, 
 with its twenty-two illustrations; and I have respectfully to recommend that it be printed 
 at the Government Printing-Office, and that 1,500 copies be furnished for the use of 
 the Engineer Department upon the usual requisition; also, that this Office be authorized 
 to procure the necessary copies of the illustrations. 
 
 Very respectfully, your obedient servant, 
 
 A. A. HUMPHREYS, 
 Brig. Gen., Chief of Engineers. 
 Hon. WILLIAM W. BELKNAP, 
 
 Secretary of War. 
 Approved: 
 
 By order of the Secretary of War : 
 
 H. T. CROSBY, 
 
 Chief Clerk. 
 JUNE 28, 1875. 
 
CONTENTS, 
 
 / 
 
 LETTER OF TRANSMITTAL. 
 GENERAL REPORT. 
 
 Report of November 1, 1800. 
 Report of November 27, 1861. 
 
 GEOLOGICAL REPORT. 
 
 PREFATORY NOTE. 
 LETTER OF TRANSMITTAL. 
 
 CHAPTER I. 
 GEOLOGY OP THE ROUTE BETWEEN ST. Louis AND SANTA FK. 
 
 General geological sketch Independence to Dragoon Creek Carboniferous strata Character of coal and Coal" 
 Measures of Kansas Due to what causes Coal-plants of Kansas Molluscous fossils Dragoon Creek to Cotton wood 
 Creek Permo-Curhoniferous and Permian strata Difficulty of separating these formations Cotton wood Creek to 
 Walnut Creek Gypsum formation Its parallelism Walnut Creek to Pawnee Fork Lower Cretaceous rocks Sand- 
 stones withimpressions of leaves Pawnee Fork toCimarron Tertiary strata Arkansas basin Its relation to that of 
 White River Cimarron to Enchanted Spring Jurassic? rocks Enchanted Spring to Cottonwool! Spring Lower 
 Cretaceous and Tertiary beds Cottonwood Spring to Canadian Trap buttes and mesas near Raton Mountains- 
 Cretaceous rocks of the Canadian Table-lands skirting the Rocky Mountains Canadian to Las Vegas Trap plateau 
 at Burgwiii's Spring Cretaceous strata at Fort Union and Las Vegas. 
 
 CHAPTER II. 
 
 GEOLOGY OF THE VICINITY OP SANTA FE. 
 
 Santa F6 Mountains Granite General geological features, its character and contained minerals Relations of the 
 Santa F<5 mountains Placer Mountains Cretaceous and Triassic rooks Cretaceous lignite converted into anthra- 
 cite by an outburst of trap Gold of the Placer Mountains Copper Iron The Crreillos Gold Silver Lead 
 Copper Iron Turquoise Ancient Chalchuitl mines The Sandia Mountain The Valles Stratified rocks Carbo- 
 niferous formations Santa Fe section Section at Pecos Village Peruio-Carboniferous beds Gypsum formation 
 Section at San Jos<S Fossil plants Cretaceous formation Subdivisions of the system Yellow sandstones of 
 Canon Blanco Cretaceous Sections at Gallisteo and Pope's Well Tertiary beds of fresh-water origin. 
 
 CHAPTER III. 
 GENERAL VIEW OF THE GEOLOGY OF THE COUNTRY BORDERING THE UPPER COLORADO. 
 
 Bird's-eye view of the Colorado plateau and its surroundings Mountain-chains by which the plateau is encircled 
 Rocky Mountain system Its extent and general structure Different features which it presents on difi'erent paral- 
 lels Different ranges of the Rocky Mountains, probably uot of the same age Rocky Mountain region has suffered 
 
 v 
 
VI TABLE OF CONTENTS. 
 
 alternations of elevation and depression The Cretaceous epoch an era of subsidence The Tertiary, of elevation 
 Mogollou Mountains Probably not a distinct system Mountains of the Lower Colorado a part of the Sierra 
 Nevada system Relation of the Sierra Nevada to the Rocky Mountains Cerbat Mountains AVasatch Mountains 
 San Francisco group Recent volcanic phenomena of the Great Central Plateau Mount Taylor Sierra Tucaue 
 Sierras Abajo, La Sal, &c. Structure of the Colorado plateau Devonian and Silurian rocks of the Great CaTion 
 Carboniferous formation Triassic and Cretaceous rocks Similarity of structure of 'the valleys of the, Little 
 Colorado, San Juan, Grand, and Green Rivers High mesas of Navajo country and Upper Sail Juan. 
 
 CHAPTER IV. % 
 
 GEOLOGY OF THE ROUTE FROM SANTA FE TO THE SIERRA DE LA PLATA. 
 
 Structure of the valley of the Rio Grande The valley of the Chama Abiquiu Copper-mines Fossil plants Ruins 
 of Los Caflones Abiquiu Peak Plateau country bordering tins Upper Chama Arroyo Seco Triassic marls 
 Navajo Spring Cretaceous sandstones and plateau Hanks of the Nutria Middle Cretaceous beds Vada del 
 Chama Section of valley of the Chama High mesa of Upper Cretaceous rocks Laguna de los Cavallos Divide 
 between the waters of the Rio Grande and San Juan General view of the structure of the surrounding country 
 Mountain-chains Belt of foot-bills Table-lands Rio Navajo Cerro del Navajo Sierra del Navajo Kito Blanco 
 The Pagosa Sierra San Juan and associated mountain-ranges Cretaceous rocks and fossils The Piedra Parada 
 liio Piedra Broken mesa View from high divide Rio de Los Piuos Sierra de Los Pinos Rio Florido Valley of 
 the Animas Ruins on the Animus Crossing of the Animus Structure of the mountains drained by the Aiiimas 
 Rio de La Plata Delightful camp Cretaceous rocks and fossils Sierra de La Plata Metalliferous veins of the 
 Sierra de La Plata. 
 
 CHAPTER V. 
 
 'GEOLOGY OF THE SAGE PLAIN AND VALLEY OF THK UPPER COLORADO. 
 
 General features of the northern portion of the Colorado basin Aspects and structure of the Sago plain Mesa Verde 
 Enormous denudation of the Colorado plateau Crossing the Sage plain Rio de Los Mancos Rio Dolores Section 
 of Lower Cretaceous rocks Ruins on the Dolores Sierra San Miguel Suronara Tierra lilanca Guajelotcs Canon 
 Pintado Triassic rocks Saurian bones La Senejal Eroded buttes Casa Colorado Ojo Verde Sierra La Sal 
 Excursion to Grand River Canon Colorado Plateau bordering the Colorado River Eroded monuments 
 Labyrinth Canon Ruined buildings Summit of the Carboniferous formation Section of Triassic rocks Remark- 
 able country about the junction of Grand and Green Rivers Singular eroded buttes and pinnacles Net-work of 
 canons Canon of Grand River Section of Carboniferous strata Transverse section of the Colorado Valley 
 Return to Sage plain Journey southward to the San Juan Sierra Abajo. 
 
 CHAPTER. VI. 
 GEOLOGY OF THK BANKS OF THE SAN JUAN. 
 
 General features of the country bordering the San Juan Section of Lower Cretaceous strata south of Sierra Abajo 
 Bird's-eye view of country bordering San Juan High mesas of the Navajo country Triassic rocks of Lower San 
 Juan Lower Cretaceous strata of Camp 37 Middle Cretaceous beds and fossils south of Lo Late The, Needles 
 The Creston Upper Cretaceous strata at mouth of the Animas Ruins in the San Juan Valley Canon Largo 
 Sections of Upper Cretaceous strata Plateau country bordering Canon Largo Buttes of marls and sandstones, 
 highest members of the series of sedimentary rocks composing Colorado plateau General section of Upper Creta- 
 ceous strata Nascimiento Mountain, its structure and relations Notes on the different formations exposed on its 
 sides- Journey through country bordering western base of Nascimionto Mountain Divide between San Juan and 
 Rio Grande Mount Taylor Cabiezou Tertiary strata at Jeinez The Vallos Trap plateaus. 
 
 DESCRIPTIONS OF CRETACEOUS FOSSILS, BY F. B. MEEK. 
 
 DESCRIPTIONS OF CARBONIFEROUS AND TRIASSIC FOSSILS, BY J. S. NEWBERRY, GEOLOGIST OF THE 
 
 EXPEDITION. 
 
TABLE OF CONTENTS. VII 
 
 * 
 
 ILLUSTRATIONS. 
 
 LANDSCAPE VIEWS. . 
 
 Tii^f - 
 
 Plate I. Abicjuiu Peak, looking westerly !>!> 
 
 Plate II. Near Vado del Chaina, upper cretaceous mesa 71 
 
 Plate III. La Piedra Parada, looking west 78 
 
 Plate IV. The Pagosa and San Juan River, looking easterly 76 
 
 Plate V. Bio Dolores g Sierra de la Plata. From near Camp 21 * 
 
 Plato VI. Casa Colorado and La Sal Mountains, looking northerly 
 
 Plate VII. Head of Labyrinth Crook, looking southeasterly 
 
 Plate VIII. Head of Canon Colorado. Erosion of Triassic series. 
 
 Plate IX. Lower San Juan, looking west. From near Camp 35 102 
 
 Plate X. The Needles, looking southwesterly 106 
 
 Plate XI. The Cabazon, from near Camp 54 - 112 
 
 Trap Dike, Pope's Well, south of Santa F6, New Mexico 51 
 
 The Pagosa, S. W. Colorado 75 
 
 Ruins of stone houses on cliffs, Labyrinth Canon 
 
 PALEONTOLOGY. 
 Plates I to VIII, inclusive, at cud of Descriptions of Fossils, by F. B. Meek and Dr. J. S. Newborry. 
 
LETTER OF TRANSMITTAL. 
 
 UNITED STATES ENGINEER'S OFFICE, 
 
 Hock Island, III., June 18, 1875. 
 
 GENERAL : I have this day forwarded to you the Geological Report of Dr. J. S. 
 Newberry, geologist of the San Juan exploration party, which went from Santa Fd, 
 New Mexico, to the vicinity of the junction of Grand and Green Rivers, in Utah, and 
 back to Santa Fc, in the summer of 1859, and which party was in my charge. 
 
 This is the report to which I alluded in my report to you of November 1, 1860, 
 MS setting forth wha.te.ver the route above mentioned afforded of interest to the public 
 at large or to the man of science. I trust it may be found possible to publish it. 
 
 The report is arranged in seven chapters, with a prefatory note, and is accom- 
 panied by the following sketches and drawings, viz: 
 
 p]leven water-color sketches, showing characteristic scenery of the region in 
 Northwestern New Mexico, Southwestern Colorado, and Southeastern Utah. Also, 
 eleven drawings (eight of fossils and three of scenery), all of which are interesting and 
 important in connection with the report. 
 
 My map of the route was engraved on a steel plate, and is on the files of the 
 Engineer Department. 
 
 I remain, very respectfully, your most obedient, servant, 
 
 J. N. MACOMB, 
 
 Colonel of Engineers, United States Army. 
 Brig. Gen. A. A. HUMPHREYS, 
 
 Chief of Engineers, United States Army. 
 
EXPLORING EXPEDITION FROM SANTA Ftf TO JUNCTION OF GRAND AND GREEN RIVERS. 
 
 GENEEAL REPOET.' 
 
REPORT. 
 
 WASHINGTON, D. d, Noiriiilirr 1, 1S(!(). 
 
 SIR: For the information of the War Department, I beg leave to submit the fol- 
 lowing remarks upon the exploration made by me, during the summer of 1859, in 
 New Mexico and Utah. 
 
 About the middle of July, 1S5!, my party set out from Santa Fe, New Mexico, 
 and pursued a northwesterly course, crossing the Rio Grande Bravo del Norte at tin- 
 old Indian pueblo of San Juan, and following up the valley of the Rio Cliania, pas. 
 ing by the pueblo of Abiquiu, the outpost, of settlement in that direction, being about 
 fifty-two miles from Santa Fe. We continued up the Chama Valley for some forty -five 
 miles more, when we left, it and crossed the dividing ridge between the waters of the 
 Gulf of Mexico and those of the Gulf of California, at a remarkable point, where then- 
 is a small lake called Laguna de los Caballos, when we struck upon the headwaters 
 of the San Juan River, crossing several branches before we came to the main stream. 
 This we crossed in latitude 37 14' 48" north and longitude 107 2' 47" west*wh<-iv there 
 is a hot spring, of temperature about 140 Fahrenheit and of magnificent dimensions. 
 We looked down through its limpid waters until the power of vision was lost in the 
 cavernous depths whence the waters now. From this point our route was westerly for 
 about seventy miles, over a region very much broken and intersected by rapid mount- 
 ain streams (branches of the San Juan), which afford an abundant supply of good 
 water and have the appearance of being permanent. We had fryjruent rains, however, 
 in this part of our route, and the grazing was thus far excellent. Up to a point abouf 
 forty-five miles westward from the " Pagosa," or great hot spring above alluded to, we 
 were accompanied by Mr. Albert II. Pfeiffer, sub-agent for the Utah Indians, and his 
 interpreter, Neponocino Valdez, to both of whom we are indebted for acts of hospi- 
 tality and for facilitating our passage through the country of the Capotes and other 
 bands of the Utah Indians, in whose vicinity our route happened to lead us. 
 
 In latitude 37 16' and longitude 108 4', we passed along the southern base ol 
 the mountain group 1< no wi i as "Sierra de la Plata,;" hence in a northwesterly direction 
 for about one hundred and twenty miles, over gloomy barrens, covered chieily with 
 ArtcmesicB, but affording a scanty pasturage in some of the small valleys. The August 
 rains favored us, and we had no scarcity of water on our route to the "Ojo Verde," in 
 latitude 38 14' 50", longitude 10 ( J 26' 40", a point about three hundred and forty 
 miles from Santa Fe. The greater part of our journey from Abiquiu to this point was 
 
C, EXPLORING EXPEDITION FUOM SANTA i'fi 
 
 by the old Spanish trail, which has not heretofore boon accurately laid down upon any 
 map. This trail is much talked of as having been the route of commerce between 
 California and New Mexico in the days of the old Spanish rule, but it seems to have 
 been superseded by the routes to the north and south of it, which have been opened 
 by modern enterprise. 
 
 At the "Ojo Verde" the Spanish trail strikes oil' more northwardly, to seek a prac- 
 ticable crossing of Grand and Green Rivers. We left the trail here, and, leaving the 
 main bod^y of our party encamped at the spring, with a small party of nine, went to the 
 westward some thirty miles, under the guidance of an Indian, who had joined us 
 many days previously, on our route to look for the junction of the Grand and Green 
 Rivers. This part of our journey was very rough and dangerous, from the precipitous 
 nature of the' route, winding down the sides of deep and grand canons, and it is fortu- 
 nate that no attempt was made to bring forward our pack-train, as we must have lost 
 many mules by it, and, moreover, there was not sutlicient pasture for the few animals 
 that we had with us. I cannot conceive of a more worthless and impracticable region 
 than the one we now found ourselves in. 1 doubt not there are repetitions and 
 riir/rtii's of it for hundreds of miles down the canon of the Great Colorado, for I have 
 heard of hut one crossing of that river above the vicinity of the Mojave villages, and 
 I have reason to doubt if that one (El Vado de los Padres) is practicable, except with 
 ihe utmost care, even for a pack-mule. 
 
 On leaving the "Ojo Verde" we traveled south for about seventy miles, passing 
 by the eastern base of the Sierra Abajo, until we struck the San Juan River, in lati- 
 tude 37 16' 27" and longitude 109 24' 43", on the 2d September, 1851). We found 
 bottom-land of the river at this point of a light and loose soil, into which the feet of 
 the mules would frequently sink for some 18 inches. We followed up the river, 
 remaining on its right bank for some one hundred and twenty miles, until we came oppo- 
 site to the mouth of Canon Largo, in latitude ;)(l 43' 28" and longitude 107 43' 29". 
 In the course of our march we observed many ruins of houses and found quantities 
 of fragments of pottery scattered over the ground, indicating that the valley was once 
 occupied by a race probably of the same origin and character as the Pueblo Indians 
 extant in New Mexico. The fate of those former occupants of that dreary region is 
 ..involved in mystery-. It requires, however, no ell'ort of the imagination to fancy that 
 they may have been starved or frozen to death ; for the winters are severe and fuel is 
 very scarce there. 
 
 I have no doubt that the warm season is very short there, otherwise more of the 
 valley of the San Juan would be cultivated by the Navajos, who are a corn-growing 
 people, for the river affords abundant water for irrigation, and carries soil enough to 
 enrich and renew the fields. 
 
 On the 15th September, IS.")!), we forded the San Juan, opposite Canon Largo, with 
 no little danger, the strong current and deep water sweeping down some of the mules, 
 which were recovered with difficulty. We were fortunate in passing through Cation 
 Largo just after heavy rains, as 1 learned afterward that the command of Major Simon- 
 son, which passed through the canon in July, had suffered much for the want of water. 
 There is one fine spring in the canon, about thirty-five miles from San Juan, but no other 
 
TO JUNCTION OF GRAND AND GREEN RIVERS. 7 
 
 reliable water until the San Jose spring is readied, abrmt thirty miles farther to the 
 southeast. From the last-named water \ve followed down' the vallev of the Puerco (a 
 branch of the Rio del Norte) for about fort}- miles, when we crossed the southern spur 
 of the Nacimiento Mountain and came to the old pueblo of Jemez, about fifty-six 
 miles to the west by south from Santa Ft'. The route has been passed over by 
 
 <J J 
 
 wagons from Santa. Fe to a point, a short distance to the westward of ,Iemex>, and also 
 from Santa Fe to the upper valley of the (,'liama, a short distance above Abiquiu, but 
 on the remainder of the route passed over by my party there is no evidence of a 
 wagon having- ever been seen, and a suitable road for wagons could only be made al 
 a heavy cost for construction, and it would doubtless meet with much opposition on 
 the part, of the Navajos and Utahs, whose country it would pass through. 
 
 During the expedition my time was taken up with the astronomical observations 
 requisite for laying down the route. In these observations 1 was assisted by Mr. F. I'. 
 Fisher, who noted the; time and kept the record for me with accuracy and neatness. 
 Mr. Fisher also carried a barometer throughout the march. All computations required 
 for the astronomical observations were necessarily made by myself. 
 
 Mr. C. H. Dimmock made an excellent sketch of the route, which he has drawn in 
 one large map upon a, scale of half an inch to the mile. This map I have tested by the 
 results of my astronomical observations and computations with very great satisfaction. 
 
 Messrs. Dorsey and Vail carried barometers and thermometers, and kept daily 
 records of the indications of those instruments, chiefly from the readings of Mr. Vail. 
 Mr. Dorsey also assisted the geologist in making some of the collections of natural 
 history specimens. 
 
 Dr. J. S. Newberry, the geologist, of the expedition, was particularly zealous and 
 energetic in his examinations of the country, and I expect from him a report, setting 
 forth whatever there may be of interest, in the route either to the public at large or to 
 the man of science. 
 
 I am now engaged, under your direction, in preparing for publication, upon a scale 
 suitable for ordinary use, a map of the region visited by my party, which will exhibit 
 with all requisite minuteness and accuracy of detail the features of the country, cover- 
 ing an area of some twelve thousand square miles, which has heretofore been indicated 
 upon the maps under the head of "unexplored." 
 
 The expedition was accompanied by a detachment of infantry under the command 
 of Lieut. M. Cogswell, of the Eighth Regiment, to whom we are indebted for our safe 
 escort through a wild and inhospitable tract of country, partly occupied by hostile and 
 treacherous Indians. 
 
 I was directed, on my return to Santa Fe, to reduce my party and come in to 
 Washington to prepare my report, and, on my way, to stop at the southwest corner of 
 the Territory of Kansas, to set up a new monument at a point some two and a, quarter 
 miles to the east of the one originally placed there. I accordingly diverged from the 
 usual route across the plains from Fort Union and went up the Cimarron to the point 
 indicated, and retraced that part of the thirty-seventh parallel from the old monument to 
 the merdian of 10,'5, as laid down upon the map accompanying my instructions, and at 
 the intersection of these two geographical lines I erected a rough stone monument. The 
 
8 KXPLOIUNG EXPEDITION FROM SANTA Ffi 
 
 original monument above alluded to is of earth and sods. This duty \vas finished about 
 tlio middle; of November, lsf>!>, when the thermometer was ranging from zero to about 
 li; above. 
 
 I \vas accompanied to this position bv a small detachment of troops under the 
 
 command of Lieut, H. M. Knos, of the regiment of mounted riflemen, to whose vigi- 
 
 lance i am indebted for a sate transit to Fort Leavenwortli, at a time when the Indians 
 
 of the reat, plains had manifested the most decided determination to be troublesome. 
 
 I remain, very respectfully, your most obedient servant, 
 
 J. N. MACOMB, 
 ( 'a/if ah/, Topographical 
 Capt. A. A. HUMPHREYS, 
 
 Toj>. Kiii/nim-s, in charge of Office of Explorations <nul 
 
 \VASIII\CTO\, 1). C., November 27, 
 
 COLOXI-.N: At the time of making my last annual report 1 was engaged in the 
 preparation of a map of the region visited by the party which I conducted in the summer 
 of IS")!). The map was finished, and is now in the hands of an engraver, who prom- 
 ises to give me the finished plate by the month of March next. 
 
 The report upon the geology, &c., of the same region has been written by Dr. 
 Newberry, and I hoped to have had it in my possession to send in for publication with 
 the animal report from the Bureau of Topographical Engineers, but, owing to the delay 
 in finishing some of the drawings for illustrating the report, and to the fact that the 
 geologist has for some months been actively employed with the duties of the "sanitary 
 commission" in the West, I am not yet in the receipt of his results. I may add for 
 myself that, as in the case of every available officer of the Government, my time has 
 been so much engrossed by the duties which have pressed upon me, arising out of the 
 existing state of affairs in our country, that I have been prevented from pushing the 
 reports and maps, &c., of the San Juan exploration to a conclusion. I hope, however, 
 that they will all be rendered to me before the close of the session of Congress now 
 about to commence. 
 
 All of which is respectfully submitted by your obedient servant, 
 
 J. N. .M.\ COMB, 
 Lieut. Col., Atd-dc-camjt i/> M<tj. (len. McClclluii, it ml Major TojH En<i'niccrn. 
 
 Lieut. Col. H. BACHK, 
 
 Commanding Corps Topographical Engineers, U. S. A. 
 
EXPLORING EXPEDITION FROM SANTA Ffi TO JUNCTION OF GRAND AND GREEN RIVERS. 
 
 GEOLOGICAL EEPOET, 
 
 J. S. NEWBKRRY, M. D., LL. D., 
 
 GEOLOGIST TO THE EXPEDITION. 
 
 2 S F 
 
PREFATORY NOTE, 
 
 COLUMBIA COLLEGE, 
 
 New York, June 1, 1875. 
 
 The following report was prepared for publication at the time indicated by the 
 date of my letter to Captain (now Colonel) Maconib, but the breaking out of the 
 rebellion arrested the publication of all the reports of surveys made by the Govern- 
 ment expeditions immediately previous to this event. The reports of the surveys 
 made by Lieutenant (now General) G. K. Warren, United States Engineers, Captain 
 (now General) W. F. Raynolds, the report of the Northwestern Boundary Commission, 
 and some others, were in this category, and much most valuable information in regard 
 to the far West has been lost to the country and the world by the suppression of 
 these important dociiments. 
 
 As attention is now again drawn to the region bordering the San Juan and Upper 
 Colorado, and several parties are occupied in exploring adjacent districts, the results 
 of the explorations made by the San Juan Exploring Expedition have acquired an 
 importance in this connection which has rendered their publication desirable. They 
 are therefore now given to the public. Although much has been learned in regard to 
 the geology of the country drained by the Colorado River during the last ten years, 
 and much that has a bearing on the subject-matter of this report, none of this lately- 
 acquired knowledge is referred to on its pages, but they are printed precisely as written 
 in 1860. 
 
 This course has been pursued as the only just and natural one. The observations 
 made fifteen years ago, if accurately made, have equal value now as then; if inaccurate, 
 it is only right that the credit of the correction of errors should belong to those who 
 make such corrections. The geological narrative now given stands, therefore, just as 
 written, and is a fair exponent of the state of our geographical and geological knowledge 
 of the West at the date of its preparation. It is evident that to modify the report so as 
 to conform to all the conclusions more recently reached, would be to falsify the record 
 and greatly impair the independence and value of the statements it includes. The 
 truth or error of these statements will soon be demonstrated by the extension of the 
 explorations of other parties into this field. It is but just that the credit or discredit of 
 the trial to which the report is to be subjected should belong to the writer. Knowing 
 that his work was done honestly, and believing that it was in the main accurately done, 
 he accepts the entire responsibility of it, whether for praise or blame. 
 
 J. S. N. 
 
LETTER OF TRANSM1TTAL, 
 
 WASHINGTON, D. C., May 1, 18(id. 
 
 DEAR SIK : I submit herewith my report on the geology of the country traversed 
 by the San Juan Exploring Expedition; in which I had the honor to serve under your 
 command. 
 
 Very respectfully, your obedient servant, 
 
 J. S. NEWHKKRY. 
 Capt. J. N. MACOMH, 
 
 Topographical Eni/'ntccrs, United States Army. 
 
CHAPTER 1. 
 
 GEOLOGY OF THE ROUTE BETWEEN INDEPENDENCE AND 
 
 SANTA FE. 
 
 GENERAL GEOLOGICAL SKETCH INDEPENDENCE TO DRAGOON CREEK CARBONIFEROUS 
 STRATA CHARACTER OF COAL AND COAL MEASURES OF KANSAS DUE TO WHAT 
 CAUSES COAL-PLANTS OF KANSAS MORUSCAS FOSSILS DRAGOON CREEK TO COTTON- 
 WOOD CREEK PERMO-CARBONIFEROUS AND PERMIAN STRATA DIFFICULTY OF SEPA- 
 RATING THESE FORMATIONS COTTONWOOD CREEK TO WALNUT CREEK GYPSUM FORMA. 
 
 TION ITS PARALLELISM WALNUT CREEK TO PAWNEE FORK LOWER CRETACEOUS 
 ROCKS SANDSTONES WITH IMPRESSIONS OF CAVES PAWNEE FORK TO CIMARRON TERTI- 
 ARY STRATA ARKANSAS BASIN ITS RELATION TO THAT OF WHITE RIVER CIMARRON TO 
 ENCHANTED SPRING JURASSIC (?) ROCKS ENCHANTED SPRING TO COTTONWOOD SPRING 
 LOWER CRETACEOUS AND TERTIARY BEDS COTTONWOOD SPRING TO CANADIAN TRAP 
 BUTTES AND MESAS NEAR EATON MOUNTAINS CRETACEOUS ROCKS OF THE CANADIAN 
 TABLE-LANDS SKIRTING THE KOCKY MOUNTAINS CANADIAN TO LAS VEGAS TRAP 
 PLATEAU TO BURGEOIN'S SPRING CRETACEOUS STRATA AT FORT UNION AND LAS 
 VEGAS. 
 
 The geology of the country bordering the Santa FC" road is described somewhat 
 in detail in Chapter X of my report to Lieut. J. C. Ives, U. S. A., on the geology of 
 the Colorado country. It will not, therefore, be necessary to devote as much time 
 and space to this portion of our field of explorations as though it were before wholly 
 unknown. In our recent journey from Independence, Mo., to Santa Fe, however, we 
 passed over quite a large area not traversed on the route from Santa FC" to Fort 
 Leavenworth. In repassmg also the route formerly traveled, our stopping-places 
 were, in many instances, different ; many new exposures of the rocks were examined, 
 and observations were made by which it is now possible to define much more accu- 
 rately than was formerly done the geographical limits of the different formations met 
 with. I am happy to say that the conclusions arrived at in my former report on the 
 geology of this region, in regard to the relative position of the various strata noticed, 
 were fully confirmed by our later observations; and the value of the facts now 
 reported consists, for the most part, .in the more accurate limitation of the surface- 
 boundaries of the formations, and in the paleontological evidence which they furnish 
 of the age of strata before, in a great degree, conjectural. The number of fossils 
 discovered in our late transit of the plains was large in the Carboniferous, Permian, and 
 Cretaceous rocks, but I had constant occasion to regret that our means of transporta- 
 
!(} EXPLORING EXPEDITION FROM SANTA FE 
 
 tion were so limited that I was compelled to leave much behind that would have been 
 cit' great interest if brought in. Among the localities most rich in fossils, to which I 
 would call the attention of future collectors, are the exposures of the Upper Carbon- 
 iferous series in Eastern K;ins;is, near Uniontown, at Rockhouse, Walter's Station, 
 and Burlingame ; Permo-Carboniferous, at Dragoon Creek and Wilmington; true 
 Permian on the hill-tops east of Council Grove, and on Cottonwood Creek; Lower 
 Cretaceous at the crossing of Pawnee Fork, at Cedar and Cottonwood Springs, and 
 Whetstone Creek; Middle Cretaceous (Upper Cretaceous of former report) in the 
 valley of Red Fork of Canadian, particularly at the " Breaks of Red River." 
 
 INDEPENDENCE TO DRAGOON CREEK. 
 
 The surface-rocks of all Eastern Kansas and Western Missouri belong to the 
 Coal-Measures. These are exposed in many places along the banks of the Missouri, 
 and include beds of coal which are extensively worked at Lexington. In Kansas I 
 have examined the out-crops of the Coal-Measures at various points on the road from 
 Independence westward, about Leavenworth City, along the valley of the Kansas, on the 
 Stranger, Grasshopper Creeks, &c. Taken as a whole, the Coal-Measures of this region 
 present a marked contrast with those of the northern portion of the Illinois coal-field, 
 and a still greater one with those of the Ohio and Pennsylvania. This difference con- 
 sists in the much smaller aggregate quantity of carbonaceous matter and in the vast 
 preponderance of organic over mechanical sediments, i. e., of limestones over the sand- 
 stones and shales, which make up the great mass of the Carboniferous series in the 
 northern portion of the Allegheny coal-field. As I have formerly remarked, this dif- 
 ference seems to be a consequence of the fact that, during the Carboniferous epoch, the 
 region occupied by the coal-basin of Missouri and Kansas was more remote from the 
 source from which the mechanical sediments were derived, and was much more fre- 
 quently, or at least for longer periods, submerged beneath the water of the ocean than 
 the region with which I have compared it. Professor Hall has indicated a similar dif- 
 ference of structure between the northern and southern portions of the Illinois coal- 
 field, and has clearly shown how the great calcareous masses of the southern extremity 
 of this coal-basin are the records of the existence of an open sea in the regions where 
 they exist, while the coal, sandstones, and shales were accumulating on the low shores 
 or shallows bordering the continent which lay to the north! 
 
 In my former report, I have described the progressive change which was noticed 
 in the structure of the Carboniferous series in going from New Mexico to Ohio, and 
 have shown how the great masses of limestone without beds of coal, and almost with- 
 out any mechanical admixture, were succeeded in Kansas by a series of thick, but 
 distinct!}' separated beds of Fusilina limestone, between which were thinner strata of 
 fine argillaceous shale, with a few seams of cannel or cannel-like coal; and that in 
 Ohio the Fusilina limestones, not individually, but as a group, are represented by the 
 thin calcareous bands which separate the greatly-preponderating masses of mechan- 
 ical sediment. Further examination lias fully verified tlie accuracy of these observa- 
 tions, and has confirmed in all its general bearings the theory by which the phenomena 
 were explained. It should be observed, however, that the change which has been 
 
TO JUNCTION OF GRAND AND GREEN RIVERS. 17 
 
 remarked by Professor Hall in the structure of the coal-basins, going from north to 
 south, and by myself from northeast to southwest, is not uniformly progressive through- 
 out their entire extent, but was modified locally by the sinuosities of the shore-line of 
 the northern main-land, and by the presence of islands at a greater or less distance from 
 the shore toward the south and southwest; in illustration of which we may cite the 
 comparative barrenness uf the Coal- Measures of Northern and Central Illinois, where, 
 as in Kansas, the calcareous strata, vastly predominate, with the greater development 
 of strata and mechanical sediments in Southern Illinois and Kentucky; so also the 
 productive Coal-Measures of the region about Fort Belknap, in Texas, where the quan- 
 tity of carbonaceous and sandv matter is equal to, if not greater than, that of Kansas 
 directly north. At Saute Fe, also, as will be seen from the description hereafter to be 
 given of the geology of that vicinity, the Carboniferous series includes a great thickness 
 of coarse sandstone filled with the impressions of land-plants, evidently transported no 
 very great distance from their place of origin. As we progress southward, however, 
 we ultimately reach the limit of traces of the existence of terrestrial surfaces during 
 the coal period, as in Southern and Southwestern New Mexico, where the entire Car- 
 boniferous series is represented by a calcareous mass, all an organic or chemical pre- 
 cipitate from the waters of the ocean, and the proof of the uninterrupted existence of 
 an open sea in that region throughout the entire carboniferous epoch. 
 
 Coal. The coals of Missouri and Kansas have all, to a certain extent, a common 
 character, as compared with those of the Alleghany coal-fields ; they are softer, and 
 contain a larger amount of volatile matter, of water, and of sulphur. Some of them 
 are cannel, frequently handsome and of good quality, and those which are not strictly 
 cannel are more or loss like it in chemical composition and physical structure, and they 
 frequently have layers of cannel running through them. They are generally quite 
 tender, and when exposed to the action of the weather, like the Cretaceous and Ter- 
 tiary coals of the western part of the continent, which they so much resemble, they 
 are prone to "slack," or to break up into innumerable rhomboidal or cubical fragments. 
 
 The causes of the peculiar character of the coals of Kansas are to be sought, I 
 think, in the physical conditions attending their formation, rather than in any peculi- 
 arity of the vegetation from which they were derived. In a paper, published in the 
 American Journal of Science, of March, 1857, I have attempted to show that the char- 
 acters which distinguish cannels from other bituminous coals are for the most part due 
 to the excess of water in which they were submerged during the process of their for- 
 mation. I have also been led to suppose that this cause has, to a considerable degree, 
 given to the western coals the characters they exhibit; that the carbonaceous matter 
 composing them was, during its accumulation, more thoroughly saturated or more 
 completely submerged than that composing the coal-strata of the Alleghany basin; 
 and that when the coal-seams had attained their entire thickness they were not imme- 
 diately buried beneath heavy masses of mechanical sediment, by the weight of which 
 all the effects of great pressure would bo obtained, but, instead, were submerged per- 
 haps deeply beneath water, the pressure of which would be expended in all directions, 
 and would, therefore, not -act as a distinct compress on the saturated mass. That the 
 chemical characters of these coals have been in any great degree modified by this cause 
 
 3SF 
 
18 EXPLORING EXPEDITION FROM SANTA FE 
 
 I will not insist, but, by submerging a porous body, such as a sponge, it will be seen 
 that the pressure of the .superincumbent water lias no tendency to bring its particles in 
 contactor consolidate it. The excess of sulphur is doubtless due to the decomposition 
 of the numerous marine organisms which inhabited the water by which the coal was 
 saturated or submerged. 
 
 Fossils. The conditions under which the coal-strata of Kansas have been formed 
 were not favorable to the preservation of a large number of plants; less than a dozen 
 species having been discovered there up to the present time. These are 
 borassifolia, Atmxlunu H]>]/<>>/i>]>//i/</i<l<'x, Sphettopkyttum di'i/fuhiin, Ali'/liojitrri* Hn-l 
 teris arborescens, Neuropteris jfaKuosOj N. hh'x/tfit, ami sif/'illai-in M> n/u'<li. These plants 
 are all found in the coal-formation east of the Mississippi. 
 
 The molluscous fossils of this region have been pretty thoroughly worked up by 
 Messrs. Shumard, Swallow, and 'Meek. The}- are enumerated in the papers of these 
 gentlemen in the proceedings of the Saint Louis and Philadelphia academies; and in 
 Chapter X of my report on the Geology of the Colorado Country. 
 
 In some portions of Eastern Kansas the Upper Carboniferous limestones contain 
 the remains of echinoderms, of which the spines and plates sometimes almost com- 
 pletely cover the weathered surfaces of the rocks. They all belong to the genus 
 Archceocidaris, and constitute several species described bv Messrs. Shumard and Hall. 
 These fossils present a new feature in the Carboniferous fauna to one who has studied 
 that formation only east of the Mississippi, where they are exceedingly rare. They are, 
 however, equally common in the Carboniferous rocks of Ne\v Mexico; one of the 
 Kansas species recurring in great numbers at 1'ccos Village, near Santa Fe, and sev- 
 eral others of large size, described in my report to Lieutenant Ives, are conspicuous 
 features in the limestones, equivalents of the Coal-Measures, on the banks of the Col- 
 orado. 
 
 The Fusilinas, which give character to the Fusilina limestones of Missouri and 
 Kansas, have attracted the attention and excited the surprise! of every geologist who 
 has visited that region. The Coal-Measure limestones are almost everywhere crowded 
 with them, and in many instances they compose by far the greater portion of their 
 mass. It is not easy to say what influences could have fostered this enormous develop- 
 ment of Foraminiferous life in the sea from which the Kansas limestones were deposited ; 
 for these fossils, like the echinoderms of which I have spoken, are almost unknown 
 east of the Mississippi; but, unlike them, are comparatively rare in the limestones of 
 
 New Mexico. 
 
 DRAGOON CREEK TO (JOTTONVVOOD CttKEK. 
 
 The Carboniferous rocks which I have described as so characteristic of Eastern 
 Kansas, prevail without interruption overall the interval between Independence, Mo., 
 and Dragoon Creek. Although the exposures of the underlying rocks are frequent 
 along the Sante Fd road, the surface is merely undulated, nowhere broken, and there 
 are no deep excavations formed by the draining streams. As a consequence the order of 
 succession of strata could not be fully made out, and it is probable that not every nun i- 
 ber of the series is anywhere visible along our line of exa.nrina.tion. It is not certain, 
 therefore, that there are not beds of coal or other valuable minerals still lying concealed 
 
TO JUNCTION OF GRAND AND GREEN EIVERS. 19 
 
 by the 1 prairie-grass or beneath the widely-spread Drift deposits over which passes the 
 great thoroughfare of the Sante Fe road. As far as I could see or learn, however, the 
 Coal-Measures are then* generally barren of useful minerals. The iron-ores and the 
 fire-clays, so abundantly associated with the coal-beds in Ohio and Pennsylvania, are 
 almost entirely wanting, and but a single outcrop of a coal-seam of workable thick- 
 ness that of Buriingarae, described in my former report is known in the vicinity of 
 our route. The coal-strata of this region are, however, not only less numerous, but 
 less continuous than are those east of the Mississippi, and it is highly probable that 
 local but valuable deposits of mineral-fuel will hereafter be discovered where their 
 existence is not now suspected. 
 
 At Dragoon Creek we read: the extreme summit of the Carboniferous formation, 
 and first meet with those which may be regarded as distinctly Permian. As has been 
 remarked, in the discussion of this question on a former occasion, it is exceedingly 
 difficult, if not impossible, to separate these two formations in this region by any well- 
 defined line This is clearly shown also by the able analysis of the geological struc- 
 ture of Eastern Kansas by Messrs. Meek and Hayden, and Swallow and llawu, and 
 especially by the difference of 'opinion which still exists among these gentlemen as to 
 where the line of demarcation should be drawn. The rocks of that country are conform- 
 able throughout, and the materials composing them are so similar as to indicate great 
 uniformity in the physical conditions which attended their deposition. The fossils 
 which they contain must therefore be our only guide in their classification ; and these, 
 though numerous and well marked, are so distributed as to give fair ground for con- 
 siderable difference of honest opinion 
 
 Beneath the variegated non-fossiliferous series of the Trias, are certain beds of 
 magnesian limestone which contain a large number of fossils, for the most part gener- 
 ieally identical with, and specifically closely allied to, the most characteristic forms of 
 the Permian of Europe. These consist of species of Balcevellia, Lcda, Axinu*, Monotis, 
 f//<t/hi(/, l'/<'iii-<>j>litif(i/i.^ J'roilxrtus, Atliyrix, Cltoiirlrx, Xanli/ti^, Hr/lrn>j>'/t(t, 
 , &c. Of these one species of Monotis, and another of Myaliiitt, are scarcely 
 distinguishable from those which occur in the Coal-Measures below, though very possi- 
 bly distinct. The Athyiis, however a variety of A. subtil ita, but broader and more 
 gibbous than the common form recurs in the underlying strata with a fauna decidedly 
 Carboniferous. The same is probably true of a species of Betterophon common in these 
 magnesian limestones. The 1'rodnctns mentioned (P. Calhouni(tiittx) is scarcely differ- 
 ent from P. st'inirciiciiltifnu. With the possible exceptions I have enumerated the fauna 
 of this group is decidedly Permian in character; and if the Permian formation is to be 
 regarded as distinct from the Carboniferous, which is scarcely to be doubted, although 
 the separation would not have been made if our American strata had been the basis of 
 ideological classification, this upper group of magnesian limestones should undoubtedly 
 be called Permian. Below the magnesian rocks to which I h;we referred, occur numer- 
 ous alternations of magnesian limestones and variously-colored clays which contain a 
 mingling of Carboniferous and Permian fossils, or perhaps more properly a, mingling of 
 the species contained in the upper group of magnesian limestones with others common 
 in the Carboniferous st.j-a.ta below, added to which are a few species that seem to be 
 
20 EXPLORING EXPEDITION FEOM SANTA FE 
 
 restricted to this geological horizon. In the upper part of this intermediate group of 
 strata, we have the Bakevettia, Pleitrophorous, Axinus, c&c., of tlie beds above, and a fauna 
 perhaps more Permian than Carboniferous, but below we soon reach a level where the 
 Carboniferous types predominate. This group of strata has been regarded by Professor 
 Swallow as all of Permian age, while Mr. Meek terms it Permo-Carboniferous, draw- 
 ing the line which marks the base of the Permian at the base of the first group of mag- 
 nesian limestones, and restricting this term to those members of the series in which the 
 Permian fauna predominates over the Carboniferous. 
 
 From this interlocking of the Carboniferous and Permian faiinse, it is evident that 
 the line of separation., between the two formations must continue to be debatable 
 ground; and as there is, in fact, a group which contains a mingled fauna in truth, a 
 Permo-Carboniferous group we must introduce this new member into the geological 
 series, or fix upon some conventional line which shall form the boundary between the 
 summit of the Carboniferous and the base of the Permian formations. To avoid com- 
 plicating the geological sCale, the latter course would undoubtedly be the wiser one; 
 and since there is neither physical nor vital break in the series, it is perhaps not a 
 matter of great consequence whether the line be drawn at the horizon where the first 
 Permian type makes its appearance, or at the horizon beyond which the last Carbon- 
 iferous species ceases to exist, or even at the point, if indeed it were determinable, 
 where the species of the two formations are represented in eqiial numbers; in other 
 words, whether at the top, bottom, or middle of the Permo-Carboniferous group. It 
 will be seen by reference to the papers which have been before cited, that, while con- 
 taining several Permian types, the fauna of the "Lower Permian" group of Swallow 
 and Hawn has considerably more of the Carboniferous than Permian character; and 
 as great bodies attract more strongly than small ones, it seems more natural that the 
 debatable ground should be ceded to the great and well-defined Carboniferous series, 
 of which the symmetry would suffer without it, rather than to the comparatively insig- 
 nificant and ill-defined Permian formation. It seems probable, therefore, that the 
 "Lower Permian " group of Swallow and Hawn will be regarded as an integral portion 
 of the Carboniferous system, while the term Permian will be restricted to the Permian 
 of Meek and Hayden, to the "Upper Permian" of Swallow and Hawn. It is evident 
 that only those strata should be regarded as Permian in which the Permian fauna pre- 
 dominates. 
 
 In the hills bordering Dragoon Creek I first found limestones containing the group 
 of fossils Pleurophorom, Bahevellia, Axinus, Jirl/ci-opkon, &c. to which I have referred 
 above. Farther west, toward Council Grove, the hills are capped with yellow mag- 
 nesian limestone, in many places crowded with the valves of I><il;cr<>IH<( parva. Over a 
 considerable area in this vicinity the highlands are occupied by what may be consid- 
 ered true Permian strata, while the valleys of all the water-courses are excavated to 
 and into the Permo-Carboniferous, or, as I have called them, Upper Carboniferous 
 strata. 
 
 At Council Grove, Diamond Spring, Lost Spring, and Cottonwood Creek, obser- 
 vations were made and fossils collected by Major Hawn, Messrs. Meek and Hayden, 
 and myself last year. The geology of all these points is nearly the same. At each the 
 
TO JUNCTION OF GRAND AND GREEN RIVERS. 21 
 
 Permian magnesian limestones occupy the general surface, but are cut through bythe 
 valleys of the draining .streams. Below them are exposed strata containing Orlliix'nta 
 Hiitlirtirtiltiui J'roi/tirfii:-; C(i/l/<ntiii<ni,t<.<i ; spines of a species of Archceocidaris, regarded 
 by Professor Swallow as identical with A. V(.'rncit(/i(ii/(i, King; a small Athi/ris, and a 
 lili/inchiiiii'lla ; all of which belong rather to the Carboniferous than to the Permian 
 fauna, .Near Cottonwood Creek the Upper Magnesian limestone, or true Permian, is 
 highly fossil iferous; containing great numbers of Myalina perattenuata, Monotis (Pseu- 
 (loinoiKiti.s), I/dint/, Hnh'ri'lliK /><irr<t, and many other species described by Meek and 
 Hayden, who collected largely at this locality. 
 
 COTTONWOOD CREEK TO WALNUT CHEKK. 
 
 THE GYPSUM FORMATION. 
 
 On the west side; of Cottonwood Creek, the Permian limestones pass beneath the 
 surface, and are not distinctly recognizable at any western' point niton the Saute F(5 
 road. They are succeeded by a series of reddish-yellow and white indurated marls, 
 forming a part of the great " Gypsum formation," which is so conspicuous a feature in 
 the geology of the Indian Territory, New Mexico, and Western Texas. This group 
 fills the interval between the Permian strata, which I have described, and the base of 
 the Cretaceous system; including representatives of perhaps portions of the Permian, 
 the Triassic, and Jurassic formations of the Old World. The magnificent exposures of 
 this series which abound in New Mexico, have been noticed by every geologist and 
 almost every trayeler who has entered that country. It will be seen by reference to 
 the reports upon the geology of the Southwest made to the Government bythe writer 
 or others, that this formation is everywhere characterized by great poverty of fos- 
 sils, and for this reason, as well as from the general similarity of its lithological char- 
 acters from base to summit, and in different localities, it has been hitherto impossible to 
 separate it by satisfactory dividing lines, or to determine with accuracy the equivalence 
 of any of its parts with the different formations which it may be supposed to repre- 
 sent. The study devoted to this group of strata by the writer, while connected with 
 the party under the command of Lieutenant Ives, was not wholly fruitless, but it must 
 be confessed that, as far as regards the determination of the parallelism of its sub- 
 divisions with the strata to which they have been referred, it enables him rather to say 
 what they are not, than what they are. The observations made upon this formation in 
 our recent explorations of the country bordering the San Juan and Upper Colorado 
 Rivers where it is very largely developed will be detailed in the subsequent chap- 
 ters of this report, and it is hoped that they will serve to throw some additional light 
 on this difficult and perplexing subject 
 
 The materials composing the Gypsum formation are usually so soft that in a 
 country well supplied with rain and covered with vegetation they present few satisfac- 
 tory exposures, and are even usually wholly concealed from view. This is the char- 
 acter of the district now under consideration, and it is only here and there that the 
 traveler can obtain even a glimpse of its geological substructure. It is evident, how- 
 ever, from the limited space occupied by the outcrop of this group, taken in counec- 
 
22 EXPLORING EXPEDITION FROM SANTA FE 
 
 tion with tlu 1 nearly horizontal position of the strata, that the interval which here sep- 
 arates the Carboniferous and Cretaceous series is far less than at any point where it 
 lias been examined farther to the south and west. This is also proved from the sec- 
 tions given by Messrs. Meek and llayden in the report of their explorations in Kansas, 
 where it is shown that the rocks Oiling this gap have not more than one-third or one- 
 fourth the thickness of those which occupy the same relative position in New. Mexico. 
 
 The interesting discovery by Dr. llayden of a group of strata in the Jilack 
 Hills, which represent a portion of the Gypsum formation and yet contain numerous 
 well-marked Jurassic fossils, shows that this series exhibits in different localities consid- 
 erable diversity of character and development, and encourages us to hope that here- 
 after similar industry and energy, by bringing to light other localities where these 
 strata are fossil iferous, will permit an accurate classification to be made of them on 
 paleontologies! grounds. It may then be possible to establish a parallelism between 
 subdivisions of this group and the Jura and Trias of Europe, but it is evident that 
 until unmistakable Triassic fossils are discovered in the Southwest, even this general 
 parallelism can hardly be said to be established. That it will ever be possible to iden- 
 tify in the members of the Gypsum formation the Oolite, Lias, the Marnes-Irisees, the 
 Muschei/ca//:, and (Ircx-hir/unr, is more than doubtful. 
 
 On the banks of the Little Arkansas there is an exposure of laminated, yellowish- 
 white, fine-grained, rippled-marked sandstone, and a singular cellular amygdaloid-lite 
 magnesian (?) limestone, which apparently belong to the Gypsum formation, yet which 
 exhibit lithological characters such as I have not elsewhere seen in any member of 
 that group. As far as observed they contain no fossils whatever, and without further 
 evidence it is impossible to say what are their precise equivalents in other localities. 
 
 I shall soon have occasion, in speaking of the geology of the; region bordering the 
 Upper Cimarron, to refer to another group of strata which underlie the Lower Creta- 
 ceous rocks and hold a place usually occupied by a portion of the Gypsum series. 
 These strata present characters somewhat at variance' with those usually exhibited by 
 the Gypsiferous group, and such as have led me to suspect that they form part of a 
 somewhat local deposit, which may be the representative of the Jurassic strata, dis- 
 covered by Dr. llayden in Nebraska. I have been able to discover no evidence 
 of the existence of similar rocks, beneath the Cretaceous and above the Permian, east 
 of Walnut Creek. 
 
 WALNUT CliEEK TO PAWNEE FORK. 
 
 LOWER CRETACEOUS ROCKS. 
 
 Before reaching Walnut Creek, the Santa Fe road enters the valley of the Arkansas, 
 which is several miles in width, and is bounded on the north and west by the abrupt 
 edges of the "high prairie," a nearly level plateau, which occupies an immense; area west 
 of this point. In this plateau the tributaries of the Arkansas have excavated valleys 
 of greater or less breadth, but they are generally narrow and are separated by "divides" 
 of the high prairie, which to the eye are as level as the surface of still water, and are 
 everywhere covered with a velvety carpet of buffalo-grass. Smoky Hill Fork of the 
 Kansas, Cotton wood Creek, the Little Arkansas, Cow Creek, Walnut Creek, etc., all 
 
TO JUNCTION OF GRAND A.ND GREEN RIVERS. 23 
 
 traverse, at least through a part, of tli^ir courses, channels^ which they have excavated 
 in the "high prairie.'' 
 
 Throughout the greater part of the area, drained by these streams the geological 
 substratum of the plateau I have described is the Lower Cretaceous sandstone, or, 
 more- properly, a f/roitji if strata, though sometimes consisting of but a single bed, 
 which forms the base of the Cretaceous system; No. 1 of Meek and Hayden's Ne- 
 braska section of the Cretaceous series. This group is composed principally and some- 
 times exclusively of thick-bedded, coarse-grained, ferruginous sandstone, containing 
 as characteristic fossils a large number of species of angiospermous leaves. Around 
 the edge of the high prairie this sa IK Istone caps or composes many isolated buttes which 
 have been severed from their connection with the plateau by aqueous erosion. Such, 
 we learn from Messrs. Meek and llayden, is the structure of the Smoky Hills, from 
 which they obtained a large part of the impressions of leaves described by the writer, 
 and such also is- the structure of 1'awiiee Rock, which stands near the road be- 
 tween Walnut Creek and Pawnee Fork. At Allison's ranch, on Walnut Creek, this 
 sandstone has precisely the lithological characters of that from the Smoky Hills, but 
 I was not able to detect in it an v traces of fossils. At Walnut Creek, however, twenty- 
 five miles distant, vegetable impressions are abundant, including, apparently, some of 
 the same species obtained from Smoky Hill, Blackbird Hill, &c. 
 
 The geological horizon marked by this Lower Cretaceous sandstone group is per- 
 haps the best delined of all in the entire geological series in the Southwest, and' more 
 generally useful as a plane of reference than any other. From the resistant character 
 of the materials composing this group, it has held its place over an immense extent of 
 country from which the softer superior strata have been removed. When the upper 
 members of the Cretaceous formation are present, as is the case in much of the coun- 
 try hereafter to be described, the Lower Cretaceous sandstones are covered with more 
 than a thousand feet of limestones, or calcareous shales filled with the remains of ma- 
 rine organisms, and evidently a deposit from the waters of the ocean. In an analysis 
 of the Cretaceous formation, to be given in a succeeding chapter of this report, I shall 
 attempt to deduce, from the composition and fossil contents of the different members 
 of this series, something of the history of the changing phases of the physical geog- 
 raphy of the central portion of the continent during their deposition. I may say s 
 however, in passing, that these coarse Cretaceous sandstones are exclusively mechan- 
 ical deposits, and such as have not been transported any very great distance from their 
 place of origin; that, extending as they do from the vicinity of the Mississippi all the way 
 to the base of the Kocky Mountains, they mark a period of general subsidence in all this 
 portion of the continent a period through which the sea was gradually encroaching 
 upon the land. The shore-line was then constantly inarching inland, leaving behind it 
 proofs of the power of its littoral waxes; -which comminuted and sifted the barriers op- 
 posing their progress, and formed of their ruins these beds of stratified sands and 
 pebbles, which may be regarded as only an unbroken series of ancient sea-beaches. 
 The finer materials, washed by the shore-waves, were taken into suspension or solu- 
 tion by the sea-water, and, mingled with or composing the remains of marine animals, 
 were spread over the ocean bottom as the shales and limestones of which I have before 
 
24 EXPLORING EXPEDITION FROM SANTA FE 
 
 s] token. This encroachment of the sea took place from east to west, and the invading 
 flood is now represented by the Gulf of Mexico. This is indicated by the facts that 
 the Lower Cretaceous sandstones thin out and disappear toward the south and east, 
 where nearly the entire Cretaceous series is represented by marine and organic sedi- 
 ments ; while, as we go toward the west and northwest, on the contrary, the sandstones 
 increase in thickness, the superincumbent strata become less and less calcareous, until 
 ultimately, as we approach the shores of the continent not submerged by the Creta- 
 ceous ocean, the mechanical sediments greatly preponderate over the organic, and beds 
 of sandstone and shale of enormous thickness, the direct ilcltrix of the land, represent 
 all the subdivisions of the chalk formation. 
 
 I have spoken in my former report of the parallelism between the Lower Creta- 
 ceous strata of New Mexico and those of Nebraska, as described by Meek and Hay- 
 den, and those of New Jersey, by Professor Cook. How accurately the Lower Cre- 
 taceous rocks of the district now under consideration represent those of the regions 
 just mentioned will be seen in the following section : 
 
 Section of Lower Cretaceous rocks at the crossing of Pawnee Fork. 
 
 No. 1. Soft, coarse sandstone, dark reddish-brown, yellow, or nearly white; lower 
 part finer, and containing impressions of dicotyledonous leaves (Salir, occ.) to summit 
 of cliff, about 50 feet. 
 
 2. Light dove-colored clay, with lignite and broken leaves, 10 feet. 
 
 3. Yellow sandy clay with vegetable impressions to bed of stream ; about 15 feet 
 exposed. 
 
 I had not time fully to explore this locality, but the fossils are quite numerous and 
 very accessible. The species of Salix referred to is apparently identical with S. J/yr/vV, 
 obtained at Smoky Hill by Meek and Hayden. The dove-colored clay which under- 
 lies the sandstone is scarcely distinguishable from that which holds a similar position 
 in New Jersey, and which, like this, is filled with vegetable matter. 
 
 By reference to the section of the rocks of Kansas given by Messrs. Meek and 
 Hayden, in the Proceedings of the Philadelphia Academy, January, 185!), it will be 
 noticed that the "red, brown, and yellowish coarse-grained sandstone, containing 
 leaves of dicotyledonous trees, forming the summits of the Smoky Hills," is underlaid 
 by " whitish, very fine-grained, argillaceous sandstone, with bluish, purple, and ash- 
 colored clays." Though containing at that locality no vegetable impressions, it is 
 evident that these latter beds are the equivalents of those exposed beneath the sand- 
 stone on Pawnee Fork. 
 
 PAWNEE FORK TO GROSSING OF CIMARRON. 
 
 TERTIARY STRATA. 
 
 After leaving Pawnee Fork the Santa Fe road crosses the margin of an immense 
 Tertiary basin, to which I first called attention in my report on the geology of the 
 Colorado country, and designated by the name of the " Tertiary basin of the 
 Arkansas." 
 
TO .JUNCTION OF GRAND AND (JUEKN UIVUHH.' 25 
 
 During my former transit of tlic plains 1 funned tin; opinion that the western 
 boundary of this Tertiary belt was passed near the crossing of the Cimarron ; and it 
 is still possible that Tertiary strata will not be found west of that point which are con- 
 tinuous with those; forming the table-lands bordering tin; Arkansas, but during the past 
 season 1 noticed similar beds recurring at various points quite up to the bases of the 
 Rocky Mountains, and I think we have evidence that at one time Tertiary rocks 
 occupied the surface of a larg;> territory in this region, from which they have been 
 entire! v removed, or so nearly so as to be represented by isolated and often widely 
 separated patches. 
 
 As will be seen bv reference to the sections exposed at various points along the 
 western portion of the Santa 1'Y road, these Tertiary rocks are entirely unconformable 
 to those upon which they rest ; are of very much later date, and were deposited, not 
 only subsequent to the period when the entire series of Cretaceous strata had been 
 laid down, but after they had been much disturbed, and elevated to such a point that 
 vallevs, eroded by surface action, had been cut down to and through the base of that 
 series. In different localities the Tertiary strata rest up on the Middle or Lower 
 Cretaceous rocks, or even on the underlying Triassic formation. 
 
 The vicinity of the Raton Mountains has, in former times, been the theater of 
 violent and wide-spread volcanic action. At that time numerous mountain masses and 
 subordinate buttes of trap were thrown up, and floods of lava poured out, covering an 
 extensive area in their vicinity. During this period of violence the Cretaceous rocks 
 were locally much disturbed and metamorphosed, and the lowest members of that 
 series elevated to, and pea-haps far above, the surface of the ocean. At some time sub- 
 sequent to the period of greatest volcanic activity, and yet apparently before the tires 
 in this great furnace were entirely extinguished, the Tertiary strata began to be 
 deposited in the depressions, and over the irregularities which then existed on the 
 surface. Unfortunately, in all the localities where I examined these strata, they seemed 
 to be destitute of fossils. We are, therefore, as yet without the light which they 
 woidd throw upon the conditions of their deposition, and the conclusions to which I 
 have arrived in reference to the precise age of these beds are to a certain extent con- 
 jectural, and liable to be modified by future discoveries, yet there seems to be good 
 reason for supposing that they are what I have called them, Tertiary, and that they 
 are continuous with the Tertiary basins of Northwestern Kansas and Nebraska. The 
 reasons for this conclusion are, first, that these deposits are considerably more recent 
 than any portion of the Cretaceous series represented in the region in which they 
 exist; second, that in their lithological characters and the circumstances of their depo- 
 sition the\' are the exact counterparts of the fresh-water Tertiary strata of the basins 
 to which 1 have referred, and which are also only locally and rarely fossiliferous ; third, 
 that the Tertiary strata of the Upper Platte extend southward toward the Arkansas, 
 where their only possible representatives are those under consideration ; fourth, 
 Tertiary fossils are said to have been found in these beds on the banks of the Arkansas, 
 above the crossing. 
 
 In lithological characters the Tertiary rocks of the Arkansas basin are considerably 
 unlike any marine deposit with which I am familiar, but the greater portion of them 
 4 s F 
 
26 EXPLORING EXl'KIMTION FROM SANTA Fft 
 
 strikingly resemble the fresh-water Tertiary limestones of the Paris basin ; and, as I 
 have said, are undistinguishable from those of the "bad-lands" of tin- l T pper Missouri, 
 shown by their fossils to be all of fresh -water or estuary origin The great mass ot 
 the Arkansas beds is made up of white or cream-colored limestone, closely resembling 
 much of the calcareous tufa deposited from springs, and frequently containing masses of 
 black or red, very light and porous scoria; with this tiiiaceous limestone are associated 
 strata of more compact laminated cream-colored limestone; abed of coarse, friable 
 light-colored sandstone, frequently a conglomerate; and at a higher level a stratum of 
 exceedingly coarse conglomerate, of which the pebbles, if such they can be called, 
 are often 6 or 8 inches in diameter. These pebbles are principally composed of 
 quartz or the harder erupted rocks, basalt, porphyry, &c,, with occasionally a frag- 
 ment of Carboniferous limestone. 1 noticed that in going toward the west the mate- 
 rials composing these sandstones and conglomerates became much coarser, showing that 
 they had been derived from the direction of the Ivocky Mountains. Although the 
 Tertiary basins of the West have been studied in but a small portion of their extent, 
 and we are as yet very far from being in possession of all the facts in reference to 
 their areas, their structure, or their fossils, which will permit us to write in full the 
 history of their deposition, the observations already made all seem to point to the con- 
 clusion that the Tertiary epoch was an era of progressive elevation overall the central 
 portions of our continent ; and that during the greater part of this epoch, the continent 
 had nearly the form and area which it has at present. The purely marine Tertiaries 
 appear to be restricted to the immediate vicinity of the present ocean ; and to a 
 narrow belt along the valley of the Mississippi, which continued to be occupied till a 
 comparatively recent period by an arm of the Gulf of Mexico. So far as at present 
 known, all the Tertiary strata which are found between the Mississippi and the Sierra 
 Nevada are of fresh-water or estuary origin. The gradual retrocession of the ocean 
 is also indicated by the fact reported by Dr. Hayden that where estuary shells are 
 found in the Tertiary strata of Nebraska they are generally restricted to the lower be< Is 
 of the series; the overlying strata containing fresh-water species. We are led to infer, 
 therefore, that the Tertiary basins which skirt the bases of the Rocky Mountains, were once 
 the beds of rivers and lakes of the Tertiary continent; and, except in the immediate 
 vicinity of the coast-line, were wholly occupied by fresh water. It is also probable 
 that some of these basins occupy former lines of drainage from the Rockv Mountains; 
 and that the beds of coarse sand and gravel made up of fragments of crystalline rocks, 
 wholly foreign to the localities where they are found, but abundant in and peculiar to 
 the Rocky Mountains, were transported from their distant places of origin by the rapid 
 currents of these ancient rivers. The further consideration of these facts, as well as 
 others bearing on the subject of the physical geography of the central portions of the 
 continent during the Tertiary epoch, must be deferred to a subsequent portion of this 
 report, where it will more properly find place. 
 
 The details of structure of the Tertiary basin of the Arkansas*will be, perhaps, 
 most readily understood by a few extracts from my notes, made at various points alony- 
 our route where the Tertiary strata are exposed. "After leaving Pawnee Fork, the road 
 passes over level bottom-lands for several miles, where it divides: the left-hand branch 
 
TO JUNCTION OF GRAND AND GREEN RIVERS. 27 
 
 following the windings of the Arkansas; the other, called ^the 'dry road,' rising on to 
 and crossing the table-land which separates the valleys of Pawnee Fork and the 
 Upper Arkansas^ This table-land is underlain by a white tufaceous limestone, exposed 
 in the bed of the Coon Creeks, and still better at the point where the dry road comes 
 down again to the Arkansas. It is also thrown out in many different places from the 
 burrows of the prairie-dogs. In lithological characters, this rock is precisely like a 
 portion of the strata of the 'bad-lands' of Nebraska; contains no fossils, but a few 
 pebbles of crystalline rock. At .the ( 'aches, sixteen miles below the crossing of the 
 Arkansas, the same stratum is seen overlaid by some thirty feet of coarse, soft, light- 
 bro\vn conglomerate-, much cross-stratified. The cement is coarse silicious sand; the 
 pebbles, from the size of an egg downward, of granite, trap, quartz, porphyry, trachyte, 
 jasper, quartzite, chert, etc., with a few of Carboniferous limestone." 
 
 "At the crossing of the Arkansas, the following section is exposed: 
 
 " 1. Spongy tufaceous limestone like that on Dry road. 
 
 "2. Coarse, soft conglomerate, same as at Caches, 35 feet. 
 
 " o. Tufaceous limestone, like No. 1, to base." 
 
 "The sand-hills, which border the Arkansas on the south side, seem to have been 
 derived from the decomposition of the Tertiary conglomerate." 
 
 "The same stratum forms the banks of the Cimarron, and has apparently given 
 character to its- sandy and sterile valley. The 'Jornada,' the divide between the 
 Arkansas and Cimarron, is another portion of the high prairie, precisely like, in physi- 
 cal and geological structure, that crossed by the 'dry road.'" 
 
 "At Eighteen-mile ridge, on the Cimarron, the coarse conglomerate and chalky tufa 
 are exposed, as at many points below. The conglomerate is composed of a coarse 
 sandy cement, with pebbles from the size of shot to eight inches in diameter. The 
 larger ones are compact, fine-grained, reddish-yellow sandstone, doubtless of Lower 
 Cretaceous age, and such as comes to the surface farther westward. Others are com- 
 posed of granite, amygdaloid, clay-slate, quartz, jasper, &c. The greater size of the 
 pebbles in this conglomerate perhaps indicates that, in going westward, we are 
 approaching the source from which they were derived. The conglomerate would 
 seem to be a drift from the Rocky Mountains, where, and where only, as far as I am 
 aware, such materials occur in place. If this is true, when on the Cimarron, we were 
 doubtless standing in the channel of a great line of drainage of the Tertiary epoch." 
 
 At the middle spring of the Cimarron a very instructive and interesting section is 
 exposed, in which we again see the base of the Tertiary series. On Pawnee Fork, the 
 tufaceons limestones and conglomerate which I have described rest upon the coarse 
 ferruginous Lower Cretaceous sandstone. Here we find them underlain by soft yellow 
 or red sandstone, of which the place is considerably lower than that last mentioned. 
 In other localities further west we shall see that these Tertiary beds rest first on Lower 
 Cretaceous sandstone, then on trap, again upon the Middle Cretaceous limestones and 
 shales, and, finally, upon the red calcareous sandstones of the Trias. The elements 
 composing the section of the middle spring of the Cimarron are indicated in the fol- 
 lowing table: 
 
28 EXPLORING EXPEDITION FROM SANTA Ffi 
 
 Section of strata at Middle Si>i-h/(/ of ('hiutrron. 
 
 1. Coarse gravel from disintegrated conglomerate - (! 
 
 2. Spongy, tufaceous limestone, cream-colored - 3 
 
 3. Soft, chalky tufa, cream-colored 
 
 4. Laminated, tufaceous limestone, cream-colored '. . . G 
 
 5. Massive, tufaceous limestone, iipper part hardest, containing halls of red and 
 
 black scoria 50 
 
 6. Cream-colored tufa, similar to No. 5, but softer 19 
 
 7. Hard, foliated tufaceous limestone 5 
 
 8. Yellow or reddish, soft, massive sandstone 40 
 
 The cream-colored tufaceous limestones of the above section are the equivalents 
 of the lower tufaceous limestone of the Arkansas, and, though containing no fossils, 
 are doubtless Tertiary. The balls of scoria which they include, though not positive 
 evidence of the fact, may be regarded as an indication that volcanic action was going 
 on somewhere in this vicinity during their deposition. If this was the case, the scoria 
 must have been derived from the vicinity of the Raton Mountains, where volcanic 
 eruptions were taking place, geologically speaking, about that time. 
 
 Scoria is very frequently contained in the Tertiary strata near the Rocky Mount- 
 ains; a fact which has suggested the thought that the water from which these tufaceous 
 limestones were deposited may, in some instances, have been heated, and that this is 
 one reason why they contain so few fossils. 
 
 The sandstone which forms the base of the section, at the Middle Spring of the 
 Cimarron, will be soon noticed, in connection with the group to which it belongs; but 
 its place in the series, as has been stated, is below the Lower Cretaceous sandstone. 
 
 We have here abundant evidence of the entire unconformability of the Tertiary 
 beds with those on which they rest, and that they were deposited in basins scooped out 
 of the underlying rocks, doubtless by subaerial action, precisely as similar valleys or 
 basins are forming at the present day. 
 
 A few miles further westward the Lower Cretaceous, and even some portions of 
 the Middle Cretaceous strata, are found in place, and there is no question but that they 
 once stretched over all the adjacent country, and occupied the place since held by the 
 Tertiary beds, but, by the long action of eroding agents, they had been entirely re- 
 moved or deeply excavated before the Tertiary limestones began to be deposited; and 
 that subsequently this latter series filled up and obliterated all traces of that ancient 
 denudation. During the present epoch the process of erosion has again begun, and the 
 valleys of the Cimarron and Arkansas are being for the second time excavated. 
 
 GROSSING OF GIMARRON TO ENGIIANTED SPRING. 
 
 JURASSIC ? ROCKS. 
 
 At the crossing of the Cimarron, and for some miles west of that point, the Ter- 
 tiary strata have been entirely removed; the bottom of the basin exposed and deeply 
 eroded. It is here composed of a. series of strata of which the sandstone, King at the 
 base of the cliff at, the Middle Spring, forms a part. This series consists of a number 
 
TO JUNCTION OF GRAND AND GREEN RIVERS. 29 
 
 of alternations of strata which are quite different in color., texture, and composition. 
 They are, as far as my observation extended, destitute of fossils, nnd it is therefore im- 
 possible to fix accurately their place in the geological Scale. It will be seen from the 
 section i>'iven below that they underlie the coarse red and yellow sandstones of Lower 
 Cretaceous age, which have been so frequently referred to in the preceding pages. 
 They are, however, in Hthological characters quite unlike the strata which ;ir<> gen- 
 erally found immediately beneath ihe Lower Cretaceous sandstones of New Mexico. 
 The position they hold is apparently the same with that of the Jurassic rocks discov- 
 ered by Dr. Hayden in the Black Hills. It is possible, therefore, and perhaps prob- 
 able, that they are of the same age. It will, however, be necessary to wait the 
 detection of fossils in the group before its place in the series can be more than conjec- 
 tured. The section taken from the summits of the hills at Enchanted Spring, down 
 the side of the valley toward the Cimarron, as far as the rocks were exposed, is as 
 follows : 
 
 1. Gray, yellow, or brown coarse sand-rock, the equivalent of that of the Smoky 
 Hills, here containing obscure impressions of large dicotyledonous leaves, 70 
 feet. 
 
 '2. Thin layers of laminated brown sandstones, with very smooth surfaces, 20 feet. 
 
 ,">. I hn'il lif/lit-h/itr tii' ilorc-colnrcil /'nitcx/iiiti' in tltiu layers, Jurassic? 50 feet. 
 
 4. Slope covered, about 30 feel. 
 
 5. Yellow or reddish quartzose sandstone, 2 feet. 
 (I. lied shale, 5 feet. 
 
 7. Yellow calcareous sandstone or silicious limestone, with ferruginous concretions, 
 
 20 feet. 
 
 S. Brecciated conglomerate, 5 feet. 
 
 !). Blood-red shale, 25 feet. 
 
 10. Yellow calcareous sandstone, similar to No. 7, 8 feet, 
 
 11. Blood-red shale, with one or two narrow bands of green, 10 feet. 
 
 12. Red and yellow argillaceous limestone, somewhat concretionary, often laminated, 
 
 sun-cracked and ripple-marked, pierced by vertical cavities from one to two 
 inches in diameter, to bast*, 8 feet. 
 
 Much of the coarse sand-rock, No. 1 of the section, is precisely like that contain- 
 ing the fossil plants of Blackbird Hill, Nebraska; being partly dark-brown and ferru- 
 ginous, and partly gray, quartz-like, and intensely hard. Other portions of the mass 
 are yellow and softer, in this respect resembling the general aspect of this rock in New 
 Mexico. The limestone, No. 3 of the section, is the most interesting feature of the group, 
 and the one to which we must look for fossils that shall determine its age. It is a fine- 
 grained, homogeneous rock, such as I have nowhere seen near the same geological 
 horizon in the Southwest. With the exception of the limestone, I should have no great 
 difficulty in supposing that this group represented the strata which in New Mexico im- 
 mediately underlie; the Lower Cretaceous sandstones; 4mt the limestone is entirely for- 
 eign to the geology of those; portions of New Mexico which I have examined. I am 
 strongly inclined to believe that it is a member of the series not represented further to 
 the south and west, and I shall be surprised if it does not yield to future explorers well- 
 marked Jurassic fossils. 
 
30 EXPLORING EXPEDITION FROM SANTA F 
 
 ENCHANTED SPUING TO COTTONWOOD SPRING. 
 
 TERTIARY AND LOWER CRETACEOUS STRATA. 
 
 At Enchanted Spring the Lower Cretaceous sandstones form a line of bold Mull's, 
 which border the excavated valley of the Cimarron. From this point up to the base 
 of the mountains the surface has nothing of the monotony of the plains below, but is 
 greatly varied, and the scenery is frequently impressive, occasionally grand. With 
 the exception, however, of the volcanic outlayers of the Raton Mountains, there arc- 
 few evidences of the action of violent disturbing causes, and the variety which the 
 scenery presents is due almost entirely to the erosion of nearly horizontal strata by the 
 drainage from the Rocky Mountains. Here the traveler, journeying to New Mexico, 
 obtains his first view of the peculiar and impressive scenery so characteristic of nearly 
 all portions of the great central plateau of the continent. Here he first hears the word 
 mesa, and sees it embodied in the long lines of table-lands which fill the horizon and 
 stretch away in perspective, like the walls of Cyclopean cities. I have, in a former 
 report, described somewhat in detail the phenomena of erosion which are presented by 
 the high table-land bordering the Rocky Mountains. It is, therefore, only necessary 
 for me to say in this connection that the views then advanced in reference to the origin 
 of the great natural features of that region, its mesas and canons, have been fully con- 
 firmed by subsequent observation, and that there can be no question that they are to 
 be regarded simply as phenomena of surface erosion, of which they are the grandest 
 examples known. 
 
 The geology of the region lying between Enchanted Spring and Cottonwood 
 Spring is similar throughout. The rocky basis of the country is formed by the Lower 
 Cretaceous sandstone, covered here and there with patches of white tufaceous Tertiary 
 limestone. These Tertiary beds were, perhaps, once continuous, but now form only a 
 relatively thin covering over the divides between the streams, being wholly removed 
 from the valleys and lowlands. As on the Arkansas, they an; without fossils as far as 
 ol (served, and were deposited nearly horizontally over the irregular surface of the 
 underlying sandstone. 
 
 A section of the strata at Cedar Spring is as follows: 
 
 (.) Tertiary. 
 
 1. White, chalky, tufaceous limestone, with hard, gray, compact bands If) feet. 
 
 2. Cream-colored, spongy, tufaceous limestone, (similar to that on the Arkan- 
 
 sas and Cimarron) 40 feet. 
 
 (/>.) Cretaceous. 
 
 1. Yellow fine-grained sandstone, with obscure impressions of fucoids G feet. 
 
 2. Light blue or white shale, \\*ith many obscure vegetable impressions, about 4 feet. 
 
 3. Yellow sandstone, soft and rather coarse, in thin (often rippled-marked) 
 
 layers, containing impressions of dicotyledonous leaves, resembling those 
 
 of Salix and Quercus 5 feet. 
 
TO JUNCTION OF GRAND AND GREEN KIVERS. 31 
 
 4. Bluish shale, containing impressions of leaves, and a thin lc<l of lignite. 4 feet. 
 
 f>. Yellow soft sandstone, with impressions of dicotyledonous leaves, apparently 
 
 identical with some of those from Smoky Hill, to base of section 50 feet. 
 
 From Cedar Spring to McNee's Creek the road passes over a high prairie under- 
 lain by Tertiary limestones. At, McXee's Creek the Tertiary rocks are cut through and 
 the Cretaceous series freely opened. No fossils were found here, but the rock is gener- 
 allv similar to that at Cedar Spring. At Cotton wood Spring the surface rock is Tertiary 
 tufaceous limestone, which is cut through by the stream, and its line of junction with 
 the underlying Cretaceous rocks exposed. The sandstone is here considerably disturbed 
 and metamorphosed apparently by the upheaval of the erupted mass of the "Rabbit- 
 ear Buttes," which are near by. l^pon the uneven surface of the sandstone the 
 Tertiary strata are laid down nearly or quite horizontally, and have evidently been but 
 little disturbed since their deposition. In the upper part of the Cretaceous sandstone 
 near the spring I found many vegetable impressions, generally trunks of trees and 
 fragments of wood, and also some leaves. One of these is apparently a Salix, and 
 perhaps identical with S. ]\feeJ>ii. There are also others, which are similar to the leaves 
 found at Smoky Hill. The metamorphosis of the Cretaceous strata is shown not only in 
 tint peroxidationof the iron which the}' contain, but an associated clay-shale is rendered 
 nearly as white and as hard as porcelain; the contained iron being segregated in thin 
 vein-like bands. 
 
 OOTTONWOOD SPRING TO RED FORK ( F CANADIAN. 
 TKAP, TERTIARY, AND CRETACEOUS ROCKS. 
 
 The interval indicated by the above heading includes a portion of the volcanic 
 district adjacent to the Raton Mountains, to which I have before alluded. Rabbit-ear, 
 Round Mound, Wagon Mound, &c., form part of a group of trap buttes, which are 
 scattered over the prairie for a long distance east of the mountains. They are in some 
 cases entirely isolated, and seem to mark minor vents, where a portion of the molten 
 matter contained in some vast subterranean reservoir found exit. ( >thers are connected 
 by sheets of trap, and in some instances are but portions of a volcanic flood, separated 
 from their connections by subsequent erosions. Toward the mountains the erupted 
 material more completely covers the country, and forms extensive mesas, or high table- 
 lands, which have been deeply cut by the canons of the streams once flowing over 
 but now through them. They have also been left in strong relief by the cutting down 
 of the country bordering them on the east. 
 
 In many places the sheets of trap are covered by Tertiary tufa, which has been 
 deposited quietly and uniformly over their surfaces, and is evidently much more recent 
 than they. This Tertiary bed is here not of great thickness, and perhaps represents 
 only the extreme upper portion of the series described in the preceding pages. 
 
 Wherever the trap is cut through in the stream-beds it is found resting on the 
 Lower Cretaceous sandstones, which are in such cases somewhat metamorphosed ; being 
 vitrified, or at least hardened; the iron being peroxidized, and more or less segregated 
 in bands or veins. In other localities the Lower Cretaceous sandstone is covered by 
 
32 EXPLORING EXPEDITION FROM SANTA FE 
 
 the Tertiary tufa; but, over large areas, it is itself the surface rock. At Whetstone 
 Creek this group is exposed iu the hanks of the stream, and shows a great number of 
 alternations of very fine-grained, laminated sandstone, with more argillaceous hands. 
 These strata contain fossil plants in large numbers, which would undoubtedly well 
 reward collectors who could have more time to devote to the locality than was at my 
 command. Several of the species noticed there are apparently different from those 
 obtained from outcrops of this formation from other localities, but a narrow leaf, per- 
 haps a Salix, seems to be identical with one obtained at Smoky Hill, Pawnee Fork, ivc. 
 A remarkable fissure has been opened by volcanic force in the rocks containing 
 these plants. It is aboiit four and a half feet wide following the main jointings of the 
 sandstones, which here run nearly east and west, No trap fills the fissure, but it is 
 evident that it was once a kind of flue through which a vast amount of heat escaped 
 from below. Its sides are blackened, glazed, and blistered, and the sandstone which 
 forms its immediate walls is considerably metamorphosed; to the depth of an inch it is 
 vitrified; back of this it is converted into a hard, blue, sonorous rock, resembling a 
 compact basalt, The effect of heat is noticeable in the changed condition of the sand- 
 stone several feet from the sides of the fissure, but at a distance of twenty feet the rock 
 again exhibits its normal appearance. 
 
 VALLEY OF THE CANADIAN. 
 MIDDLE CRETACEOUS STRATA. 
 
 The valley of the Red Fork of the Canadian is a broad eroded trough, excavated 
 almost entirely irt the great group of limestones and calcareous shales which rest upon 
 the sandstone group I have so frequently referred to as the Lower Cretaceous sand- 
 stones. The overlying calcareous mass, which contains immense numbers of Cre- 
 taceous fossils, is apparently the equivalent of Nos. 2, 3, and 4 of Meek and Hayden's 
 Nebraska section. 
 
 In my former notes on the geology of this region, I designated this series as I 'pper 
 Cretaceous, to distinguish it from the Lower Cretaceous sandstone group. At that time 
 I had seen no evidence of the existence in New Mexico of higher members of the 
 Cretaceous formation. In our recent explorations of the San Juan countrv, where 
 this series is very largely developed, I- found the equivalents of the strata under con- 
 sideration covered by soft sandstones and marls, which I regarded as also members ol 
 the great Cretaceous formation. This latter group is, therefore, more properly I'pper 
 Cretaceous, and the calcareous strata of the Canadian and their equivalents will be 
 designated in the subsequent portions of this report as Middle Cretaceous. 
 
 In describing the Cretaceous strata of the country bordering the San Juan, I shall 
 have occasion to return to the subject of the classification of the rocks belonging to 
 this series, as developed in New Mexico, and, as far as practicable, establish a. paral- 
 lelism between them and those of the Upper Missouri, as described in the Nebraska 
 section of Messrs. Meek and Ilayden. I may here say, however, that the division of 
 the ( 'retaceous rocks of New Mexico into three great groups Upper, Middle, and 
 Lower will be found to be the most convenient, if not the only one practicable 
 
TO JUNCTION OF GRAND AND GREEN RIVERS. 33 
 
 Wherever I have observed them these different divisions are marked by obvious and 
 distinctive Hthological characters, and the fossils contained by each group are usually 
 recognizable at a glance. Those of the Lower sandstone group being generally angi- 
 ospermous leaves; those of the Middle group, marine shells and the remains of fishes; 
 those of the Upper division, as far as yet observed, being leaves and trunks of trees 
 different from those found below. It is true, that in Southeastern New Mexico and 
 Texas there is veiy little sandy matter in any of the Cretaceous rocks, while in the 
 Rocky Mountains the upper and lower arenaceous divisions are greatly developed, and 
 the limestones have nearly disappeared from the middle division. This latter group is, 
 however, distinctly marked even there; consisting of calcareous shales, with thin bands 
 of limestone and beds of lignite, interstratified with layers, of greater or less thickness, 
 of fine-grained sandstones, usually containing considerable lime. 
 
 On the banks of the Canadian, from 800 to 1,000 feet of the Middle Cretaceous 
 strata all exposed. 
 
 The section from the summit of the hills at the "Breaks of Red River," down to 
 the bed of the stream, is as follows: 
 
 1. Rolled gravel, composed of fragments of porphyry, trap, Paleozoic limestone, 
 &c., drift from the Rocky Mountains. 
 
 "2. Light-blue compact limestone, on exposure cracking into flattish chips or 
 "spalls," containing Inoccmmus problemati&us, Gryphcea Pitcheri, &c. 
 
 3. Ferruginous, laminated, sandy limestone, with rounded concretions, one to five 
 feet in diameter, of compact blue limestone, much cracked, and fissures filled with 
 crystallized carbonate of lime. This rock is a great store-house of fossils, of which, 
 perhaps, the most abundant is a remarkably neat little Ostrea, hitherto undescribed, 
 which I have called Ostrea clcgantula ; one of the most common and widely distributed 
 Middle Cretaceous fossils of New Mexico. With this are Inoceramus frayilis, H. & M., 
 /. Crispiif, Ammonites percarinatus, Shark's teeth (Lamna and Oxyrhma), &c. The 
 surfaces of the layers of this stratum are covered with small Ostreas (0. conyeata), and 
 fragments of Inoceramus, which resemble fish-scales; thickness 80 feet. 
 
 4. Light-blue compact limestone in thin beds, weathering white, similar to No. 2; 
 about 30 feet exposed. From this point to the bed of the river, some 700 to 800 feet, 
 the cliffs are composed of blue compact limestone in thin beds, alternating with dark- 
 blue and brownish bituminous calcareous shales, which underlie the preceding mem- 
 bers of the section, and rest upon the Lower Cretaceous sandstones In every part of 
 these lower limestones Inoccrannis problematicus is exceedingly abundant. They also 
 contain large numbers of (iriiplKca I'l/cl/cri, of which remarkably large and fine speci- 
 mens were collected a- short distance east of the crossing. 
 
 All the foregoing calcareous beds rest upon the sandstones of Lower Creta- 
 ceous age to which I have so frequently referred. These sandstones form the bed of 
 the Canadian at the crossing and the walls of the canon below, and here exhibit nearly 
 the same Hthological characters as at many localities where they are exposed farther 
 eastward. They seem to be somewhat disturbed and hardened, and it is possible that 
 a slight unconformability may be discovered between them and the overlying rocks- 
 This is a mere suspicion, however, which I could not verify or disprove in the time at 
 5 s F 
 
34 EXPLORING EXPEDITION FROM SANTA FE 
 
 my command. The divide between the valleys of the Red Fork and its tributary, the 
 Ocate, a swell as the western bank of the Ocate", is formed of the Middle Cretaceous 
 limestones and marl, enumerated in the preceding- section. 
 
 The structure of the picturesque table-lands from which these streams issue I had 
 no opportunity of determining, as they lie several miles north of the road, but I could 
 see that they are in part covered by a thick layer of trap, to which their nearly hori- 
 zontal surfaces and precipitous sides are doubtless due. 
 
 VALLEY OF THE CANADIAN TO LAS VEGAS. 
 
 As far westward as Burgwin's Spring, patches of Tertiary tufa appear in 
 numerous localities, usually resting upon trap, which is the prevailing surface-rock, and 
 which caps the picturesque mesas bordering the road on either side. Here, as farther 
 cast, numerous trap buttes stud the prairies, and there are several lines of trap hills 
 which run off toward the south as diverging spurs from the Raton Mountains. Near 
 Dragoon Spring, by a long and painful ascent we reached the summit of a trap mesa, 
 apparently the continuation of the table-lands bordering the Upper Canadian. The 
 underlying sedimentary rocks are here concealed by the debris of their trappcan cover- 
 ing. A few miles farther westward, however, the Lower Cretaceous sandstones again 
 come into view, and it is probable that they here form the surface over which the vol- 
 canic flood was poured. The trap of all this region exhibits great similarity of char- 
 acter; its weathered surfaces are black, while within it is dark brown or gray. It is 
 generally more or less vesicular, sometimes quite scoriaceous. 
 
 Aboitt Fort Union the only rocks visible are a mass of vesicular trap similar to 
 that just described, apparently only a narrow and local lava-stream, and the Lower 
 Cretaceous sandstones, which are very fully exposed. This latter groiip has here a 
 thickness of at least 300 feet, perhaps considerably more, as its line of junction with 
 the underlying rocks is nowhere reached. It forms the hills at the base of which the 
 fort is located, and a large part of Gallinas Mountain.- Probably still older strata ant 
 thrown up at the latter locality, but I had no opportunity to look for them. Just 
 below Fort Union the Cretaceous sandstones, dipping to the south and east, away 
 from the mountains, pass beneath the surface, and are succeeded by the Middle Creta- 
 ceous limestones so fully exposed on the banks of the Canadian. These rocks occupy all 
 the interval between this point and Las Vegas. On my former visit, to Las Vegas I \\ as 
 unable to discover any fossils in the blue limestone which crops out there, though I 
 regarded it as equivalent to the Middle Cretaceous beds elsewhere examined. This 
 conjecture I was able more recently fully to confirm by finding in it Inoceramus prob- 
 lematicus and other fossils of that horizon. 
 
 At Las Vegas the road leaves the prairies, and thence to Santa Fe is constantly 
 involved in the foot-hills of the Rocky Mountains. As the geology of this portion of 
 our route is somewhat complicated, and was studied principally on excursions made at 
 different times from Santa Fe, it will perhaps more properly form part of a distinct 
 chapter, where the structure of a limited geographical district is considered by itself, 
 and where the light derived from this one of its parts may serve to illuminate the 
 others. This division is the more natural, as in this vicinity we passed out of the 
 
TO JUNCTION OF GRAND AND GEEEN KIVEKS. 35 
 
 great basin in which we hud so long been journeying the- valley of the Mississippi 
 and entered that of the Rio Grande. At Las Vegas, too, the granite of the Rocky 
 Mountains is first seen in place, forming the axis of a subordinate anticlinal, on the 
 eastern flanks of which the Triassic and the Carboniferous formations re -appear in suc- 
 cession, thus bringing us to the base of the section which has occupied our attention 
 in the preceding pages. The exposures of these strata are much less full and satisfac- 
 tory here than nearer Santa Fe, where they are also less metamorphosed and more 
 lossiliferotis, and where the contrast and coincidences which their exposures present 
 with their eastern outcrops may be more accurately determined. 
 
36 EXPLORING EXPEDITION FROM SANTA Ffi 
 
 CHAPTER II. 
 
 GEOLOGY OF THE VICINITY OF SANTA FE. 
 
 GENERAL GEOLOGICAL FEATURES SANTA FE MOUNTAINS GRANITE ITS CHARACTER AND 
 CONTAINED MINERALS RELATIONS OF THE SANTA FE MOUNTAINS PLACER MOUNTAINS 
 CRETACEOUS AND TRIASSIC ROCKS CRETACEOUS LIGNITE CONVERTED INTO ANTHRACITE 
 BY AN OUTKUUST OF TRAP GoLD OF THE PLACER MOUNTAINS COPPER IRON TlIE 
 CERRILLOS GOLD SILVER LEAD COPPER IRON TURQUOISE ANCIENT CHALCIIUITL 
 MINES THE SANDIA MOUNTAIN THE VALLES STRATIFIED ROCKS CARBONIFEROUS 
 FORMATION SANTA FE SECTION SECTION AT PECOS VILLAGE PERMO-CARBONIFEROUS 
 BEDS GYPSUM FORMATION SECTION AT SAN JOSE FOSSIL PLANTS CRETACEOUS FORMA- 
 TION SUBDIVISION OF THE SYSTEM YELLOW SANDSTONES OF CANON BLANCO CRETA- 
 CEOUS SECTIONS AT GALLISTEO AND POPE'S WELL TERTIARY BEDS OF FRESH- WATER 
 ORIGIN. 
 
 The region about Santa Fe has occupied the attention of several geologists who 
 have visited New Mexico, among whom Messrs. Wislizenus, Marcou, and Blake have 
 given full reports of their observations upon it. I also was able to devote a short time 
 to its study while connected with the party of Lieutenant Ives in 1858, a resume of 
 the observations then made being given in my report to that officer. It might, there- 
 fore, be supposed -that this subject was by this time freed from all obscurity, and, per- 
 haps, exhausted of all interest. This is, however, far from being true, as may be shown 
 in few words. The geological structure of that region is complicated by several distinct 
 lines of upheaval, which have been classed together in the so-called Rocky Mountain 
 system; and yet the relations of these groups and chains of mountains are far from 
 being fully understood, or at least demonstrated. They have been regarded, perhaps 
 justly, as of the same age, but, as will be seen, when we come to speak of them more 
 in detail, evidence of complete synchronism is yet wanting, while there are some facts 
 which seem to point to a contrary conclusion. 
 
 Aside from the obscurity which hangs over the erupted rocks, an obscurity that 
 cannot be dissipated without much careful study in the field as well as in the labora- 
 tory, the splendid exposures of the three great groups of sedimentary strata, the Car- 
 boniferous, the Triassic, and the Cretaceous to say nothing of the Tertiary beds 
 largely developed, but without fossils: deserve and demand for their full analysis more 
 time than has yet been devoted to them. The three; months spout in the vicinity of 
 Santa Fe during the past season by our party have, I trust, not been entirely without 
 
TO JUNCTION OF GRAND AND GREEN RIVERS. 37 
 
 value, as regards the determination of doubtful points in- the geology of this region. 
 It must be confessed, however, that many questions are left unsettled which we had 
 hoped to solve, and I am convinced that there are few localities within the field of the 
 American geologist where patient and accurate investigation would be so likely to 
 result in the discovery of facts of high scientific value as in that under consideration. 
 
 SANTA FE MOUNTAINS. 
 
 As I have mentioned in my former report, the great mass of the Santa Fe Mount- 
 ains is composed of coarse, red, feldspathic granite, which , if not peculiar to, is at least 
 highly characteristic of, many of the mountain ranges of the central portion of the con- 
 tinent included in what is known as the Rocky Mountain system. As we shall see 
 further on, a granite to the eye identical with this forms the core or axis of the Nasci- 
 miento Mountain, the Sierra de la Plata, and other of the more westerly ranges of this 
 system. In the Coast Mountains of California or Oregon, in the Cascade Mountains, 
 or in the Sierra Nevada, though I have examined outcrops of granite in many thousand 
 different localities, I have never seen even a hand specimen similar in character to the 
 red granite of the Rocky Mountains. It will be seen, by reference to the description 
 formerly given of the country bordering the Lower Colorado, that the granites of all 
 the mountain ranges which cross that stream in the lower 500 miles of its course are 
 like those of the Pacific coast, white or grey, and contain a large quantity of albite. 
 In the bottom of the canon of the Great Colorado, north of the San Francisco Mount- 
 ain, where the river flows in a granitic trough, this rock, which is covered by several 
 thousand feet of Paleozoic strata, is generally grey and fine-grained. It is, however, 
 in many places penetrated by veins, or replaced by masses of a bright-red granite 
 very similar to that of the Santa Fe Mountains. This was the first locality in which, 
 coming eastward from the Pacific, I met with a rock of this character. In the Alle- 
 ghanies, or the mountains of New England, I have never seen any granite like that 
 of the Rocky Mountains, but, in the bowlder-drift of the Mississippi, and in places 
 north of the great lakes, a rock is found much more closely resembling it. In this, 
 however, the crystals of feldspar are of a less decided red than those of the Canadian 
 rock, being pale rose-red, those of Santa Fe a bright brick-red. To the erosion of the 
 red granites of the Rocky Mountains, during the Paleozoic and Secondary ages, I have 
 been inclined to attribute the prevailing red color of so large a part of the sedimentary 
 rocks. On the banks of the Colorado, several hundred feet of the Carboniferous strata 
 consist of blood-red sandstones and shales, witli large quantities of gypsum; nearly the 
 entire interval between the summit of the Carboniferous system and the base of the 
 Cretaceous is filled with similar materials, and some portions of the Upper Cretaceous 
 strata have the same decided tint. 
 
 The granite of the Santa Fe Mountains is not universally of the character I have 
 described; occasionally it is seen to be light-colored, gvcy or white, as it is near Rock 
 Corral, a few miles cast of Santa Fc, on the Independence road. Veins of quartz 
 and epidote are very common in the granite of the Santa Fe Mountains; the former 
 being numerous and large. I was never able, however, to discover in them any traces 
 of metallic minerals. They are certainly not the repositories of the copper, lead, 
 silver, and gold which are found in the region immediately about Santa Fd. 
 
38 EXPLORING EXPEDITION FROM SANTA FE 
 
 The relations which thfc Santa Fe Mountains sustain to the geology of the sur- 
 roundiBg region may be given in a few words. Like most of the ranges which go to 
 make up the complex group of the Rocky Mountains, though attaining a great altitude, 
 this is comparatively short. How far it may be traced to the north, we are at present 
 not able to say; probably not more than fifty or sixty miles. It is then succeeded by 
 other ranges, which, with more or less interruption, extend to and beyond the parks, 
 forming the broad mountain belt which gives character to the topography of the cen- 
 tral portions of the continent. On the south it falls off abruptly near Santa Fe, and 
 either wholly disappears or is represented at a distant point by some of the mountain 
 chains which lie east of the Rio Grande. The trend of this chain a few degrees west 
 of north and east of south would, if prolonged, strike altogether to the eastward of 
 its nearest neighbors on the south, Placer and Sandia Mountains. The altitude of its 
 highest peak is supposed to be between twelve and thirteen thousand feet. 
 
 Upon the flanks of the Santa Fe Mountains, where not removed, the sedimentary 
 rocks rest in regular order, and are, with the exception of the Tertiary, nearly or 
 
 quite conformable. 
 
 THE PLACER MOUNTAINS. 
 
 From the southern base of the Santa FC" Mountains the surface descends toward 
 the south, to the valley of Galisteo Creek, some twenty miles distant ; thence it rises 
 again, three or four miles, to the base of the Placer Mountains; the course of Galisteo 
 Creek being nearly east and west, following the line of greatest depression between 
 the adjacent mountain groups. This depression forms a natural pass from the plains 
 to the valley of the Rio Grande, affording a practicable and convenient railroad route. 
 Viewed as a whole, the interval between the Santa Fe" and Placer Mountains may be 
 regarded as a plain, the inequalities of the surface being slight compared with those 
 of the surrounding country. It is cut, however, by numerous eroded valleys and 
 ravines, and a limited portion of it is occupied by a group of erupted hills Los Cer- 
 rillos some of which have an altitude of several hundred feet. 
 
 The rocks exposed in the valley of Galisteo Creek are mostly of a sedimentary 
 character, representing portions of the Triassic, Cretaceous, and Tertiary formations 
 East of the Cerrillos, though much disturbed, these are but little changed in structure; 
 the Cretaceous strata abounding in fossils characteristic of the middle and lower beds 
 the first, mollusks; the second, angiospermous leaves the Triassic rocks containing 
 great numbers of silicified trunks of coniferous trees similar to those so frequently 
 met with in the same formation farther westward. The stratified rocks are, however 
 in several localities, cut by trap dikes, which, offering greater resistance to erosion, 
 have been left in strong relief above the surface. Two of these, one north, the other 
 south of the village of Galisteo, are particularly conspicuous, running with a nearly 
 parallel course in an east and west direction for several miles across the country. Of 
 these the southern is the most remarkable, standing like a huge, Dearly-continuous 
 wall, its crest being in many places a hundred and fifty feet above the plain bordering 
 it on either side. West of the Cerrillos similar but smaller dikes arc common, and a 
 large area on both sides of the Rio Grande is nothing less than a lava-plain, the flood 
 which formed it having apparently flowed from one or several volcanic vents near the 
 
TO JUNCTION OF GRAND AND GREEN RIVERS. 39 
 
 eastern base of the Valles, the mountain-chain forming the western boundary of this 
 portion of the valley of the Rio Grande. In this lava-plain the Ilio Grande has 
 excavated the canon through which it flows above Santo Domingo, and its cut edge 
 forms the high mesa-wall which borders Galisteo Creek on the north, from the Cerril- 
 los to its month. 
 
 It is only near the Rio Grande that the Tertiary beds to which I have referred 
 make their appearance. Here they are altogether similar to those I have described as 
 occurring on the Arkansas and other localities east of the mountains, viz, white tnfa- 
 ceons limestones and beds of conglomerate, the pebbles mainly of pumice or trap, and 
 all without fossils. 
 
 ( )n both sides of Galisteo Creek the Cretaceous strata contain beds of lignite. 
 ( )n the south side, in the foot-hills of the Placer Mountains, an outburst and overflow 
 of trap has, over a limited area, changed the lignite into bright, hard anthracite 
 coal. This will doubtless have considerable economical value. The bed is four to 
 five feet thick, included between strata of bluish argillaceous shale, with bands of 
 nodular iron-ore, the whole forming an accurate copy of the most characteristic sec- 
 tions a Horded by the Coal-Measures of the. Mississippi Valley. 
 
 The Placer Mountains form a group rather than a chain, their extent east and 
 west being nearly or quite equal to that north and south. They are made up, how- 
 ever, of a series of short lines of upheaval, having a trend somewhat, north of west 
 and south of east. Like most -isolated mountains and mountain groups, as distinguished 
 from the chains which have come under my observation in Central and Western North 
 America, they are composed, for the most part, of rocks decidedly eruptive in charac- 
 ter, and to a much less degree than their neighbors the Sandia and Santa Fe Mount- 
 ains, consist of granite or stratified materials. 
 
 The principal constituents of the Placer Mountains are porphyry, trachyte, tufa, 
 and trap, with masses of granite and mica-slate. About their bases, and in some cases 
 upon their flanks, the stratified rocks of the country may all be found, but are less 
 fully exposed than in the more important mountain ranges of this region. The Placer 
 Mountains have received their name from the gold which they furnish; considerable 
 quantities having been taken during a long period of years from the placers of their 
 bases and slopes. More recently, systematic, mining operations have been commenced 
 in the auriferous rocks, and a limited amount of gold has been extracted from them. 
 The gold of the Placer Mountains is of remarkable purity, and there is no question 
 but that a great deal of it exists there, yet it is quite doubtful whether these gold-dig- 
 gings will ever become vcrv productive, from the fact that it will be difficult, if not 
 impossible, ever to bring to the placers an adequate supply of water, and the gold is 
 so sparsely and widely distributed through the metalliferous rock that mining and crush- 
 ing it. will be but moderately compensated by the quantity obtained. 
 
 The "Old Placer" has been worked by the Mexican population since the first occu- 
 pation of the country by the Spaniards, and probably was a place of resort by their 
 predecessors the Pueblo Indians. The gold is obtained in the bed of an intermittent 
 stream flowing through a. ravine which separates two of the principal peaks, and in and 
 beneath the debris which has accumulated where this gorge opens into the valley of 
 
40 EXPLORING EXPEDITION FROM SANTA FE 
 
 Galisteo Creek. It generally occurs in fine scales, and but few nuggets of any consid- 
 erable size have been found. The supply of water for washing out the metal is so 
 small and irregular that gold-digging here is too uncertain a business to be depended 
 upon as a means of subsistence by any considerable number of miners. Only a fen- 
 Mexican families reside in the vicinity, and these employ but part of their time in gold- 
 washing. When the quantity of water is sufficient to enable them to wash out the 
 gold, the average gain of each man provided with shovel and shallow wooden wash- 
 pan, batea, may perhaps be estimated at a dollar per day. 
 
 Some Frenchmen formerly resided here, who, for a long time, carried on mining 
 operations in a somewhat systematic manner. They excavated the gold-bearing rock; 
 crushed it between blocks of porphyry, made to revolve by mule-power; the gold 
 being extracted by quicksilver. The auriferous rock is said to have yielded about 
 thirty dollars of gold to the ton. With their rude processes of obtaining the gold it is 
 probable that the operations of these parties were not very remunerative, as they have 
 been now for some years discontinued. An American company has recently purchased a 
 proprietorship at the Old Placer; but, as they represent, from the want of proper machin- 
 ery and the difficulty of obtaining laborers skilled in the business, the experiment has so 
 far been unsuccessful. The quantity of gold which exists here is, however, evidently 
 large, and it is quite possible that, with more ample means, with more skillful operators, 
 and better machinery, these mines might be worked with profit to the proprietors. It is 
 possible, too, that something might be done by building reservoirs to increase, or at 
 least to regulate, the supply of water for the placer, and thus render it more produc- 
 tive. It is true, however, that the fall of rain in all this region is both small and exceed- 
 ingly irregular, and the structure of this mountain group, so limited in extent and so 
 simple, would render it difficult, if not impossible., to utilize fully the few and fitful 
 rains by which it is visited. 
 
 The rock containing the gold at the Old Placer has been regarded by some who ha ve 
 visited the locality as an altered sandstone, but there can be, I think, little doubt that it 
 is the gossan of an auriferous quartz vein. The material now excavated is a cellular 
 silicious rock, of which some portions are soft and oclirey, others hard and quartz-like. 
 In some localities itis associated with a soft yellow tufa, in others with a hard trachyte! 
 or porphyry. The same rock recurs in the Cerrillos; and I have received from tin- 
 gold diggings of Pike's Peak specimens of auriferous vein-stone presenting precisely 
 the same characters. 
 
 Copper. Considerable copper is found at the Old Placer, though as yet no effort 
 has been made to turn it to account, and it is doubtful whether the quantity is sufficient 
 to make it a proper object of attention in an economical point of view. I obtained 
 from there, however, very beautiful specimens of the sulphides of copper and iron, both 
 yellow and variegated (chalcopyrite and bornite). 
 
 Iron. Many large masses of magnetic iron ore were noticed about the Old Placer, 
 and it is said to occur in abundance there in place. This ore is very pure, of a nearly 
 uniform dull black color, less crystalline in appearance, and containing less silica, than 
 the Cliamplain and Canada ores. That which is freshly mined is highly magnetic in 
 character, and often exhibits the properties of the loadstone. 
 
TO JUNCTION OP GEAND AND GEEEN EIVERS. 41 
 
 LOS CEEEILLOS. 
 
 These are a group of hills or small mountains between Santa F6 and the Placer 
 Mountains, on the north side of Galisteo Creek. The highest has an altitude of per- 
 haps a thousand feet; they are somewhat conical in form, and have no distinct linear 
 arrangement. West of them are several smaller hills, extending oft 7 toward the Rio 
 Grande, of which one, from its perfect symmetry called the Potato Hill, will probably 
 attract the attention of all who visit that region. The Cerrillos are wholly eruptive in 
 character, mainly trap and trachyte, and by their upheaval seem to have little disturbed 
 the sedimentary plateau on which they rest. They are principally, interesting from 
 their minerals, and contain many old mines worked by the Spaniards or Indians. 
 There are found there gold, silver, lead, copper, iron, and turquoise or "chalclmitl." 
 The gold apparently exists in but small quantity; a single locality only, so far as known, 
 having furnished it. It there occurs in a quartz vein, running through a yellow sili- 
 cious trachyte similar to that of the Placer Mountains. The silver is found, in combi- 
 nation with lead and copper, in veins in trachyte. These veins have a direction a little 
 \vcst of north and east of south. By many it is believed that the silver mines of the 
 Cerrillos are very rich, and that they will at some time be a source of great wealth to 
 their possessors. The veins which I examined, however, are not promising; where 
 exposed they are not rich, and the evidence is wholly wanting that they will prove 
 more so upon further exploration. The most interesting mines of the Cerrillos are 
 those from which the chakhuitl was taken by the ancient inhabitants of the country. 
 Of these there are several, but one much more extensive than the others that so fully 
 described by Mr. W. P. Blake, Amer. Jour. Science, Vol. xxv, p. 227. The chakhuitl 
 occurs in a yellow, porous, trycUytic porphyry, in numerous thin and interrupted 
 veins. The mineral is rather abundant, but most of it is of an inferior quality, being 
 of an apple-green color. Pieces of the requisite blue tint, and of sufficient size to form 
 the ear-drops or nose-jewels worn by the Indians, could probably only be obtained by 
 long and laborious excavation; the value which they have always borne attesting their 
 rarity. We found but a single specimen of the requisite purity after some hours' search, 
 and that less than a fourth of an inch in diameter. These mines have undoubtedly 
 been worked for ages; the conical cavity which marks the site of the most extensive 
 one being still a hundred feet in depth by nearly two hundred feet in diameter. Prob- 
 ably no excavation has been made here since the occupation of the country by the 
 Spaniards, but the Pueblo Indians and the Navajoes are still in the habit of visiting the 
 spot and digging in the loose rock thrown out by the ancient miners for fragments 
 which they have overlooked. The chakhuitl is not unfrequently found about the ruins 
 which are scattered over New Mexico, and the value set upon it by the ancient inhab- 
 itants is still retained by the modern Indians. I have seen ornaments of it worn by 
 the Apaches, Mohaves, the Navajoes and Pueblos, and so highly prized that a fragment 
 of fine quality no larger than the nail of one's little finger and one-eighth of an inch in 
 thickness was regarded as worth a mule or a good horse. The Indians are excellent 
 judges, too, of the quality of the article, discriminating accurately between the different 
 shades of color, and not to be deceived by any base imitation. 
 6 s F 
 
42 EXPLORING- EXPEDITION FROM SANTA FE 
 
 Of the two great mountain chains visible from Santa FC", referred to in the pre- 
 ceding pages, the Sandia and the Valles, the former is so fully described in the reports 
 of other geologists (Messrs. Marcou and Blake), and in my report upon the geology of 
 the country bordering the Colorado, that it is scarcely necessary that anything more 
 should now be said in reference to it. The Valles, lying west of the Rio Grande, will 
 be more appropriately noticed hereafter in the description to be given of the geology 
 of the country between the Rio Grande and the Colorado along the route of our ex- 
 pedition. This region includes numerous important mountain ranges, which will be 
 best examined from a point of view where their relations can be most clearly seen. 
 
 The stratified rocks of the neighborhood of Santa Fe now claim our attention, and 
 the features which they present will perhaps be most readily appreciated from a resume 
 of each formation considered by itself. 
 
 CARBONIFEROUS STRATA. 
 
 The rocks of this age are exposed in numerous localities in the vicinity of Santa 
 F6", and are apparently the oldest sedimentary strata represented in that region. It is 
 possible that Devonian and Silurian rocks exist in this part of New Mexico ; but if so, 
 they have hitherto escaped detection, and are probably concealed by a covering of 
 more recent materials. It is certain that at Santa F6, in several localities where I had 
 an opportunity of seeing the line of junction of the sedimentary and crystalline rocks, 
 the Carboniferous limestones, the equivalents of the Coal-Measures, rest directly upon 
 the granite, or a layer of coarse sandstone two or three feet thick intervenes, the only 
 possible representative of the older rocks. It will be remembered by those who have 
 read the description given in the report of Lieutenant Ives of the section presented 
 in the canon of the Great Colorado, that in the table-lands west of the Rocky Mount- 
 ains an interval of over three thousand feet occurs between the base of the Coal- 
 Measure limestones and the surface of the granite. This interval is filled by a series 
 of limestones," shales, and sandstones, which I have supposed to represent the Lower 
 Carboniferous, Devonian, and Silurian formations. All that great mass of sediment is 
 wanting at Santa Fe. It is wanting, too, on the more westerly ranges of the Rocky 
 Mountains, and also from those which border the table-lands at their western verge. 
 The absence of this group of rocks in all these localities seems to me to be accounted 
 for only by supposing that they were deposited after some of the great lines of up- 
 heaval which traverse the central portion of the continent had already attained consid- 
 erable elevation above the surfaces which bordered them. The facts revealed in the 
 canon of the Colorado show plainly that the granitic basis of this country was consol- 
 idated previous to the deposition of the Paleozoic strata, and that over many of the 
 minor irregularities of the sea-bottom the older sedimentary rocks were quietly and 
 horizontally laid down, surrounding and abutting against granitic pinnacles, which 
 rose above the shallow waters in which they were deposited. These inferences, if con- 
 firmed by future observations, will considerably modify the hitherto accepted ideas in 
 regard to the age of the ranges of the Rocky Mountains. We are at least warranted 
 in the conclusion that these great lines of fracture in the earth's crust are few of them 
 wholly of modern date, and it even seems probable that through all the geological 
 
TO JUNCTION OF GRAND AND GEEEN EIVERS. 43 
 
 ages they have served as hinges upon which the great plates of the earth's crust 
 turned, as, in repeated elevations and depressions, the angles which they inclose have 
 been ever varying. 
 
 The following detailed sections of the Carboniferous strata, exposed in the hills 
 immediately back of Santa Fe, will be read with interest by all those who are familiar 
 with the Carboniferous rocks of the valley of the Mississippi. 
 
 Section of strata at Santa Fe. 
 No. 1. 
 
 Feet. 
 
 1. Soft reddish-yellow conglomerate 
 
 2. Red shale and sandstone, without fossils 45 
 
 3. Yellow magnesian, shaly limestone, containing large numbers of Orthisina 
 
 iimbraculum and Productus semireticulatus 
 
 4. Red and yellow shale without fossils 25 
 
 5. Red and yellow argillaceous shale, with thin bands of ferruginous sandy lime- 
 
 stone 20 
 
 6. Yellow and pink shale, with bands of calcareous nodules 8 
 
 7. Yellowish-pink (flesh-colored) limestone, containing Productus nodosus, Spirifer 
 
 cameratus, Retzia mormoni, &c 7 
 
 8. Red and yellow shale, with layers of limestone nodules 15 
 
 9. Yellow limestone, with partings of shale 6 
 
 10. Soft red shales, with two bands of intensely hard, grey, quartzose, fine con- 
 
 glomerate, with numerous but obscure impressions of stems of plants. ... 45 
 
 11. Yellowish-blue compact limestone, with Productus semireticulatus, Spirifer cam- 
 
 eratus, etc., in great numbers 
 
 12. Purple, pink, and yellow shales, with thin bands of ferruginous limestone, con- 
 
 taining the same fossils as the bed above 50 
 
 13. Coarse, brown, sandy limestone, full of crinoidal columns 16 
 
 14. Coarse, gray saiulstone - 5 
 
 15. Gray clay 3 
 
 1 6. Coarse, reddish sandstone 7 
 
 17. Coarse, massive, silicious sandstone, with large grains of quartz, containing 
 
 Spirifer cameratus 10 
 
 18. Gray clay 
 
 19. Gray limestone, with Productus semireticulatus, P. nodosus, &c 8 
 
 20. Pinkish and variegated sandstone 12 
 
 21. Gray limestone 4 
 
 22. Ferruginous and micaceous sandstone 6 
 
 23. Ferruginous foliated limestone, with Orthisina iimbraculum, Spirifer cameratus, 
 
 Athyris Roysii 7 
 
 2 I. Reddish-gray, compact limestone, with Spirifer cameratus, S. lincatus, Prodiic- 
 tus nodosus, P. Puogcrsi, P. scabricidus, P. semireticulatus, Atlujris snlitdita, 
 &c . . 5 
 
44 EXPLORING EXPEDITION FROM SANTA Ffi 
 
 , Feet. 
 
 25. Gray shale -_-.- 2 
 
 26. Ferruginous sandstone 3 
 
 27. Gray shale 7 
 
 28. Dark-red or coarse gray sandstone, with obscure impressions of Lcpidodcndra 
 
 and Sigillaria 
 
 29. Gray and red shales, or indurated clays 5 
 
 30. Dark-red ferruginous limestones, with nodules of red chert 15 
 
 31. Grayish-blue 01 reddish silicious limestone, rather massive, without fossils. . 30 
 
 32. Compact crinoidal limestone, reddish or gray in places, made up of bodies and 
 
 stems of crinoids, the latter often large; also containing fish-teeth, spines 
 of Arcliccocidaris and great numbers of Prodiidus nodosus, 1\ Itoycryi, 
 A tliyris stiltlUta, Spirifvr cameratus, &c 25 
 
 33. Dark-red ferruginous sandstone, sometimes a conglomerate and quartzose, in 
 
 other localities soft and coarse 10 
 
 34. Red, blue, green, and yellow, and mottled indurated clay, with nodules of . 
 
 jaspery chert at bottom 18 
 
 35. Cherty concretionary limestone, gray, yellow, blue, red, and contains a few 
 
 Spirifers of an undescribed species 35 
 
 36. Foliated silicious limestone, gray, yellow, or mottled, with dendritic man- 
 
 ganese in the joints; no fossils; like the last, frequently a handsome marble. - 20 
 
 37. Red massive granite to base. 
 
 In the preceding section bed No. 1 is certainly not a member of the Carboniferous 
 series, but is probably the base of the Triassic formation. It is, however, less coherent 
 and of lighter color than any of the lower members of this group as they appear when 
 exposed near Santa Fe. It is conformable to the rocks below, while the Tertiaries of 
 that vicinity are, I believe, always un conformable. It will be seen that in this section 
 well-known Carboniferous fossils are found within less than 50 feet of the granite. It, 
 therefore, the older rocks are represented here, they are restricted to a portion of that 
 limited space. Without positive evidence to the contrary, I must regard all the rocks 
 of the section, except bed No. 1, as Carboniferous, and as the equivalents of the upper 
 division of that great formation; that is, the Coal-Measures. As before remarked, in 
 the walls of the canon of the Great Colorado is a limestone mass, lying beneath the Coal- 
 Measure limestones, which I have supposed might be the Mountain limestone; but of 
 whatever age, that rock and the strata which underlie it are here wholly wanting. 
 There are doubtless some geologists who will regard the granitic base of the preceding 
 section as a metamorphosed condition of the sedimentary rocks which are here due 
 beneath the Carboniferous strata; but this view of the case seems to me wholly unten- 
 able. The massive, unstratified, red granite of the Santa Fe Mountains presents char- 
 acters, both iri its physical structure and chemical composition, which could never be 
 assumed in any possible phase of metamorphism by the older Paleozoic rocks of the 
 Colorado Canon. Much the greater part of their mass is calcareous, and only the 
 extreme upper and lower portions are red. Again, the lower members of the scries of 
 sedimentary strata at Santa Fd are but slight!}', if at all, metamorphosed. Even if 
 those which rest on the granite in the preceding section be supposed to be changed from 
 
TO JUNCTION OP GEAND AND GEEBN BIVEKS. 45 
 
 their original condition, in the succeeding section, taken in a locality 'less than two miles 
 distant, the lowest sedimentary rock is not in the least affected by the proximity of the 
 granite. These facts conclusively show, as it seems to ni e, that the granite was already 
 consolidated before the sedimentary rocks were deposited upon it, and that the reason why 
 the strata underlying the Carboniferous rocks in the Colorado basin are here wanting is 
 simply this: that the surface of the granite upon which they should have been deposited 
 was here too high to receive them. It will be noticed that in the foregoing section of 
 the Coal-Measure strata there are no beds of coal, and yet the preponderance of 
 mechanical over organic sediments, that is, of shales and sandstones over limestones, 
 and especially the presence of coarse sandstones and conglomerates, give to this section 
 a character strongly contrasting with that of the strata of the same age in Kansas a 
 character unquestionably due to the closer and more constant proximity to high land. 
 
 Section of the Carboniferous rocks in the yorye of Santa Fe River. 
 
 No. 2. 
 
 Fort. Inches. 
 
 1. Compact blue limestone 10 
 
 '2. Gray, brown, and black shales 1 - 
 
 3. Pinkish shelly limestone, a mass of fossils, containing Atlujris Roysii, 
 
 A. locidei/x, A. stibtUita, Spirifcr cameratHs, S. Hm-atus, Producing 
 I/IH/OSUS, P. semireticulatus, P. Ncal/ricidus, P. Itogersi, OrthlaliM tinihra- 
 ciihun, Ortlds MicltU'uii (."), lihi/i/choncUa iita, 1'lati/ccras, sp., Nautilus, 
 
 SI)., &G '- 5 
 
 4. Brown, black, and greenish shale 4 
 
 5. Gray limestone (> 
 
 <i. Coal - 4 
 
 7. Green and blue shale 1 
 
 S. Crinoidal limestone, equivalent of No. 32 of preceding section ; very fos- 
 
 siliferous 4 
 
 9. Bituminous and argillaceous shale 1 i 
 
 10. Crinoidal limestone, equivalent of No. 32 of preceding section (> 
 
 11. Gray and blue shale, with bands of bituminous shale and coaly matter, 
 
 with Calamites and leaves of Cor dalles 5 
 
 12. Ferruginous sandstone 4 
 
 1 ,">. G ray and blue shale - 8 
 
 14. Massive concretionary and brecciated gray limestone, containing crinoi- 
 
 dal columns, Atliyris suUilita, Productus semireticulatus, &c G 
 
 15. Foliated limestone, gray and mottled, with dendritic manganese. . . 15 
 
 1 f i. Coarse, soft, white sandstone 3 
 
 17. Red granite, passing into mica slate, to base. 
 
 In this section the Carboniferous fossils approach nearer the granite than in the 
 preceding one, and the sandstone No. 16 is very soft, and exhibits no trace of ineta- 
 morphism. Another section, (No. 3), taken at the south base of Ccrm (iordo, will, with 
 tha preceding one, suffice to give a clear idea of the character of the Carboniferous 
 strata near Santa Fe. 
 
46 EXPLOKING EXPEDITION FEOM SANTA FE. 
 
 Section No. 3. 
 
 Feet. 
 
 1 . Greenish shale 10 
 
 2. Soft greenish sandstone, including a band of ferruginous conglomerate, con- 
 
 taining impressions of Lepidodendrq 16 
 
 3. Gray marl, with nodules of blue limestone 6 
 
 4. Yellow and mottled limestone, (a handsome marble) 10 
 
 5. Blue, concretionary, cherty, silicious limestone, same as No. 35, section No. 1 . 50 
 
 6. Shelly argillaceous limestone, (same as No. 36 of section No. 1) 16 
 
 7. Yellow micaceous sandy shale, very soft 3 
 
 8. Coarse, soft white sandstone, sometimes a conglomerate 5 
 
 9. Red massive granite, to base. 
 
 The other localities in the vicinity, where the Carboniferous strata are exposed, 
 are on the Sandia, Placer, and Jemez Mountains, and in the valley of the Pecos, at 
 and below Pecos Village. They underlie, it is true, almost all parts of New Mexico, 
 but are only visible on the flanks of the mountains and in some of the valleys, which 
 are cut through the overlying rocks. I had not an opportunity of obtaining a complete 
 section of the Carboniferous group on the Sandia and Placer Mountains, as only a 
 portion of the series is exposed in the localities which I examined. As far as 
 observed, however, they seem there to be but little metamorphosed, and contain many of 
 the fossils most characteristic of the Coal-Measure strata of Santa Fe and of the valley 
 of the Mississippi. At Jemez, the rocks of this age rest upon the opposite sides of the 
 red granite core of the mountain, are inclined at a high angle, and are highly fossil- 
 iferous. The features which they present there will, however, be described more in 
 detail in a succeeding portion of this report. 
 
 The exposures of the Carboniferous strata, at and near Pecos Village, are of pecu- 
 liar interest, for, although the section which they afford is less complete than at Santa 
 Fd, the line of junction between the Carboniferous and Triassic series is more distinctly 
 marked, and the upper beds of the former group are more fossiliferous. The strata 
 forming the cliff at Pecos Village are the equivalents of the upper portion of the Santa 
 Fe" section, consisting of beds of limestone, separated by layers of shale and sandstone, 
 the former containing, as characteristic fossils, Athyris subtilita, Producing scmireticu- 
 latus, P. scabriculus, P. Rogersi, Spirifer cameratus, &c. The dip is here from the 
 mountains toward the south and east, and, near the old Pecos church, all the Carbon- 
 iferous series pass beneath the chocolate-colored sandstones and shales the base of 
 the Triassic formation and disappear. The upper member of the underlying group 
 is a brownish, rough, somewhat sandy limestone, of which portions are more purely 
 calcareous. This bed contains a large number of fossils, as far as observed, without 
 exception, such as are common in the Upper Carboniferous strata Permo-Carbonifer- 
 ous of Meek and Ilayden of Kansas. These are a Monotis, not well preserved, but 
 resembling M. Ilawni (and, perhaps, as much, another found in the Middle and Upper 
 Coal-Measures of Missouri and Kansas), Athyris subtilita f, the same found in the 
 Upper Carboniferous and Permian beds of Kansas, referred doubtfully to A. subtiUta 
 by Mr. Meek, and which is larger, broader, and more gibbous than what is known 
 
TO JUNCTION OF GEAND AND GEEEN RIVERS. 47 
 
 under that name in the Coal-Measures east of the Mississippi, yet accords well with 
 the figures and descriptions of the type specimens by Professor Hall; spines of Archce- 
 ocidaris, in great numbers, scarcely distinguishable from A. aculeattis of Shumard; 
 a Betteroplion, very like, if not identical with, one found in the Upper Carboniferous 
 and Permian of Kansas ; a species of Myalina (M. perattenuata), and an undeter- 
 mined Avicula. These fossils occur in great numbers, and there are, perhaps, other 
 species, which I have not enumerated, contained in the bed. It will be seen that in 
 this list of fossils there are none which are peculiarly Permian. The Bakevellia, Pleuro- 
 phorus, Axinus, and the species of Murchisonia, which give character to the fauna of the 
 upper magnesian limestone of Kansas, are here all wanting. It is evident, therefore, 
 that the question whether this bed shall be regarded as of Permian age depends upon 
 where the conventional line shall be drawn dividing the Permian and Carboniferous 
 formations in Kansas. If that line be drawn at the base of No. 10 of Meek and Hay- 
 den's section, this stratum would be excluded from the Permian and connected with the 
 Carboniferous series below. Should the Permo-Carboniferous beds of Meek and Hay- 
 den be included in the Permian, this would, of course, be Permian. If these beds 
 were divided midway, this would probably fall into the Permian division, but it might 
 be necessary to divide even this stratum, only 3 or 4 feet in thickness. 
 
 TRIASSIG FOEMATION. 
 
 The Red Beds of the Gypsiferous series form a conspicuous feature in the geology 
 of the neighborhood of Santa FC", being very freely opened both in the valley of the 
 Rio Grande and in that of the Pecos. In a previous report I have given a general 
 description of the rocks of this formation as developed in this vicinity, and have com- 
 pared the sections which they present with those of their equivalents in the Navajo 
 country and other parts of New Mexico, where I have examined them. The question 
 of their precise place in the geological series is also there discussed at some length, so 
 that already much has been said, which, though essential to a full presentation of the 
 facts relating to this group, need not be here repeated. A general re*sume" of this for- 
 mation will also be given in a succeeding chapter. I have before remarked, in the 
 description given of the geology of the country bordering the Santa Fd road, that the 
 vertical interval occupied by the Gypsum series in Kansas is much less than in New 
 Mexico. This fact will be at once obvious to the traveler coming from the East when 
 he enters the valley of the Pecos. Where last seen on' the Kansas, Little Arkansas, 
 or Cow Creek, "the Red Beds" which represent this group have nowhere a thickness 
 of more than 500 or 600 feet, while at Pecos 'village more than 1,000 feet of the series 
 is exposed in a single section, and its entire thickness in the vicinity of Santa Fd can- 
 not be less than 1,500 or 1,600 feet. By Mr. Marcou, this formation, considered as the 
 equivalent of the Trias of Europe, is represented as attaining a thickness of 5,000 to 
 6,000 feet ; but even in the Navajo country or on the San Juan, where it is apparently 
 most fully developed, its entire thickness is not more than 2,500 feet. In the Pecos 
 section the red sandstones and shales rest directly upon the Coal-Measure limestones, 
 and the Permian magnesian rocks of Kansas are entirely wanting. It is possible, 
 however, as I have before stated, that they are represented by the extreme upper 
 portion of the calcareous beds and by a part of the overlying red sandstones and 
 
48 EXPLORING EXPEDITION FROM SANTA FE. 
 
 shales the "Saliferous group" of my former report; the "Bimtcr Sandstein" or lower 
 division of the Trias of Marcou. In the valley of the Pecos, both at Pecos Village and 
 San Jose", I obtained from the Lower Red Beds vegetable impressions, which, if more 
 perfectly preserved, would probably enable us to draw the lines of classification more 
 sharply than has hitherto been possible. As it is, they give us reason to suspect that 
 the lower portion of the Gypsum series should be regarded as of Permian age; and, 
 by proving that these strata are not entirely without fossils, encourage us to hope that 
 their place in the series may soon be accurately determined. 
 
 The mesa bordering the valley of the Pecos on the south forms a part of the great 
 table-land which stretches away eastward from the base of the mountains, of which a 
 portion has received the name of the Llano Estacado. Except where cut by the valleys 
 it is continued throughout, and has, apparently, everywhere the same geological struc- 
 ture. The section afforded by its cut edge in the valley of the Pecos is as follows: 
 
 Fccf 
 
 1. Yellow and brownish foliated sandstones with alternations of red, purple, and 
 
 gray shale, forming detached buttes on the mesa, without fossils 200 
 
 2. Yellow, massive sandstone, summit of cliff, without fossils 150 
 
 3. Red, white, or green, soft calcareous sandstones and shales with gypsxim, with- 
 
 out fossils 800 
 
 4. Red and green sandstones and conglomerates, separated by thicker beds of 
 
 green, blue, and purple shales, with oxide of iron and copper, and with ferns, 
 Walchiaf and Catamites '. . . 200 
 
 5. Limestones and sandstones containing Carboniferous fossils, to bed of stream. 
 
 In this section I have supposed Nos. 1 and 2 to represent the Lower Cretaceous 
 sandstone group. No fossils wei*e discovered in them in this vicinity, but on the banks 
 of Galisteo Creek, a few miles farther south, in the yellow sandstones which rest on 
 the red gypsiferous strata, I found the leaves of angiospermous dicotyledonous trees, 
 which prove them to belong to the Cretaceous system. 
 
 No. 3 of the section is apparently entirely without fossils, and consists of a series of 
 alternations of deep or pale red and white rarely greenish indurated marls or soft, 
 fine calcareous sandstones. No analysis has been made of these beds, but they prob- 
 ably contain as much sulphate as carbonate of lime. They are precisely similar to 
 the strata forming the upper of the two plainly-marked divisions of the Gypsum series 
 throughout Western New Mexico what I have called in my former report the Varie- 
 gated marls and are distinguished by striking lithological characters from the 
 "Saliferous sandstone group" which underlie them, and form No. 4 of the section. 
 
 This latter group is nowhere exposed in a section which could conveniently be 
 measured, but its thickness is somewhere between 200 and 250 feet. A very good 
 idea may be formed of its prevailing character from the following section taken at the 
 village of San Jose ; the first stratum being the highest: 
 
 Fret. 
 
 1. Coarse reddish or gray sandstone, frequently a conglomerate 8 
 
 2. Chocolate-colored or greenish foliated micaceous sandstone shading into shale; 
 
 containing a band of compact dark-gray silicious limestone, weathering 
 brown . 20 
 
TO JUNCTION OF (IRANI) AND GKEEN KIVKRS. 49 
 
 
 
 Feet. 
 
 3. Foliated micaceous sandstone, generally gray, but often brownish-red, with 
 
 very smooth surfaces ; the red portions presenting precisely the lithological 
 characters of the brown freestone of the Northern Atlantic States. The 
 lighter portions more compact, containing many impressions of vegetable 
 stems and small branches of Walrhia f 11 . 
 
 4. Chocolate and greenish micaceous shales 18 
 
 5. Purplish-gray conglomerate, quite hard, containing much peroxide of iron. . . 10 
 (j. Purple and green shales 30 
 
 7. Conglomerate, with masses of peroxide of iron and copper 9 
 
 8. Purple and green shales to covered slope 20 
 
 At Pecos, on about the same level geologically with the stratum containing the 
 vegetable remains of the preceding section, I found the surfaces of slabs of red sand- 
 stone marked with impressions of a large and handsome fern, evidently a Pccopteris, 
 but too imperfect for specific determination or description. There is no doubt that, 
 with more time than I had at command, fossil plants would be found in the valley of 
 the Pecos, which would throw much light upon the geological age of the lower divi- 
 sion of the Gypsum formation. Those which I obtained are insufficient to decide any 
 of the questions which have been raised in regard to the parallelism of the beds con- 
 taining them with those of other countries, while they may perhaps justly afford 
 ground for a suspicion that the classification which refers all the Gypsum formation to 
 the Trias may be in part erroneous. Calamites are ordinarily of little value in deter- 
 mining nice points of geological parallelism, and the specimens here obtained are few 
 and imperfect. The same has been said of the ferns. The Walchia however, if 
 undoubtedly such, would afford good evidence that the strata which contain it should 
 be classed with the Permian of Europe, as that genus, as restricted by Brongniart, is 
 confined to the Permian and older formations. But in the Trias, Walchia is succeeded 
 and represented by Voltzia, a closely allied conifer, so similar that imperfect specimens 
 of the two genera are not readily distinguishable; and until more and better specimens 
 can be procured from the Pecos Valley, I should scarcely be justified in saying that 
 the plant to which I have referred is a Walchia of Permian age, and not a Volteia, an 
 evidence of the Triassic date of the rock containing it. The specimens before me, 
 however, have all the characters, so far as preserved, of the Walchias, but exhibit none 
 of the cones, which wcmld be decisive. The branchlets are closely approximated, 
 pinnate and parallel,, covered with small falcate or subulate, acute leaves, apparently 
 more acute and less fleshy than the smaller leaves of Voltzia heterophylla, or even V. 
 acutifolia. There is also, apparently, no tendency of the foliage to assume the dimor- 
 phous character so marked a feature in the Voltzias. If a Voltzia, it is evidently a new 
 species, quite distinct from those of Europe. Until farther information can be obtained 
 in reference to this plant, I am disposed to regard it as a Walchia, and as very similar 
 in its general aspects to W. Schlotheimii of the schists of Lodeve. By Messrs. Unger 
 and Endlicher the genus Walchia is not recognized, its species being placed by these 
 authors, as formerly by Brongniart, in Lycopodites. Sternberg, and more recently 
 Brongniart, have, however, regarded it as distinct, and the latter author compares it with 
 the Norfolk Island pine (Araucaria excclsa). 
 
 7 S F 
 
50 EXPLORING EXPEDITION FROM SANTA FE 
 
 CRETACEOUS FORMATION. 
 
 * 
 
 Kxcept for the surface erosion, which has so greatly modified the topography of 
 the region surrounding Santa Ft', we should still find the Cretaceous strata reaching 
 high up on the slo|>es of the mountains and completely covering the underlying rocks, 
 now so freely exposed, both on the mountain-sides and in the valleys of the streams. 
 So deej) and wide-spread has been the denudation, however, that, from the mountains 
 proper, the Triassic and Cretaceous rocks have been wholly removed, and of the 
 sedimentary series nothing- but a part of the Carboniferous strata is left. The Triassic 
 beds are generally soft and have offered little resistance to the mountain-torrents which 
 have acted upon them, but they were once all covered with the massive, though not 
 hard, sandstones of the Lower ( Cretaceous group, and, wliere these were not broken up 
 by the upheaval of the mountain crests and cones, they have protected the lied Beds 
 below, so that we find the latter in full thickness all around the bases of the mountain 
 masses, still covered by the harder strata to which they owe their preservation. 
 
 The Upper Cretaceous rocks are also soft, and it is now necessary to go a long 1 
 way from Santa Fe before anything like a fair representation of the upper portion of 
 this series can be found. Indeed, east of the mountains the extreme Upper Cretaceous 
 strata are only seen in place near the Mississippi and the Gulf of Mexico. In tlie 
 valley of the Rio Grande none remain, and it is only after crossing- the main divide, 
 between the waters of the Atlantic and Pacific, and seeing the magnificent exposures 
 of the Cretaceous series in the valley of the Sail .Juan, that we can form a just con- 
 ception of the grand scale on which the Chalk formation was originally built up in 
 New Mexico, or of the enormous denudation which this region has suffered since it 
 was raised above the surface of the ocean. The attention of every traveler over the 
 great central plateau of our continent is attracted to the canons which give character 
 to the scenery, and when he learns that they are simply the effects of surface 
 erosion, they become sources of unending wonder and interest; but, notwithstanding 
 their magnitude and impressiveness as records of the lapse of countless ages, it is quite 
 certain that they are referable to a single producing cause, viz., the slow, though con- 
 stant, erosive action of running water. The proof of the truth of this assertion is given 
 in my report on the geology of the country bordering the Lower Colorado, to which 
 I have already frequently referred. 
 
 In the description of the Cretaceous strata, which came under our observation on 
 our first expedition through New Mexico, I divided them into two groups, which I 
 denominated Upper and Lower Cretaceous ; that being the most simple and natural 
 division of the strata exposed in Kastern New Mexico and the Indian Territory. I had 
 at that time, however, no opportunity <>f examining the extreme upper portion of the 
 formation, and it was only when, going west from Santa 1'V, we had passed the divide 
 between the waters of the Atlantic and Pacific, that we gained any knowledge of the 
 upper thousand feet of the series. These we found to be made up of a group of rocks 
 quite unlike, in lithological characters and fossils, the calcareous beds Upper Creta- 
 ceous of my former report of the banks of the Canadian. These true Upper Creta- 
 ceous beds will be described in detail in a. subsequent chapter, and, as they do not 
 
TO JUNCTION OF GRAND AND GREEN ItlVEUS. 51 
 
 appear in the vicinity of Santa Fe, they require to be mentioned only as constituting 
 the group which I have denominated Upper Cretaceous in the present report, and to 
 distinguish them from the "Upper Cretaceous" of a former one, which I am compelled 
 
 to regard as the middle portion of the series. 
 
 The Cretaceous formation, then, as exhibited in the vicinity of Santa I'Y, consists 
 of the two groups to which I have- referred in the preceding pages as Lower and Mid- 
 dle, on a former occasion as Lower and Upper Cretaceous. Of these the first con- 
 sists, as elsewhere in New Mexico, mainly of coarse yellow sandstones with impres- 
 sions of angiospenn dicotyledonous leaves; the second, of calcareous shales and 
 ferruginous, shaly, sandy limestones, with numerous marine fossils, such as Amman it<'*, 
 Nautilus, I'Hoa-ntmtiK, (lr</)>lt', fish -teeth, ttc. Of these two groups the lower caps the 
 cliffs bordering the valley of the Pecos on the south, forming the floor of the great plateau 
 which stretches away southeast, where it becomes the Llano Fstacado. It is not yet 
 demonstrated that all the yellow standstoiie formation of this plateau belongs to the Creta- 
 ceous formation, and that it is not in part, as claimed by M. Marcou, of Jurassic' age. I 
 should say, however, that in the vicinity of Santa Fe I was able to discover no Jurassic. 
 fossils ; but, on the contrary, near < Jalistco, in the yellow sandstone specifically noticed 
 by M. Marcou, and regarded by him as Jurassic and identical with that of the Llano, I 
 found impressions of dicotyledonous leaves, which prove it to be Cretaceous. In the vicin- 
 ity of the mountains the stratification is considerably disturbed, and in man)- localities 
 the Cretaceous rocks are broken through or removed by erosion ; but, with local excep- 
 tions, they constitute the surface formation in all the area examined by our party east of 
 the Sandia and Placer Mountains, and south and east of the mountains of Santa Fe. 
 
 The valley of Galisteo Creek has cut through the Middle and Lower ( YHaccons 
 rocks, and has freely exposed the Red Hods below, doing from the base of the Cer- 
 rillos to Clalisteo Creek, after passing the eruptive material which composes this group 
 of hills, the Middle Cretaceous shales are seen occupying a belt a mile or more in 
 width on the north side of the stream. Ueneath them are the yellow Cretaceous sand- 
 stones, underlying which are the blood-red sandstones and shales of the Trias. On 
 the south side of the creek, ascending toward the base of the Placer Mountains, this 
 section is again encountered. The Middle Cretaceous shales here contain beds of lig- 
 nite several feet in thickness: at one point, by an' eruption and overflow of trap, this 
 li<mite has been metamorphosed and converted into a compact and brilliant 
 anthracite. 
 
 The boring made by Captain Pope, T- S. A., near Galisteo, in the hope of obtain- 
 ing water that should spontaneously rise above the surface, was nearly all done in the 
 Middle Cretaceous shales, which here have a thickness of at least thirteen hundred 
 feet. The work was commenced in Tertiary tufaceous limestone precisely like that 
 so frequently mentioned in Chapter I. After passing through twenty-five feet of this 
 material the shales were struck, and they had not been passed through at the time the 
 work was abandoned It is to be regretted that the experiment had not been carried 
 somewhat further, as it is highly probable that the Lower Cretaceous sandstones would 
 soon have been reached, and, dipping down as they do from the Placer Mountains, it 
 is at least possible that the water flowing through them would rise to the surface. A 
 
52 EXPLORING EXPEDITION FKOM. SANTA FE 
 
 section of the rocks exposed east of Captain Pope's well is as follows, the thicknesses 
 being estimated : 
 
 Feet. 
 
 1. Concretionary tnfaceous Tertiary limestone, cream-colored or white 25 
 
 2. Gray and yellow shales, with concretions of yellowish-brown limestone, 3 to 
 
 5 feet in diameter, with numerous casts of Circeopsis crassa, &c., traversed 
 by bands of blue compact limestone, containing' impressions of Inocera- 
 m-us 1, 000 
 
 3. Grayish or yellowish sandstone 100 
 
 4. Gray or bluish shale, with bands of red, including thin layers of arenaceous 
 
 limestone, containing, as characteristic fossils, Ostrca luf/ubris, Gryplicca 
 Pitcheri, Ammonites percarinatus, Inoceramus problematicus 300 
 
 5. Brownish or yellow thick -bedded sandstone, with layers of shale con- 
 
 taining impressions of dicotyledonous leaves 350 
 
 6. White, fine-grained, calcareous sandstones. 
 
 7. Red calcareous sandstones and marls. 
 
 In this section Nos. 6 and 7 belong to the Trias, and are the equivalents of 
 the red and white calcareous sandstones exposed in the valley of the Pecos and in 
 Apache Canon. 
 
 TEKTIAltY FORMATIONS. 
 
 Tertiary rocks are not a marked feature in the geology of the vicinity of Santa 
 Fd, but they are visible in a great number of exposures, and usually form isolated 
 patches of limited area, the remnants of more extensive deposits, now for the most 
 part removed by surface-erosion, to which their yielding nature has offered little 
 resistance. As is true of the patches of Tertiary lying along the eastern bases of the 
 mountains, these beds are of very unequal thickness in different localities, and, in 
 many instances, are mere local accumulations, filling depressions or excavations in the 
 surfaces on which they were deposited. So far as my observation extended, they 
 contained no fossils. In lithological characters they exhibit a remarkable resemblance 
 to the Tertiary strata of the Arkansas basin ; like those, consisting of beds of calcareous 
 tufa, with bands of more compact tufaceous limestone and conglomerates, in which the 
 pebbles are, for the most part, composed of volcanic, materials, basalt, porphyry, 
 trachyte, and scoria, I have little doubt that these beds have been stratified in fresh 
 water, and that the period of their deposition was one in which volcanic forces were 
 in vigorous action in the region where they occur. As will be noticed in the succeed- 
 ing portions of our geological narrative, no similar deposits were discovered by our 
 party in the region bordering the San Juan and Upper Colorado, though older Terti- 
 aries, probably Eocene, occupy a limited district west of the Nacimiento Mountains, 
 
TO JUNCTION OF GRAND AND GREEN RIVERS. 53 
 
 CHAPTER III. 
 
 GENERAL VIEW OF THE GEOLOGY OF THE COUNTRY BORDERING 
 
 THE UPPER COLORADO. 
 
 BIRDS -K YE VIEW OF THE COLORADO PLATEAU AND ITS SURROUNDINGS MOUNTAIN CHAINS 
 BY WHICH THE PLATEAU IS ENCIRCLED ROCKY MOUNTAIN SYSTEM ITS EXTENT AND 
 GENERAL STRUCTURE DIFFERENT FEATURES WHICH IT PRESENTS ON DIFFERENT PARAL- 
 LELS DIFFERENT RANGES OF THE ROCKY MOUNTAINS PROBABLY NOT OF THE SAME 
 AGE ROCKY MOUNTAIN REGION HAS SUFFERED ALTERNATIONS OF ELEVATION AND DEPRES- 
 SIONTHE CRETACEOUS EPOCH AN ERA OF SUBSIDENCE THE TERTIARY OF ELEVATION 
 MOGOLLON MOUNTAINS PROBABLY NOT A DISTINCT SYSTEM MOUNTAINS OF THE LOWER 
 COLOR ADOS A PART OF THE SIERRA NEVADA SYSTEM RELATIONS OF THK SIERRA 
 NEVADA TO THE ROCKY MOUNTAINS CERBAT MOUNTAINS WASATCH MOUNTAINS SAN 
 FRANCISCO GROUP RECENT VOLCANIC PHENOMENA OF THE GREAT CENTRAL PLATEAU- 
 MOUNT TAYLOR SIERRA TUCANE SIERRAS ABAJO, LA SAL, ETC. STRUCTURE OF THE 
 COLORADO PLATEAU DEVONIAN AND SILURIAN ROCKS OF THE GREAT CANON CARBON- 
 IFEROUS FORMATION TRIASSIC AND CRETACEOUS ROCKS SIMILARITY OF STRUCTURE OF 
 
 THE VALLEYS OF THE LITTLE COLORADO, SAN JUAN, GRAND, AND GREEN KlVERS 
 HIGH MESAS OF NAVAJO COUNTRY AND UPPER SAN JUAN. 
 
 A brief description of the general features of the structure of the country border- 
 ing the Colorado will be a necessary introduction to the more detailed analysis of the 
 geology of the region west of the Rio Grande, explored by the San Juan expedition. 
 
 The country bordering the San Juan forms a part of one great geological district, 
 of which the structure, though not alike throughout, considered in its totality, exhibits 
 a remarkable symmetry. This district I have in part described in the fifth chapter of 
 my report to Lieutenant Ives, and have designated by the name of the Basin of (lie 
 Colorado. It is, in fact, geologically a basin; topographically, a great plateau. Could 
 one be elevated to a sufficient height over the center of this region, and be gifted with 
 superhuman powers of vision, he would see beneath him what would appear to be a 
 great plain, bounded on every side by mountain ranges, and here and there dotted by 
 isolated mountain masses, rising like islands above its surface. He would see, too, the 
 profound chasm of the Colorado Canon scoring with tortuous and diagonal course the 
 plain, throughout the entire length of its greatest diameter; for nearly five hundred 
 miles the stream flowing from 3,000 to 6,000 feet below the general level, and at all 
 points bordered by abrupt, frequently perpendicular crags and precipices. Most of 
 the .surface beneath him he would perceive to be arid and desert-like; barren wastes 
 of rock and sand; nowhere continuous forests or carpets of herbaceous vegetation; 
 
54 EXPLOITING EXPEDITION FROM SANTA Ffi 
 
 only here and there dwarfed and scattered pines and cedars and threads of green along 
 the streams; the surface marked with long lines of mesa walls, the abrupt, ofte.n verti- 
 cal sides of broad valleys of erosion; over considerable areas the denudation of soft 
 materials, of varied and vivid colors, having fretted the surface into wonderfully truth- 
 ful imitations of Cyclopean cities, crumbled by 'time, or devastated by fire, giving 
 double force to the sense of desolation which the scene inspired. 
 
 Such, in general terms, are the external features of the plateau country west of 
 the Rocky Mountains, through which the Colorado flows. Perhaps no portion of the 
 earth's surface is more irremediably sterile, none more hopelessly lost to human occu- 
 pation, and yet it is but the wreck and ruin of a region rich and beautiful, changed 
 and impoverished by the deepening channels of its draining streams; the most striking 
 and suggestive example of over-drainage of which we have any knowledge. 
 
 To prevent misapprehension, it should be stated that, around the margins of the 
 Colorado plateau, at the immediate bases of the mountains, the traveler will behold 
 many scenes of beauty and fertility strikingly in contrast with the aspect of the country 
 nearer the river. Here are limited districts deserving our highest encomiums; regions 
 of green and flowery mountain valleys, of clear, cold, and copious streams; of magnifi- 
 cent forests; with an atmosphere of unrivalled purity, and a climate delightfully tem- 
 pered. Here, too, are the mineral treasures of which the sedimentary rocks of the 
 plateau furnish almost none; and here will be congregated the mining population, 
 whose business it will be through future ages to extract for our use the mineral wealth 
 with which many of these mountain ranges are stored. 
 
 Though valueless to the agriculturist ; dreaded and shunned by the emigrant, 
 the miner, and even the adventurous trapper, the Colorado plateau is to the geologist 
 a paradise. Nowhere on the earth's surface, so far as we know, are the secrets of its 
 structure so fully revealed as here. 
 
 I need hardly say that, with the exception of the isolated mountains to which 1 
 have referred, the rocks composing the plateau are sedimentary throughout. They 
 include strata representing the entire Cretaceous formation, the Triassic, perhaps 
 locally, though not yet identified the Jurassic, the Carboniferous, Devonian, and 
 Silurian. In the different parts of its course the Colorado cuts through successively all 
 these strata, and near the western margin of the table-land has worn a furrow (!()') feet 
 deej) in the underlying granite. The sections afforded by the canons of the Colorado 
 and its tributaries reveal in the most clear and unmistakable manner the superposi- 
 tion, thickness, Jind mineral character of the sediments forming the table-land to even 
 the most hurried observer; and when, with time and patience, we shall have collected 
 a full series of their characteristic, fossils there as elsewhere only locally abundant 
 we shall be able to write with unusual fullness and precision both the zoological and 
 physical history of the epochs of their deposition. 
 
 A summary of the results of geological observations made while connected with 
 two expeditions organized for the exploration of the course of the Colorado is briefly 
 as follows : 
 
 The phenomena presented by the geology of the area drained by the Colorado 
 which embraces all Arizona, the western half of New Mexico, and much of Colorado 
 
TO JUNCTION OF GRAND AND GREEN RIVERS. 55 
 
 and Utah naturally fall into two great groups: first, that of the mountain ranges; 
 second, that of the great plateau which they inclose. For convenience, these will be 
 considered separately. 
 
 MOUNTAINS SURROUNDING THE COLORADO BASIN. 
 
 Nothing like a thorough exploration of the numerous and complicated mountain 
 systems of the region under consideration lias as yet been made, and years of patient 
 study must be devoted to the subject before their intimate structure or relations to each 
 other will be fully comprehended. Only <i skeleton sketch of their extent, structure, 
 and direction can now be honestly given, and the inferences drawn from the facts 
 already observed will be liable to considerable modification in the'light of future ex- 
 plorations. 
 
 The mountain chains and groups under consideration are as follows: 
 
 1. The Rocky Mountain system. 
 
 2. The Mogollon Mountains. 
 
 3. Cerbat and Aquarius ranges. 
 
 4. The mountains of Lower Colorado (Black and Mohave Mountains, &c-.). 
 f). The Wasatdi Mountains. 
 
 (j. The San Francisco group (lately an active volcano). 
 
 7. The Mount Taylor (San Mateo) (lately an active volcano). 
 
 8. The Sierra Tucane (isolated .mountain). 
 
 9. The Sierra Abajo (isolated mountain). 
 
 10. The Sierra La Sal (isolated mountain). 
 
 11. The Sierra La Late (isolated mountain). 
 
 By reference to the accompanying map it will be seen that the vast mountain-belt 
 of the Rocky Mountain system, the great backbone of our continent, forms the eastern 
 boundary of the Colorado basin, and, by its drainage, supplies by far the greater part 
 of the flow of that stream. In the deep sinuosities of outline, occasioned by the inter- 
 riiption of many of the ranges of this great system, the courses of the San Juan, Grand 
 River, and Little Colorado are laid. Between the Rocky Mountains on the east, and 
 the Wasatch, Aquarius, and Cerbat ranges on the west, the Colorado plateau lies as 
 a comparatively level plain, its northern and southern boundaries less accurately 
 defined, and in part as yet unknown. 
 
 ROCKY MOUNTAIN SYSTEM. 
 
 In the preceding chapter and in another report, I have given my own observa- 
 tions on portions of this mountain system, and have expressed my views upon the 
 indefinite and shadowy nature of the classification, according to which all portions 
 of the immense and irregular mountain-belt which traverses the central portion 
 of our continent are included in a single name and referred to a single epoch in 
 geological history. So far as the limited explorations by geologists have extended, 
 it is true that a general imiformity of composition and trend has been observed, 
 and, as will be seen in the subsequent pages, I have now no new facts to report 
 which indicate the necessity of its separation into several distinct systems. The 
 
56 EXPLORING EXPEDITION FROM SANTA FF, 
 
 evidence on this point, is, however, for the most part negative. Many great ranges, 
 now supposed to belong to the Rocky Mountains, have not been visited, and of those 
 which have been examined almost none have been studied as closely as is desirable. 
 If, as the facts in our possession seem to render probable, all the ranges now grouped 
 together in the Rocky Mountain system have the same essential structure, the contem- 
 plation of this system as a whole is calculated to give us new and broader views of the 
 action of the forces by which mountain-chains have been elevated. For example, con- 
 fining our observation to our present field of inquiry, we have in Southern Utah and 
 Northern New Mexico a broad, almost unbroken mountain-belt, extending from the 
 western margin of the plains, westwardly to the western bases of the Sierra La Plata 
 and Sierra San Miguel, a distance of nearly three hundred miles. This area is, with 
 the exception of the valley of the Rio Grande, wholly occupied by mountain-ranges 
 of great elevation, and the narrow valleys which divide them. On all the older maps 
 the western half of this region is represented as occupied by the great ranges of the 
 Sierra San Juan and Sierra La Plata, to which a nearly east and west trend was 
 assigned. Our recent explorations, however, have given a new aspect to this mountain 
 group. We found the western, like the eastern portion, to be composed of a number 
 of prominent chains having a general north and south trend. The structure of these 
 western mountains is similar to that of the ranges near Santa Fe", described in the pre- 
 ceding chapter, viz : an axis of red granite, flanked on either side by strata of highly 
 inclined but almost unchanged Carboniferous limestone, containing most of our charac- 
 teristic Coal-Measure fossils ; above the limestones, entirely conformable, the red 
 beds of the Gypsum series, (Triassic); upon this, also conformable, the different mem- 
 bers of the Cretaceous formation. All these western mountain-ranges are comparatively 
 short; terminating on the north in the open area traversed by Grand River and its 
 tributaries; on the south reaching out, like so many fingers, into the plain country 
 bordering the San Juan. 
 
 A transverse section of the Rocky Moinitains, drawn a little north of west from 
 Anton Chico across the Rio Grande, exhibits features as different from that just 
 described as could well be imagined. Just north of this line the lofty ranges of the 
 Santa Fe" Mountains fall off abruptly and disappear. West of the Rio Grande, and in 
 its immediate vicinity, lie the north and south ranges of the Valles, and the Nacimi- 
 ento Mountain; altogether perhaps twenty miles in width. West of the Nacimiento 
 the sedimentary plateau extends to and beyond the Colorado. On the line of this 
 profile, or in its immediate vicinity, the Rocky Mountain ranges have dwindled to 
 comparative insignificance. 
 
 In a profile drawn parallel with the last, a little farther south, the Rocky Mountain 
 belt assumes far more respectable dimensions. East of the Rio Grande the Sandia 
 Mountain rises as a frowning wall 7,000 feet above the valley; 12,000 above the sea. 
 West of the river is the extinct volcano of San Mateo, to which I shall have occasion 
 to refer again, then the Sierra Madre, northwest of which, en echelon, are the chains 
 of the Sierras Tunecha and Cariso, both of which terminate south of the San Juan. 
 
 South of this line the mountains again narrow and diminish, and the headwaters 
 of the Colorado Chiquito reach far over toward the Rio Grande. 
 
TO JUNCTION OF GRAND AND GREEN RIVERS. 57 
 
 Still further south, on and below the parallel of 34, an almost unbroken succes- 
 sion of mountains stretch from the Sierra Blanca, the Sacramento, and Guadalupe 
 Mountains, all the way across to the Colorado. Of these, those lying near the Rio 
 Grande, both east and west, have apparently a structure similar to that of the ranges of 
 the Rocky Mountains further north. West of these an immense area is occupied by 
 the Mogollon Sierras, as yet almost unknown. Still further west are the ranges cross- 
 ing the Lower Colorado, and belong-ing to the system of the Sierra Nevada. What is 
 the relative space occupied by these different mountain groups; whether they repre- 
 sent one, two, or three distinct systems; and if distinct, what are their relative ages, 
 are questions which future observations alone can answer. 
 
 In regard to the precise age of the Rocky Mountains, as before stated, we want 
 more extended and minute observations before we can determine whether the elevation 
 of all parts of the system was synchronous, and whether, if so, it is to be referred to 
 a single epoch, or was continued through several geological periods. There are, how- 
 ever, some facts which lead me to conclude that the elevation of the different ranges 
 now referred to this system was not in all cases synchronous, and that they are the 
 result of the action of forces operating through all geological time, from the earliest 
 Paleozoic period to the- present. Still further as a corollary to the last proposition 
 the Rocky Mountain region has suffered several alternations of elevation and depression. 
 Much of the evidence on this subject is given in my report to Lieutenant Ives, page 
 . It is briefly as follows : 
 
 1. The Paleozoic strata, several thousand feet in thickness, which underlie the Car- 
 boniferous formation in the great canon of the Colorado, are wholly wanting on the sides 
 and summits of the mountain ranges which bound the Colorado basin, both on the east 
 and west Cerbat and Aquarius ranges, Santa F^ and Nacimiento Mountains, Sierras 
 La Plata, Cariso, &c. On these ranges the Carboniferous strata, very little metamor- 
 phosed, rest directly upon the granite ; the natural inference from these facts being that 
 the mountains enumerated above existed, at least in embryo, previous to the deposi- 
 tion of the older Paleozoic rocks, and were elevated above the ocean from which the 
 lower strata of the Colorado section were deposited. 
 
 2. The explorations of Dr. Hayden have demonstrated that the granitic axis of 
 the Black Hills is flanked by the Potsdam sandstone, now exposed by upheaval, and 
 overlaid by the Carboniferous and more recent strata; the evidence being conclusive 
 that this portion of the Rocky Mountain system was beneath the waters of the primeval 
 ocean. 
 
 3. In the fresh lava-streams of the Raton Mountains, the Valles, in the Mal- 
 pais near Fort Stanton, and about San Mateo, as well as in various other portions of 
 the Rocky Mountain region, we have evidence that most violent volcanic action has 
 been in operation distinctly within the present epoch, having been continued from the 
 Middle Tertiary period, if not dating back still further. 
 
 4. As stated in the descriptions of the Arkansas Tertiary basin and the geology 
 of the region about Cottonwood Spring, (Chapter I,) we have satisfactory proof that, 
 previous to the deposition of the Lower Cretaceous strata, the central portion of the 
 continent was above the ocean level, and that the Cretaceous sediments were mainly 
 
 8 s F 
 
58 EXPLORING EXPEDITION FROM SANTA FE 
 
 deposited during a period in which a subsidence of several thousand feet took place. 
 This is shown by the immense extent of the Lower Cretaceous sandstones, a littoral 
 formation, the immediate debris of the land, containing only and abundantly the remains 
 of land-plants; these sandstones being overlaid by a great thickness of marine strata. 
 
 5. At the close of the Cretaceous age a period of elevation began, which continued 
 to the Drift epoch, when the continent was again depressed, to be again elevated, 
 though not having as yet reached its former level. 
 
 The facts upon which these conclusions are based are briefly these: (.) The 
 Tertiary beds of the country bordering the Rocky Mountains on the east are mainly 
 fresh-water deposits. (?;.) They were precipitated upon surfaces which had suffered 
 enormous subaerial erosion, filling troughs and basins excavated in the Cretaceous or 
 Gypsum formations; the Tertiary strata being unconformable. (c.) The investigations 
 of Messrs. Meek and Hayden have shown that in these Tertiary basins the lower beds 
 sometimes contain estuary shells, the upper exclusively fresh-water species. 
 
 6. We may fairly infer from the facts given above that the great elevatory move- 
 ment, which gave to the Rocky Mountain region the character it now exhibits, took 
 place between the close of the Cretaceous period and that of the Miocene Tertiary. 
 To this general rule, however, we cannot yet say that there are' not marked exceptions. 
 
 MOGOLLON MOUNTAINS. 
 
 Perhaps no important moiintain chains within the territory of the United States 
 are so little known as these. No geologist has ever visited the region which they 
 occupy, and I am not aware that any record has been made of the observations 
 of the Army officers or others who have traversed it. In his synopsis of the 
 mountains of North America, M. Marcou has referred the Mogollon ranges to a 
 distinct system, and has assigned to them a trend very different from those of the 
 mountains nearest them on either side. This classification has been, however, advanced 
 on grounds wholly inswfficient, and may be considered as purely imaginary. As I 
 have stated in my former report, my own convictions are that future explorations will 
 show that the ranges of the Mogollon and Sierra Blanca have a north and south or 
 northwest and southeast trend, and are to be grouped with the Rocky Mountain ranges 
 on the east, or those of the Sierra Nevada system on the west. My reasons for this 
 belief are, that verbal statements of parties who have visited these mountains indicate 
 their structure to be essentially that of the Rocky Mountains; i. e., axes of red or 
 grayish granite, flanked by Carboniferous limestones with their characteristic fossils; 
 some of which, such as Productus semireticulatus, have been brought in. In addition to 
 this, it may be said that ranges of mountains, with an east and west trend, would be a 
 strange anomaly in the topography of New Mexico. Such a thing I have not yet met 
 with in any portion of the central or western parts of our continent which I have visited. 
 
 MOUNTAINS OF THE LOWEK COLORADO. 
 
 These ranges, which form the southwestern boundary of the table-lands, seem 
 but continuations of the metalliferous chains of Sonora, passing with a northwest 
 trend up into Nevada and California, there blending with the Sierra Nevada. In trend 
 
TO JUNCTION OF GRAND AND GREEN RIVERS. 59 
 
 and structure they seem to accord with that system, and in the present state of our 
 knowledge would naturally be included in it. In composition they generally exhibit 
 a marked difference from the ranges of the Rocky Mountain system. They are 
 composed in a much greater degree of purely eruptive rocks, whole ranges being formed 
 of trachytes, tufas, porphyries, amygdaloids, &c., in endless variety. Their granites 
 are generally white or gray. Metamorphic rocks are abundant among them, consisting 
 of gneiss, mica-slate, clay-slate, talcose-slate, and limestone, the latter highly meta- 
 morphosed and crystalline, forming white, blue, gray, and clouded marbles; so far as 
 observed, wholly destitute of fossils. They are rich in valuable minerals; large quanti- 
 ties of gold, silver, copper, lead, and iron having already been discovered in them. 
 The Black Mountains may be regarded as the most northerly, as well as the most 
 important, of these ranges which cross the Colorado. This chain crosses below the 
 mouth of the Virgen, and thence seems to trend away northwesterly toward Washoe. 
 It may be anticipated that the stores of metallic wealth so characteristic of these ranges 
 will be discovered in the unexplored region into which they are prolonged after crossing 
 the Colorado. 
 
 The question of the relative age of the Colorado Mountains, and hence of the 
 Sierra Nevada and Rocky Mountains, is one of great geological interest, and yet one 
 on which at present we have almost no light. The prevailing mineralogical characters 
 of the two systems are, as has been said, considerably alike, and yet it remains to be 
 proven that in their southern prolongations they do not blend in one. 
 
 I have suspected that the metamorphic limestone of the Sierra Nevada is of Car- 
 boniferous age, and that -it holds a position corresponding to that of the Rocky Moun- 
 tains. It is, however, so generally metamorphosed that all traces of fossils have disap- 
 peared. By reference to my report to Lieutenant Williamson, (P. R. R. Rep., vol. 
 VI, Greol. Rep., p. 27,) it will be seen that near Mount Shasta a Paleozoic limestone of 
 great thickness is exposed, which is highly fosilliferous. By Dr. Trask, who has exam- 
 ined it, it is regarded as Carboniferous. A further examination of this interesting locality 
 may, perhaps, give us the information which we so much desire. 
 
 CERBAT MOUNTAINS. 
 
 These mountains, with their associates, the Aquarius and Aztec ranges, are so 
 fully described in my first report on the geology of the Colorado country, that 
 nothing need now be said of them further than what is necessary to give them their 
 proper place in the wider view which later observations permit me to give of the Colo- 
 rado Basin; of this basin these mountains form the western margin. Against their 
 sides the older Paleozoic rocks seem to abut, and on their flanks the Carboniferous 
 rocks rest, just as on the slopes of the Rocky Mountains, three hundred miles eastward. 
 
 In trend and composition these mountains seem to share the characters of the 
 Sierra Nevada and Rocky Mountain systems. Their granites are gray, and the sedi- 
 mentary rocks rest upon them nearly unchanged; the metamorphic slates and limestones 
 of the Colorado ranges not having been discovered. Their trend is slightly west of 
 north, nearly parallel with that of the Sierra Madre, their vis-a-vis. 
 
60 EXPLORING EXPEDITION FKOM SANTA FE 
 
 WASATCH MOUNTAINS. 
 
 At present it is impossible to say what is the extent, or very definitely what 
 is the structure of the great mountain groups bordering the Great Salt Lake and 
 extending thence southward toward the Colorado. Of these the more conspicuous 
 ranges, lying east and south of the lake, have been designated by the name of 
 Wasatch. From the explorations of Captains Gunnison, Whipple, and Fremont, we 
 learn that a series of mountain ranges extend south and west from these to and be- 
 yond the Vegas de Santa Clara. In this region they form the northwestern boundary 
 of the Colorado plateau, holding the same relation to that great area of stratified 
 rocks as do the Aquarius and Aztec ranges farther south. Their flanks are covered 
 with Carboniferous limestones, turned up and broken through by their granitic axis. 
 How broad the mountain belt may be which exhibits this character we do not yet 
 definitely know. We are informed, however, that there are several distinct ranges 
 having a trend north and south, or a little east of north by west of south. Going 
 westward these ranges merge insensibly in the "lost mountains" of the Great Basin, 
 some of which retain, in a greater or less degree, the structure of the Wasatch ranges, 
 while others are composed mainly of trappean rocks, having the composition and 
 ragged, picturesque outlines of the cockscomb sierras of the Lower Colorado. All this 
 portion of the continent is thickly set with mountain groups or ranges, forming a laby- 
 rinth whose mysteries years of patient effort will hardly suffice to penetrate and reveal. 
 This region has been recently traversed by Captain Simpson, United States Topograph- 
 ical Engineers, with interesting thoiigh as yet unpublished results. Among the collec- 
 tions made by Mr. H. Engelman, the geologist of the party, are a few Devonian fos- 
 sils, such as Atrypa reticularis and several species of Spirifera, described by Mr. Meek 
 (Proc. Acad. Nat. Sci. Phila., July, 1860), the first instance where fossils of this age 
 have been found so far west. 
 
 Up to the present time we have no well-marked geological criteria by which to 
 distinguish the Wasatch ranges from those of the Rocky Mountains, and it is possible 
 that future explorations will show that the Colorado Basin is completely encircled by 
 the widely separated chains of the same vast mountain system. 
 
 SAN FRANCISCO GROUP. 
 
 Of the San Francisco Mountain and its associates, Bill Williams, Mount Ken- 
 drick, and Mount Sitgreaves, a detailed description is given in the seventh chap- 
 ter of my report to Lieutenant Ives, United States Topographical Engineers. By 
 reference to that description and the accompanying geological map it will be seen 
 that these mountains are great volcanic foci, the eruptions from which have cov- 
 ered all the adjacent country with lava. The precise date of the commencement of 
 the volcanic action in this region cannot, perhaps, be accurately determined, but it is evi- 
 dent that the greater portion of the erupted material was thrown out, geologically speak- 
 ing, at a comparatively recent epoch, at a time when the topographical features of that 
 vicinity were in all essential particulars the same as now ; when the high plateau from 
 which these mountains rise was already a plateau elevated several thousand feet above 
 
TO JUNCTION OF GRAND AND GREEN RIVERS. 61 
 
 the sea. Its surface-rock Avas then Carboniferous limestone, from which the overlying 
 formations had been entirely removed, and in which lines of drainage had been exca- 
 vated, having the general direction and character of the present stream-beds. There 
 is evidence that the cones of the mountains themselves, and the floods of lava which 
 surround them, have been formed by a series of eruptions, and that the latest of these 
 paroxysms occurred within a few years. 
 
 As I have previously remarked, the eruption of the material composing and sur- 
 rounding these volcanoes has produced comparatively little disturbance of the sedi- 
 mentary rocks upon which they rest. We have as yet no evidence that they form part 
 of any well-marked line of upheaval, nor is there any obvious connection between 
 these mountains and any of the chains which surround them, or with any of the other 
 volcanic vents which are scattered over the great central plateau. My attention was 
 particularly directed to this point by Baron Humboldt, through Mr. Mollhausen, before 
 visiting New Mexico ; and I was particularly requested to examine the country be- 
 tween the San Francisco Mountain and San Mateo, to detect, if possible, some connect- 
 ing link, such as lines of upheaval or of volcanic vents. I was, however, able to dis- 
 cover no proof whatever of any relationship between the two other than the perfect 
 correspondence which their local phenomena present. It is true that east of the Little 
 Colorado, just south of the Moqui Villages, is a series of buttes composed of compar- 
 atively recent volcanic matter, which made 'its exit from a number of vents in that 
 vicinity; but the sedimentary rocks are scarcely at all disturbed, even in the intervals 
 between these trap buttes, and the country on either side is entirely free from dikes, 
 faults, or displacements of any kind which would indicate the action of disturbing 
 forces along the line connecting San Francisco Mountain and San Mateo. 
 
 It is a somewhat remarkable fact that volcanic vents similar to those under con- 
 sideration, though of less magnitude, are scattered over the entire area of the central 
 table-lands, from Mexico far up into the British possessions. About many of these the 
 evidence abounds that their fires have only been quite recently extinguished, and yet 
 in none, so far as we know, are they now burning. The cause of this simultaneous 
 cessation of an action, lately so wide-spread and vigorous, becomes an interesting sub- 
 ject of inquiry. 
 
 SAN MATEO (MOUNT TAYLOR). 
 
 This is the second in importance of the great extinct volcanoes of the central por- 
 tion of our continent which have come under my observation. It has an altitude of 
 between 11,000 to 12,000 feet, perhaps a thousand feet less than that of the San Fran- 
 cisco Mountain. It stands quite alone, and has no apparent connection with any other 
 peak or range. Like most isolated mountains, it is composed of erupted material, and 
 seems to have been wholly formed by the acciimulation of ejected matter around a 
 volcanic vent. As has been remarked of the San Francisco Mountain, this volcano has 
 been in vigorous action at a very recent period. The lava-streams of its latest eruptions 
 present precisely the same appearance as those of Vesuvius, when but just cooled; and 
 it is difficult to believe that they have been exposed to the action of the atmosphere 
 even for so much as a hundred years. 
 
62 EXPLORING EXPEDITION FROM SANTA F 
 
 The existence of great volcanos, like San Francisco Mountain and San Mateo, in 
 full blast, many hundred miles from the sea, is a powerful argument against the theory 
 which restricts all volcanos to the vicinity of large bodies of water. 
 
 SIERRA TUCANE (NAVAJO MOUNTAIN). 
 
 This mountain is situated near the junction of the San Juan and Colorado 
 Rivers, and was, therefore, not reached by either of the expeditions with which I 
 have been connected. As seen from a distance, it seems to be a mountain of very 
 considerable elevation, either solitary or associated with a few subordinate peaks, 
 forming a group of limited extent. What its structure is we can, of course, only con- 
 jecture, but from its isolated character we may be quite sure that it is composed of 
 erupted material ; and it should probably be grouped with the North Side Mountains, 
 the Sierra Abajo, Sierra La Sal, La Late, &c., which are scattered like islands over 
 the surface of the plateau. The description of these latter groups, as well as that of 
 the Rocky Mountain ranges lying on or near our trail, will be given in the succeeding 
 chapters devoted to the geology of our route. 
 
 THE COLORADO PLATEAU. 
 
 In the preceding pages, where I have referred to the area under consideration, 
 I have used indiscriminately the terms plateau and basin; the one having reference 
 to the prevailing character of the surface, the other to the geological structure. Both 
 terms are sufficiently appropriate; for, when viewed as a whole, it has a distinctly 
 plateau character, formed by a series of table-lands, which rise step by step from the 
 Carboniferous limestone to the summit of the Cretaceous formation, and from the broad 
 valleys of erosion, in which its canons are scored, to the summits of the divides between 
 its draining streams. In the geological portion of the report of the Colorado Expedition 
 will be found both a general and a detailed description of the topography and structure 
 of the central and southern portions of the Colorado Plateau. The observations made 
 on our recent explorations enable me to complete, in a great degree, the sketch, much 
 of which was then only given in. outline ; to make important additions to the informa- 
 tion then gained of both the geographical and vertical extension of the sedimentary 
 strata which are there represented, and, by satisfactory proofs, confirm views before 
 only conjectural. 
 
 Adding to the facts then given those more recently observed, we find that the 
 generalities of the structure of the Colorado plateau or basin are as follows : v 
 
 On both the eastern and western sides, Carboniferous strata, the equivalents of the 
 Coal-Measures in age, are seen resting on the granitic axes of the bounding mountains ; 
 dipping at first rapidly, then more gradually, toward the center of the basin or 
 trough. On the eastern side the Carboniferous strata are exposed only in a, narrow 
 belt along the mountain-sides, almost immediately passing beneath the Triassic and 
 Cretaceous strata, which there have an aggregate thickness of 5,000 feet or more. On 
 the western side, on the contrary, the first easterly dip of the Carboniferous rocks is 
 succeeded by a gentle rise toward the east ; a broad arch being formed, of which the 
 
TO JUNCTION OF GRAND AND GREEN RIVERS. 63 
 
 eastern slope reaches as far as the Little Colorado. Up to this point the more recent 
 formations have been removed from the Carboniferous, and this occupies a broad belt 
 of country, indicated in the geological map, accompanying the report of Lieuten- 
 ant Ives. As we go northward this Carboniferous belt rapidly narrows, and on the 
 flanks of the Wasatch Mountains it exhibits simply aline of outcrop, as on the opposite 
 ranges of the Rocky Mountains. Along the Little Colorado the Carboniferous lime- 
 stones dip beneath the overlying rocks, and are lost to view in all the interval between 
 that point and the Rocky Mountains. On the east side of the Little Colorado, its 
 valley is bounded by a mesa composed of the Triassic marls and red sandstones, which 
 form a distinct step in the table-lands, reaching eastward for many miles, with a still 
 greater extension north and south. Above this, on the east and north, the Lower Creta- 
 ceous rocks form a third plateau, along its margin cut into detached mesas and messil- 
 las by valleys of excavation. Farther east and north these mesas combine, and the 
 Cretaceoiis rocks in an unbroken sheet underlie the whole country. 
 
 The broad eroded valleys of the San Juan, of Grand and Green Rivers, and the 
 Upper Colorado generally, exliibit precisely the same structure as that of the valley 
 of the Little Colorado. The Carboniferous limestones are exposed in the canons of 
 these streams, while the broader valleys through which they flow are excavated in the 
 red Triassic rocks ; large surfaces of which are exposed on the banks of all these 
 streams. The process of erosion has there, as on the Little Colorado, everywhere left 
 the most surprising monuments of its action; domes, castles, walls, spires, which by 
 their vivid colors and fantastic outlines attract the attention and excite the wonder of 
 every explorer who beholds them. Above the Triassic rocks the Lower Cretaceous 
 sandstones massive beds of comparatively resistent material cap mesas which stretch 
 away to a great distance both east and west of the Colorado. They form the floor of 
 the great sage-plain lying between the Sierra La Plata and Sierra Abajo. South of 
 the Sierra La Plata they are covered by the Middle and Upper Cretaceous beds form- 
 ing the Mesa Verde the third great step in the table-lands above the Carboniferous 
 which on the east connects with the plateau bordering Canon Largo and extending to 
 the base of the Nacimiento Mountain. High table-lands are visible west of the 
 Colorado, where it is formed by the junction of Grand and Green Rivers, evidently 
 corresponding to the Cretaceous mesas just mentioned, but whether they correspond 
 precisely to it in geological structure can only be determined by further explorations. 
 
 The country bordering the Upper Grand and Green Rivers, as described by Dr. 
 Schiel (Pacific R. R. Rep., vol. 2), by Mr. Egloffstein and Colonel Henderson, who 
 have kindly communicated to me their observations, has essentially the same structure 
 with that bordering the Little Colorado and the San Juan. The Triassic rocks are 
 freely exposed in the valleys of erosion, while table-lands floored with Cretaceous 
 strata occupy the greater portion of the intervals between the mountain chains. This 
 margin of the Colorado basin is very irregular, and its outline has not been accurately 
 traced. 
 
 Between the Little Colorado and the San Juan the country is almost exclusively 
 occupied by Cretaceous rocks. The Lower Cretaceous sandstones are here largely 
 developed, containing numerous impressions of leaves of land-plants and heavy beds 
 
64 EXPLOBING EXPEDITION FEOM SANTA FE 
 
 of lignite, which have attracted the attention of all the exploring parties who have 
 entered this region, and have been mentioned in their notes as beds of bituminous coal. 
 The higher table-lands between the San Juan and Little Colorado have an altitude of 
 about 8,000 feet, and are composed of the upper members of the Cretaceous forma- 
 tion, corresponding in all respects with the Mesa Verde north of the San Juan, with 
 which they were at one time undoubtedly continuous; the immense void which now 
 separates them having been removed by erosion. This high table-land the "white 
 mesa" of my former report seems to reach westwardly to and beyond the Great 
 Colorado, but its western boundaries have not been accurately determined. Where 
 this mesa is cut by the Colorado that stream is supposed to have an elevation of less than 
 2,000 feet above the level of the sea. The awfully grand precipices over a mile in 
 height which overhang it, I have described in my former report on the geology of 
 this region. 
 
 On the eastern margin of the Colorado plateau, especially in that part of it which 
 borders Cafion Largo, and forms the western base of the Nacimiento Mountain, a 
 series of variegated gypsiferous strata overlie the Upper Cretaceous beds of the Mesa 
 Verde, and occupy a considerable superficial area. These strata seem to be conform- 
 able to the Cretaceous rocks below, and may form the summit of this sei'ies, or, as I 
 have suggested in another chapter, they may be Tertiary. If so, they belong to an 
 older division of the Tertiary series than the chalky beds of Santa Fe and the plains, 
 and represent a group not elsewhere seen in any part of the Colorado plateau. What- 
 ever their age, these strata form the geological summit of the plateau series of sediments. 
 
TO JUNCTION OF GRAND AND GREEN RIV.ERS. 05 
 
 CIIA.P'TER IV. 
 
 GEOLOGY OF THE ROUTE FROM SANTA FE TO THE SIERRA LA 
 
 PLATA. 
 
 STRUCTURE OF THE VALLEY OF THE Rio GRANDE THE VALLEY OF THE CHAMA ABIQUIU- 
 (JorrER MINES FOSSIL PLANTS RUINS OF Los CANONES ABIQUIU PEAK PLATEAU 
 COUNTRY BORDERING THE UPPER ClIAMA ARROYO SECO TRIASSIC MARLS NAVA.TO 
 SPRING CRETACEOUS SANDSTONES AND PLATEAU BANKS OF THE NUTRIA MIDDLE CRE- 
 TACEOUS BEDS V ADA DEL CHAMA SECTION OF VALLEY OF THE ClIAMA HIGH MESA 
 
 OF UPPER CRETACEOUS ROCKS LAGUNA DE LOS CAVALLOS DIVIDE BETWEEN THE 
 WATERS OF THE RlO GRANDE AND SAN JUAN GENERAL VIEW OF THE STRUCTURE OF 
 THE SURROUNDING COUNTRY MOUNTAIN CHAINS BELT OF FOOT-HILLS TABLE LANDS 
 Rio NAVAJO CERRO DEL NAVAJO SIERRA DEL NAVAJO RITO BLANCO THE PAGOSA 
 SIERRA SAN JUAN AND ASSOCIATED MOUNTAIN RANGES CRETACEOUS ROCKS AND FOS- 
 SILSTHE PIEDRA PARADA Rio PIEDRA BROKEN MESA VIEW FROM HIGH DIVIDE- 
 RIO DE LOS PINOS SIERRA DE LOS PINOS Rio FLORIDO VALLEY OF THE ANIMAS 
 RUINS ON THE ANIMAS CROSSING OF THE ANIMAS STRUCTURE OF THE MOUNTAINS 
 DRAINED BY THE ANIMAS RlO DE LA PLATA DELIGHTFUL CAMP CRETACEOUS ROCKS 
 AND FOSSILS SIERRA DE LA PLATA METALLIFEROUS VEINS OF THE SIERRA DE LA PLATA. 
 
 VALLEY OF TOE RIO GRANDE. 
 
 The structure of the Rio Grande Valley seems to be essentially the same 
 throughout, its entire extent that is, as far as it is really a valley, viz., from its 
 northern extremity to El Paso. Throughout all this interval it is a synclinal 
 trough, lying between imperfectly parallel ranges of mountains. At El Paso the 
 river breaks through its eastern wall, and, thence to its mouth, follows a devious 
 course determined by the local obstacles which it meets, no longer modified by the 
 meridional topography of the Rocky Mountain system. Opposite and above Santa Fe 
 the trough in which the river flows is bounded on the east by the lofty ranges of the 
 Santa Fe Mountains and their northern representatives, which extend in an unbroken 
 series to the Parks ; on the west, immediately opposite Santa Fe, by the bold and 
 picturesque chains of the Valles. These mountains have but a limited extent, falling 
 oflf suddenly on the north, and leaving a low pass, which is traversed by the Chama. 
 Xorlh of the Chama they are succeeded by the mountains of Conejos, which connect 
 with the wide-spread and tangled maze of high sierras, to which I have referred in the 
 
 9SF 
 
G6 EXPLORING EXPEDITION FROM SANTA FE 
 
 preceding chapter; mountains somewhat vaguely designated on different maps as 
 Sierras San Juan, Salnvatcli, &c. By the Mexican mountaineers, all the mountain 
 mass, drained by the western headwaters of the Rio Grande, is known under the name 
 of the Sierra El Wanico. 
 
 On both sides of the valley the Carboniferous strata may be seen exposed in 
 numerous localities, dipping rapidly inward toward the river; resting 'conformably upon 
 these, the red beds of the Triassic series, here soft, sandy, and extensively eroded. Over 
 a large part of the valley surface the drift from the adjacent mountains is spread so 
 thickly that the rocky substrata are wholly concealed. It is possible, therefore, that 
 in some localities the Cretaceous rocks hold their relative position there, as elsewhere, 
 upon the Trias. I cannot say, however, that I have ever seen the Cretaceous strata 
 in the immediate valley of the Rio Grande, except on the slopes of the Organ Mount- 
 ains, above El Paso. 
 
 Between Santa F<5 and the month of the Chama the country is much broken and 
 generally sterile. Rounded gravel hills, dotted with scrubby trees of cedar and pin on, 
 and eroded buttes of pale red, pulverulent sandstone, everywhere meet the eye and 
 give character to the scenery. Among these, wind threads of fertility, following the 
 courses of the streams, marked by lines of cottonwood, by meadows of coarse grass, 
 and, in some localities, by fields of grain. On the west side of the river the scenery is 
 bolder, the surface more broken and unproductive; the character which it exhibits hav- 
 ing been given, for the most, part, by floods of lava poured out from the Valles, now 
 remaining in sheets and masses of black and ragged trap. Reaching up toward the 
 mountains are many valleys of erosion in which the parti-colored strata of the Triassic 
 series are visible, even at a distance of many miles. 
 
 VALLEY OF THE COAMA. 
 
 The course of the Chama, as before stated, lies in a natural gap in the mountains 
 bordering the Rio Grande on the west. Below Abiquiu its valley has essentially the 
 character of that of the Rio Grande, of which it may be indeed said to form a part. 
 On the southwest it is bounded by the slopes and the trap mesas of the Valles, and on 
 the north by the gentler declivities of the mountains of Conejos. At Abiquiu Ihesc 
 boundaries closely approach each other, and the river seems to have burst through the 
 low axis of elevation connecting the Valles with the northern mountains. On the 
 south side the trap mesas come flush up to the stream, and, just below the village, 
 overhang it in a cliff 800 feet in height. On the north side are high and broken 
 hills of erupted rock, formed by a series of dikes crossing each other at different, 
 angles; the principal one having a trend nearly north and south, from which diverge 
 one with a northeast and southwest trend, and another running a little north of west 
 by south of east. These minor dikes are also much broken and forked. The gate 
 through which the river passes this axis of elevation is exceedingly bold and 
 picturesque; its beauty being enhanced by a high and ragged bntte of rock, wjiich 
 stands disconnected from either side, partially blocking up the gap. It should also be 
 mentioned that a similar line of displacement crosses the river below Abiquiu, in the 
 form of a sharp interrupted ridge, known throughout that region as the Cuchillo or 
 
TO JUNCTION OF GRAND AND GREEN RIVERS. 67 
 
 Knife. By both these axes the sedimentary rocks are much disturbed and metamor- 
 phosed. 
 
 On the north side of the river at Abiquiu, just beyond the ancient ruins which 
 crown the bluff, is a little valley cut from soft white and blue conglomerate, sand- 
 stones, and tufas, which, though destitute of fossils, I have suspected to be of Tertiary 
 age. This deposit is entirely local, and seems to have filled a basin or valley, as -the 
 fresh-water Tertiaries of the interior of the continent so frequently do. The strata 
 have a thickness of perhaps 150 feet, and have been worn by erosion into most strik- 
 ing imitations of spires, churches, pyramids, monumental columns, and castles. At 
 Jemez, a few miles south of Abiquiu, the picturesque buttes, which stand isolated in 
 the open valley, are composed of precisely similar materials. These latter are 
 evidently remnants of a mass which once filled the valley about them, nearly all of 
 which has been removed by erosion. They are to be classed with the other patches 
 of fresh-water Tertiary in the vicinity of Santa Fe ; local deposits made after all the 
 great topographical features of the surrounding country had received nearly their 
 present forms. As the most perfect parallelism seems to exist between the castellated 
 buttes of Abiquiu and Jemez, I am disposed to refer them to the same epoch. 
 
 Above Abiquiu the Chama flows through a country quite different from that which 
 I have described. West of the Valles, the Nacimiento Mountain terminates abruptly, 
 leaving a large area of open country between it and the mountains which may be 
 supposed to be its representative on the north. This area, topographically and geo- 
 logically, is but a portion of the great Colorado plateau ; there being nothing but a 
 low line of elevation the prolongation of the Nacimiento axis, by which the strata 
 tiro not often broken through to separate it from the table-lands bordering Canon 
 Largo and the Upper San Juan. After leaving the mountains in which it takes its 
 rise, the valley of the Chama is, therefore, as far as Abiquiu, a valley of erosion, and 
 is bordered on either side by the cut edges of the different steps of the plateau. Im- 
 mediately above Abiquiu, the sides of the valley are composed of the Triassic forma- 
 tion. A few miles further west, the Lower Cretaceous sandstones cap the table-lands 
 and floor a plain, the precise counterpart, except in extent, of the great sage-plain west 
 of the Sierra de la Plata. At the Vada del Chama, still higher up the stream, we reach 
 the base of a wall, more than a thousand feet in height, composed of the Middle and 
 Upper Cretaceous strata, corresponding, and perhaps connecting, with the table-land 
 bordering Canon Largo, 'of which a full description will be given hereafter. 
 
 ABIQUIU COPPER MINES. 
 
 lu a former chapter I have referred to the deposits of copper found in the sedi- 
 mentary strata in various portions of New Mexico, and have enumerated several locali- 
 ties San Miguel, Jemez, etc. where this copper exists in considerable abundance, 
 and where mines were formerly extensively worked to obtain it. The old mines of 
 Abiquiu belong to this category. To the residents of the vicinity they are objects of 
 much interest and some wonder, and having had our curiosity excited by their glow- 
 ing accounts of them, while our party was at Abiquiu we paid them a visit, under the 
 guidance of Mr. Albert H. Ffeiffor, resident Indian agent, whose intimate knowledge 
 
68 EXPLORING EXPEDITION FKOM SANTA FE 
 
 of the country, joined to his unextinguishable enthusiasm and good nature, made him 
 an invaluable companion in our explorations during the time that he accompanied us. 
 A 3 these deposits of copper are matters of some geological interest, I take the liberty 
 of transcribing from my journal the description of our visit to the "Cobre" of Abiquiu. 
 
 "July 17. Started this morning, with Mr. Pfeiffer and several members of our 
 party, for the copper mines, situated some nine miles north of Abiquiu. As we rose 
 from the valley, we were gratified by the most charming view we had yet beheld in 
 New Mexico. The alluvial bottom-lands, covered with groves of vivid green cotton-. 
 Avoods, alternating with fields of wheat and corn, interspersed among which were the 
 white-washed adobe houses of the residents, each with its walled corral, its garden, 
 and its clumps of apricot-trees, formed a scene of fertility and rural beauty rare enough 
 in a country whose sterility is proverbial. Above the valley rose the frowning battle- 
 ments of the trap mesas, which sweep around the foot of the Vallcs, and the rough 
 and rocky slopes stretching up to their lofty and picturesque summits. In another 
 direction were above, the peculiar outline of Abiquiu Peak, and below, the rocky gate 
 from whidi the river issues. 
 
 "Leaving the Chama, we passed up the eroded valley of an intermittent tributary. 
 This is excavated in the Triassic series, and its sides exhibit bands of brilliant color, 
 red, orange, blue, white, &c., as vivid as could be drawn from an artist's color-box. 
 In some localities the red sandstones usually soft and fine-grained are replaced In- 
 coarse conglomerates or masses of cemented bowlders, generally of large size. These 
 bowlders .are composed of quartzose and syenitic rock, hard and smoothly rounded. 
 They indicate stronger currents and more violence of action, during the deposition of 
 the Trias, .than in any other locality where I have observed it; also, closer approach 
 to the source of the material of which these beds are composed. Ascending the arroyo, 
 toward its head, we found the strata rising rapidly toward the north, and cut through 
 so as to expose the saliferous sandstones the lowest member of the Trias in sections 
 of at least 200 feet. This group here consists of thick-bedded, chocolate sandstones, 
 like those of New Jersey and the Connecticut Valley, except that here and there they 
 showed large patches of white, interstratified with green and brown shales. Here, as 
 on the Little Colorado, this formation contains much saline matter, as shown by num- 
 erous salt springs and a white saline efflorescence on the surfaces of the rock itself. 
 The Cobre is situated in the face of the cliff's, bordering an eroded valley drained into 
 the Chama below Abiquiu. These cliffs are composed at base of the saliferous sand- 
 stones and interstratified marls, some 250 feet in thickness; above these, blood-red 
 marls and calcareous sandstones, 200 feet thick; the whole crowned by coarse yellow 
 sandstones, having a thickness of about 150 feet; a section corresponding to that on 
 the Pecos, but exhibiting a much less thickness of the red marls and calcareous sand-, 
 stones. The copper occurs in the base of the yellow sandstones just above the marls. 
 To reach the most important of the ancient mines of this vicinity, we climbed up the 
 face of the southern cliff's of the valley, over the red sandstones and marls, till we 
 reached the coarse yellow sandstones which overlie them. Here we found an entrance, 
 five by six feet in dimensions, which led to a scries of galleries, having a. combined 
 length of perhaps a hundred yards. The work exhibits considerable skill in the use 
 
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TO JUNCTION OF GRAND AND GREEN KI-VEKS. 69 
 
 of tools, and a familiarity with the business of mining. The roof is carefully braced 
 where weak, and old galleries are closed by well-laid walls of masonry. From the 
 style in which the excavation is done, and from the perfect preservation of the wood- 
 work, I attribute this and other similai mines ill this region to the earlier Spanish 
 explorers. The rock which contains the ore is very coarse, frequently a conglomerate, 
 with bands of light-gray clay. The copper is distributed with considerable uniformity 
 through a layer four or five feet in thickness. It occurs in the form of sulphide of 
 copper and iron, (erubescitc,) and green carbonate, replacing trunks of trees and frng- 
 ments of wood, and in concretions and botryoidal masses scattered among the pebbles 
 of quartz, or as minute points of carbonate specking the shales. It has evidently been 
 deposited from solution, investing and replacing the wood precisely as the sulphide of 
 iron is prone to do. 
 
 "The most interesting incident of our visit to this copper-mine was the discovery 
 in the shale roof-stone of thousands of impressions of plants, of which abundant speci- 
 mens were procured. They are mostly cycadaceous Otazamites and Ptcrozamitca 
 with a few conifers (Brachyphyttum and Voltzia!}. The species are probably new, and 
 will not afford the means of determining with precision the age of the stratum contain- 
 ing them, but the discovery is of great geological interest, as showing the wide distri- 
 bution of the cycadaceous flora of the Triassic and Jurassic epochs, and gives addi- 
 tional confirmation of the generalization of Brongniart, who characterized this epoch in 
 the botanical history of the world as the reign of Gynmosperms."* 
 
 On the 19th of July we left Abiquiu for the ascent of the Abiquiu Peak. My 
 notes of the trip are as follows: 
 
 "Left camp at 7 a. m. The train, moving on to the Arroyo Seco, passed up the 
 Chama to a point just above Abiquiu, and then turned to the left and ascended, by a 
 long and difficult road, the high mesa which overlooks the valley on the south side. 
 This mesa is hero full a thousand feet above the Chama, and is connected with that of 
 which the broken edge forms a bold headland below the town, known as Abiquiu 
 Cliff. The upper part of this mesa is composed of trap, below which are exposed sev- 
 eral hundred feet of the variegated marls (Trias), and the white tufaceous Tertiary beds, 
 all quite soft, and, in many places on both sides of the Chama, very fantastically eroded. 
 The mesa over which we passed extended, with a nearly level surface, several miles 
 toward the peak. It is covered with groves of piflon, separated by prairies uniformly 
 coated with grama- grass, now very short and dry. Arriving at the western border of 
 this mesa, we looked directly down into the narrow but fertile valley in which is nestled 
 the little Mexican village of Los Canones. Descending by a steep and tortuous path, 
 we left our mules at the bottom and climbed a detached mesilla which stands at the 
 junction of the two branches of the valley, and on which is situated an ancient and 
 ruined pueblo, once a stone-built town of considerable size. Even its name is now lost, 
 and of the inhabitants whose busy hands constructed its walls, and whose feet in suc- 
 
 * Descriptions of those plants will bo found in another chapter, where it is shown that the most ccmsi>icnmis species 
 ( <l/n:umilfs Mucomliii) is the same with one found in the Triassic strata of Los Broncos, Sonora, where it occurs in com- 
 pany with 1'ecoptci'i* Stntgttfdtensii, Tirniopleris magnifolia, and other well-known Triassic plants of Virginia, North Caro- 
 lina, and Europe. Wo have, therefore, in those plants evidence of the Triassic ago of all the variegated gypalferoua 
 rocks of northern Now Mexico; for the Lower Cretaceous sandstones immediately ovorlio the plant-bed of the Cobre. 
 
70 EXPLORING EXPEDITION FEOM SANTA Ffi 
 
 cessive generations wore so deeply the threshold of its entrance, no tradition now re- 
 mains. The mesa on which it stands is some 500 feet in height, is composed of a cel- 
 lular trachyte, and the top is only to be reached by a narrow and difficult path. The 
 houses are now in ruins, but were once numerous, and all built of dressed stone. 
 Within the town we noticed a dozen or more cstuffas excavated from the solid rock. 
 They are circular in form, 18-20 feet in diameter by 10 or 12 in depth. They all ex- 
 hibited evidence of once having been covered with wooden superstructures. In most of 
 them, four excavations on opposite sides would seem to have been used as the sockets 
 for the insertion of wooden posts, and in one is a niche cut in the side, witli a chimney 
 leading from it; probably the place where the sacred fire was kept perpetually burning. 
 The style of architecture in which this town was built, as well as the estuffas, show that 
 its inhabitants belonged to the race of Pueblo Indians; a race now nearly extinct, but 
 once occupying every habitable portion of New Mexico. 
 
 "Spending the night at Los Caiiones, we started this morning very early for the 
 ascent of the peak. This we mostly accomplished on mule-back; passing over a suc- 
 cession of- hills composed of the variegated marls containing beds of gypsum of great 
 thickness covered with a forest of pinon and cedar. When we had arrived within 500 
 feet of the summit, we left our mules and commenced the ascent on foot, This part of 
 the mountain is very steep, and the upper 200 feet is a perpendicular wall of trap-rock. 
 The summit we found to form a cucliillo, a narrow, knife-like ridge, bounded on every 
 side by vertical precipices. Its height above the sea is about !), 000 feet. The extreme 
 summit is covered with pinon, and the slope with yello\v pi ire, Douglass spruce, the 
 western balsam-fir, and the quaking-asp. The view from the summit was particularly 
 fine, sweeping a circle of fifty miles radius, except toward the Valles, which are very 
 near, and fill the southeastern horizon. On the east we looked down the valley of the 
 Chama, across that of the liio Grande, and our view in this direction was bounded by 
 the high and unbroken ranges of the Santa Fe Mountains. Northeast the Taos Mount- 
 ains and the Spanish Peaks were plainly visible. On the north the foreground w;is 
 filled with the low and near mountains of Conejos, beyond which, north of west, we 
 could just discern the picturesque summits of the Sierra San Juan, and Sierra de la 
 Plata. In the northwest we overlooked the course of the Chama for m;iny miles, and 
 the comparatively level and open country through which it flows. Almost beneath us 
 was the junction of the Puerco and Chama, in a broad valley of excavation, as red as 
 blood, from the exposed surfaces of the eroded marls; farther west, higher table-lands, 
 composed of the yellow and blue rocks of the Lower and Middle Cretaceous. 
 
 "Descending from the mountain, we regained the trail of our party at Arroyo Seco. 
 There we were surrounded by a series of buttes of most varied and fantastic, forms, 
 worked out by erosion from the marl series of the Trias. Their colors are exceed- 
 ingly brilliant, -crimson and orange being the most conspicuous. The vivid green and 
 level valley is framed by these colored cliffs, forming a most beautiful and impressive 
 picture." 
 
 At Arroyo Seco the trail we were following leaves the river and enters a canon, 
 which cuts the plateau bordering the valley from base to summit. Most of the section 
 exposed in its walls is composed of the Triassic marls, which includes beds of gypsum 
 

 
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TO JUNCTION OF GRAND AND GEEEN EIYEES. 71 
 
 in some places 150 feet thick. Above the marls are the yellow sandstones the base 
 of the Cretaceous which floor tho plateau on either side. Pursuing a northerly 
 direction, we gradually rose through the Trias, and at Navajo Springs reached the base 
 of the Cretaceous sandstones. Continuing our ascent, two or three miles farther on we 
 reached the base of the canon, and emerged upon the plateau of which I have before 
 spoken. This plateau extends northward to the Vada del Chama, where it begins to 
 be broken by the foot-lulls of the mountains. Westward it reaches to and beyond 
 the source of the Chama, and is broken through and locally disturbed by the upheaval 
 of the Gallinas Mountain, which seems to be situated on the Nacimiento axis. Over 
 this plateau the Lower Cretaceous sandstones form the general substratum, but here 
 and there are rounded knolls, composed of the dark shales and blue shaly limestones, 
 the loAver part of the middle division of the Cretaceous formation, here, as at a thou- 
 sand other points on our route, characterized by the presence of Gryplica Pitcheri, Ino- 
 ceranuts problcmatkus, Ostra congesta, &c. The more level portions of the plateau are 
 covered with sage bushes, with here and there more moist and fertile spots, sustaining- 
 grasses and annual plants, conspicuous among which is the wild sunflower (Ifcli(nt- 
 t/iii-s). The knolls are usually covered with groves of pifion. As a whole, this pla- 
 teau country has little agricultural value, although there are portions of it which will 
 afford good grazing for stock. 
 
 Between the Cebolla and Nutria, the Middle Cretaceous rocks occupy a consider- 
 able area, and attain a thickness of perhaps a hundred feet. They present precisely 
 the same lithological characters and fossils as do their equivalents on the banks of the 
 Canadian and Ocate, east of the Rocky Mountains, viz., thin layers of hard dark- 
 blue or ferruginous limestone alternating with layers of bitumino-calcareous shales. 
 
 At the Vada del Chama we again encamped on the banks of this stream in a very 
 beautiful region, one of considerable fertility and of great geological interest. On 
 the east side of the river are high and broken hills the foot-hills of the mountains 
 covered with forests of splendid pine timber. These hills are mainly composed of the 
 Lower Cretaceous sandstones, having a thickness of nearly 300 feet. Here, as farther 
 west, they contain beds of lignite, and the impressions of dicotyledonous leaves. They 
 are considerably broken up, but have a general and rapid dip toward the southwest. 
 On the opposite side of the valley is a mesa, with bold, nearly perpendicular faces 
 over 1,000 feet high, composed of the Middle and Upper Cretaceous rocks lying nearly 
 horizontal. Between these elevated banks lies the excavated valley of the river, with 
 its narrow but fertile bottom-lands, its winding stream of pure cold water, its groves 
 of cottonwood, and its grassy meadows spangled with flowers. The structure of the 
 valley will be more readily comprehended from the accompanying section than from 
 any detailed description I could give of it. 
 
 Transverse section of the valley of the Cltama at the V<i<l<i. 
 
 Feet. 
 
 1. Yellowish brown sandstone (Lower Cretaceoiis) 125 
 
 2. Brown and black shales, often dark olive, with beds of lignite , r >0 
 
 3. Sandstone similar to No. 1 .... 70 
 
72 EXPLORING EXPEDITION FEOM SANTA Ffi 
 
 Foot. 
 
 4. Black shales with bands of light-dove-colorcd limestone 150 
 
 The upper of these shale-beds is greenish-brown, with bands of foliated 
 sandy limestone, containing immense numbers of fragmentary or entire 
 fossils. These are principally Inoceramus problcmaticus, J. fray/Us, Ostrcn 
 congcsta, J3aculitcs anccps, Scapliites Warrcni, 8. laviformis, <&c. 
 
 5. Bluish-black shales, with concretions and bands of limestone containing a 
 
 large undulated Inoceramus, the broken fragments of which are thickly 
 
 set with Ostrca congesta 1 , 000 
 
 The lithological characters of this division are nearly the same through- 
 out, but the limestone bands and fossils are nearly restricted to the lower 
 portion. The layers of limestone are from 6 to 12 inches in thickness, 
 quite pure and compact, blue in color, but weathering reddish yellow, 
 and breaking on exposure in vertical prisms, like starch. 
 H. A light dove-colored sandy limestone or calcareous sandstone, weathering 
 
 yellow, massive toward the top, foliated below, without fossils 200 
 
 7. This, the cap-rock of the high mesa, is a higher member of the Cretaceous 
 
 series than has before been met with in New Mexico. Our subsequent 
 observations showed it to be the base of the third great division of this 
 formation as developed on the Colorado Plateau. 
 
 8. Gravel hills, valley drift. 
 
 At the Laguna de los Cavallos we reached the summit of the divide between the 
 waters of the Pacific and the Atlantic, at the height of 7,600 feet. No conspicuous 
 elevation marks the summit, but the strata are somewhat broken by a line of displace- 
 ment, apparently a continuation of the Nacimiento axis. The country about the 
 Laguna may be taken as a type, both as regards its general aspects and its geological 
 structure, of all that bordering our route while we were skirting the bases of the 
 mountain ranges, the drainage of which supplies the flow of the San Juan River and 
 its tributaries. This region includes three topographical belts or districts in which the 
 physical features exhibit the most striking contrasts, viz., the mountains, the foot-hill.*, 
 and the table-lands. The mountainous district includes a large number of lofty 
 chains, having a north and south trend and the general characteristics of the Rocky 
 Mountain system, connected by thousands of interlocking spurs, or separated by nar- 
 row valleys, traversed by clear, cold, and rapid streams. These ranges terminate 
 southward en echelon, and, when viewed from a distance, present the appearance of 
 a continuous sierra, having a northwest and southeast trend. The oxitlines of these 
 mountains are bold and picturesque ; their highest summits having an altitude of 
 12,000 or 13,000 feet, entirely bare of vegetation, and showing, here and there, 
 patches of perpetual snow; their slopes covered with forests of spruce and fir above, 
 of yellow pine below; many of their gorges set with thickets of scrub-oak and quak- 
 ing-asp. 
 
 Along the base of the mountains stretches a belt of foot-hills, a region of which 
 the surface is broken into rounded or abrupt hills, from 100 to 1,000 feet in height, 
 generally composed of sedimentary rocks, very much disturbed, often pitched about 
 
TO JUNCTION OF GRAND AND GREEN RIVERS. 73 
 
 in the greatest confusion. These hills are covered with noble forests of yellow pine, with 
 
 open intervals where grama and Imneli grass grow with great luxuriance. Between the 
 lulls are charming mountain valleys, carpeted with fine grass, in the summer season 
 perfect gardens of flowers, through which meander cool and sparkling mountain 
 streams, fringed with thickets of willow, or shaded by groves of the narrow-leaved 
 COttonwood. Through this delightful region our route lay, going from Santa'Fe" 
 toward the Colorado. On our return we traversed the third of the districts 1 have 
 enumerated, that of the table-lands. Where unaffected by the disturbing forces 
 which have elevated the mountain chains, the sedimentary rooks lie nearly horizontal, 
 forming a wide plateau deeply canoned by the streams which take their rise in the 
 mountains. 
 
 Although the generalities of the country of the foot-hills, with which we at present 
 have to do, may be given in few words, perhaps a more detailed description will be 
 needed ti convex- all the information that may be sought of a region destined to become 
 the home of many of our countrymen, and, therefore, of considerable economical and 
 political importance. For the purpose of satisfying the want I have anticipated, I shall, 
 from lime to time, copy from -my journal such detailed descriptions of local scenery or 
 structure as may seem best fitted to complete the picture I have already sketched. 
 From my mites made at our camp on the Rio Navajo, sixteen miles west of Laguna 
 de los Cavallos, I take the following extracts: 
 
 "From the Laguna our route westward passed through a beautiful -and fertile 
 countrv, the trail winding among hills composed of Upper Cretaceous rocks, covered 
 with trees of yellow pine, often attaining large size. On the south is a high mesa,, with 
 picturesque broken edges, a continuation of that east of the Laguna bordering the 
 valley of the Chama. On the north is a similar wall in which the strata are more highly 
 inclined. IJevond this is another valley or series of valleys which border the bases of 
 the mountains connected on the east with the Tierra Maria, a charming spot at the 
 forks of the Chama, where the Mexicans had formerly a settlement, now abandoned 
 on account of the depredations of the Indians. The drainage toward the west begins 
 a mile -west of the Laguna, and the Ri<*Navajo is the first of the tributaries of the San 
 Juan. This is a small but rapid stream which rises in the Sierra del Navajo, of which the 
 southern extremity is but a few miles distant from our camp. This range apparently 
 forms the divide north of the Laguna, the drainage of its eastern slope falling into the 
 Chama, its western forming the Rio Navajo. The material washed down from the 
 Sierra del Navajo is mostly eruptive in character, trap, trachyte, and porphyry, and 
 the outlines of this extremity of the range show that it is mainly composed of rocks of 
 this character, .lust above our cam]) the river issues from a magnificent wooded 
 goi-o'e, which it has cut through the chain of Cretaceous hills that 1 have mentioned 
 as bordering our route of to-day on the right, A little below our camp is an isolated 
 mesa, an outlier of the great table-lands which spread out to the south. This mesa, 
 called by our guide the Cerro del Navajo, has a superficial area of perhaps 100 acres, 
 a relative altitude of l,. r )()0 or 1,600 feet, and an absolute altitude of about 8,500 feet. 
 It is entirely composed of the Middle and Upper Cretaceous rocks, lying nearly hori- 
 zontal, and stands a stupendous monument of the erosion which this region has suffered. 
 
 10 s K 
 
74 EXPLORING EXPEDITION FROM SANTA FE 
 
 * * * As we approached Rito Blanco we entered a narrow ravine or canon 
 cut in the Upper Cretaceous rocks yellow sandstones and gray shales which rapidly 
 deepens till, at its junction with the Rito, its bounding hills have an altitude of ;i 
 least 1,000 feet. 
 
 "This canon is verv picturesque; the sides covered with vellow pine, Douglas' 
 and Menx.ies' spruc.es, the latter now tor the first time seen in Xevv Mexico. It grows 
 here very beautifully, somewhat more spreading than in Oregon, the foliage very 
 dense and silvered. Among the evergreens are slopes on which grow thickets of wild 
 cherry, serviceberry, and gooseberry, all now in fruit. In the bottom are bushes of 
 black currant, also fruiting, all these berries are called HHtn.:niit<tx little apples by 
 the Mexicans, but the serviceberrv is particularly distinguished hv this name by those 
 who would be exact. The California iiuutztMta lias better claim to the name, and is a 
 very different plant. The cliffs of Rito Blanco arc? frequently precipitous, but so 
 widely separated as to leave a pretty valley between. They are wholly composed of 
 Cretaceous strata, mainly of the middle division, with a capping of the yellow sand- 
 stones and marls of the upper member of the formation." 
 
 Pagosa, July 28. "Left Rito Blanco early this morning, passing through a 
 country similar to that of yesterday. At i) o'clock, came down a pretty ravine to the 
 San Juan, here 30 yards wide, 3 feet deep, very rapid. At this point it enters a 
 canon, cut in the Upper Cretaceous sandstone, which lias a strong local dip toward the 
 north. Above this canon is a delightful valley, running up to the foot-hills of the San 
 Juan Mountains, which are here very beautiful in form, and lofty, as patches of snow 
 are visible upon them. The river San Juan here issues from the narrow valley 
 between the Sierra San Juan and Sierra del Navajo, where it takes its rise, and this is 
 apparently the first intei-val of level land through which it Hows. In the upper part 
 of this valley is the I'agosa, one of the most remarkable hot springs on the continent, 
 well known, even famous, among the Indian tribes, but, up to the lime of our visit, 
 never having been seen by the whites. It can hardly be doubted that in future years 
 it will become a celebrated place of resort, both for those who shall reside in the sur- 
 rounding country, and for wonder-hunting htalth-seeking travelers from other lands. 
 There is scarcely a more beautiful place on the face of the earth. The' valley is 
 three miles long by one broad; a verdant meadow of the finest grass, thick! v 
 strewed with flowers, through which winds the bright and rapid river, margined by 
 clumps of willows, and most graceful groups of cotton-wood. On every side are hills 
 covered with gigantic pines or the slender Oregon spruces, and on the north, far above 
 these, rise the forest-clad slopes and craggy crests of two great Sierras. The 1'agosa 
 is at the edge of this prairie. As the river leaves the great wooded gorge embraced 
 between the San Juan and Navajo Mountains, and comes out into this beautiful 
 amphitheater, it sweeps round in a curve, inclosing some 20 acres. From all parts 
 of this space, which is evenly turfed over, the surface rises very gently to the center. 
 Here is a great basin, oval in form, 40 by . r >() feet in diameter, its walls of white rock, 
 of unfathomable depth, in which the deep-blue water seethes and surges as in a boil- 
 ing caldron, giving off a column of vapor which in damp weather is visible for miles. 
 The water, though hot, is not at the boiling-point, and the ebullition is produced by 
 
i 
 
 a 
 
TO JUNCTION OF GRAND AND GREEN RIVERS. 75 
 
 the escape of ibises, wliieli :ire generated in enormous quantities. The temperature at 
 the side of the basin is 140; in the center, perhaps something higher. The gases 
 with which the water is charged consist, in part at least, of carbonic acid and sulphu- 
 retted hydrogen ; .the former giving it an effervescence, like that of soda-water, and the 
 same pungent taste. The sulphur is also perceptible by taste and smell; a strong sul- 
 phurous odor, which is distinguishable at some distance, being exhaled from the spring. 
 When cooled, the water has a strong mineral taste, though rather agreeable than other- 
 wise. It was freely drank by all our party while in this vicinity with no unpleasant 
 effects, but, on the contrary, a decided sharpening of the appetite. No analysis has 
 yet been made of it, but it is evident that the large amount of saline matter it contains 
 is of somewhat complex composition, and such as gives it a character unlike that of 
 the water of any other mineral spring with which I am familiar. To make a rude 
 comparison, the water of the I'agosa might be imperfectly imitated by mixing Blue 
 Lick and Congress water and heating the compound to 140. The flow of water 
 from the 1'agosa is very large, and it finds its way into the San Juan by several subter- 
 terranean channels. The deposit, from it is very copious, generally snow-white, 
 but in many places bright pink or green in color. It floats in crusts which revolve 
 upon the surface of the basin I have described, and which envelop the bodies of 
 water-beetles, frogs and snakes that have incautiously plunged into it. When iirst 
 precipitated this deposit consists, in a great degree, of chloride of sodium, but. mingled 
 with this are silicates probably of soda, lime, and potassa which form a hard and 
 indestructible white rock. In the lapse of ages an immense amount of this material 
 has been thrown out from this spring. All the low, broad mound, which I have men- 
 tioned as surrounding the basin, is composed of it, and over an area of ten to twenty jvcres 
 it has a thickness of at least twenty feet. This is shown on the banks of the San Juan, 
 which is for some distance bordered by walls of this material, having an altitude of 
 twelve to fifteen feet. 
 
 The geology of all this region is Cretaceous. The upper members of the series 
 are exposed in all the hills surrounding the I'agosa; and it is evident its waters issue 
 from the bitumino-calcareous shales forming its middle division. These shales are of 
 marine origin, have a thickness of over 1,000 feet, contain many animal remains, and 
 are highly charged with salts and sulphur; in all these respects resembling the Hamil- 
 ton group of the New York geologists. I think it is true that mineral springs more 
 frequently flow from rocks of this character than any other, and I have, been led to 
 suppose that the water of such springs derives its peculiar character immediately from 
 the rock from which it emanates. It is certain that hot water, forced through these 
 strata, would dissolve and carry off many of their constituent elements, and would 
 become the agent by which an extensive range of chemical combinations would take 
 place. In the case of the I'agosa, the hot water is doubtless derived from a great depth, 
 yet it is entirely possible that the gases and salts which it contains are all derived from 
 the superficial strata, through which it passes. 
 
 THE SIERRA SAN JUAN. 
 
 This name has been applied by geographers to several distinct mountain 
 ranges wliich really exist in this portion of the continent; or, more generally, to 
 
7<> EXPLORING EXPEDITION FROM SANTA FE 
 
 a great imaginary chain, which was assigned an inordinate extent and a trend 
 altogether hypothetical and abnormal. It is to be hoped that one result of our 
 expedition will be to bring 1 something- like order out of the confusion of ideas which 
 has prevailed in regard to the intricate mountain ranges of this region. As has been 
 before Intimated, thgse ranges, though numerous, exhibit no exceptional features, and 
 are comparatively simple and harmonious in structure and trend; while it is true that 
 the great mountain belt north of the San Juan River, with its higher chains, their thou- 
 sand interlocking' spurs and narrow valleys, form a labyrinth whose extent and intri- 
 cacy will at present defy all attempts at detailed topographical analysis. It is equally 
 true that a general topographical character has been given to all of this region by a 
 comparatively few lines of lofty summits, which have nearly a north and south trend, 
 and seem to form an integral portion of the, Rocky Mountain system. This great truth 
 may be learned at a glance by the drainage of this country; tin's all flows through 
 streams which have approximately a north and south direction. On the south, the 
 tributaries of the San Juan, the Navajo, the Blanco, the Upper San Juan, the Piedra, 
 the 1'inos, the Florido, theAnimas, the La Plata, and the Mancos, all flow southward- 
 and most of them issue from the north and south valleys, lying between the parallel 
 ranges to which I have so frequently referred. On the north side of this mountain-belt 
 similar topographical features present themselves. The tributaries of Grand River, 
 which sweep the bases of the northern extremities of these ranges, almost without 
 exception issue from valleys which have approximately a north and south direction; 
 hence, it is plainly apparent that one great fundamental idea pervades the topography 
 of all this region, and that one great force has given shape to all its principal topo- 
 graphical features. 
 
 Most of the prominent ranges visible from our route have received from the Indians 
 and Mexicans distinct names, by which they are well known to those who know the 
 country; for example, the chain north of the Lagnna, of which the southern extremity 
 is drained by the Chama and Rio Navajo, is called the Sierra del Rio Navajo or the 
 Sierra del Navajo. From between the spurs of this sierra flows the Rito Blanco (Little 
 White River), so called from the milky color given to its waters by the Cretaceous 
 shales. From the valley separating the upper part of this sierra from the Sierra San 
 Juan, which does not extend so far south, issues that branch of the San Juan River 
 which retains its name. West of the San Juan Mountains, as we shall see as we pro- 
 gress with our geological narrative, the b'io de los Pinos issues from the. valley between 
 the Sierra San .Juan and the Sierra de los Pinos; beyond the Sierra de los Pinos 
 the great valley of the Animas; then the Sierra de la. Plata, west and north of which 
 lies the Sferra San Miguel; west and south of the latter chain, the broad expanse of the 
 Colorado Plateau. From this sketch, it will be seen that the great cast and west chains 
 of the Sierra San Juan and Sierra, de la Plata, which form so conspicuous features on 
 some of our maps, have really no existence, and need therefore no longer vex us as 
 incongruous elements in theorology of our country. 
 
 Like the Santa Fc Mountains, the Sierra San Juan terminates abruptly south- 
 ward, standing out as a bold headland on the margin of the sea-like plateau. The 
 altitude of its highest summits must be nearly 1,"., 000 feet, as snow lies on them in 
 
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TO JUNCTION OP GRAND AND GREEN RIVERS. 77 
 
 places throughout the year, while from the Sandia and Santa Fe Mountains over 
 12,000 feet in height it entirely disappears in midsummer. Only a small portion of 
 the range came under our observation ; but enough was seen to show that its struc- 
 ture was essentially the same with that of the other chains belonging to the same 
 scries which we were able to examine more fully. The southern extremity is mostly 
 eruptive in character, consisting of basaltic trap, porphyry, and trachyte, some of the 
 latter containing crystals of feldspar of large size. As usual, the summits composed of 
 these materials present very varied and picturesque outlines. In the opposite chain 
 of the Sierra del Navajo are some castellated summits, which, as seen through a 
 powerful glass, presented an appearance exceedingly imposing and beautiful. Among 
 these are precipices, ornamented with imitations of columns, arches, and pilasters, 
 which form some of the grandest specimens of nature's Gothic architecture I have 
 ever beheld. When viewed from some nearer point they must be even awful in their 
 sublimity. 
 
 The Cretaceous strata at the base of the San Juan Mountains are highly fossil- 
 lil'eroiis, and yielded me a large number of species. The ferruginous, sandy lime- 
 stones and shales near the base of the middle division of the Cretaceous series, where 
 exposed just north of the I'agosa, are almost made, up of the shells of (Mmi, Inocera- 
 iittiH, sliiniHHtifi'H, c. This is the horizon from which the oysters, gryplueas, fish- 
 teeth, &(.'.., were collected in such abundance on the Canadian, at Galisteo, at the ford 
 of the Chama, and various other points on our route. These fossils are limited to the 
 first hundred feet of the shale-beds above the Lower Cretaceous sandstones; the most 
 abundant at the Pagosa are Ostrca lutjubris, 0. uniformis, Meek, n. sp., Inoceromus prob- 
 Iciiittticnx, and /. frayilis. I also found here an interesting series of the teeth of 
 I'tijchotlns Whlpitlei, described at length in the chapter on Paleontology. Above the 
 beils in which these fossils are found, the black bituminous shales contain large, gener- 
 ally broken, shells of Nautilus and InoceraiintN, thickly set with Ostrea coitf/rx/ii. 
 
 All the interval between the I'agosa and Rio Piedra is occupied by Cretaceous 
 rocks. Over large surfaces the Lower Cretaceous sandstones are laid bare, generally 
 much disturbed, and somewhat changed. The only fossils discovered were indistinct 
 vegetable impressions, among which the most conspicuous is a tuberculated fucoid 
 (Hdft/iiK'nifcn) common in the Cretaceous sandstones of all this region. 1 1 ere, as at the 
 Tierra Maria, these rocks arc cut by joints into blocks of nearly uniform size. Of these 
 joints the most strongly marked have a bearing approximately north and south; the 
 others cross these nearly at right angles. In the great number of localities in New 
 Mexico where I observed jointings of these rocks, I found them to have similar direc- 
 tions, and to be in no case influenced by local disturbances, nor having any obvious 
 connection with the prevailing dip. This rule is of so general application that I have 
 been driven to refer the jointing of all "the rocks of this region to one great common 
 cause. This has seemed to me probably magnetic, but may possibly be connected 
 with the action of the forces which have given to all the great lines of elevation a 
 general north and south trend. 
 
 ( )n the Nutria Frances, a small tributary of the Rio Piedra, the black shales of 
 the Middle Cretaceous are exposed in various places. They here contain large Ino- 
 
78 EXPLORING EXPEDITION FROM SANTA KK 
 
 crnniti, Nautili, and fish-scales. The Piedra Parada, a well-known landmark, which 
 has conferred its name upon the Rio Piedra, is a chimney-like column of rock, rising 
 with its base to the height of eight or nine hundred feet above the surrounding conn- 
 try. It is itself composed of the Upper Cretaceous sandstone, resting upon a base of 
 dark shales, (Middle Cretaceous,) and is a remnant of a- plateau now almost entirely 
 removed by urosiou. 
 
 The valley of the Rio Piedra is, in physical aspect and geological structure, the 
 counterpart of that of the Rito Blanco, already described; the only noteworthy point 
 of difference being that the Upper Cretaceous sandstone here contains beds of lig- 
 nite of considerable thickness, though of limited lateral extent. The disturbances 
 which the Cretaceous strata have suffered in this region are very well shown 
 in the immediate vicinity of our camp on the Piedra. On the east side of the 
 river the plateau, with which the Piedra Parada was once connected, stretches 
 away south for several miles, with a rapid dip in that direction. On the west 
 side is a mesa of which the .cut-edge rises abruptly from the margin of the 
 stream to the height of over twelve hundred feet. This me.sa is composed of 
 precisely the same materials as that bounding the valley on the east, but its strain 
 are almost perfectly horizontal. Just above our camp this mesa is broken short 
 off by a lino of fracture running nearly east and west; its component rocks, set nearly 
 on edge, forming a wall which rises to the height of eighteen hundred feet above the 
 river. Between this disrupted mass and the mesa from which it has been broken is a 
 low pass through which our trail ran. 
 
 Soon after leaving the Rio Piedra we began to ascend rapidly and soon rose on 
 to a high divide between the Piedra and Rio de los Pinos. This divide seems to bean 
 axis of elevation, running southward from the mountains between the Piedra and Pinos. 
 It is composed of Cretaceous rocks irregularly broken up, generally inclined at a high 
 angle. It has an altitude of about sixteen hundred feet above our camp on the I'iedra. 
 The view from its summit is peculiarly grand and interesting; eastward the Xavajoand 
 Sau Juan mountains bound the horizon, terminating southward in the Cerro del Nav- 
 ajo. On the south and west sides of these ranges the fixers we have recently passed 
 take their rise, and their valleys may in part, be followed by the eye. None of the 
 summits visible in this direction are covered with perpetual snow, but all bear patches 
 in the higher valleys. 
 
 Nearer us than the mountains was a labyrinth of hills, spread out before us as on 
 a. map. These seern to have been generally formed by a series of breaks in the Cre- 
 taceous rocks, and, so far as we could see, are all composed of these materials. 
 
 Toward the west our view was quite different. In that direction we looked 
 down on . what seemed an extensive plain, extending northward to the base of the 
 Sierra de la Plata, now for the first time distinctly seen, and on the south bounded by 
 high mesas, through an opening in which, the gap of the Rio las Animas, was visible 
 the high chain of the Carriso Mountains south of the San Juan This plain before us 
 we subsequently found to be a basin-like space, lying between the mountains on the 
 north and the table-lands south; a depressed area, completely inclosed in high 
 lands, except where these are cut by the narrow- gorges through which the waters of 
 
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TO JUNCTION OF GRAND AND GREEN RIVERS. 79 
 
 the Animas and the Pinos have forced their way to join the San Juan. It is, in fact, an 
 expansion of the valley of the Animas, has been mainly excavated by its current, and 
 is everywhere covered with beds of transported material washed down from the mount- 
 ains.* 
 
 As we descended into the valley and thus opened it more to the north, we gained 
 sight of a chain of mountains in that direction, which our guide calls Sierra de los 
 Pinos. These are quite lofty, and consist, as 1 discovered from the drift brought down 
 from them, of quart/ites, silicious slates, limestone, and granite, with some trap, but 
 with a prevalence of metamorphic over erupted rocks. The Rio de los Pinos is a clear, 
 cold, trout-stream, full as large as the San .Juan at the Pagosa. The bottom-lands are 
 wooded with willows, cottomvood, alder, etc., and scattered trees of yellow pine, the 
 latter of which mark its course in the open sage-covered country through Avhich it 
 flows, and have naturally suggested the name which it bears. 
 
 The interval between the Rio de los 1'inos and Rio Florido is underlaid by the 
 Middle Cretaceous shales; is gently. rolling in outline, its more level surfaces covered 
 with sage (Artriiiixid /I'/rlci/ldta.), its rounded hills with cedars or scrub-oak. Here 
 and there are meadows of good grass, with a strong growth of annual plants. On the 
 whole, however, the nuintrv is less picturesque and less productive than that lying 
 south and east of it. 
 
 The Rio Florido, or River of Flowers, is so named from the flowery meadows which 
 line its banks; meadows which, so far as we could see, are no broader, greener, or 
 more flowery than those which border the other rivers of this region. It is, however, 
 a bright, handsome stream, similar in character to the Pinos, and about half as large. 
 It is probably not more than thirty or forty miles in length; rises in the foot-hills of the 
 Sierra, de los Pinos, aud joins the Animas some fifteen miles southwest from where we 
 crossed it. The bowlders which it has brought down from its sources are quite varied 
 in character, aud probably give a very fair representation of the geology of the 
 mountains which it drains. Of these many are composed of coarse red granite, much 
 like that of the Santa Fe Mountains, black and white porphyry, closely resembling 
 that which is so abundant at the gold-mines in the Placer Mountains ; blue limestone, 
 containing many of the characteristic Coal-Measure fossils so common at Santa Fe, such 
 as 1'nxlnr/nx xrniim-firH/utus, P. nodosus, Spirifer camcratus, Chonetes mesolnl>, etc.; with 
 these are masses of red and white sandstone, probably Triassic. 
 
 The course of the Florido lies altogether within the basin-like area of which I 
 have before spoken. The extent and character of this area were fully learned in an 
 excursion which I made from our camp on the Florido, about forty miles down the 
 Animas, to visit some extensive 1 and interesting ruins situated in the valley of that 
 stream some twenty miles above its mouth. From my notes of this trip I make the 
 following extracts : 
 
 "Aiif/Hxf I/A. Left camp early with Pfeiffer, the Indian agent, Messrs. Fisher and 
 Dorsey, and several Indians, to visit the ruins reported to exist at a certain point on the 
 banks of the Animas ; crossed over in a direct line to the Animas, a distance of about 
 ten miles. All this interval is occupied by a gravel mesa, of which the surface is 
 
 * Since named Animas Park. 
 
80 EXPLORING EXPEDITION FROM SANTA FK 
 
 gently rolling, generally covered with grass or sage-bushes, with scattered trees of 
 pi fioii and cedar. Reaching the Animas we found it flowing- in a valley one to three 
 miles wide, bounded by gravel terraces, of which there are two, sometimes three, dis- 
 tinctly visible. Near the month of the Florido the first terrace, which is near the 
 stream, has an altitude of about 50 feet; the second, 260 feet higher; the third, the 
 general surface of the plain which we crossed, 200 feet higher still. All these terraces 
 are, I suppose, of local origin, having been left by the sinking of the bed of the stream 
 consequent upon the cutting down of the gorge it has opened in the table-lands south. 
 Between the junction of the Florido with the Animas and the valley of the San .luan, 
 the table-land seems to be continuous, but has its greatest altitude along its northern 
 margin. Immediately after receiving the Florido the Animas enters a deep and narrow 
 canon, in which it flows for several miles; the walls of this canon are l,f>(>0 to l,(i(M) 
 feet in height; in places nearly vertical ; the rocks exposed are principally sandstones, 
 of which the prevailing color is a light brownish-yellow, sometimes becoming a pale 
 red. These sandstones belong to the Upper Cretaceous series, which is hen* more 
 fully exposed than anywhere in that portion of our route already passed over. 
 Through the canon the river is very rapid and much obstructed bv rocks, and can- 
 not be followed on horseback; below this the valley widens and the declivities of 
 the bluffs which bound it become more gentle ; the bottom-lands are from a mile to 
 two. miles in width, and quite fertile; the river is bordered bv thickets of willow and 
 buffalo-berry, with groups and sometimes groves of cottomvood. It is in this part, of 
 the valley that the ruins are situated. The principal structures are large pueblos, 
 handsomely built of stone, and in a. pretty good state of preservation. The external 
 walls are composed of yellow Cretaceous sandstone, dressed to a, common smooth 
 surface without hammer-marks; in some places they are still 25 feet in height. As 
 usual in buildings of this kind, the walls were unbroken by door or window to tin* 
 height of 15 feet above the foundation. The interior shows a great number of small 
 rooms, many of which are in a perfect, state of preservation, and handsomely plastered. 
 These larger structures are surrounded by mounds and fragments of masonry, mark- 
 ing the sites of great numbers of subordinate buildings; the whole affording conclu- 
 sive evidence that a large population once had its home here. The fragments of highly 
 ornamented and glazed pottery which cover the surface in the vicinity of these build- 
 ings, as well as the peculiar style of architecture in which thev are constructed, show 
 that the people who -built and occupied these structures belonged to the common 
 aboriginal race of this region, now generally known as the Pueblo Indians. 
 
 "After our return from the ruins on the Animas, our party moved over and encamped 
 on that'stream, at the point where it is crossed by the old Spanish trail. It is nearly 
 a hundred yards wide, deep and rapid, and, at, the present, stage of water, not easily 
 forded. It here issues from the hills and enters the basin before described. Above 
 this point it flows through a, broad mountain valley not yet explored, but of which the 
 general features are given by the two great mountain groups which border it on the 
 cast and Avest the Sierra de los 1'inos and Sierra de la Plata. ( )f these the Sierra de 
 la Plata is the most conspicuous feature in the scenery, a broad and lofty mountain 
 belt stretching continuously northward as far as the eye can reach. 
 
TO JUNCTION OF GRAND AND GREEN RIVERS. 81 
 
 "The drift from the moinitiiins drained by tin; Animus shows that their structure is 
 essentially that of the Santa Fe Mountains and the other principal ranges of the Uocky 
 .Mountain system. In this transported material are blocks, often weighing several tons, 
 of red granite, similar to that of Santa Fe; gray granite, not unlike that forming the 
 base of the section in the Colorado Canon at the mouth of Diamond River, described 
 in my former report; Carboniferous limestone, with many of the fossils found at Santa 
 Fe and in the Coal-Measures of the Mississippi Valley; black and white porphyry, 
 trachyte, trap, and metamorphosed red sandstone. No traces of Silurian or Devonian 
 rocks were discovered. The hills just above our camp are composed of red sandstone 
 and conglomerate (Triassic), very much disturbed." 
 
 ISelow the crossing- of the Spanish trail the valley of the Animas is susceptible of 
 cultivation to the junction of the Florido, though the belt of arable land is narrow, and, 
 in part at least, can only be cultivated by irrigation. 
 
 In regard to the origin of the broad valley or basin which borders this part of the 
 course of the Animas, I think \ve may safely say that its features were give:: by the 
 disturbances which this region has sulVered; that, in the breaking up of the table-lands, 
 a basin-like depression was left, into which the Animas flowed, and which it partially 
 filled with gravel and bowlders brought down from the mountains above. Subse- 
 quently, the enclosing walls of this area, were cut down, along the natural line of drain- 
 age, until the river reached its present level, and what was its bed at different epochs, 
 now forms gravel terraces high above it. 
 
 The geology of that portion of our route lying between the Animas and the l\io 
 de la Plata is precisely similar to that of most of the country previously passed through; 
 the only rocks exposed are those of the upper portion of the Cretaceous formation, which 
 compose broken hills flanking the eastern and southern slopes of the Sierra de la Plata. 
 Among these hills the trail winds, following the courses of the picturesque and fertile, 
 though narrow, valleys which separate them. From the headwaters of a small tribu- 
 tary of the Animas we crossed over a divide which rises to the height of about l,ii()i) 
 feet above our Camp 17; thence descending nearly as much, we struck the La Plata, 
 just where it issues from the mountain-gorges in which it takes its rise. Of our camp 
 on the La Plata I find the following description in my notes: "The l\io de la Plata is a 
 beautifully clear, cold, mountain-brook; like the Animas and other streams we have 
 recently crossed, well-stocked with trout. The valley in which it flows, as it issues 
 from the mountains, is exceedingly beautiful, and our camp one, of the most delightful 
 imaginable. Our tents are pitched in the shade of a cluster of gigantic pines, such as 
 are scattered, here and there, singly or in groups, over the surface of the valley, sepa- 
 rated by meadows thickly coated with the finest gramma grass. Stretching off south- 
 ward, a wall of verdure, tinted with the fresh and vivid green of cottonwoods and 
 willows, marks, while it conceals, the course of the sparkling stream whose murmuring 
 How conies softly to the ear. On either side of the valley rise picturesque wooded 
 hills, which bound the view both east and west; between these on the south an open 
 vista reveals, far in the distance, the blue chains of the Sierra del Carriso and Tune- 
 cha. On the north the bold and lofty summits of the Sierra de la Plata look down 
 upon us in this pure atmosphere with an apparent proximity almost startling. Patches 
 11 s F 
 
82 BXPLOKING EXPEDITION FROM SANTA Ffi 
 
 of snow are visible upon them, which, by their wasting, supply the flow of the Rio le 
 la Plata, which rises in the gorges beneath them." 
 
 The geology of the vicinity is similar to that of much of our route already passed; 
 the prevailing rocks are Upper Cretaceous, which compose the hills bordering the val- 
 ley ; the thick mass of sandstone, which forms the Piedra Parada, caps these hills and lias 
 a rapid dip away from the mountains; this is succeeded below by a series of gray and 
 yellow foliated sandstones or sandy shales, containing immense quantities of fucoidal 
 stems, so many indeed that these casts make up the greater part of the deposit. They 
 are a half-inch in diameter, the surface covered with indistinct annular markings. Be- 
 side the fucoids, these beds contain the well-known Cretaceous fossil, Ammonites pla- 
 centa, and in lenticular masses of limestone immense numbers of BacuUtcs aitct')>x, ( 1 nr- 
 (liiun lellalum, Meek, Astarte Shumanli, M., Aporrhais Ncwlern/i, Meek, &c. 
 
 Several of these fossils are common in the Upper Cretaceous beds of Nebraska 
 (Nos. 4 and 5 of Meek and Hayden's section of the Cretaceous rocks of Nebraska,), 
 and afford satisfactory confirmation of the parallelism before suggested between the 
 rocks of this region and those of more eastern localities. The Baculitcs are so numer- 
 ous as to form in some places half the bulk of the rock. Of these, the greater num- 
 ber are ornamented with nodes, in the manner of B. asper (Roemer), with which they 
 maybe identical. The smooth ones resemble //. ovatus and II. coiitpressus. They vary 
 much in form, some being nearly cylindrical, others much compressed, with every pos- 
 sible variety between these extremes. All, however, as it seems to me, belongs to one 
 species. 
 
 From the summit of the hills, near camp, we have a fine view of the country 
 south of us to the San Juan. All this interval is occupied by a mesa composed of the 
 Upper Cretaceous rocks, deeply scored along the lines of drainage. The dip of the 
 rocks composing this plateau is here southward, and very rapid; farther from the bases 
 of the mountains they seem to lie nearly horizontal. 
 
 The southern end of the Sierra, de la Plata is composed mainly of light-colored 
 porphyry and other forms of erupted rock. It also consists in part of granite, with 
 mica and clay-slate, traversed by extensive veins of quartz and epidote, which are 
 metalliferous, containing magnetic iron, and sulphides of iron, copper, and lead; doubt- 
 less, also, in certain localities, silver and gold; at least there is better promise of the 
 discovery of the precious metals in these mountains than in any others we have visited 
 since leaving the Rro Grande. 
 
 The name given by the Spaniards to this great sierra, Silver Mountain, would 
 seem to indicate that at some time silver had been found there, but I cannot learn 
 that any definite knowledge is possessed by the Mexicans or the Indians of the existence 
 of metallic veins such as would justify their choice of a title so significant. 
 
TO JUNCTION OF GRAND AND GREEN RIVERS. 8L> 
 
 C II A I J T K R 
 
 GEOLOGY OF THE SAGE-PLAIN AND VALLEY OF THE UPPER COLO- 
 RADO. 
 
 GENERAL FKATURES op THE NORTHERN PORTION OF THE COLORADO BASIN ASPECTS AND 
 
 STRUCTURE, OF THE SAGE PLAIN MESA VEHDK ENORMOUS DENUDATION OF THE COLO- 
 RADO PLATEAU CROSSING THE SAGE PLAIN Rio DE LOS MANGOS RioDoLORES SECTION 
 OF LOWER CRETACEOUS ROCKS RUINS ON THE DOLORES Si EUR A SAN MIGUEL SUROU- 
 
 ARA TlERRA 1JLANCA GlTA.TELOTES CANON PINTADO TRIASSIO ROCKS SAURIAN BONES 
 
 LA TENEJAL ERODED BUTTES CASA COLORADO Ojo VERDE SIERRA LA SAI EXCUR- 
 SION TO GRAND RIVER CANON COLORADO PLATEAU BORDERING THE COLORADO RIVER 
 ERODED MONUMENTS LABYRINTH CANON RUINED BUILDINGS SUMMIT OF THE CARBON- 
 IFKROUS FORMATION SECTION OF TRIASSIC ROCKS REMARKABLE COUNTRY ABOUT THE 
 JUNCTION OF GRAND AND GREEN RIVERS SINGULAR ERODED BUTTES AND PINNACLES 
 NETWORK OF CANONS CANON OF GRAND RIVER SECTION OF CARBONIFEROUS STRATA 
 TRANSVERSE SECTION OF THE COLORADO VALLEY RETURN TO SAGE-PLAIN JOURNEY 
 SOUTHWARD TO THE SAN JUAN SlERRA ABAJO. 
 
 Uetween the Rio dela Plata and the Rio de los^ Mancos we skirted the base of the 
 extreme southern point of the Sierra de la Plata. These mountains terminate south- 
 ward in a loiiy slope, which falls down to a level of about 7,500 feet above; the sea 7 
 forming a plateau which extends southward to the San Juan, the Mesa Verde, to which 
 T shall soon have occasion again to refer. This mesa terminates on the west by an 
 abrupt nearly vertical precipice from 1,"20) to 1,500 feet in height. Between the mesa 
 and the mountains is a natural pass or jitu'rfu, through which the Spanish trail leads 
 where it crosses the divide. On the west this puerta opens to the right and left; 
 bounded on the north by the retreating southwesterly slopes of the Sierra de la Plata, 
 on the south by the wall-like edges of the Mesa Verde. As we stood on its threshold 
 \ve looked far out over a great plain, to the eye as limitless as the sea; the monotonous 
 outline of its surface varied only by two or three small island-like mountains, so distant 
 as scarcely to rise above the horizon line. Here we were to leave the lofty sierras of 
 the Kocky Mountain system, which had so long looked down on our- camps and marches, 
 the picturesque scenery of the foot-hills, their flowery valleys and sparkling streams, 
 the grateful shade of their noble forests, and take our weary way across the arid ex- 
 panse of the great western plateau; a region whose dreary monotony is only broken by 
 frightful chasms, where alone the weary traveler finds shelter from the burning heat of 
 a cloudless sun, and where he seeks, too often in vain, a cooling draught that shall 
 slake his thirst, To us, however, as well as to all the civilized world, it was a terra 
 
84 EXPLORING EXPEDITION FROM SANTA FE 
 
 incM/itita, and was'viewed with eager interest, both as the scene of our future explora- 
 tions and MS the possible repository of truth which we might gM.ther and add to the sum 
 total of human knowledge. 
 
 An outline sketch of this portion of the Colorado Plateau has been already given in 
 Chap. Ill, and but little more need be said to make its general features clearly compre- 
 hended. The plain which stretches westward from the Sierra de la Plata indicated on 
 the accompanying map, where it is called the Great Sage-plain is part of an immense 
 plateau which once stretched continuously far beyond the course of the( Jolwrado. 1 low 
 it has been divided by the canons of the draining streams, and how, by erosion, its 
 plateau character has been so modified as to be locally lost, will full) appear in tin- 
 progress of our geological narrative; yet no one who observes the orderly and un- 
 broken arrangement of its underlying rocks, the perfect correspondence of the sections 
 on opposite sides of the profound canons which cut it, will hesitate to assent to the 
 assertion that an unbroken table-land once stretched from the base of the Sierra de la 
 Plata all the way across to the mountain chains west of tin; Colorado, and that from 
 this plateau, grain by grain, the sedimentary materials which once filled the broad and 
 deep valleys of the Colorado and San Juan have been removed by the currents of 
 these streams. The mind is awestruck in the contemplation of the magnitude of the 
 element of time which enters into the analysis of the process by which these stupendous 
 monuments of erosion have been produced; but if the numerical faculty is baffled in 
 the effort to count the years or ages which must have; been consumed in the erosion of 
 the valleys and canons to which I have referred, even the imagination itself is lost when 
 called upon to estimate the cycles on cycles during which the much grander features 
 of the high table-lands were wrought from a plateau which once overspread most of 
 the area of the Colorado Basin, burying the present Sage-plain 2,000 feet beneath its 
 upper surface. 
 
 As I have before said, the Great Sage-plain is everywhere floored by the' Lower 
 Cretaceous sandstones; massive resistent strata, 300 to 500 feet in thickness. These 
 are succeeded in the ascending series, where the upper members of the formation are 
 present, by the Middle Cretaceous shales, principally soft argillaceous beds, from 1,200 
 to 1 ,500 feet in thickness. Above these belong the Upper Cretaceous sandstones and 
 marls, occupying an equal vertical space. Now, over the great plateau, floored and 
 protected by the Lower Cretaceous sandstones, are everywhere scattered mounds of 
 greater or less elevation, composed of the Middle Cretaceous shales, and in the inter- 
 val between these mounds are scattered thousands and millions of the fossils charac- 
 teristic of these shale-beds, washed, like pebbles, from their soft envelope!. Here we 
 have conclusive evidence that the Middle Cretaceous shales once completely covered 
 the sandstone-floor of the Sage-plain from which they have been nearly removed by 
 aqueous action. As we approach the margin of the sandstone plateau, we find the 
 mounds of overlying shale becoming more numerous and higher, until, reaching tin- 
 edge of the high mesa, they blend in solid escarpments more than 1,000 feet in 
 altitude, crowned by the massive, but soft, sandstones which form the third and upper 
 division of the Cretaceous series. 
 
 Such are some of the facts which may be observed about the base of the Mesa 
 
TO JUNCTION OF GRAND AND GREEN RIVERS. 85 
 
 Vorde, facts of which the significance will be readily appreciated; but these are not 
 all the things that may lie seen from the vicinity of our present standpoint. The Mesa 
 Verde is, geologically, but a portion of the high table-lands which border the Upper 
 San Juan; the northern margin of which is followed by our route from the ford of the 
 Chama to the Mancos. I Fere this plateau terminates abruptly in a bold and most pic- 
 turesque wall, of which the general course, though varied by many salient and 
 re-entering angles, is nearly north and south from the Sierra de la Plata to the San Juan. 
 This mesa we completely encircled; examined it at a thousand points, and can speak 
 of its structure and extent with confidence. To obtain a just conception of the enor- 
 mous denudation which the Colorado Plateau has suffered, no better point of view 
 could possibly be selected than that of the summit of the Mesa Verde. The geologist 
 here has, as it seems to me, satisfactory proof of the proposition I have before made, 
 that, from the greater portion of the Colorado Plateau, strata more than 2,000 feet in 
 thickness ha.ve been removed by erosion. He here has a view toward the west, limited 
 only by the powers of human vision. 1 )irectly west the Sage-plain stretches out nearly 
 horizontal, unmarked by any prominent feature, to the distance of a hundred miles. 
 .There the island-like mountains, the Sierra Abajo and Sierra La Sal, rise from its sur- 
 face. South of these is the little doubled-peaked mountain, called by the Mexicans Las 
 Ort'JKK del Oso the bear's ears; beyond these his vision could not reach, but our 
 explorations enable us to tell him there lies the broad eroded valley of the Colorado, 
 bounded by two steps, of over 1,000 feet each, below the level of the Sage-plain, and 
 in the bottom of that valley, the chasm of the Colorado Canon, whose perpendicular 
 walls are 1, ">()() feet in height; beyond the trough of the Colorado, a plateau corre- 
 sponding to the Sage-plain, and beyond this a representative of the Mesa Verde. 
 Looking southwest, he would see the Sage-plain terminated in that direction by the 
 excavated valley of the San Juan; beyond this its representatives of similar character 
 and elevation; higher and more distant than these, the long perspective lines of the 
 lofty mesas north and west of the Moqui villages; the precise counterpart of that on 
 which he is supposed to stand. 
 
 On the northern margin of the plateau, we are assured by those who have been 
 there that the constituent rocks of the Mesa Verde are exposed, holding the same posi- 
 tions as here Are we not then driven by these facts to conclude that, over all this 
 area of undisturbed sedimentary rocks, surrounded by table-lands composed of like 
 strata, presenting corresponding, but now widely separated faces, these strata once 
 stretched in unbroken connection; and that, from the great interval, where now wanting, 
 they have been removed by the same all-potent influence which has left such grand 
 and so similar records in tin; canons of the Colorado and its tributaries. 
 
 The geology of the country lying between the Sierra La Plata and Sierra Abajo 
 is so monotonous as to require no lengthy description; all that need be said of it is 
 in brief notes of our different days' marches contained in my journal. From these I 
 make the following extracts: 
 
 "Aitf/itxt \(}//>, (!<i>u/> 21, on ilio Dolores. The Rio de los Mancos is a clear mount- 
 ain stream, formed by two branches, which unite just below our camp, and which 
 rise in the foot-hills of the Sierra, de la Plata, on its western side;. Each of the two 
 
86 EXPLORING EXPEDITION FKOM SANTA Ffi 
 
 branches is about the size of the La Plata; they flow through a pretty valley, and are 
 bordered by thickets of willow and alder, and groves of pine and cottonwood. As 
 usual, at such high elevation, the cottonwood is all of the narrow-leaved species 
 I'lijtitlttH uiif/tiNtifvlia. The immediate banks of the Mancos are at this point composed 
 of the black shales, which overlie the Lower Cretaceous sandstones, containing (Mrcd 
 c/ii/f/rxla, IiKii-n-ttnniK probfomatieus, &c. Very near camp (19) is a clear, cold spring, of 
 which the water is highly charged with sulphuretted hydrogen ; another of the mineral 
 springs flowing from the dark Cretaceous shales, so common in New Mexico, where 
 they are known as Ojos lieriondns. Soon after leaving the Mancos, we came upon the 
 Lower Cretaceous sandstones, which form the surface-rock to the Dolores. These 
 sandstones are covered in places by detached hills of overlying shales and light-blue 
 limestone, as usual, crowded with their characteristic fossils. The sandstones below 
 are exposed in all the ravines which we crossed, and in nearly every locality where I 
 examined them, I found in them impressions of angiospermous leaves, I'O/HI/HH, Hufi.r, 
 QuercuSj &c. After traveling 15 miles, we descended into a narrow valley of erosion, 
 traversed by a small clear stream, a tributary of the Dolores. The walls of the valley 
 are in places nearly perpendicular, and are composed of the Lower Cretaceous sand-- 
 stones, of which some 200 feet are exposed. These are general! v yellow and coarse, 
 but alternate with laminated, greenish, ripple-marked layers, beds of greenish and gra v 
 shales, and occasional bands of lignite. Nearly all contain the impressions of the 
 stems of plants and dicotyledonous leaves, similar to those so frequently before seen 
 in the same formation. The lowest stratum visible at this point, is a fine-grained com- 
 pact sandstone, very uniform in texture, and as white as loaf-sugar; a most beautiful 
 building material." 
 
 The country lying between the Mancos and Dolores is generally dry and sterile, 
 yet is everywhere covered with fragments of broken pottery, showing its former occu- 
 pation by a, considerable number of inhabitants; it is now utterly deserted. Near the 
 mountains it is pretty well timbered ; farther west, trees become more scattered and 
 smaller, the pines confined to the narrow valleys, the uplands dotted with groves of 
 pinon and cedar, with wide intervals covered with sage-bushes and soap-plant, VIK-CH 
 tntf/ustifolia. The Dolores rises on the west side; of the Sierra do la Plata, many miles 
 north of our route, and is here a clear, rapid stream, as large as the San Juan at the 
 Pagosa. It runs through a beautiful but narrow valley, several hundred feet below 
 the surface of the surrounding country. This is a valley of excavation, cut in tin- 
 Lower Cretaceous rocks, which form bluffs on either side over 200 feet high, in ma.nv 
 places perpendicular. The bottom-lands are nearly level, half a mile wide, and verv 
 fertile, covered with fine grass, with groves of cottonwood and willow, and scattered 
 trees of yellow pine. Near the river the thickets are overgrown with virgin's bower 
 and hop, which form almost impenetrable jungles. Great numbers of flowers ornament 
 the open grounds, generally of the species so common in the valleys before! passed 
 through. 
 
 The blufVs bounding the river below our camp show the following section: 
 1. Soil with rolled gravel and bowlders, drift from the Sierra, de la Plata, princi- 
 pally white and black porphyry like that on the Mancos and La Plata. 
 
33 
 O 
 O 
 
 o 
 
 r 
 o 
 7) 
 
 m 
 
 x 
 
 O 
 
 z 
 rn 
 
 m 
 Z) 
 
 D 
 m 
 
 Tl 
 
 r 
 
 
 CD 
 
 o 
 
 o 
 
 3 
 
 X 
 
 "O 
 
 2 
 
 3 
 
 V 
 
 ej 
 3" 
 
TO JUNCTION OF GRAND AND GREEN RIVERS. 87 
 
 2. Dark-blue calcareous shales with bands of dove-colored limestone, weathering 
 light-ash, with thinner layers oi' brown sandy limestone. 
 
 In the shales are imbedded great numbers of Gr//i>l/(c- I'itcheri, generally of small 
 si/,o but beautifully perfect They exhibit a great variety of form, some being very 
 high and narrow; others broader, like the typical G. Pitcheri; others nearly orbicular 
 like G. dilatntn of the Oxford clay; others still broader, with a transverse diameter con- 
 siderably greater than the antero-posterior. Between these various forms are connect- 
 ing links which seem to prove that all belong to one species. The dove-colored lime- 
 stones, here as on the (Jhama and Canadian, contain almost exclusively Inoccramtiy 
 problematictis, and also exhibit the peculiar fracture noticed in the localities mentioned 
 above, and others, on exposure, cracking horizontally into concavo-convex chip-like 
 fragments, having sharp edges. 
 
 The ferruginous layers represent the fish-bed of the Pagosa, the Chama, the 
 Canadian, &c., a clearly defined geological horizon throughout all the Cretaceous area 
 of New Mexico; they contain hen; (Mira liii/nhri.^ and many fragments of Inoceramus 
 I. i>i-i)l>/t'iiiiifi<-n* and a much larger species probably not described. 
 
 .'!. Coarse yellow sandstone, often a conglomerate, containing impressions of dico- 
 tyledonous leaves, Salix, &c., and thin bands of lignite. 
 
 4. Greenish or light-brown soft calcareous sandstone, with local layers of blue 
 clay-shale and thin seams of lignite ; no fossils observed. 
 
 5. Thick-bedded light-yellow or white sandstone, locally coarse or fine, some- 
 times a conglomerate containing quart/ pebbles, generally fine-grained and nearly 
 white; no fossils. 
 
 6. Green or purple clay stones and shales. 
 
 7. Soft greenish sandstone. 
 
 Most of the strata enumerated above are exposed in the cliffs bordering the valley; 
 for several miles are entirely unbroken, conformable throughout, and have a gentle dip 
 to the west. The facts here observed are of special interest as deciding" beyond all 
 appeal the question of the relative age of the sandstone group containing angiosperm- 
 ons leaves, so marked a feature in the geology of New Mexico. This is but one of 
 the great number of cases where these sandstones were found overlaid by strata con- 
 taining well known Cretaceous fossils. It is to be hoped that this mooted question 
 will now be considered settled, since it must be so in the mind of every honest inves- 
 tigator. 
 
 From the summit of the hill from which the preceding section was taken, we 
 obtained a magnificent view of a wide extent of country lying on every side of us. In 
 the east the Sierra de la Plata rose as a high and unbroken wall, presenting a more 
 varied outline than when seen from the other side ; south of the Sierra, the puerta 
 through which we had passed; beyond this, stretching far off southward, the green 
 slopes and lofty battlements of the Mesa Verde beetling over the plain like some high 
 and rock-bound coast above the level ocean; south, and near us, the miniature peak 
 and chain of La Late ; far more distant, the Sierras Carriso and Tunecha in the Navajo 
 country ; occupying the whole western horizon the monotonous expanse of the Sage- 
 plain, beyond which rose the low summits of the Orejas del Oso, Sierra Abajo, and 
 
88 EXPLORING EXPEDITION FltOM SANTA FE 
 
 Sierra l;i Sal. In the north appeared a new and grand topographical feature. From 
 N. 10 W. to N. E. magnetic stretched a chain of great mountains, higher and more 
 picturesque than any we had seen. These have no common name, Imt one of the 
 peaks is called, from the stream which washes its base, Sierra San Miguel. 
 
 Whether these mountains form a single chain or several, and what is their prevail- 
 ing trend cannot he said with certainty without closer inspection ; the overlapping lines 
 of their bases, which would decide that question, being concealed by intervening high- 
 lands. I should infer, however, from the view \vo had of them, that, they represent 
 several distinct ranges, with a trend nearly north and south, set >'// n-lirloii. Between 
 the most easterly of these mountains and the Sierra de la Plata is a low gap, in which 
 stands a remarkable pinnacle of rock; even at a distance of seventy or eighty miles a 
 striking object. One of the mountains in this group bears a large surface of snow, and 
 its height cannot be less than 13,000 feet. Several others are nearly as lofty, and are 
 cones of great beauty. * 
 
 The hill from which we obtained this view is crowned with an extensive series of 
 very ancient ruins. The principal one is a pueblo, nearly 100 feet square, once sub- 
 stantially built of dressed stone, now a shapeless heap, in which the plan of the original 
 structure can, however, be traced. Like most of the ruined pueblos of New Mexico, 
 it consisted of a series of small rooms clustered together, like cells in a beehive. Xear 
 the principal edifice are mounds of stone, representing subordinate buildings. Among 
 these are numerous large depressions marking the places of cisterns or cxltij/<tx. (Quan- 
 tities of broken- pottery, similar to that so commonly seen in like circumstances, but 
 bearing the marks of great age, strew the ground about these ruins. 
 
 A mile or two up the river are several other stone houses built high up in the 
 cliffs, l.')0 feet above the stream; they are usually placed on ledges covered by pro- 
 jecting rocks, which act as roofs. These houses are not large, and were probably 
 only occupied by the guardians of the iields once in cultivation below. All of these, as 
 well as the more extensive ruins Jbefore mentioned, are admirably located for defense, 
 and would be easily held by a handful of determined men against any number ol 
 assailants armed only with the weapons of savage warfare. 
 
 Between our camp on the Dolores and Surouara no new geological feature was 
 'noticed. The Lower Cretaceous sandstones everywhere form the rocky substratum, 
 here and there covered with patches of the overlying shale. From these shale-beds 
 millions of Gryphseas have washed out, covering the surface and rattling under the 
 mule's feet like gravel-stones. Sage is the predominant vegetation, and no water is 
 found in the interval; yet we passed several ruined buildings, and broken potter}' is 
 scattered everywhere. 
 
 Surouaro is the name of a ruined town which must once have contained a popu- 
 lation of several thousands. The name is said to be of Indian (Utah) origin, and to 
 signify desolation, and certainly no better could have been selected. The surround- 
 ing country is hopelessly sterile ; and, whatever it once may have been, Surouaro is 
 now desolate enough. Here are two canons, cut in the sandstone by two former 
 streams. These unite nearly a mile below camp. All the interval of mesa between 
 them is covered with ruins. The houses are, many of them, large, and all built of 
 
TO JUNCTION OF GRAND AND GREEN RIVERS. 89 
 
 stone, hammer-dressed on the exposed faces. Fragments of pottery are exceedingly 
 common, though, like the buildings, showing great age. There is every evidence that 
 a large population resided here for many years, perhaps centuries, and that they 
 deserted it several hundred years ago ; that they were Pueblo Indians, and hence 
 peaceful, industrious, and agricultural. How they managed to exist here, and how 
 their town was depopulated, are questions that suggest themselves at once, but cer- 
 tainly the former is the more puzzling. They may have been exterminated by the 
 Navajos and Utahs, warlike and aggressive tribes who occupy the adjacent region; but 
 where a population of many thousands once existed, now as many hundreds could not 
 be sustained, either by agriculture or the chase. The surrounding country contains 
 very little animal life, and almost none of it is now cultivable. It is 7,000 feet in 
 altitude, intensely cold in winter, and very dry throughout the year. The want of 
 water alone would forbid the residence of any considerable number of persons at 
 Snrouaro if everything else were furnished them. The arroyos, through which 
 streams seem to have once flowed, are now dry, and it was only with great difficulty 
 that sufficient water Avas obtained for the supply of our train. The remains of 
 mcfates (corn-mills) are abundant about the ruins, and corn was doubtless the staple 
 article of their existence, biit none could now be raised here. The ruins of several 
 large reservoirs, built of masonry, may be seen at Suroiiaro, and there are traces of 
 (K-rt/uias, which led to these, through which water was brought perhaps from a great 
 distance. At first sight the difficulties in the way of obtaining a supply of water 
 for any considerable population at this point would seem insurmountable, and the 
 readiest solution of the problem would be to infer a change of climate, by which this 
 region was made uninhabitable. Such a conclusion is not necessary, however, for the 
 skill and industry of the ancient inhabitants of the arid table-lands of New Mexico 
 and Arizona achieved wonders in the way of procuring a supply of water. Some- 
 times this was done by carefully collecting, in cisterns of masonry, every drop of a 
 trickling spring ; sometimes by canals, through which water was brought from long 
 distances. The Moqui villages are now supplied, though rather scantily, by such 
 means, where, if the cisterns were to fall into ruins, a single traveler could hardly find 
 water enough for himself and horse. 
 
 From Surouaro to the base of the Sierra Abajo our experience was exceedingly mo- 
 notonous. The physical aspects of the country are everywhere the same, and its geologi- 
 cal structure equally unvaried. The Lower Cretaceous sandstones here lie nearly 
 level, but are exposed in all the ravines, generally dry, which we crossed, while 
 low mounds of the overlying shales were almost constantly in sight; their characteris- 
 tic fossils lying about in such profusion that thousands of tons of them might have 
 been collected. 
 
 After leaving the immediate vicinity of the mountains, no beds of drift or trans- 
 ported materials of any kind were met with, and it is evident that the denudation 
 which the strata once covering the Sage-plain have suffered has not been effected by 
 any deep and wide-spread currents by which this country has been swept, but by the 
 quiet and long-continued action of atmospheric influences rains, frosts, &c. No 
 flowing stream was met with in all this part of our route, and we were compelled to 
 12 s F 
 
90 EXPLORING EXPEDITION FROM SANTA 
 
 depend for our supply of water upon the springs or pools to which we were led by 
 the trail we were following. At the Tierra. Blanca we encamped at the finest of these 
 springs which we saw. Here the water issues from the base of a low cliff of sand- 
 stone, of which the surfaces are whitened by a saline effioresence, consisting in a great 
 degree of chloride of sodium ; a phenomenon which has given to the locality the name 
 it bears. 
 
 Our next stopping place was at the Guajelotes, a large pool of bad surface-water; 
 a natural reservoir in the sandstone rocks, containing great numbers of water-lizards 
 Siredon called by the Mexicans guajelotes. 
 
 The Ojo del Cuerbo is a small spring similar to that of the Tierra Blanca, except 
 that the water is less abundant and is sulphurous. 
 
 We had here approached comparatively near to the Sierras Abajo and La Sal, 
 the one being twenty, the other forty miles distant. Of isolated mountain groups the 
 La Sal is considerably the higher and more extensive ; both are, however, of insig- 
 nificant dimensions as compared with the lofty ranges of the Sierra San Migxiel. 
 
 Up to this point we had constantly met with fragments of broken pottery scat- 
 tered over the surface, and had frequently seen traces of ruined buildings. 
 
 CANON PINTADO. 
 
 Between the Sierras Abajo and La Sal passes a natural line of drainage, marked 
 above by a formidable canon, which furrows the Sage-plain many miles up toward the 
 Sierra San Miguel. North of the Sierra Abajo this canon terminates, or rather it opens 
 to the right and left, its walls extending to the bases of the two groups of mountains 
 I have mentioned, forming here the western terminus of the Sage-plain. To reach the 
 second and lower plateau it is necessary to descend the cliffs which are formed by the 
 cut edge of the first ; this we did, following the Spanish trail, at a point about fifteen 
 miles northeast of the Sierra Abajo, where a lateral canon enters the great one I have 
 described a few miles above its mouth. Here we descended at once more than 1,000 
 feet, leaving behind us the plateau of the Sage-plain, with its imvarying topography 
 and monotonous Cretaceous geology, to enter the great eroded valley of the Colo- 
 rado ; a region of which the geology is all Triassic or Jurassic, and where the scenery 
 exhibits all the brilliant colors which characterize the rocks of these formations in the 
 West, combined with all the variety of form which erosion can produce. From the 
 vivid colors of the walls of the canon where we entered it, it was named by our party 
 Canon Pintado. Its walls are precipitous, generally almost perpendicular, the lower 
 half composed of strata which are bright red, green, yellow or white; soft but massive 
 beds weathering, as such materials are so prone to do in this region, into arches, domes, 
 spires, towers, and a thousand other imitations of human architecture, all on a colos- 
 sal scale. The bottom is smooth and nearly level, in many places covered with the 
 finest gama grass, in others with the salt-bush (Sarcolatii.s~). 
 
 A section of the rocks exposed in the canon is as follows, the thickness of the 
 strata being estimated : 
 
TO JUNCTION OF GRAND AND GREEN EIVERS. 91 
 
 Section of the cliffs of Canon Pintado. 
 
 Feet. 
 
 1. Coarse yellow sandstone, floor of Sage-plain 200 
 
 2. Gray and green shales, interstratified with coarse gray sandstones and yellow 
 
 conglomerate 250 
 
 3. Red and green shales, with bands of whitish and greenish sandstone, with silici- 
 
 fied wood and Saurian bones - . 350 
 
 4. Yellow and red massive calcareous sandstones 200 
 
 In the foregoing section No. 1 is the Lower Cretaceous sandstone forming the 
 surface-rock over all the country lying Iretween the Sierra La Plata and Sierra Abajo. 
 A short distance back from the canon it is overlaid by patches of shale with Gryphaeas, 
 and therefore represents the surface of the Lower Cretaceous group. No. 2 is proba- 
 bly also Cretaceous, though here containing no fossils by which this question could be 
 determined with certainty. A group of rocks, having similar lithological characters, 
 at the Moqui villages, lies between the red beds below and the massive leaf-bearing 
 sandstones above, and there contains Ammonites percannatus and other Lower Creta- 
 ceous fossils. As will be seen in the progress of our geological narrative, at interme- 
 diate points on the San Juan a thickness of several hundred feet of soft green sand- 
 stones and green sandy shales separates the coarse yellow sandstones (the floor of the 
 Sage-plain) from the red gypsiferous rocks below. Until fossils shall be discovered in 
 these beds, it will be impossible to draw any sharply defined line marking the base of 
 the Cretaceous formation; and since the strata are here everywhere conformable, it is 
 extremely doubtful whether any such line of demarcation exists in nature. 
 
 Saurian bones. On the north side of the canon just opposite our camp (26), in the 
 face of the cliff, about 250 feet above its base, I discovered the bones of a large Saurian. 
 Probably the greater part of the skeleton is still imbedded in the rock, as, although I spent 
 two days, with several assistants, in excavating at this point, the tools at our command 
 were too light for such heavy work as it proved to be, and we were compelled to 
 leave many bones, which we could see, but had not the means to extricate from their 
 envelopes. The special object of our efforts, the head, was not reached, but still 
 remains to reward some future geologist who shall visit this interesting locality, with 
 more time at his command and more adequate implements for rock excavation than 
 we possessed. The bones we obtained were mainly those of the extremities: a femur 
 entire; the greater part of a humerus; several of the phalanges of the[toes; portions of 
 the ribs, and other large and, to me, quite incomprehensible bones. All of these have 
 been placed in the hands of the distinguished anatomist, Professor Leidy, who will 
 make them the subject of a special report. The size of the animal, as indicated by 
 these bones, must have been very large. The femur taken out measured 30 inches in 
 length, by 4 in diameter, at its smallest part, the articulations being much thicker. A 
 portion of the scapula which was taken out was 22 inches long and 16 wide at the 
 broadest part, and this but a fragment. 
 
 Near the locality where the larger skeleton was found a part of a rib of a smaller 
 individual was picked up, and on the opposite side of the valley a shapeless fragment 
 of a large bone was found at the foot of the cliff. From these facts it is evident that 
 
92 EXPLORING EXPEDITION FEOM SANTA FE 
 
 the Gypsum formation, usually so entirely barren of fossils, would here well repay 
 labor spent in its examination; and it is greatly to be desired that future explorers of 
 this far-off region will make an earnest effort to obtain what is, perhaps, here alone 
 obtainable, the means of settling the vexed question of the parallelism of the Gypsum 
 formation with deposits whose age has been accurately determined elsewhere. 
 
 In the same stratum with the Saurian bones I discovered the only fossil shells I 
 have ever seen from that group of rocks in New Mexico. These have the form of Natica, 
 but are probably not susceptible of accurate classification. 
 
 Three miles below our "Saurian camp" (26), we reached the mouth of the Canon 
 Pintado, which here opens out on to the second step of the table-lands in the descent to 
 the Colorado. The surface-rock of this plateau is everywhere the soft, massive, cal- 
 careous sandstone or indurated marl which forms the base of the section in Canon 
 Pintado. It is a comparatively soft rock, and contains a great deal of gypsum, very 
 uniformly disseminated. It lies in thick beds, scarcely separated by any distinct part- 
 ings, and yet exhibits the most striking examples of oblique stratification which have 
 ever come under my observation; the inclined layers, which compose some of the beds, 
 forming an angle of 30 and 40 with the primary planes of stratification, which are 
 horizontal. The slopes of the inclined layers are often or 60 feet in length, with a 
 rise of 20 or 30, showing that they were deposited from water, at times very much 
 agitated. The colors of this rock are always very decided, but, in the same stratum, 
 or on the same horizon, they are exceedingly local; a lemon or orange yellow being 
 succeeded quite abruptly by rose-red, and this again by white. The prevailing shade 
 is, however, a red, deep blood-red, or some lighter tint, such as brick-red, rose- tint, or 
 flesh-color. It is a rather remarkable fact, that with such inclined and contorted layers 
 of deposition this rock should include so little coarse material, and it is impossible to 
 resist the conclusion that it is far more a chemical than mechanical precipitate, and 
 that the period of its deposition was the commencement of a great epoch, during which 
 peculiar physical conditions prevailed over not only the greater part of our continent, 
 but of the world, so peculiar and so widespread that we may almost call them cosmical. 
 
 Everywhere over the second plateau are scattered buttes and pinnacles, wrought, 
 from the massive calcareous sandstone and the overlying Saurian beds, by the erosion 
 which has swept from this surface all traces but these of the immense mass of sedi- 
 mentary rocks wliich once covered it. Of these one of the most striking seen from 
 our route is the Casa Colorado, represented on Plate VI. It is a detached butte, some 
 300 feet in height, composed of red sandstone covered with the harder layers of the 
 Saurian beds. Another symmetrical and beautiful dome, composed of the same mate- 
 rials, is lemon-yellow, with a base of red. 
 
 Our camps 27 and 28 were on what I have called the second plateau. Of these the 
 first was at La Tenejal, a deep excavation in the red sandstone, which retains so large 
 a quantity of surface-water, and for so long a time, as to become an important water- 
 ing-place on the Spanish trail. These natural reservoirs are frequently met with in 
 this region, and during the dry season are of vital importance not only to such travelers 
 as may be passing through it, but also to the small number of animals which here 
 make their home. It is not at all uncommon to meet with them even on the summits 
 
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TO JUNCTION OF GRAND AND GREEN RIVERS. 93 
 
 of the sandstone buttes, which I have described, and it has often happened to me, after 
 a fatiguing climb to the top of some high cliff or pinnacle, to find its smooth-washed 
 summit-rock scooped out in cavities from- 2 to 20 feet in diameter, holding sometimes 
 many barrels of the clearest rain-water, and affording me the two rarest possible 
 luxuries in this arid region a drink of pure water and a cleansing and refreshing bath. 
 The Ojo Verde is a copious spring in a canon cut out of the red sandstone, ten 
 miles west of La Teneja. The surrounding country is very sterile, sparsely set with 
 sage bushes and small cedars, but about the spring the bottom of the canon is cov- 
 ered with the greenest and most luxuriant grass. The La Sal Mountain shows very 
 finely from this point, distant twenty miles. It is seen to be composed of several short 
 ranges, separated by narrow valleys, having a trend several degrees north of east, but 
 these are set somewhat en echelon, and the direction of the longest diameter of the mount- 
 ain mass is north-northwest and south-southeast ; such, at least, seems to be the 
 structure of this sierra as seen from a distance. Perhaps closer inspection would show 
 that the view obtained from this point was in some respects deceptive. Of the compo- 
 sition of the Sierra La Sal we know nothing except what was taught by the drifted 
 materials brought down in the canons through which the drainage from it flows. Of 
 this transported material we saw but little, but that consisted mainly of trachytes and 
 porphyry, indicating that it is composed of erupted rocks similar to those which form 
 the Sierra Abajo, of which it is in fact almost an exact counterpart. From the cliffs 
 over Ojo Verde we could see the strata composing both the upper and second plateaus, 
 rising from the east, south, and southwest on to the base of the Sierra La Sal, each 
 conspicuous stratum being distinctly traceable in the walls of the canons and valleys 
 which head in the sierra. It is evident, therefore, that the rocks composing the Colo- 
 rado .Plateau are there locally upheaved, precisely as around the Sierra Abajo and the 
 other isolated mountains which I have already before enumerated, and to which I shall 
 have occasion again to refer. 
 
 VALLEY OF THE COLORADO. 
 
 The general features of the trough of the Colorado, at the junction of Grand 
 and Green Rivers, have been already sketched, but the detailed description of our ex- 
 plorations of this remarkable region yet remains to be given. From the difficulties in 
 the way of such exploration, reported by our scouts, it was not thought advisable to 
 attempt to reach the river with our entire party. A depot camp was therefore estab- 
 lished at Ojo Verde, where most of the men and animals remained, while a small de- 
 tachment, with which I was connected, made the desired reconnoissance of this part of 
 our route. Of this excitrsion I find in my journal the following descriptive notes: 
 
 Any list 22. Started this morning for the junction of Grand and Green Rivers, 
 Captain Macomb, Lieutenant Cogswell, Mr. Dimmock, Mr. Campean, myself, and 
 three servants forming the party. On leaving camp we struck southwest, gradually 
 ascending for six miles, when we reached the brink of a magnificent canon twelve 
 hundred feet in depth, called, from the prevailing color of its walls, Canon Colorado, 
 into which with great difficulty we descended. The summits of the cliffs are here 
 nearly five hundred feet above the Ojo Verde, composed of the same rock exposed 
 
94 EXPLORING EXPEDITION FROM SANTA FE 
 
 there, the base of the section in Canon Pintado. The sandstone is here yellow or 
 straw-color, very massive, without fossils, and very remarkably cross-stratified. About 
 four hundred feet of this stratum are here exposed. 
 
 Below this succeed one hundred and fifty feet of red, foliated sandstone, with 
 some bands of red shale, precisely like the red sandstones of New Jersey and the 
 Connecticut River Valley. Below this two hundred and seventy feet of reddish-brown 
 sandstone, very massive, forming perpendicular faces. Still below, a series of green 
 and red thin-bedded sandstones and red and purple shales, three hundred and fifty feet 
 in thickness. The strata here rise gently to the westward, till, at a point ten miles 
 from Camp 28, a low anticlinal crosses our route. From thence to the river the dip is 
 westward. This part of the canon is exceedingly grand and beautiful, both from the 
 form and coloring of its walls. A few piilons and cedars cling to the sides and crown 
 the summits of the walls, while scattered cottonwoods and thickets of willow, with 
 here and there a small tree of a new and peculiar species of ash, form a narrow thread 
 of vegetation along its bottom. This, and many similar gorges, form the channels 
 through which the drainage of the western slope of the Sierra Abajo reaches the Col- 
 orado. Twelve miles west from the Ojo Verde the several canons unite by the elimi- 
 nation of their dividing walls, and debouch into a comparatively open country. De- 
 scending the canon we, therefore, at its mouth come out upon a third distinct plateau, 
 from which the mesa cut by the Canon Colorado has been removed; its edges reced- 
 ing in magnificent broken walls south and northwest. From this point the view swept 
 westward over a wide extent of country, in its general aspects a plain, but everywhere 
 deeply cut by a tangled maze of canons, and thickly set with towers, castles, and spires 
 of most varied and striking forms; the most wonderful monuments of erosion which 
 our eyes, already experienced in objects of this kind, had beheld. Near the mesa we 
 were leaving stand detached portions of it of every possible form, from broad, flat 
 tables to slender cones crowned with, pinnacles of the massive sandstone Avhich 
 forms the perpendicular faces of the walls of the Canon Colorado. These castellated 
 buttes are from one thousand to fifteen hundred feet in height, and no language is ad- 
 equate to convey a just idea of the strange and impressive scenery formed by their 
 grand and varied outlines. Toward the west the view reached some thirty miles, there 
 bounded by long lines and bold angles of mesa walls similar to those behind us, while 
 in the intervening space the surface was diversified by columns, spires, castles, and 
 battlemented towers of colossal but often beautiful proportions, closely resembling 
 elaborate structures of art, but in effect f;ir surpassing the most imposing monumeiils 
 of human skill. In the southwest was a long line of spires of white stone, standing 
 on red bases, thousands in numbe: 1 , but so slender as to recall the most delicate carv- 
 ing in ivory or the fairy architecture of some Gothic cathedral; yet many, perhaps 
 most, were over five hundred feet in height, and thickly set in a narrow belt or series 
 some miles in length. Their appearance was so strange and beautiful as to call out 
 exclamations of delight from all our party. 
 
 Next to the pinnacles the most striking objects in our view were buttes of dark, 
 chocolate-colored rock, which had weathered into exact imitation of some of the feudal 
 castles of the Old World ; yet, like all the other features in the scene, they were on a 
 
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TO JUNCTION OF GRAND AND GREEN RIVERS. 95 
 
 gigantic scale. These buttes are composed of the liver-colored sandstones and choc 
 olate shales of the walls of the Canon Colorado, which consist of a great number of 
 alternations of thinner or thicker layers of sandstone with those of shale. This struc- 
 ture in erosion gives rise to many curious and beautiful results, such as a beaded ap- 
 pearance in columns, while harder or thicker layers form their capitals and bases. It 
 also produces what seem to be walls of masonry, with frieze and cornice. 
 
 Soon after issuing from the mouth of Canon Colorado, the little intermittent stream 
 which traverses it begins to cut the floor of the rocky plain that borders the Colorado 
 Uiver, and, following that stream as the only possible avenue through which we could 
 reach our destination, we were soon buried in a deep and narrow gorge, which is thence 
 continuous till it joins the greater canon of Grand River. This canon, from its many 
 windings and the many branches which open into it, we designated by the name of 
 Labyrinth Canon. Its walls are from one to two hundred feet in height, so that there 
 is no egress from it for many miles. The bottom is occupied with cotton-woods, and 
 thickets of narrow-leaved willow, cane, and salt-bush ; all of which, with fallen rocks, 
 quicksands, and deep water-holes, made the passage through it almost impossible- 
 Some two miles below the head of Labyrinth Canon we came upon the ruins of a large 
 number of houses of stone, evidently built by the Pueblo Indians, as they are similar 
 to those on the Dolores, and the pottery scattered about is identical with that before found 
 in so many places. It is very old but of excellent quality, made of red clay coated 
 with white, and handsomely figured. Here the houses are built in the sides of the 
 cliffs. A mile or two below we saw others crowning the inaccessible summits inac- 
 cessible except by ladders of picturesque detached buttes of red sandstone, which 
 rise to the height of one hundred and fifty feet above the bottom of the canon. Simi- 
 lar buildings were found lower down, and broken pottery was picked up upon the 
 summits of the cliffs overhanging Grand River; evidence that these dreadful canons 
 were once the homes of families belonging to that great people formerly spread over 
 all this region now so utterly sterile, solitary, and desolate. 
 
 At the ruined pueblos we reached the surface of the Carboniferous formation ; 
 having passed through the entire thickness of the Gypsum series since leaving the 
 Sage-plain. 
 
 The complete section of the walls of the Canon Colorado continued to this point, 
 is as follows: 
 
 Feet. 
 
 1. Yellow massive calcareous sandstone, base of preceding section 400 
 
 2. Red micaceous sandstones, interstratified with red shales 150 
 
 3. Red and brown massive sandstone 270 
 
 4. Green and red shelly sandstones, and red shales, softer than No. 2 350 
 
 5. Greenish-gray micaceous conglomerate 15 
 
 G. Red and purple shale 60 
 
 7. Grayish sandstone 18 
 
 8. Chocolate and purple soft sandstones and shales in thin bands 275 
 
 9. Soft liver-colored and white sandstone - . 75 
 
 10. Brick-colored massive, calcareous sandstone, weathering into towers and bot- 
 tle-shaped buttes 80 
 
96 EXPLORING EXPEDITION FROM SANNA Ffi 
 
 Feet. 
 
 11. Liver-colored sandstone 15 
 
 12. Gray limestone 2 
 
 13. Brick-red sandstone, like No. 10 25 
 
 14. Chocolate sandstone, like Nos. 8 and 11 12 
 
 15. Blue limestone, containing Atliyris siiUilita, Spirifer camcrutus, &c., and other 
 
 Carboniferous fossils. 
 
 Descending the canon till night came upon us, we made our camp under the over- 
 hanging cliff's on the north side, whei'e some pot-holes in the rocky bottom promised 
 us a supply of water. 
 
 August 23, Camp 29 to Grand River. Leaving servants and packs in camp, we to- 
 day descended the Cailon of Labyrinth Creek, to its junction with Grand River. Until 
 within a mile of the junction, the character of the canon remains the same; a narrowgorgc, 
 with vertical sides, from 150 to 300 feet in height, its bottom thickly grown with bushes 
 and obstructed with fallen rocks and timber, passable but with infinite difficulty. At 
 the place mentioned above, however, our progress was arrested by a perpendicular fall, 
 some 200 feet in height, occupying the whole breadth of the canon, and to reach Grand 
 River it was necessary to scale the walls which shut us in. This we accomplished 
 with some difficulty on the south side, to find ourselves upon the level of the rocky 
 plain into which we sunk when entering the canon. The view we here obtained was 
 most interesting, yet too limited to satisfy us. Looking down into the canon we had 
 been following, we could see it deepening by successive falls until, a mile below, it 
 opened into the greater Canon of Grand River, a dark yawning chasm, with vertical 
 sides, in which we caught glimpses of the river 1,500 feet below where we stood. On 
 every side we were surrounded by columns, pinnacles, and castles of fantastic shapes, 
 which limited our view, and by impassable canons, which restricted our movements. 
 South of us, about a mile distant, rose one of the castle-like buttes, which I have 
 already mentioned, and to which, though with difficulty, we made our way. This 
 butte was composed of alternate layers of chocolate-colored sandstone and shale, 
 about 1,000 feet in height^Jts sides nearly perpendicular, but most curiously orna- 
 mented with columns and'pilasters, porticos and colonnades, cornices and battlements, 
 flanked here and there with tall outstanding towers, and crowned with spires so slender 
 that it seemed as though a breath of air would suffice to topple them from their foun- 
 dations. To accomplish the object for which we had come so far, it seemed necessary 
 that we should ascend this butte. The day was perfectly clear and intensely hot; the 
 mercury standing at 92 in the shade, and the red sandstone, out of which the land- 
 scape was carved, glowed in the heat of the burning sunshine. Stripping off nearly 
 all our clothing, we made the attempt, and after two hours of most arduous labor 
 succeeded in reaching the summit. The view which there burst upon us was such as 
 amply repaid tis for all our toil. It baffles description, however, and I can only hope 
 that our sketches will give some faint idea of its strange and unearthly character. 
 
 The great canon of the Lower Colorado, with its cliffs a mile in height, affords 
 grander and more impressive scenes, but those having far less variety and beauty of 
 detail than this. From the pinnacle on which we stood the eye swept over an area 
 some fifty miles in diameter, everywhere marked by features of more than ordinary 
 
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TO JUNCTION OF GRAND AND GEEEN K1VEES. 97 
 
 interest ; lofty lines of massive mesas rising in successive steps to form the frame of the 
 picture ; the interval between them more than 2,000 feet below their summits. A 
 great basin or sunken plain lay stretched out before us as on a map. Not a particle of 
 vegetation was anywhere discernible ; nothing but bare and barren rocks of rich and 
 varied colors shimmering in the sunlight. Scattered over the plain were thousands of 
 the fantastically formed buttes to which I have so often referred in my notes; pyramids, 
 domes, towers, columns, spires, of every conceivable form and size. Among these by 
 far the most remarkable was the forest of Gothic spires, first and imperfectly seen as 
 we issued from the mouth of the Canon Colorado. Nothing I can say will give 
 an adequate idea of the singular and surprising appearance which they presented from 
 this new and advantageous point of view. Singly, or in groups, they extend like 
 a belt of timber for a distance of several miles. Nothing in nature or in art offers a 
 parallel to these singular objects, but some idea of their appearance may be gained by 
 imagining the island of New York thickly set with spires like that of Trinity church, 
 but many of them full twice its height. Scarcely less striking features in the landscape 
 were the innumerable canons by which the plain is cut. In every direction they ran 
 and ramified deep, dark, and ragged, impassable to everything but the winged bird. 
 Of these the most stupendous was that of Grand River, which washes two sides of the 
 base of the pinnacle on which we stood, a narrow chasm, as we estimated, full 1,500 
 feet in depth, into which the sun scarcely seemed to penetrate. At the bottom the 
 whole breadth of this canon is occupied by the turbid waters of Grand River, here a 
 sluggish stream, at least with no current visible to us who were more than 2,000 feet 
 above it. In this great artery a thousand lateral tributaries terminate, flowing through 
 channels precisely like that of Labyrinth Creek ; underground passages by which inter- 
 mittent floods from the distant highlands are conducted through this country, producing 
 upon it no other effect than constantly to deepen their own beds. Toward the south 
 the cafion of Grand River was easily traced. Perhaps four miles below our position it 
 is joined by another great chasm coming in from the northwest, said by the Indians to 
 be that of Green River. From the point where we were it was inaccessible, but we 
 had every reason to credit their report in reference to it. 
 
 After reaching the elevated point from which we obtained this view, I neglected 
 to take the rest I so much needed, but spent the little time at my command in endeavor- 
 ing to put on paper some of the more striking features of the scene before us. Stand- 
 ing on the highest point, I made a hasty panoramic sketch of the entire landscape. 
 The effort had, however, nearly cost me dear ; for before I had completed the circle 
 of the horizon I was seized with dreadful headache, giddiness, and nausea, and, alone 
 as I then was, had the greatest difficulty in rejoining my companions. 
 
 The greater part of the walls of the canon of Grand River are formed of Car- 
 boniferous rocks; the summits of the cliff's are, however, composed of Triassic red 
 sandstone, the equivalent of those resting on the Carboniferous limestone on the Little 
 Colorado and in the valley of the Pecos. The Carboniferous cannot, therefore, be said 
 to be the surface formation anywhere in this region, as it is nowhere exposed except 
 in the trough of the Colorado, and there in the cafions. The composition of that 
 portion of this formation to which I had access in the canon of Labyrinth Creek is as 
 follows; the Triassic sandstone resting on the upper member of the section : 
 13 s P 
 
98 EXPLORING EXPEDITION FROM SANTA FE 
 
 Section of Carboniferous rod's in Labyrinth Canon. 
 
 Feet. 
 
 1. Blue slaty argillaceous limestone, with nodules of chert, and containing cri- 
 
 noidal columns in great numbers, Athyris subtilita, Bellerophon, Product us, dr.. 20 
 
 2. Massive blue limestone, portions of which are quite sandy, generally variable 
 
 in color and composition 50 
 
 3. Slaty blue argillaceous limestone, somewhat cherty, crowded with fossils, among 
 
 which are Athyris sultilita, Spirifer camcratus, Productus scmireticidatus, P. 
 scabriculus, P. Rogersi, P. punctatus, P. nodosits, Ortliisina wnbracidum, Mya- 
 lina ampla, Plcurotomarla excclsa a large and fine new species Allorisma 
 
 subcuncata, &c 40 
 
 4. Eed shale, no fossils 6 
 
 5. Bluish- white, red or mottled sandy limestone, no fossils 35 
 
 6. Red calcareous shale, no fossils 7 
 
 7. Red or bluish- white, mottled sandy limestone, massive, no fossils 25 
 
 8. Coarse blood-red sandstone, in some localities becoming red shale, no fossils. . 22 
 
 9. Hard blue cherty limestone, with a few fossils of the same species found in No. 3 . 36 
 
 The last number of the series forms the fall or precipice which stopped our prog- 
 ress down the canon. The remainder of the section was inaccessible to us; as seen 
 from above it seemed to consist of alternations of strata, similar to those already 
 enumerated. If we may judge of the thickness of the Carboniferous formation in this 
 vicinity by what it is lower down on the Colorado, we cannot suppose that the base of 
 the series is reached in the canon of Grand River. 
 
 On comparing this exposure of the Carboniferous strata with that at Santa Fe, 
 described in Chapter II of this report, and those of the banks of the Colorado below 
 the mouth of the Little Colorado, noticed in my report to Lieutenant Ives, Chapter VI, 
 pp. GO and G2, it will be seen that the fossils are generally identical; that, while two 
 or three neAv species were added in each localit}^ to the Carboniferous fauna of the 
 Mississippi Valley, most of them are the same with the most common and characteristic 
 fossils of our Coal-Measures in Illinois, Ohio, and Pennsylvania. 
 
 In lithological characters there is a general correspondence between all the locali- 
 ties in New Mexico where the Carboniferous rocks are fully exposed, but at Santa Fe 
 there is a greater proportion of coarse material, sandstones and conglomerates, than at 
 the more western localities. At Santa Fe, too, we find land-plants, characteristic Coal- 
 Measure form's, and even a thin bed of coal; all of which indicate the immediate prox- 
 imity of dry land. 
 
 Too little was learned of the lower part of the series on Grand River to enable 
 me to institute a fair comparison between the Carboniferous rocks at this locality and 
 those on Cataract Creek, 150 miles below. In the upper part of the formation we find, 
 however, here as there, cherty limestones with similar fossils, but the great beds of 
 gypsum of Cataract Creek are certainly wanting here. 
 
 Combining the sections exposed at different points along our route in our descent, 
 step by step, from the summit of the Mesa Verde to the canon of Grand River, we 
 have the following rc^umr of the strata and formations passed through: 
 
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TO JUNCTION OF GKAND AND GKEEN 1UVERS. 
 
 General section of the Valley of the Colorado. 
 
 No. 
 
 Strata. 
 
 Feet. 
 
 Formation. 
 
 Locality. 
 
 1 
 
 Soft, yellow sandstones, alternating with gray, purple, and green- 
 
 
 
 
 
 ish marls, containing silicified coniferous wood 
 
 COO 
 
 Cretaceous. 
 
 Mesa Verde. 
 
 2 
 
 Dark bitumino-calcareous shales, with concretions and thin bands 
 of compact bine limestone weathering yellow. Fossils in the 
 upper part, immediately beneath No. 1, Ammonites placenta, 
 Jlacitlites anceps, Aporrhait ^'twberryi, &c. ; toward the lower 
 part, Iiioceramus, Nautilus, Ostred conyesta, fish-scales 
 
 1 200 
 
 do 
 
 Do 
 
 3 
 
 Gray or dark-brown shales, -with bands of dove-colored limestone 
 weathering white, and thin layers of brown sandy limestone. 
 Fossils: GrypJuea Pitcheri, Inoceramns problematicus, I. fragilis, 
 Ammonites percarinatus, A. Macombi, Oztrea luyubris, 0. unifurmis, 
 Ptychodus Whipplei, Lamna Texana, &c - 
 
 150 
 
 do 
 
 Sage-plain. 
 
 4 
 
 Coarse, yellow sandstone, sometimes interstratified with beds of 
 shale and lignite. Fossils : Leaves of angiospermons plants, 
 Salix, Qitercus, \c...... . . ... . 
 
 250 
 
 do 
 
 Do 
 
 5 
 
 Green and gray shales, and soft green or yellowish sandstones or 
 conglomerate .... . .... 
 
 200 
 
 do 
 
 
 G 
 
 Red and green shales, with bands of soft, white, red or greenish 
 micaceous sandstones. Fossils: Saurian bones and silicifled 
 
 350 
 
 
 
 7 
 
 8 
 
 Red, yellow, or white massive calcareous sandstone. No fossils 
 Red, thin-bedded sandstones; with red shales. No fossils 
 
 550 
 150 
 
 Triassic. 
 ....do 
 
 Do. 
 Do. 
 
 9 
 
 Red and brown massive sandstone, fine-graiued, not hard. No 
 fossils 
 
 270 
 
 do 
 
 Colorado Canon. 
 
 10 
 
 Soft red sandstone, in thin layers, separated by beds of red or dark 
 brown shales 
 
 350 
 
 ..do 
 
 Do. 
 
 11 
 
 Greenish-gray micaceous conglomerate and gray sandstone, sepa- 
 rated by red and purple shales . ..... .. 
 
 1)2 
 
 .... do 
 
 Do. 
 
 12 
 
 Soft, liver-colored sandstones, becoming, suddenly and locally, 
 uearly white, with partings of shale . 
 
 350 
 
 .do 
 
 Do. 
 
 13 
 
 Brick-red massive calcareous sandstones, with some like the last 
 
 164 
 
 do.. . 
 
 Do. 
 
 14 
 
 Blue limestone, somewhat chorty. Fossils : Spirifer cameratits, 
 
 110 
 
 
 Canon of Grand 
 
 15 
 
 Bluish-white, red, or mottled sandy limestone, with partings of 
 red shale ... ... ... .. 
 
 95 
 
 
 River. 
 Do 
 
 ir, 
 
 Hard bine cherty limestone. Fossils same as No. 14 
 
 36 
 
 . do . . 
 
 Do. 
 
 17 
 
 Alternations of blue limestone, red and gray sandstone, to bottom 
 
 1 000 
 
 do 
 
 Do 
 
 
 
 
 
 
 Finding it impossible to pass down in the vicinity of the Colorado to its junction 
 with the San Juan, we were compelled to retrace our steps, and again ascending to 
 the Sage-plain, crossed southwardly over its western extremity, along the eastern base 
 of the Sierra Abajo, to the San Juan Valley. This part of our route afforded us little 
 that was new in any department, and need not, therefore, long detain its. We found 
 the structure of this portion of the Sage-plain precisely like that before passed over. 
 The Lower Cretaceous sandstones everywhere form the surface-rock, except where 
 covered with the overlying shales. The fossils of these shale-beds are often thickly 
 scattered over the surface, as in many localities enumerated on the preceding pages. 
 The plateau is here, as farther eastward, more or less broken by the canons of the 
 draining streams. These head in the Sierra Abajo and progressively deepen until they 
 terminate in the eroded valley of the San Juan. At various points along this part of 
 our route we saw ruins of ancient buildings, similar in character to those on the 
 Dolores ; and fragments of broken pottery, an equally characteristic record of the 
 Pueblo race, were everywhere met with. 
 
 Sierra Abajo. Our near approach to the Sierra Abajo, while skirting its northern 
 and eastern bases, gave us a better knowledge of its extent and structure than we had 
 before obtained. The impressions we then received of it are given in the following 
 extract from my notes: "August 30, Camp 31, Mormon Spring. Our last camp was 
 
100 EXPLORING EXPEDITION FKOM SANTA Ffi 
 
 at the eastern base of the Sierra Abajo. Within the last few weeks we have been on 
 three sides of this sierra, and have learned its structure quite definitely. It is a 
 mountain group of no great elevation, its highest point rising some 2,000 feet above 
 the Sage-plain, or perhaps 9,000 feet above the sea. It is composed of several distinct 
 ranges, of which the most westerly one is quite detached from the others. All these 
 ranges, of which there are apparently four, have a trend of about 25 east of north, 
 but being arranged somewhat en echelon, the most westerly range reaching farthest 
 north, the principal axis of the group has a northwest and southeast direction. The 
 sierra is composed geologically of an erupted nucleus, mainly a gray or bluish-white 
 trachyte, sometimes becoming a porphyry, surrounded by the upheaved, partially 
 eroded, sedimentary rocks. The Lower Cretaceous sandstones and Middle Cretaceous 
 shales are cut and exposed in all the ravines leading down from it, while nearly the 
 entire thickness of the Cretaceous series is shown in spurs which, in some localities, 
 project from its sides ; apparently the remnants of a plateau corresponding to, and 
 once connected with, the Mesa Verde. Whether the Paleozoic rocks are anywhere 
 exposed upon the flanks of the Siei'ra Abajo I cannot certainly say, though we dis- 
 covered no traces of them. It is, however, probable that they will be found in some 
 of the deeper ravines, where, as in most of these isolated mountains composed mainly 
 of erupted material, they are doubtless but little disturbed, but are buried beneath the 
 ejected matter which has been thrown up through them. 
 
 The relations of the Cretaceous rocks to the igneous nucleus of the Sierra Abajo 
 are very peculiar, for, although we did not make the entire circuit of the mountain 
 mass, and I can, therefore, not speak definitely in regard to the western side. As far 
 as our observations extended we found the sedimentary strata rising on to the trachyte 
 core, as though it had been pushed up through them. 
 
TO JUNCTION OF GRAND AND GREEN RIVERS. 101 
 
 CHAPTER VI 
 
 GEOLOGY OF THE BANKS OF THE SAN JUAN. 
 
 
 
 GENERAL FEATURES OF THE COUNTRY BORDERING THE SAN JUAN SECTION OF LOWER CRE- 
 TACEOUS STRATA SOUTH OF SlERRA ABAJO BlRD'S-EYE VIEW OF COUNTRY BORDERING 
 
 SAN JUAN HIGH MESAS OF THE NAVAJO COUNTRY TRIASSIC ROCKS OF LOWER SAN 
 JUAN LOWER CRETACEOUS STRATA OF CAMP 37 MIDDLE CRETACEOUS BEDS AND FOS- 
 SILS SOUTH OF LE LATE THE NEEDLES THE CRESTON UPPER CRETACEOUS STRATA 
 AT MOUTH OF THE ANIMAS RUINS IN THE SAN JUAN VALLEY CANON LARGO SECTIONS 
 OF UPPER CRETACEOUS STRATA PLATEAU COUNTRY BORDERING CANON LARGO BUTTES 
 OF MARLS AND SANDSTONES, HIGHEST MEMBERS OF THE SERIES OF SEDIMENTARY ROCKS 
 COMPOSING COLORADO PLATEAU GENERAL SECTION OF UPPER CRETACEOUS STRATA 
 NACIMIENTO MOUNTAIN, ITS STRUCTURE AND RELATIONS NOTES ON THE DIFFERENT FOR- 
 MATIONS EXPOSED ON ITS SIDES JOURNEY THROUGH COUNTRY BORDERING WESTERN BASE 
 
 OF NACIMIENTO MOUNTAIN DIVIDE BETWEEN SAN JUAN AND Rio GRANDE MOUNT TAY- 
 LOR CABEZON TERTIARY STRATA AT JEMEZ THE VALLES TRAP PLATEAUS. 
 
 The great features in the structure of the country traversed by the San Juan 
 River have been given in a preceding chapter, and there now remains for the comple- 
 tion of the picture only the presentation of the more local details upon which the gen- 
 eralizations before advanced were based. 
 
 Anticipating in some degree the progress of our geological narrative, to render 
 the subject more readily comprehensible, the following outline sketch of the geology 
 of the immediate banks of the San Juan is here given : 
 
 Taking their rise in the valleys dividing the parallel ranges of the Rocky Moun- 
 tains, Sierra de la Plata, Sierra de los Pinos, Sierra San Juan, &c., the tributaries of the 
 San Juan unite in the open country lying south of these mountain ranges to form a chan- 
 nel of drainage, having nearly an east and west course, to the Colorado. In addition 
 to the tributaries of the San Juan which have been enumerated, far less important ones 
 flow from the east and south. These are the rivulet traversing Canon Largo, rising at 
 the north end of the Nacimiento Mountain, the Chaco, Gothic Creek, and the Chelly, 
 which drain the arid mesas of the Navajo country and the slopes of the Tunecha and 
 Carrizo. 
 
 The country traversed by the northern and more important branches of the San 
 Juan, bordering our outward-bound trail, has been fully described in the preceding 
 chapters. That bordering Canon Largo and the course of the Chaco opens to us a new 
 geological field, and one which includes the exposures of the highest portion of the 
 
102 EXPLORING EXPEDITION FROM SANTA Ffi 
 
 series forming the table-lands of the Colorado Plateau. This interesting region requires 
 for its full illustration the detailed description to be hereafter given. 
 
 Its general character is, however, as follows: 
 
 The Nacimiento Mountain here bursts up through the table-lands in an unbroken 
 wall forty miles in length, with a nearly north and south trend. On its western flank 
 the various stratified rocks composing the Colorado Plateau lie inclined at a high angle 
 with the horizon. Of these the Carboniferous series and the overlying Triassic forma- 
 tion stand nearly vertical. Upon these the Lower and Middle Cretaceous groups rest 
 with a gentler inclination, while the Upper Cretaceous sandstones, and perhaps Tertiary 
 strata, are represented in detached buttes and mesillas, the remnants of continuous 
 sheets mostly removed by erosion. A few miles westward the disturbing influence of 
 the elevation of the Nacimiento range ceases to be visible, and the different stratified 
 rocks, which I have enumerated, hold a nearly horizontal position, which they main- 
 tain thence westward, with little variation, to and beyond the Colorado. Through the 
 table-lands which they here form, Canon Largo is excavated, gradually deepening till it 
 joins the valley of the San Juan, where its walls have an altitude of 700 to 800 feet. 
 At the eastern terminus of Canon Largo, and along the base of the Nacimiento Mount- 
 ain, are scattered the insulated buttes to which I have before referred as representing 
 the summit of the series of conformable strata composing the Colorado Plateau ; a group 
 of purple, white, and gray marls, interstratified with soft, yellow calcareous sandstones, 
 the latter predominating as we descend, and forming what has been described in the 
 preceding pages as the Upper Cretaceous group, containing, near its base, the fossils 
 collected on the Rio de la Plata, Ammonites placenta, Baculitcs anceps, &c.; a horizon 
 probably corresponding to No. IV of Meek and Hayden's Nebraska section. From the 
 perfect conformability throughout this group of rocks, their general lithological simi- 
 larity from summit to base, where they contain Cretaceous fossils; in short, from 
 absence of proof to the contrary, I have been driven to include them all provisionally 
 in the Cretaceous formation. It is by no means certain, however, that this classifica- 
 tion is rigidly correct, for it is not impossible that future investigations will prove that 
 the upper part of this group should be regarded as Eocene Tertiary. That no Miocene 
 beds occur here, is, I think, certain, as all the information obtained of the geology of 
 the Rocky Mountain region goes to show that, between the time of the deposition of 
 the Upper Cretaceous strata and the Miocene epoch, important changes occurred in 
 the physical geography of the central portion of our continent changes of level by 
 which the conformability prevailing throughout the sedimentary strata, from the Silu- 
 rian up, was finally interrupted. The only reasons we yet have for suspecting that 
 the upper portion of the series on the San Juan is Tertiary, are the inordinate thick- 
 ness (if all Cretaceous) 3,000 to 4,000 feet of the rocks which are more recent than 
 the Triassic formation; and the more suggestive fact that, in Texas, the Eocene beds 
 exhibit a marked lithological similarity to those forming the summit of the series at the 
 head of Canon Largo, and follow the Cretaceous strata in perfect conformability. We 
 can only say, therefore, that, with the evidence now before us, while it is possible, and 
 perhaps probable, that the uppermost members of the Colorado series are Eocene Ter- 
 tiary, we have as yet no proof that such is the case. 
 
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TO JUNCTION OF GRAND AND GREEN RIVERS. 103 
 
 The area occupied by the most recent strata found in the San Juan country is but 
 limited. The detached buttes which they form, and to which reference has before been 
 made, stretch southwesterly from the north end of Nacimiento Mountain toward San 
 Mateo, along the line of the divide between the Chaco and the Chelly; in other words, 
 between the waters of the Rio Granda and those of the San Juan. Westward from this 
 summit the table-land, which I have described in the preceding chapters as the pla- 
 teau of the Upper San Juan, extends to the distance of one hundred miles or more, 
 terminating in the mural faces of the Mesa Verde. Through this plateau Cafion 
 Largo and its continuation, the valley of the San Juan, are cut to the meridian of the 
 Sierra de la Plata; thence, westward, the lower plateau of the Sage-plain stretches to 
 the margin of the valley of the Colorado. In this lower plateau the trough of the San 
 Juan is also deeply sunk; cutting through the Lower Cretaceous group, and exposing, 
 especially toward its mouth, many hundred feet of the underlying Triassic formation. 
 Throughout the whole of its course through the table-lands the valley of the San Juan 
 is a narrow trough, bounded by abrupt, often perpendicular, rocky sides; its rich and 
 verdant bottom-lands forming a thread of fertility which traverses a region elsewhere 
 arid and barren. 
 
 On our way south from the Sierra Abajo we struck the San Juan at a point some 
 fifty miles or more above its mouth. Before descending from the plateau of the Sage- 
 plain into the valley of the river, we obtained from several points views which swept 
 over all the country bordering the lower part of its course. Of these that from the 
 vicinity of Camp 33 was peculiarly comprehensive and grand; revealing features so 
 novel and striking that I regarded them as worthy of somewhat detailed description in 
 my note-book,, That description is as follows : 
 
 " Soon after leaving camp (33) we obtained a beautiful view of all the country bor- 
 dering the Lower San Juan, of which nearly 10,000 square miles were at once visible. 
 From this point the eye swept a great semicircle from the Sierra de la Plata in the east 
 around southward to the Bear's Ears in the west. From the Sierra de la Plata the long 
 line of the lofty Mesa Verde stretched southward to the valley of the San Juan, there 
 terminating in high and abrupt cliffs. In the open valley of the river stood the isolated 
 pinnacles of the Needles, a peculiar and picturesque feature even at this great distance. 
 In the southeast the bold front of the northern end of the Sierra del Carrizo rose frown- 
 ingly from the immediate borders of the valley, and stretched away southward in a 
 succession of peaks till lost in the distance. 
 
 "Directly south the view was bounded by the high and distant mesas of the Na- 
 va jo country, succeeded in the southwest by the still more lofty battlements of the great 
 white mesa formerly seen by us from the Moqui Villages, and described in my report to 
 Lieutenant Ives. Of these high table-lands the outlines were not only distinctly visible, 
 but grand and impressive at the distance of a hundred miles. Nearly west from us a, 
 great gap opened in the liigh table-lands which limit the view in that direction ; tl uit 
 through which the San Juan flows to its junction with the Colorado. The features 
 presented by this remarkable gate-way are among the most striking and impressive 
 of any included in the scenery of the Colorado country. The distance between the 
 mesa walls on the north and south is perhaps ten miles, and scattered over the interval 
 
104 EXPLORING EXPEDITION FROM SANTA Ffi 
 
 are many castle-like buttes and slender towers, none of which can be less than 1,000 
 feet in height, their sides absolutely perpendicular, their forms wonderful imitations of 
 the structures of human art. Illuminated by the setting sun, the outlines of these sin- 
 gular objects came out sharp and distinct, with such exact similitude of art, and con- 
 trast with nature as usually displayed, that we could hardly resist the conviction that 
 we beheld the walls and towers of some Cyclopean city hitherto undiscovered in this 
 far-off region. Within the great area inclosed by the grander features I have enu- 
 merated, the country is set with numberless buttes and isolated mesas, which give to 
 the scene in a high degree the peculiar character I have so often referred to as exhib- 
 ited by the eroded districts of the great central plateau. Here and there we caught 
 glimpses of the vivid green of the wooded bottom-lands of the river, generally con- 
 cealed by the intermediate and overhanging cliffs." 
 
 The general geological structure of the wide area then seen was nearly as intelli- 
 gible and apparent as it could have been upon closer inspection; the higher mesas 
 everywhere composed of the Upper Cretaceous strata isolated portions of a once con- 
 tinuous sheet; the plateau on which we stood the massive sandstones and conglomerates 
 of the Lower Cretaceous group; while the bottom of the trough of the San Juan, where 
 exposed, showed the blood-red tint of the Triassic rocks. 
 
 Near Camp 34 we descended from the plateau of the Sage-plain and encamped in 
 the valley of the Rito del Sierra Abajo, a few miles above its junction with the San 
 Juan. In this descent we passed over the cut edges of all the members of the Lower 
 Cretaceous group, which afforded me the following section: 
 
 Section of Loiver Cretaceous strata at Camp 34. 
 
 Feet. 
 
 1. Dove-colored calcareous shale, with Gryphcea Pitcltcri, in knolls on No. 2. 
 
 2. Yellow, coarse sandstone, often a conglomerate, with pebbles of black and 
 
 white flint 25 
 
 3. Gray shale, with lignite and silicified wood 12 
 
 4. Yellowish, coarse sand-rock, with pebbles of flint (locally), sometimes mas- 
 
 sive, nearly white, quartzose 50 
 
 5. Green shale 2 
 
 6. Massive, nearly white sand-rock; the same noticed on the Dolores at Tierra 
 
 Blanca, &c 16 
 
 7. Yellowish- white sand-rock, with pebbles of flint 12 
 
 8. Soft greenish-yellow sandstone, massive, but easily decomposed 10 
 
 9. Verdigris-green concretionary, hard calcareous sandstone 2 
 
 10. Green and chocolate shales, with bands of fine argillaceous and calcareous 
 
 sandstone of several colors 30 
 
 11. Soft greenish-yellow sandstone 29 
 
 12. Green, chocolate, purple, pink, and white marls, with concretionary bands of 
 
 similar colors of hard, fine argillo-silicious rock 110 
 
 13. Greenish-yellow sandstone, like No. 11 85 
 
 14. Soft greenish sandstone, decomposing like No. 8 8 
 
TO JUNCTION OF GRAND AND GEEEN RIVERS. 105 
 
 Fuet. 
 
 15. Soft greenish sandstones and shales, alternating with and replacing each other. 140 
 
 Locally, this group is very massive, hard, almost quartzose, like No. 4; in 
 
 other places, almost replaced by greenish shales. This is probably the 
 
 base of the Cretaceous system. Continuing the section down the valley 
 
 of the Rito to the San Juan, we have 
 
 1C. Red, white, and greenish thin-bedded micaceous sandstones, alternating with 
 
 red shales the Saurian beds of Camp 26, No. 2 of section on page 91 130 
 
 17. Red, massive, cross-stratified calcareous sandstones No. 3 of section of Camp 
 
 26; No. 1 of section (p. 95,) to river-bottoms ICO 
 
 The last two members of the section evidently represent the upper portion of the 
 Gypsum formation (Trias.) They form the cliffs immediately bordering the valley 
 of the river at Camp 35, and the trough in which it flows from Camp 36 to its mouth. 
 
 The second bench, or higher cliffs bordering the valley at Camp 35, composed of 
 the Lower Cretaceous rocks, contain conglomerates the equivalents of the upper 
 members of the preceding section much coarser than those observed farther north; 
 the pebbles being frequently as large as the fist, with only sufficient paste to cement 
 them. Among these pebbles I noticed several composed of silicified wood, probably 
 derived from the erosion of the Triassic rocks. 
 
 In the trough of the San Juan, at this point, are extensive beds and terraces, com- 
 posed of coarse gravel and bowlders, evidently brought down by the river from the 
 mountain-ranges which it drains, and, in some instances, the bowlders must have been 
 rolled by the stream fully two hundred miles from their place of origin. 
 
 The structure of the country about Camp 37 is quite fully given in my journal. 
 My notes are as follows: "That portion of the valley of the San Juan passed through 
 to-day is, in its general aspects, similar to that before described, but the cliffs border- 
 ing it are less continuous and abrupt. In many places they are 300 or 400 feet high, 
 perfect canon walls, but oftener they recede from the river, leaving open areas; the 
 mouths of lateral valleys cutting up through the mesas toward the mountains. 
 
 "Geologically as physically, we have ascended considerably, and have just sunk 
 the 'Saurian rocks' (Upper Triassic?), leaving the cliffs bordering the valley com- 
 posed exclusively of Lower Cretaceous strata. During the greater part of to-day's 
 march thin-bedded Triassic sandstones and shales formed the base of the wall along 
 which Ave passed. These rocks are here more argillaceous than farther north, contain 
 much saline matter, but no beds of gypsum, and no fossils so far as observed." By 
 reference to my report on the geology of the Colorado expedition, it will be seen that 
 farther south they are still less sandy ; at the Moqui Villages, consisting mostly of soft 
 red and green marls. 
 
 The Lower Cretaceous strata are here more fully exposed, and have a greater 
 thickness than where examined farther north and east ; approaching more nearly the 
 character exhibited by this group at the Moqui Villages. The cliffs near camp are 
 composed of 
 
 Feet. 
 
 1. Yellow, coarse sandstones and conglomerates ; floor of Sage-plain 200 
 
 2. Greenish shales and sandstones 175 
 
 3. Greenish-yellow sandstones and greenish shales. 250 
 
 14 s F 
 
106 EXPLORING EXPEDITION FROM SANTA FE 
 
 Tlie character of the subdivisions will be better seen by the following analysis: 
 
 1st. Yellow sandstone group; here less coarse and containing less conglomerate 
 than at camps 33, 34, and 35. As at those localities, on the Cimarron, in Kansas and 
 Nebraska a portion of this group is here an exceedingly hard, whitish, quartzose sand- 
 stone. Beds of lignite and silicified wood are common. 
 
 2d. Greenish shales and sandstones ; the same group described in my notes on 
 the geology of the vicinity of Camp 34, Nos. 10, 11, 12 of section, page 104, 
 here much less highly colored, consisting of thick beds of greenish shale, locally pink 
 or purple, with bands of yellowish, greenish or purple concretionary silicious rock; 
 no fossils. 
 
 3d. Greenish sandstones and shales; the same group exposed in the lower part of 
 the section at Camp 34. The shales and sandstones frequently replace each other; the 
 group at Camp 37 being nearly all massive, yellowish-green sandstone, while, a few 
 miles below, the shales greatly predominate; no fossils discoverable. 
 
 "Mouth of the Mancos. Camp 38, thirteen miles. We have to-day ascended in the 
 geological scale, have nearly submerged the lowest member of the section at Camp 
 37, and the mesas back from the river on the north side run far up into the Middle 
 and Upper Cretaceous group. On the south side the mesas are not as high; the Lower 
 Cretaceous rocks forming the surface almost to the Sierra Carrizo, near which the 
 Upper Cretaceous beds appear again. The mesas north of our camp, composed of the 
 Middle Cretaceous strata, 'extend north and east to the base of the Sierra Le Late, and, 
 if not cut off by the valley of the Mancos, would connect with the Mesa Verde. As 
 usual in all this region, the shales contain great numbers of Gfyphaea Pitcheri. 
 
 "In the Lower Cretaceous sandstones, I here find impressions of dicotyledonous 
 haves, similar to those found on the Dolores and elsewhere. 
 
 "As in other parts of the valley of the San Juan which we have passed through, the 
 rains of ancient buildings are here very frequently met with; some in the open ground 
 of the valley, some in or on the cliffs ; all built of stone, surrounded by broken pot- 
 tery, evidently the remains of that great Pueblo race which once occupied all this 
 region, but which is now without an inhabitant. 
 
 "Camp 38, 39, 15 miles. In our march of to-day, a marked change has taken place 
 in the valley of the San Juan, which has become more open, is bounded by less high 
 a id abrupt walls ; the bluffs, like the bottom, being covered with fine grass. This 
 change is dependent, mainly, upon the fact that we have ascended from the Lower 
 to the Middle Cretaceous strata, and have passed from a region of coarse massive 
 sandstones to one where almost nothing but soft-bhie shales are visible. 
 
 "Before leaving the Lower Cretaceous sandstones, some interesting local peculiari- 
 ties were noticed in that group. The lignite, which in greater or less quantity they 
 always contain, about and above the mouth of the Mancos becomes a very conspicu- 
 ous feature in their structure. Of one cliff which we passed, not more than 100 feet 
 in height, full one-half was composed of carbonaceous matter. The dip, as before, is 
 gently eastward, and at Camp 39 the Lower Cretaceous sandstones had entire!}' disap- 
 peared beneath the overlying rocks. 
 
 "Here the cliffs near the river are composed of the dark shales of the Middle Cre- 
 
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TO JUNCTION OP GRAND AND GEEEN EIVERS. 107 
 
 taceous series, quite rich in fossils. Perhaps a hundred feet above the sandstones is a 
 band of brown, shelly, sandy limestone, which forms a projecting ledge in the face of 
 the cliffs, giving cornices and capitals to the castles and palaces into which they have 
 been worn. This ferruginous stratum marks a distinct horizon, and may be traced 
 over an immense area in New Mexico. It is the same that I have before referred to in 
 my notes on the banks of the Dolores, Camp 21, the Pagosa, the ford of the Chama, 
 Galisteo, and the banks of the Canadian. This stratum is characterized by the following 
 fossils: Inoceramus problematicus, Ostrca luyubris, Scaphites larvlformis, Ptychodus Whip- 
 plci, &c. Several undescribed species of Inoceramus, Ostrea, Ammonites, &c., are also 
 found in it; one of the Inocerami, abundant at Camp 39, being 2-3 feet in diameter. 
 The place of Gryphaa Pitcheri is just beneath this stratum; while the overlying shales 
 are filled with fragments of a large Inoceramus, covered with the closely-set shells of 
 Ostrea congcsta. 
 
 "A few miles north of Camp 39 is the southwestern corner of the Mesa Verde, which 
 stretches from this point northward to our former trail, and, eastward, forms the north 
 bank of the San Juan as far as the eye can reach. It has an altitude of 2,000 feet 
 above camp, and presents, with its many detached buttes and pinnacles, its long and 
 lofty walls, a most grand and imposing object. On the south side of the river, now 
 quite near to us, stand out in strong relief the picturesque basaltic pinnacles of ' The 
 Needles,' while further south the view is bounded by the high ridges of the Carisso and 
 Tunecha Mountains." 
 
 From Camp 40 we obtained a nearer and still better view of "The Needles," which 
 is represented in the accompanying lithograph plate. 
 
 This is a mass of erupted rock, rising with perpendicular sides from the middle of 
 the valley. From all points, where seen by us, it has the appearance of an immense 
 cathedral, of rich umber-brown color, terminating in two spires. Its altitude is about 
 1,700 feet above its base; above the river 2,262 feet. It is everywhere surrounded by 
 stratified rocks, and its isolated position and peculiar form render its origin a matter of 
 some little doubt. My conviction, however, is very decided that its remarkable relief 
 is due to the washing away of the sediments which once surrounded it, and which 
 formed the mold in which it was cast. In no other way can I imagine its vertical 
 faces of 1,000 feet to have been formed. 
 
 For ten miles after leaving Camp 40 we were traveling along the trough of the 
 river excavated in the Middle Cretaceous shales; the Upper Cretaceous sandstones cap- 
 ping the bluffs on either side. We here reached what seemed to be, in the distance, a 
 mesa wall crossing the river. This proved, however, to be a mass of dislocated and 
 ruptured strata, forming a huge broken wall, similar to that described in the Geology 
 of the Colorado Expedition, page 95, called by the Mexicans the Creston. This wall 
 marks a great line of fracture which traverses the country in a zigzag course from the 
 Sierra de la Plata southward toward the Tunecha Mountains. It crosses the river 
 nearly at right angles, with a trend N. 20 W. magnetic, forming a wall several hun- 
 dred feet high, cut by the river in a narrow passage, through which we worked ourway 
 with extreme difficulty. 
 
 The Creston evidently once formed a dam across the valley of the San Juan, over 
 
108 EXPLOEING EXPEDITION FEOM SANTA FE 
 
 which its waters poured in a cascade. This is shown by the gravel terrace which, 
 east of it, rises to the height of 300 feet above the present bed of the stream. The 
 strata composing it are set at an angle of about 35, and are the equivalents of those 
 which form the greater part of the Mesa Verde. As affording a more complete section 
 of the Upper Cretaceous rocks in this region than any I had before observed, I ex- 
 amined them with some care, and found them to consist of the following elements : 
 
 Section of rocks composing the Creston. 
 
 Foot. 
 
 1. Yellowish-brown calcareous sandstone, generally thick-bedded 2GO 
 
 2. Yellowish-brown sandy shale, with thin bands of sandstone and beds of lig- 
 
 nite 150 
 
 3. Yellowish sandy limestone, with strata of hard blue limestone ... 70 
 
 4. Dove-colored and purplish shales, with beds of impure lignite 1 75 
 
 5. Gray and purple shales, with bands of sandy limestone, and lines of concre- 
 
 tions of umber-colored and purple iron-stones 200 
 
 6. Brown calcareous sandstones 20 
 
 7. Gray and purplish shales, with bands of ferruginous sandy limestone 170 
 
 8. Yellowish-brown sandstones, whitish above 150 
 
 9. Gray and blue shales, continuous with those of Camps 39 and 40. 
 
 In this section, No. 1 is geologically the highest, and forms the most elevated por- 
 tion of the Creston. 
 
 The shales of No. 9 immediately overlie the ferruginous limestone of Camp 39, 
 which contains so many Inocerami, fish-teeth, &c. 
 
 The interval between these two groups represents the middle and upper portions 
 of the great group of shales which form the middle division of the Cretaceous system, 
 so often referred to in the preceding pages. 
 
 As in the sections observed on the northern route, the bands of sandstone and fer- 
 ruginous sandy limestone are shown to be only local phenomena; since they sometimes 
 expand and assume great local importance, and again disappear and give place to a 
 nearly homogeneous mass of calcareous shales, 1,300 to 1,500 in thickness. 
 
 Among the strata forming the Creston are several beds of lignite, of which one, 
 six feet thick, visible for many miles along the river, is unusually compact and pure ; 
 in its general appearance precisely resembling some of the coal strata of the Carbon- 
 iferous series. 
 
 No fossils wore discovered in any of the rocks here exposed above the Inoccramus 
 limestone, but probably impressions of plants would be obtained from the shales over 
 the lignite beds, if time were given to search for them. 
 
 From the Creston to the mouth of Canon Largo the banks of the San Juan are 
 composed throughout of the strata which have just been enumerated, lying in unbroken 
 sheets, with a gentle easterly dip. In these strata the valleys of the San Juan, La 
 Plata, and Animas have been deeply cut, and are bounded by abrupt, frequently per- 
 pendicular walls, the edges of table-lands, many hundred feet in height. The bottom- 
 lands of these valleys, though narrow, are fertile; sustaining a vigorous growth of grass, 
 
TO JUNCTION OF GRAND AND GREEN RIVERS, 109 
 
 and along the margin of the streams groves of cottonwood, and thickets of willow and 
 buffalo-berry (Elcaijnus argenteus?}. 
 
 Though now entirely deserted, these valleys were once occupied by a dense pop- 
 ulation, as is shown by the extensive ruins with which they are thickly set. Those on 
 the Animus, twenty miles above its mouth, have already been noticed. 
 
 At the junction of this stream with the San Juan the remains of a large, but very 
 ancient, town are visible, the foundations of many buildings of considerable size still 
 remaining, and traces of an acequia through which water was brought from a point some 
 miles above on the Animas. 
 
 Near Camp 43 also are the ruins of several large structures, of which portions of 
 the walls of stone are still standing, twenty or more feet in height. Indeed, it may be 
 said that from the time we struck the San Juan we were never out of sight of ruins, 
 while we were following up its valley. 
 
 CANON LARGO. 
 
 At Camp 44 we left the valley of the San Juan and entered the mouth of Canon 
 Largo, which we followed up in an easterly direction until, at its head, near the western 
 base of the Nacimiento Mountain, we came out on to the surface of the great plateau 
 of the Upper San Juan, through which we had been so long passing, sunk far below 
 its surface in the excavated valleys which intersect it. Of these valleys Canon Largo 
 may be taken as a type. It differs in nothing from that of the San Juan or Animas, 
 except that, instead of a large perennial stream, a small, generally dry, arroyo traverses 
 its bottom, and its boiinding cliffs, composed of the upper strata of the table-lands, 
 exhibit geological features not met with in other portions of our route. 
 
 By the easterly dip of the rocks and the rapidity of the fall of the stream, we were 
 constantly ascending in the series from the Creston to the head of Canon Largo. At 
 the moiith of the Animas we had nearly sunk the whole of the Middle Cretaceous group, 
 its upper members (gray shales and marls) forming the base of the high cliffs, composed 
 mainly of the Upper Cretaceous sandstones, here very massive, and showing- a thick- 
 ness of 600 to 700 feet. At the mouth of Canon Largo we had risen still higher in the 
 series, the Middle Cretaceous shales having entirely disappeared; the lofty cliffs which 
 bound the valley at this point being formed entirely of the Upper Cretaceous rocks, 
 alternations of soft yellow sandstones and white, gray, or purple marls. The lowest 
 member of this series here is the same with that which forms the summit of the Creston 
 section, and more fully exposed at the mouth of the Animas, where it presents perpen- 
 dicular faces of 300 to 400 feet of massive, homogeneous, soft, yellow, calcareous sand- 
 stone. A few miles farther north, on the La Plata, this rock contains at its base Am- 
 inonitcs placenta, Baculites ovatus, &c., Avhich serve to mark very satisfactorily its place 
 in the geological scale, viz: Upper Cretaceous, No. IV or V, of Meek and Hayden's 
 Nebraska section. This is surmounted by some ten alternations of marls and sand- 
 stones in the cliffs bordering Canon Largo, the series being entirely conformable and 
 similar in lithological character throughout. At the head of Canon Largo, as we shall 
 see further on, these strata are succeeded by others, several hundred feet in thickness, 
 also conformable, but, lithologically, showing a preponderance of marls over the sand- 
 
110 EXPLORING EXPEDITION FKOM SANTA Ffi 
 
 stones. Whether all this great group belongs, like its base, to the Cretaceous system, 
 we have at present no means of determining ; the only fossils found being such as do 
 not suffice to solve the problem. These are, so far as observed, silicified trunks of large 
 coniferous trees, and abundant, though rather obscure, impressions of angiospermous 
 leaves of .species different from any found elsewhere in the Tertiary or Cretaceous 
 strata. 
 
 The character of the marls of this series is very well given in my notes upon the 
 lowest bed exposed at Camp 43, a few miles below the mouth of Canon Largo. These 
 notes are as follows: 
 
 "The hills which bound the valley opposite camp are about 250 feet high, com- 
 posed of greenish-gray and yellowish- white marls, generally very soft, but occasionally 
 containing lenticular masses of coarse sandstone and conglomerate. Dispersed through 
 the marls are many spherical concretions of ferruginous sandstone which decompose 
 on exposure; plates of selenite, in places covering the slopes, and masses of water- worn, 
 silicified, carbonized, calcified, or gypsumized wood. All the beds contain much 
 saline matter (mostly sulphates) which effloresces on the exposed surfaces. The pre- 
 vailing color of these marls is whitish, and in their general aspect the hills which 
 they form closely resemble the chalk-hills of Southern England." 
 
 At Camp 44, 1 made the following entry in my journal : 
 
 "To-day we reached the mouth of the Canon Largo, and the crossing of the San 
 Juan. The valley is here, as below, moderately fertile, bounded by rounded hills of 
 chalky strata, with terraces of gravel near the river ; all covered with good grass. The 
 soil of the bottom-lands is alkaline, often covered with salt-bush (Sarcobatus), but sus- 
 taining extensive groves of cotton wood and thickets of buffalo-berry ; the latter loaded 
 with fruit. In geology little change is noticeable; the dip of the rocks continues east- 
 erly, and we have the chalky marls mentioned in yesterday's notes, succeeded by a 
 stratum some 50 feet in thickness of yellowish, soft, oolitic, coarse-grained, calcareous 
 sandstone, so friable as to be scarcely transportable, but very massive, and standing 
 in perpendicular faces in the cliffs. In this stratum is a band of gray clay-shale, in 
 which I find abundant impressions of leaves, but have been unable to obtain any 
 specimens sufficiently perfect for determination. 
 
 "Above this sandstone is a bed of greenish- white and purple marl, weathering like 
 the marls of the Trias, and closely resembling them in all things. Above the marl is 
 another bed of sandstone similar to that below ; then another bed of marl, &c." 
 
 At Camp 45, my journal says: "Canon Largo is bounded by high and precipitous 
 walls on either side, composed of soft yellow sandstones, and white and variegated 
 marls. The cliffs are not absolutely perpendicular, but ascend in grades; the sand- 
 stone forming vertical faces, the marl, slopes." 
 
 "The alternations in this series present very little variety; the sandstones, some 
 ten in number, being very like each other ; the marls, of about equal force, showing 
 no marked differences. They often form rounded but furrowed hills, of which the 
 surfaces are whitened by a saline efflorescence or are covered with fragments of ferru- 
 ginous concretions and fossil wood. This silicified wood is very abundant and seems 
 to be all coniferous." 
 
TO JUNCTION OP GRAND AND GREEN RIVERS. Ill 
 
 " Since leaving the surface of the great sandstone-bed, the base of the Upper Cre- 
 taceous series, so fully exposed at the mouth of the Animas, we have passed up through 
 three 'strata of soft calcareous sandstone with an equal number of marl-beds; the 
 average thickness of the sandstone being about 50 feet, of the marl, 75." 
 
 At Camp 46 I ascended the cliff on the south side of the canon and found it to be 
 674 feet in height. The section of the strata composing it is as follows : 
 
 Feet. 
 
 1. Coarse soft yellow sandstone, partially conglomerate 55 
 
 2. Greenish- white marl, with silicified wood 50 
 
 3. Soft yellowish sandstone, partly conglomerate, with small quartz pebbles con- 
 
 taining obscure impressions of plants 120 
 
 4. Greenish argillo-silicious rock, breaking into irregular masses above, shaly 
 
 below, shading into purple marl 50 
 
 5. Soft, white, massive, calcareous sandstone, in places traversed by veins of gyp- 
 
 sum 20 
 
 6. Gray or greenish-white marl, with bands of hard bluish-gray limestone, con- 
 
 taining fucoids and silicified wood 80 
 
 7. Yellowish soft sandstone 50 
 
 8. Greenish-white and purple marl, with selenite, bands of concretionary limestone 
 
 and large trunks of silicified wood 80 
 
 9. Soft yellowish, coarse sandstone 60 
 
 10. Greenish and purple marls, with concretionary limestone 109 
 
 From the summit of this cliff I was able to overlook most of the country border- 
 ing Canon Largo, and could see that it was occupied by broad mesas extending east 
 to the Nacimiento Mountain, and north to the bases of the Sierra de la Plata, Sierra 
 San Juan, Navajo, &c., all of which were in full view. South and west higher por- 
 tions of the plateau limited my vision. 
 
 On this plain I noticed islands of higher strata than those on which I stood. 
 These are 300 or 400 feet in thickness, and of the same general character as the walls 
 of Cailon Largo. Adding these to the strata exposed in CafiOH Largo, and those noticed 
 in the San Juan above the mouth of the Animas, and we have an aggregate thickness 
 of about 1,500 feet for this upper series alone. 
 
 In my notes made at Camp 47, 'I find the following memoranda: "In the expos- 
 ures I have now examined of the Upper Cretaceous (?) strata, I have enumerated eleven 
 beds of sandstone, with an equal number of marl-beds. The aggregate force of these 
 two groiips is nearly the same, though each stratum is liable to great local variation ; 
 the section at one point being considerably different from that at others. The sand- 
 stones are quite variable in thickness, both as regards the same stratum at different 
 places, and comparing the different beds with each other. The summit of the cliffs 
 along Canon Largo is formed of a group of sandstones of unusual thickness, in places 
 full 200 feet, with only thin partings of marl. This stratum has protected the beds 
 below and produced the abruptness of the walls. It forms the floor of the adjacent 
 Sage-plain, from which the upper layers, being softer, have been removed by erosion." 
 
 At Camp 48 I write : " To-day left Canon Largo and came out on the plateau 
 
112 EXPLOKING EXPEDITION FIIOM SANTA FE 
 
 before mentioned. A sage-plain with rolling surface, fashioned by erosion, on which 
 rise the extreme Upper Cretaceous (?) strata in buttes and detached mesas." 
 One of these buttes at Camp 48 afforded me the following section : 
 
 Feet. 
 
 1. Soft yellow sandstone - 60 
 
 2. Greenish-white marl 70 
 
 3. Soft yellow sandstone with large concretions, weathering brown 50 
 
 4. Marl, greenish- white above, purple below 75 
 
 5. Soft white sandstone with hard concretions 20 
 
 6. Marls, greenish-white above, purple below, with concretions of silicious lime- 
 
 stone 50 
 
 7. Coarse, soft, whitish sandstone 30 
 
 8. Greenish-white and purple marls 90 
 
 This series should be added to that of the cliff at Camp 46. 
 
 Just before reaching the base of the Nacimiento Mountain, we crossed the divide 
 between the Pacific and Atlantic, and reached the highest point, geologically, attained 
 on any part of our route. The immediate base of the mountain is swept by a line of 
 drainage which flows south along its western side, around its southern extremity 
 passes into the Puerco, and thence into the Rio Grande. The line of divide diverges 
 from the north end of the Nacimiento Mountain, running southwesterly to San Mateo 
 and the Sierra Madre. For at least a hundred miles it stretches across the table-lands 
 unmarked by any disruption of the strata or line of upheaval. 
 
 The crest of the water-shed is here formed of series of biittes and mesas com- 
 posed of soft, marly strata : the extreme summit of the great group, which, on nega- 
 tive rather than positive evidence, I have designated as Upper Cretaceous. 
 
 BUTTES WEST OP THE NACIMIENTO MOUNTAIN (EOCENE TEETIAKY (?). 
 
 These buttes include about 400 feet of strata not included in the sections before 
 given. They are as follows : 
 
 Feet. 
 
 1. Soft yellow sandstone 40 
 
 2. Purple, yellow, and greenish soft marls 60 
 
 3. Soft yellow sandstone 35 
 
 4. Green, purple, yellow, and white marls, with thin layers of white sandstone. . 70 
 
 5. White sandstone - - 25 
 
 6. Green and purple marls 80 
 
 7. Coarse, white sandstone 20 
 
 8. White and purple marls 50 
 
 9. Soft yellow sandstone, summit of cliff in section at Camp 48. 
 
 These strata are all conformable among themselves and to those below ; lying 
 nearly or quite horizontal. The marls of this series are darker than those of the preceding 
 sections, having a purplish-green appearance at a distance. The sandstones are very 
 soft, and being thinner than the marls they form but a slight interruption to the uni- 
 formity of the slope of the sides of the buttes, and are scarcely noticeable, except 
 
CD 
 > 
 
 N 
 
 O 
 
 z 
 
 0> 
 O 
 
 o 
 
 3 
 or 
 
 M 
 
 3 
 
 S 
 
TO JUNCTION OF GRAND AND GREEN RIVERS. 113 
 
 when quite near. No fossils were found in any part of this section, and the abun- 
 dance of selenite and the profuse efflorescence of the sulphates of alumina, magnesia, 
 &c., seem to indicate the prevalence of conditions unfavorable to life during the depo- 
 sition of these strata, as well as in the similar non-fossilliferous marls of the Trias. 
 Combining the sections observed at various points between the mouth of the Animas 
 and the Nacimiento Mountain, we have, for the aggregate thickness of the conforma- 
 ble and generally similar strata resting upon the Middle Cretaceous shales, 2,000 feet, 
 made up as follows : 
 
 Feet. 
 
 1. Marls and sandstone forming buttes of divide 380 
 
 2. Marls and sandstone section at Camp 48 445 
 
 3. Marls and sandstone section at Camp 46 674 
 
 4. Marls and sandstone in valley of San Juan '500 
 
 Total... 1,990 
 
 It may be suspected, from the many alternations of similar strata in the preceding 
 sections, that there has been in some cases a repetition, but that is quite certainly not 
 the case. Although no fossils were found which might serve as criteria for the iden- 
 tification of strata, the geological exposures are so full that all the more important beds 
 may be traced without break or interruption, and the order of superposition accurately 
 determined by simple inspection of the interlocking of the different sections. In meas- 
 uring altitudes the barometer was constantly used, and the heights of inaccessible points 
 frequently obtained by triangulation. By these means, and the use of Locke's level 
 where necessary, all the generalities of the thickness of strata were determined with a 
 good degree of accuracy. 
 
 As regards the question of the precise geological age of this great group of sand- 
 stones and marls, as I have stated in the earlier part of this chapter, we have not, as 
 yet, the means of arriving at a perfectly satisfactory conclusion. The lower part of 
 the series is, we know, Cretaceous; as it contains characteristic fossils of No. IV of Meek 
 and Hayden's Nebraska section. The most natural inference, therefore, is, that a portion 
 at least of the overlying beds represent the upper part of No, IV and No. V of the 
 Nebraska section. Since there are no fossils in the upper beds, and since they are 
 apparently conformable to the lower, and generally similar to them in lithological 
 characters, we have evidence that they were deposited while the physical conditions 
 of this portion of the continent remained essentially the same. In one sense, therefore, 
 they do all belong to one great geological epoch, and, without evidence to the con- 
 trary, should be classed together. 
 
 This argument, however, has little force, for, as we have seen, all the sedimentary 
 strata of the Colorado plateau are conformable, and there is unusual similarity of 
 lithological character among those which we know, by their fossils, belong to different 
 formations. That none of these strata are Miocene may be safely affirmed, as previous 
 to that epoch great and radical changes were effected in the physical geography of our 
 continent, and the uniformity which had characterized the deposition of the sediments 
 forming the great central plateau was entirely broken up; the sea retreating from the 
 15 s F 
 
114 EXPLORING EXPEDITION FROM SANTA FK 
 
 central portion of the continent, throwing down its sediments only along the shores and 
 up the valley of the Mississippi; the inland Miocene-Tertiary having been deposited in 
 bodies of fresh water. It is possible, however, that some portion of this series is of 
 Eocene age, though of this we have as yet no proof. 
 
 It is true that, in Texas, the Eocene beds, distinctly marked by their fossils, are 
 lithologically similar to some of those under consideration, and they are there entirely 
 conformable to the Cretaceous strata, of which they seem but a continuation; the two 
 formations blending and not separable by any sharp lines of demarcation. 
 
 NACIMIENTO MOUNTAIN. 
 
 Though not a lofty or extensive moiintain range, this is perhaps the most instruct- 
 ive and interesting of all those which I had an opportunity of examining in the western 
 country. Its extreme altitude is about 1Q,000 feet; its length something like 50 miles. 
 Throughout this distance it forms a single simple ridge of nearly uniform height, with 
 no peaks nor depressions. At either end it gradually falls off, and is lost in the level 
 of the plateau country which nearly surrounds it. Although its physical features are 
 so unpretending, its geological structure is in the highest degree interesting and sug- 
 gestive; such indeed that it seems to me it not only furnishes a key to the mode of 
 formation of all the great ranges of the Rocky Mountain system to which it belongs, 
 but that, if properly studied, it would serve to explain nearly all the difficulties of 
 that now much-mooted subject, the origin of mountain chains. What its structure is 
 may be very briefly told. 
 
 The central core or axis of the Nacimiento Mountain is composed of massive red 
 granite, similar to that so common in the other ranges of the Rocky Mountain system. 
 This forms its summit and the greater part of its mass. l r pon the slope of the granite 
 axis rests the Carboniferous formation, for the most part limestone, in many places 
 nearly vertical, yet but slightly metamorphosed. Outside of the Carboniferous are the 
 white and red sandstones, marls, and gypsums of the Trias; many of these beds also 
 standing quite vertical, but wholly unchanged. Outside of the Trias the Lower Cre- 
 taceous rocks form another distinct circle; beyond these, the Middle Cretaceous shales ; 
 still beyond, the great group of Upper Cretaceous sandstones and marls, which I have 
 just described. 
 
 When we stood on the summit of the mountain all these different formations 
 were spread out before us as on a geological map, each distinguishable by its color or 
 texture, and as readily recognized as though traced on a diagram for a lecture-room. 
 
 The impression produced upon my mind by our first ascent of the Sierra do N;ici- 
 miento may be gathered from the following extracts from my notes: 
 
 "After arriving in camp (50) I went over with Mr. Fisher to the Nacimiento 
 Mountain, which we ascended. Our approach was tip a beautiful but narrow valley, 
 through which a clear, cold stream flows for some distance, then sinks and rises at 
 intervals, forming a series of fine springs. The vegetation of this valley is almost 
 identical with that of the valleys of our northern route; the elevation being nearly the 
 sniiie 7,500 feet. The timber is yellow pine, pifion, cedar, (two species,) bitter and 
 sweet cotton-wood, GambelPs oak, and the narrow-leaved willow.* On the summit of 
 
 /'. uliilin, fitiiijiurus Iclragona, J. cinjiniuna, 1'opulun amjunlifuUu, 1'. moidlifi r, < t >in-n-na l.lainlirtli, 
 tialix angustifolia. 
 
TO JUNCTION OF GllAND AND GREEN KIVER& 1 1 f> 
 
 the mountain, Douglas' spruce, yellow pine, the western balsam-fir, with thickets of 
 aspen, oak, maple, and red-flowered locust.* As we progressed we passed in succes- 
 sion over the upturned edges of all the sedimentary rocks seen on our route. 
 
 1. The Upper Cretaceous sandstones and marls, but slightly inclined, and not 
 reaching within two or three miles of the mountain. 
 
 2. The Middle Cretaceous shales, forming a broad belt of clay-soil, from which 
 project here and there ledges of the harder strata, filled with the fossils characteristic of 
 this formation Inoceramus proUematicus, Gryplum Pitcher/, Ostrca congesta, &c. 
 
 3. The Lower Cretaceous sandstones, from their hard and massive character, hav- 
 ing resisted erosion, are now. forming hills and cliffs of considerable height. 
 
 4. The Triassic formation; its soft red marls, forming bare surfaces of blood-red 
 color, its sandstones standing out in strong ^relief, forming walls and palisades, often 
 nearly vertical, sometimes 40 or 50 feet in height, and only 5 or 6 feet in thickness. 
 
 5. The Carboniferous series, mostly massive gray or whitish limestone, reaching 
 far up on the mountain sides, scarcely at all metamorphosed, arid filled with fossils. 
 
 6. A central core or axis of red granite forming the great mass of the range. 
 
 Our view from the summit was particularly fine. Immediately below us the dif- 
 ferent formations which I have enumerated were distinctly visible, running in parallel 
 bands along the mountain side. Some five miles north of our position the range falls 
 off and disappears in the plain, but the line of upheaval is distinctly marked by an 
 arching of the unbroken sedimentary rocks. The upper part of the arch is removed, 
 and the surface-rock is a pure white sandstone, probably Triassic, beneath which the 
 "red beds" appear, forming on the east side of the mountain a beautiful rose-red valley. 
 
 On the north we had a complete panorama of the mountains passed on our outward 
 route, a view sweeping from the Santa Fe" and Taos Mountains to the Sierra de la Plata. 
 
 Toward the west stretched a vast plain, deeply scored by many lines of erosion, of 
 which Canon Largo may be taken as a type. This plateau the San Juan division of 
 the Teat Colorado Plateau filled all the horizon, from the Sierra la Plata around to 
 
 CJ ' 
 
 San Mateo, the distant summits of the Carrizo and Chusca being just perceptible above 
 its surface. Tins great Cretaceous plain sweeps up with nearly horizontal strata to the 
 base of the Nacimiento ; the series being most complete, the strata still horizontal, six 
 miles west of the mountain. At this point all the formations begin to rise toward the 
 cast; their angles of elevation becoming greater as they approach the granitic axis, 
 where they are frequently quite vertical. The Nacimiento axis is here and farther 
 north the great divide between the waters of the Pacific and Atlantic, though, as before 
 stated, the drainage of most of its western slope passes around the south end into the 
 Puerco; the crest of the water-shed being formed by a line of high table-lands, which 
 passes southwesterly between the head-waters of the Chaco and the Puerco toward 
 Mount Taylor (San Mateo). The line of upheaval which forms the divide at Camp- 
 bell's Pass, is widely different from the Nacimiento axis, being indeed no other than 
 that of the Sierra Madre, which is entirely lost northward, as we saw no indication of 
 it on the San Juan. 
 
 After leaving Camp 50, we made several days' marches southward, skirting the 
 
 * Popiilus tivmuJo'ules, (Jticrcus Ganibelli, Acer. s\>. liobinia A r eo Mcxicana. 
 
lift KXPLORING EXPEDITION FROM SANTA FE 
 
 western base of the Nacimiento Mountain, until, reaching ;i practicable pass near its 
 southern extremity, we crossed over to the peublo of Jemez. The country traversed 
 in this part of our route we found to be much like the foot-hill region bordering the 
 northern mountains, very picturesque, well watered, covered with fine timber, the 
 valleys rich and productive, but from their great, elevation early touched with frost* 
 and doubtless very cold in midwinter. Here, as almost everywhere else on our route, 
 we found numerous ruins of stone-built structures, evidence of the presence in ancient 
 time of a large population, where now neither Indian nor white man dwells. 
 
 In geology our experience was for the most part but a repetition of that already 
 described, as we were passing in review all the strata before so fully examined in the 
 valley of the San Juan. 
 
 The exposures were here, however, exceedingly full and satisfactory, and 1 had 
 constantly recurring opportunities of testing the accuracy of the classification pre- 
 viously adopted. 
 
 That the evidence- furnished by our observations in this interesting region may be 
 consulted in the solution of any question that may be raised in regard to the geological 
 structure of this portion of New Mexico, I transcribe from my note-book some of the 
 records made from da}' to day as we progressed on our journey. 
 
 "September 21, Camp 50 to 51. To-day we followed south along the western base 
 of the Nacimiento Mountain, over a rolling surface, crossing many wooded hills and 
 pretty valleys formed by the erosion of the Cretaceous strata. This formation, as we 
 can see, occupies all the country southeast from us as far as Mount Taylor ; there, as 
 I learned on a former expedition, it is cut through by the valley of the San Jose", but 
 beyond that extends, we know not, how far, southward. At Camp 51 we have precisely 
 the same section as that described at Camp 50 ; all the formations, from the Carbon- 
 iferous to the Upper Cretaceous, lying in sheets, with edges upturned, along the base 
 of the mountain. There is, however, here a distinct valley worn out between the 
 Cretaceous table-land and the mountain. Near our camp are buttes and mesas several 
 hundred feet in height, composed of the yellow sandstones of Canon Largo, of which 
 the summits are thickly strewn with bowlders of red granite and limestone, evidently 
 washed down from the neighboring mountain before -the intervening valley had been 
 cut out by the stream which now flows through it. The amount of erosion indicated 
 by the presence of this local drift where it is now found is enormous. I previously 
 noticed the same phenomena in many localities among the foot-hills of the northern 
 mountains. We find here everywhere in the sandstones great numbers of silicified 
 trees, many of them of very large size, apparently all coniferous. Fragments of these 
 trunks are strewed so abundantly over the surface that they have been used very 
 generally as building-stones in the construction of the ancient pueblos. 
 
 "In seams and pockets of fine clay in the sandstones I find abundant impressions 
 of angiospermous leaves, apparently of those of sycamore, alder, oak, &c., but the 
 material inclosing them is so friable that they cannot be taken out entire, nor can the 
 fragments be transported for determination. Among these impressions are some conif- 
 erous leaves and stems of a conifer or cycad, very much like the Ulodoulrnn of the Coal- 
 Measures ; a scaly trunk with elliptical disks three inches in diameter. I also obtained 
 fragments of fern leaves, but too imperfect for determination. 
 
tO JUNCTION OP GRAND AND GREEN RIVERS. 117 
 
 "September 22. To-day we ascended the mountain in search of a pass, and found 
 the base and flanks covered by the upturned sedimentary series, just as at Camp 50; 
 the Trias here, as at Laguna, 50 miles south, containing immense masses of snowy 
 gypsum, a thing rarely seen on the San Juan or Grand River." 
 
 In the coarse yellow sandstones and conglomerates overlying the red beds of the 
 Trias I find large quantities of the sulphide of copper, replacing trunks and branches 
 of trees, just as at the "Cobre," near Abiquiu. 
 
 The summit of the mountain where we ascended is over 9,000 feet above the sea; 
 it is covered with forests of yellow and sugar pine, Douglass spruce, and the western 
 balsam-fir,* interspersed with areas occupied by oak, maple, and aspen bushes, with 
 here 'and there poison-oak f and red-flowered locust. 
 
 ''September 23, Camp 51-52. Failing to find a pass across the mountain, we to- 
 day resumed our course southward, camping as before on a tributary of the Puerco. 
 The country is generally similar to that seen yesterday, but, as we descend, the forests 
 of yellow pine are gradually succeeded by scattered clumps of pifion, and red and 
 white cedar on the hills, the valleys grassy as before. We have also descended some- 
 what in the geological scale, our present camp being surrounded by mesas of the 
 great sandstone of the Animas the base of the Upper Cretaceous group with an 
 exposure of several hundred feet of the underlying strata given in the section of the 
 Creston, viz, gray shales, with bands of concretionary iron-ore, strata of yellow or 
 brown sandstone and beds of lignite, all Middle Cretaceous; in the shale beds is much 
 crystallized gypsum. 
 
 "September 24, Camp 52 to 53. To-day our course has been southeasterly, ap- 
 proaching the southern end of the Nacimiento, through a region much like that of 
 yesterday, except that, as we have now penetrated deeply into the Middle Cretaceous 
 shales, the surface is less broken, the hills being rounded, with long, gentle slopes; the 
 timber has become more sparse, the country less picturesque and inviting. We have 
 here a fine view of all the interval between the Nacimiento and San Mateo. This was 
 apparently once occupied by an unbroken sheet of Cretaceous rocks, now for the most 
 part removed through the agency of the tributaries of the Puerco. In the west and 
 northwest, high mesas fill the horizon, forming the line of divide to which I have be- 
 fore referred. Around the base of Mount Taylor, extending many miles in every di- 
 rection, is a plateau of trap, which has apparently flowed from this great extinct vol- 
 cano, covering all the sedimentary rocks in its vicinity. In the open valley of the 
 Puerco stand many picturesque trap buttes, having a general resemblance to the 
 Needles of the San Juan. Of these the most conspicuous, called by the Mexicans the 
 Cabazon, resembles in its outline a Spanish sombrero, but is of gigantic dimensions, 
 being at least 1,500 feet in height. 
 
 "South from the Cabazon is a high level mesa, composed of Cretaceous rock, 
 which forms the divide between the Puerco and the San Jose. This I have seen 
 from the other side on a former expedition. ,_ 
 
 "September 25, Camp 53-54. To-day we crossed over the south end of the Naci- 
 miento Mountain to the pueblo of Jemez. The first part of our route was over the 
 
 " I'itms ponderos, P. Lambertiana, Abies Douglasi, and Abies graiulix. 
 \Rhiis diversiloba and Ilobinia Xco Mexictina. 
 
118 EXPLORING EXPEDITION FROM SANTA FE, ETC. 
 
 upturned edges of the Cretaceous and Triassic rocks; the angle of inclination beeom- 
 ing greater as \ve approached the mountain. ( hir march afforded us many wild and 
 picturesque views, made so both by the ragged outlines of the hills and the bright 
 colors of the materials composing them ; some consisting of blood-red sandstone; 
 others of snow-white gypsum; others still of the two intermingled. 
 
 "After winding through a labyrinth of such hills, we reached the Carboniferous 
 strata, resting directly on the granite. The rocks of this formation are here more cal- 
 careous than at Santa Fe, and abound in fossils, among which I saw most of those 
 enumerated in the Santa Ft$ section, and, in addition to these, collected a coral and a 
 crinoid, which are apparently new. On descending the eastern slope of the mountain, 
 we found the sedimentary rocks succeeding each other precisely as before. Near the 
 pueblo of Jemez, however, the Cretaceoiis strata have been entirely removed, but 
 they are visible a few miles farther north. As on the western side, copper occurs 
 here near the junction of the Trias with the Cretaceous. In the valley of Jemex 
 River are a number of buttes of white tnfaceous rock, representing a geological 
 element of which we had seen no traces in all our explorations of the San Juan coun- 
 try. These buttes are undoubtedly Tertiary, and, as I have stated in my notes on 
 the geology of the vicinity of Abiquiu, doubtless belong to the great series of fresh- 
 water deposits of Miocene and Pliocene age which skirt the eastern bases of the 
 Rocky Mountains. Here, as elsewhere, they are of local origin and limited extent ; 
 having been deposited in and partially filling an old eroded valley running north 
 and south along the eastern base of Nacimiento Mountain. By the action of Jemex 
 River this valley has again been washed out, leaving only here and there a mass of 
 Tertiary rock standing isolated or adhering unconformably to the sides of the trough 
 composed of the older strata. 
 
 "September 26, Jemez to Santo Domingo. In tin's part of our route we were almost 
 constantly upon the trap mesas which skirt the southern end of the Valles, and 
 extend on the east side of the Rio Grande to the Cerillos. This great overflow of 
 trap, though deeply eroded by the Rio Grande, is geologically quite modern, present- 
 ing the same appearance, in all respects, as the trap plateaus which surround the 
 San Francisco Mountain, Mount Taylor, the Raton, &c.; all of which I have before 
 described." 
 
 The Valles. No one has yet penetrated the Valles to study their geological 
 structure, but there can be little doubt of its general character. This mountain group 
 is composed of a number of parallel ranges, of but limited extent, having the general 
 trend of all the chains of the Rocky Mountain system of this vicinity, separated by 
 several well-marked, picturesque, and fertile valleys, from which, rather paradoxically, 
 the mountains take their name. While we know that the sedimentary rocks are 
 visible in many places in the Yalles, and that the principal axes are granitic, still the 
 presence of immense sheets and masses of trap give an aspect to the scenery and a 
 character to the geology somewhat different from those of most of the mountain regions 
 visited on the present expedition. On the eastern side of the Valles, to and beyond 
 the Rio Grande, nothing but trap is visible; and we here re-entered the region 
 so fully described in a preceding chapter. 
 
EXPLORING EXPEDITION FROM SANTA Ffi TO JUNCTION OF GRAND AND GREEN RIVERS. 
 
 DESCRIPTIONS 
 
 CRETACEOUS FOSSILS 
 
 COLLECTED ON THE 
 
 SAN JUAN EXPLORING EXPEDITION UNDER CAPT. J. N. MACOMB, U. S. ENGINEERS. 
 
 F. B. MEEK. 
 
A REPORT ON THE CRETACEOUS FOSSILS CONTAINED IN THE 
 COLLECTIONS BROUGHT FROM NEW MEXICO BY THE EXPLOR- 
 ING EXPEDITION UNDER THE COMMAND OF CAPT. J. N. MA- 
 COMB, OF THE UNITED STATES TOPOGRAPHICAL ENGINEERS. 
 
 HY V. I?. MKKK.* 
 
 The following pages and the accompanying plates contain descriptions and illus- 
 trations of eleven new species of Cretaceous fossils. Figures and descriptions have 
 also been added of a few previously known forms, of special interest as guides in iden- 
 tifying the several formations, and in determining their relations to established horizons 
 in the same system elsewhere. 
 
 By reference to the able report of Dr. Newberry, the geologist of the expedi- 
 tion, it will be seen that he divides the Cretaceous rocks of New Mexico into three 
 groups, as follows: 
 
 1. THE UPPER DIVISION, consisting of gray, white, and purple marls, alternating 
 with soft, yellow, calcareous sandstone, altogether 1,500 feet in thickness. In this 
 group, a portion of which he thinks may possibly prove to be of Tertiary age, he 
 observed numerous silicitied trunks of trees, together with leaves of Alnus, Platanus, 
 &.c. At the base of the whole, he found a thin bed containing Placenticer as placenta,^ 
 Utirit/itrx iD/cfjts, rar., Aiiclntra, Inocerantus, &c. 
 
 2. THE MIDDLE DIVISION is composed of dove-colored and ferruginous limestones, 
 shales, &c., altogether from 1,2 00 to 1,500 feet in thickness, and containing Prionocyclus, 
 Mtiroiitlii, Sccijtli/tcs larnrformis, Inoccramus problematic us, Ostrca congcsta, &c. 
 
 3. THE LOWER DIVISION, consisting of yellow or brown sandstone and green shales, 
 250 to 400 feet in thickness, containing Ammonites, Exogyra, Plicatula, and leaves of 
 Salix, PlatamiSj Qucrcns, (fee- 
 After a careful examination of the specimens from these rocks, I fully concur with 
 
 Dr. Newberry in the opinion that all of those of the Lower Division, with possibly 
 
 * This report was prepared in 1860, and has remained unpublished until this time (November, 1875). I have at 
 tliis latter date given it as careful a revision as numerous other engagements would permit ; and, in doing this, several 
 changes of nomenclature were found to be necessary, in order to bring the whole up to the present more advanced state 
 of palwontological science. Such changes as refer to other publications issued at any date after that first above incn- 
 t iom-d, were of course made in the revision of the MS. at the latter date. F. 15. M. 
 
 tThe name I'lacenticrras was first proposed by me in the Proceedings of the Philosophical Society of Philadelphia, 
 1.-VH ; and again used in Haydon's Second Annual Report of the United States Geological Survey of the Territories, 297, 
 1872 ; also in Upper Missouri rain-ontology, now in the press (November, 1875). Ammonihs placenta, Dekay, is the type 
 of the gronp. 
 
 10 S F 
 
122 EXPLORING EXPEDITION FROM SANTA Ffi 
 
 the exception of n portion of its upper beds, represent the Dakota group (No. 1) of 
 Upper Missouri Cretaceous series ; also that his Middle Division occupies the same 
 horizon as the Fort Benton and Niobrara groups (Nos. 2 and 3) of the Upper Mis- 
 souri section; while the lower bed at least, of his Upper Division, represents appar- 
 ently a blending of the Fort Pierre group and Fox Hills beds, N'os. 4 and 5 of the same. 
 The relations between the two sections will be more clearly understood by placing 1 
 the names of the several groups of each side l>y side ; thus: 
 
 NEW MEXICAN CRETACEOUS SECTION. UPPER MISSOURI CRETACEOUS SECTION. 
 
 7 T -r- /i ^ Fox Hills Beds, No. f>. 
 
 Upper Division (lowest bed at least) < -,, , ,,. , , XT . 
 
 I Fort Pierre Group, No. 4. 
 
 -.-. T 11 lv . . ( Niobrara Division, No. 3. 
 
 Middle Division < v , 7 T . XT 
 
 ( rort Union Group, No. 2. 
 
 Lower Division Dakota Group, No. 1. 
 
 The vegetable remains from the Lower Division of the New Mexican section (as 
 well as those from the others) have been investigated by Dr. Newberry, in whose 
 report the reader Avill find them fully described and illustrated. The molluscan 
 remains from the Lower Division are, Exogyra colmiilcJhi, M.; J'/icatida arcnaria, M., 
 Pinna (fragments), Gervilliat (fragments), (lri/]>li'a (undetermined fragments), and 
 Prionotropis Woolgari* ( Ammonites percarinatiifi, II. & M.). 
 
 The following is a list of the species described and identified from the Middle 
 Division, each of those followed by the letter M. being new, and described by the 
 writer from these collections, viz: Ostira congesta, Conrad, 0. lugubris, Conrad, 0. tu/i- 
 formis, M., GrypJuea Pitcher i, Morton, Exogyra arictiua, Roemer, E. lamusculit, Roemer, 
 E. columlclla, M., Anomia nitida, M., Caprothui h'n-oni'is, M., Inoceramus fragUis, Hall & 
 Meek, I.prolli'mat/ci<s,$c}i\othe'un (sp.),7. lutit*, Mantel!?, CraxsateUaShiotuirdi,^!.., Ci/pri- 
 meraf crassa, M., Turritella Leonensis, Roemer, Pridi/nci/cltix? Mac<til>'i,-\ M., .Prioi/n/nt/t/.^ 
 Woolgari, and Scapliites larwrformis, M. & II. 
 
 Of these eighteen species, the following are common to the rocks of this horizon 
 in New Mexico, Kansas and Nebraska, viz., Ox/rca coi/f/i'xta, Inoccramus )>roUcmuti- 
 cus, I. fragiUs, I. latus f, Scaphites larv&formis, and Prionotropis Woolgari. None of 
 them, however, are known to occur in New Jersey, or at other localities east of the 
 Mississippi, in the United States; though Inoccrtinin* problematicue, I. Idtttx, and .Priotio- 
 tropis Woolgari occur in Europe. 
 
 From the lowest bed of the Upper Division, the collection contains specimens of 
 Avicula Nebrascana, Evans & Shumard, Callista Dcivcyi, Meek & Hayden, Cur/Hntit 
 belhtlum, M., Ancliura ? Neivbcrryi, M., Baculitt'* di/<ri>x, Lamarck ?, and Placcnticcras 
 placenta, Dekay (sp.). 
 
 Avicula Nebrascana, Callista Deivcyi, Ihicnlile* <ut<-e/>* ?, and J'l(U-t'>iti<rnix ]>lccnfa 
 are common to this lowest bed of the Upper Division in New Mexico and the corre- 
 sponding horizon on the Upper Missouri; and I'/itm/tim-a* plnci'iilu also occurs in the 
 same position in New Jersey and Alabama, while Baculitcs <tmr/< also occurs in New 
 
 * The name 1'rioiioii'ofiix ].roji<>s<'<l by IMC in the Paleontology of the Uppi-r Alissouri, now (NovcinlxT, !>?.",) in thr 
 press; the American form there referred to JYionofropi* Woolgari, Mantel], being the type. 
 
 tThis generic name was proposed by mo in Ilayden's Report of the Geological Survey of the Territories in 1872- 
 296 (foot-note), and the genus is more fully described in the Paheoutology of the Upper Missouri, now in the press. 
 
TO JUNCTION OF GRAND AND GREEN RIVERS. 123 
 
 Jersey and in the Upper Chalk of Europe ; as well as on the North Platte, in the Fox 
 Hills Group of the Upper Missouri Cretaceous section. 
 
 Although it has been found convenient, throughout considerable areas on the 
 Upper Missouri, to subdivide the equivalents of the Middle and Upper Divisions of the 
 New Mexican section each into two groups, this is not everywhere the case, and Dr. 
 Newberry did not find any well-marked physical breaks in either of these divisions in 
 New Mexico. 
 
 It is worthy of note that, as on the Upper Missouri, the strongest paleeontological 
 break is just where Dr. Newberry draws the line between his Middle and Upper 
 Divisions. Up to this time, not a single species is known to cross this line, either on 
 the Upper Missouri, in Kansas, Nebraska, Texas, or in New Mexico. 
 
 A careful study of extensive collections of these fossils, brought by Dr. Ilayden 
 from these rocks on the Upper Missouri, has satisfied me that the beds above this 
 horizon represent the Upper or White Chalk of Europe ( "Etage Senonien," 
 d'Orbigny); while those below (from which we have yet obtained fossils) represent 
 the Lower or Gray Chalk, and probably the Upper Greensand of Europe (= the 
 Turonien and Cenomanien, d'Orbigny).* The evidence, so far as it goes, to be 
 derived from the New Mexican collections under consideration, warrants the same con- 
 clusion in regard to the rocks from which they were obtained. 
 
 LAMELLIBRANCHIATA. 
 Genus OSTREA, Linn. 
 OSTREA LUGUBRIS, Conrad. 
 
 Plato I, figs. 1 a, b, c, d. 
 (Mrt'ti liiijubiiK, Conrad (1^57), U. S. anil Hex. Bound. Report, vol. 1, p. 15(i, phito 10, tig. 5 a, b. 
 
 Shell small, thin, oval, or subcircular. Lower valve attached by most of its under 
 surface; while its lateral and ventral margins rise abruptly, usually for a short distance, 
 above the base of attachment, becoming at the same time ornamented by small regular 
 plications, which are sometimes rendered slightly rugose by marks of growth; beak 
 small, obtusely angular, usually turned a little to the left, and attached by its whole 
 under side; area short, triangular; muscular scar transversely ovate-reniform, and 
 placed near the left or anterior side. Upper valve flat, or sometimes a little convex 
 near the umbo, and slightly concave in the middle; marked by small regular plications, 
 which rarely extend to the umbo, and are often confined to the free margins. 
 
 Length of a large specimen, 0.95 inch; breadth of same, 0.65 inch; depth vary- 
 ing from 0.12 to 0.28 inch. 
 
 This seems to be a common and characteristic species in the lower portions of the 
 M iddle Cretaceous of New Mexico. The specimens usually have a proportionally larger 
 scar of attachment than that figured by Mr. Conrad. Where they are attached by the 
 whole under side of the lower valve, the plicated margins rise little above the base of 
 attachment; but where the scar of adhesion is small, the free plicated margins are more 
 produced; though it seems never to be a very deep shell. It was not gregarious to the 
 
 * Proceedings of the Academy of Natural Sciences of Philadelphia, January, l.-'IU. 
 
124 KXPLOKING EXPEDITION FROM SANTA FE 
 
 same extent as 0. congest of Conrad; the specimens being usually found scattered 
 about on the surfaces of calcareous and sandy slabs, to which, in most instances, they 
 were evidently attached during the life of the animal. 
 
 Locality and position. Banks of the Canadian, Vado del Chama, Galisteo, Pngosa, 
 Middle Cretaceous of Dr. Newberry's section. 
 
 OSTREA (GRYPHJSA!) UNIFOBMIS, Meek. 
 
 Plato I, figs. 2 a, b, c. 
 
 Shell small, rather thin, trigonal-ovate or subcircnlar inform, not oblique; under 
 valve rather deep, subcarinate along the middle, and arched beneath from the beak to 
 the opposite margin; beak curved upward, but truncated by the area so as to rise little 
 above the margins; area small; margins on each side of the area sometimes faintly 
 marked by fine crenulations along the groove for the reception of the edge of the upper 
 valve; surface marked by about three or four rather regular plications on each side of 
 the larger mesial fold or carina; lines of growth obscure; muscular scar transversely 
 oval, moderately distinct; upper value unknown. 
 
 Length from the beak to the opposite extremity, 1.16 inches; antero-posterior 
 diameter, about 1 inch; convexity or depth of the under valve, 0.65 inch. 
 
 This is a very peculiar shell, and cannot be confounded with any other species 
 with which I am acquainted. Its large, prominent, mesial fold, extending from near the 
 beak of the under valve to the opposite extremity, with three or four smaller plica- 
 tions on each side, give it much the appearance of some of the plicated Brachiapoda 
 when viewed on the under side. The folds, or plications, vary somewhat on different 
 specimens; but usually they are remarkably uniform for a species of this genus, and 
 impart to the free margin opposite the beak a zigzag character, very similar to the front 
 of some species of Spirifcr. No specimens of the upper valve were obtained; but it 
 will probably be found to have a large mesial sinus corresponding to the elevation of 
 the other valve, and must possess a projection, curving down at the middle of the free 
 margin opposite the beaks, to fill the deep notch in the margin of the other valve. 
 
 Thinking this species might be identical with one or the other of two peculiar 
 oysters described by Dr. Shumard, from the Ci'etaceous rocks of Texas, under the names 
 0. Icllaplicata and 0. quadriplicata, I sent him sketches of our shell, and he wrote that 
 it is most nearly like his 0. bellaplicata, though, he thinks, clearly distinct. The 0. l)d- 
 laplicata attains a much larger size, some of the specimens being as much as three inches 
 in diameter, while its hinge-line is proportionally much longer, and its surface distinctly 
 ornamented with concentric markings. 
 
 Locality and position. Pagosa; Middle Cretaceous of the New Mexican section. 
 
 Genus EXOGYRA, Say. 
 
 EXOGYRA COLUMBELLA, Meek. 
 Plato I, figs. 3 a, i, c, cl. 
 
 Shell small, rather thin, ovate; posterior side forming a semi-oval curve from the 
 umbo to the ventral edge; anterior side rounded below the beak; ventral margin 
 
TO JUNCTION OF GliAND AND GKEEN 1UVERS. 125 
 
 rounded. Lower valve convex, tlie most gibbous part sometimes forming an obtuse 
 unibonal prominence, which is not separated from the front by a sulcus; beak slender, 
 pointed, and distinctly coiled to the left; surface ornamented by small, but distinct, 
 rather regular, radiating eost;y, which bifurcate along the umbonal ridge; marks of 
 growth rather obscure. Upper valve flat, oval, apparently smooth or only having ob- 
 scure lines of growth. 
 
 Length from the most prominent part of the umbo to the ventral margin, 1 inch; 
 transverse breadth, 0.72 inch; depth or convexity, about 0.42 inch. 
 
 Itis possible that this shell may be identical withjE. ^mzfscwfa of Roomer (Kreid. von 
 Texas, plate ix, fig. 3 a, &, e); but with the means of comparison now within my reach, 
 I can but regard it as distinct. All the specimens of it that I have yet seen are more 
 oval in form and have a less distinctly spiral beak than the form described by Roemer. 
 They also differ in having the under valve always marked by regular radiating costas, 
 while that of E. Icviuscula is generally quite smooth, or rarely presents traces of nearly 
 obsolete, rather broad, plications, as represented by fig. 3 c of Roomer's plate ix 
 (Kreid. von Texas). It seems likewise to be a thinner and less robust shell than 
 Roomer's species, and holds a lower stratigraphies! position. In surface-markings as 
 well as in general form, it closely resembles young specimens of E. colunila of Lamarck 
 (. \niin. sans Vert., vi, 108) as figured by Goldfuss in his Petrefact. Germ, and by 
 d'Orbigny in the Paleont. Francais. It never attains more than one-eighth the size of 
 adult individuals of that species, however, and differs in having an oval instead of a 
 circular upper valve. 
 
 Locality and position. Covero, Lower Cretaceous; also at Sierra Abajo,from the 
 base of Middle Cretaceous, and at Galisteo, from the same member of Dr. Newberry's 
 section. 
 
 Genus ANOMIA, Linn. 
 
 ANOMIA NITIDA, Meek. 
 
 I'latol, figs..4a,ft. 
 
 Upper valve subcircular or a little oval transversely, very thin and brilliantly 
 pearly, depressed-convex, the most prominent part being near the middle; lateral mar- 
 gins nearly equally rounded, ventral border forming a semi-oval curve; cardinal mar- 
 gin arched, or apparently presenting a similar outline to the ventral side ; beak small, 
 much compressed, nearly or quite marginal, and located at the middle of the dorsal 
 side; surface marked by fine, rather regular, obscure, concentric striae. (Under valve 
 unknown.) 
 
 Transverse diameter, 1.07 inches; diameter from the cardinal to the ventral mar- 
 gin, 0.89 inch. 
 
 It is possible that some of the species referred to the genus Anomia from the Cre- 
 taceous and older rocks would be found to present fundamental differences from the 
 typical forms of this group if we could see the under valve and the hinge and muscu- 
 lar impressions. Some six or seven species are now known from the Cretaceous rocks 
 of this country, of nearly all of which, I believe, only upper valves have been found. 
 
 Locality and position. Pope's Well ; top of Middle Cretaceous. 
 
126 EXPLORING EXPEDITION FROM SANTA FE 
 
 Genus CAPROTINA, d'Orbigny. 
 CAPROTINA (REQUIENIA?) BIOORNIS, Meek. 
 
 Plate I, figs. 7 a, T>. 
 
 Shell apparently nearly equi valve; valves produced in the form of two 
 oblique spiral horns; beaks greatly elevated, distinctly spiral, and directed obliquely 
 forward and outward, the turns of each being widely disconnected; aperture of 
 the valves comparatively small, ovate-subtrigonal in form, being a little higher than 
 wide, and nearly straight on the basal and anterior sides, which range at right angles 
 to each other; umbonal ridges rather prominent, spiral, and curving doAvn to the antc- 
 rio-basal margin. In front of these ridges, the valves are flat, and behind them convex. 
 Surface ornamented by moderately distinct marks of growth. 
 
 Height, 2.43 inches ; antcro-posterior diameter, 1.74 inches; transverse diameter 
 between the extremities of the beaks, nearly 2.75 inches ; height of aperture of the valves, 
 1.38 inches; antero-posterior diameter of same, 1.22 inches. 
 
 The only specimen of this curious fossil I have seen is imperfect, the beak of its 
 right valve being partly broken away. As near as can be determined, its valves seem 
 to have been neai'ly equal, which, together with the greatly-produced and spiral char- 
 acter of its beaks, give it much the appearance of a Diccras. Still, as it shows no 
 traces of an external ligament, while its shell-structure and surface-marking are like 
 those of Caprotina, I do not feel warranted in placing it in the genus Diceras, though its 
 generic relations must remain doubtful until specimens showing the hinge and interior 
 can be seen. 
 
 The substance of the shell is of moderate thickness, and composed of two layers, 
 which readily separate. The inner layer seems to be compact, and presents a distinctly- 
 striated surface, the striae being parallel to each other and ranging at right angles to 
 the marks of growth. The outer layer appears to be more laminated, and breaks 
 readily at right angles to the surface. Where portions of the shell have been removed, 
 a distinct groove is seen extending from the posterior side of each valve spirally toward 
 the beak. These grooves appear to have been left by a ridge or lamina on the inner 
 side of each valve, and curve around the beak so as to be visible in an anterior view, 
 as represented at a, fig. 7 ft, plate 1. 
 
 In form and general appearance, this shell is evidently rather closely allied to AV- 
 quienia Archiaciana, d'Orbigny (Pal. Fran^ais, Terr. Oct., iv, 363, plate 51)7). The 
 grooves left upon the cast of its interior by the spiral ridge, or lamina, extending 
 from the posterior side of each valve, are also exactly as in that species. It differs, how- 
 ever, in having much less prominent and angular umbonal ridges, while its valves seem 
 to be more nearly equal, and its beaks are more produced and more widely separated. 
 
 Locality and position. Fort Lancaster, Texas; from the middle portion of Dr. 
 
 Newberry's section. 
 
 Genus PLICATULA, Lam. 
 
 PLICATULA ARENARIA, Meek. 
 
 Plate I, figs. 5 a, 1>, c. 
 
 Shell small, broad-ovate, usually a little oblique ; ventral margin rounded ; sides 
 converging to the beaks at an angle of about 70 to 80 ; beaks more or less 
 
TO JUNCTION OF GRAND AND GKEEN RIVERS. 127 
 
 angular. Under valve moderately convex. Upper valve nearly or quite flat. Sur- 
 face of each valve ornamented by eighteen to twenty small, rather sharply-elevated, 
 plications, only about half of Avhich extend to the beaks, while the intermediate ones 
 usually extend from one-third to one-half way from the free margins ; concentric 
 markings rather obscure. 
 
 Length from beak to the most prominent part of ventral margin, 0.50 inch; trans- 
 verse diameter, 0.43 inch; convexity, 0.11 inch. 
 
 Resembles in size and form P. incongrua, Conrad (United States and Mexican 
 Boundary Report, vol. 1, plate 6, fig. 10, 1857), but differs in not having squamose 
 concentric markings as well as in having shorter plications intercalated between those 
 that extend to the umbo. The substance of the shell must be thin, since the plications 
 are rather distinctly marked on internal casts. 
 
 I, nr<il it u inn! jHiNitiou. Covero ; Lower Cretaceous of Dr. Newberry's section. 
 
 Genus INOCERAMUS, Sowerby. 
 INOCEBAMUS FRAGiLis, ITjill and Meek. 
 
 Plato I, fig. 6. 
 Inooeramus fragilia, Hall anil Meek, Mom. American Acacl. Arts and Sci., vol. 5. now series, plate 2, fig. 6. 
 
 The specimens of this species in the collection are larger than that first figured 
 and described by Professor Hall and the writer, which is evidently a young shell. 
 They agree, however, so nearly in all other respects as to leave no doubts in regard to 
 their identity. In comparing the figure here given with that first published in the 
 Memoirs of the American Academy, it should be borne in mind that the anterior side 
 of the latter was mistaken for the cardinal margin, both in the description and in the 
 arrangement of the figure on the plate. The figure given on the accompanying plate 
 is correctly arranged, with the hinge-margin npward. 
 
 This species has a wide geographical distribution in the far west, having been col- 
 lected at several distantly-separated localities between Fort Benton on the Upper 
 Missouri and New Mexico in the far southwest. I have np knowledge of its occur- 
 rence anywhere east of the Mississippi. 
 
 Locality and position. Vado del Chamo ; base of the Middle Cretaceous of Dr. 
 Newberry's section. 
 
 Genus CRASSATP;LLA, Lam. 
 
 CRASSATELLA SHUMARDI, Meek. 
 
 Plato II, figs. 7 a, I, c. 
 
 Shell under medium size, very thick, oval-subtrigonal, moderately convex; extrem- 
 ities narrowly rounded ; base forming a semi-oval curve; dorsal outline sloping from 
 the beaks at an angle of about 100; beaks moderately prominent, rather obtuse, 
 located slightly in advance of the middle ; surface marked by fine lines of growth, 
 and small, regular, concentric ridges; escutcheon lanceolate ; lunule lance-oval, rather 
 deej) ; muscular scars strongly impressed. 
 
 Length, 0.78 inch; height, 0.72 inch; convexity, 0.40 inch. 
 
128 EXPLORING EXPEDITION FEOM SANTA Fft 
 
 I have not seen very satisfactorily the hinge of this shell ; but, as near as can be 
 determined from impressions left in the matrix, it appears to present the characters of 
 the genus Crassntella. It is chiefly remarkable for thickness of the valves in proportion 
 to the size of the shell. 
 
 Local/ft/ and position. Pope's Well ; top of Middle Cretaceous of New Mexican 
 section. 
 
 Genus CYPRIMERIA, Conrad. 
 
 CYPRIMERIA? CRASSA, Meek. 
 
 I'late I, figs. 8 a, I, c, tl. 
 
 -+ 
 
 Shell lenticular, rather thick, moderately convex; beaks distinctly compressed, and 
 projecting very slightly beyond the regular curve of the cardinal margin; anterior mus- 
 cular impression narrow-subovate and acute above ; posterior broader, and rhombic- 
 subquadrate ; pallial line distinct, with a very faint sinuosity, or mere truncation, 
 immediately under the posterior muscular impression; surface merely marked by con 
 centric strise. 
 
 Height, 1.93 inches; length, or antero-posterior diameter, 2 inches. 
 
 I am not altogether sure that this species will be found to agree exact/// in its 
 generic characters with Mr. Conrad's genus Cyprimeria, as its hinge-teeth do not seem 
 to agree in some slight details with that of the type of that genus. Indeed, on first 
 preparing a description of it for this report, I had proposed a provisional subgeneric 
 name for it; but, on revising the MS., and comparing the figure, I find it resembles 
 Cyprimeria at least so nearly that I have concluded to refer it to that genus. This has, 
 however, been done partly because I am unwilling to propose a new name without 
 having the type-specimen at hand for further study, it being in New York, and the cir- 
 cumstances being such that I have to revise the MS. in great haste.* 
 
 The hinge of this shell may be described as follows: hinge-plate broad and 
 flat; anterior teeth compressed, the two in the right valve close together, and re- 
 ceiving that of the left between them, ranging very obliquely forward and downward; 
 posterior tooth of righfr valve thicker, ranging obliquely backward and downward, 
 grooved along. the middle, and fitting between the posterior teeth of the left valve. 
 
 Locality and position. Pope's Well; top of the Middle Division of the New Mexican 
 Cretaceous section. 
 
 Genus CARDIUM, Linn. 
 
 CARDIUM BELLULUM, Mock. 
 
 Plate II, figs. C a, 1>. 
 
 Shell small, thin, ovate, a little oblique, gibbous, the most convex part of the 
 valves being somewhat above the middle; beaks elevated, rather slender, incurved, 
 slightly oblique, and located a little in advance of the middle; hinge very short, anterior 
 and antero-basal margins forming together a semi-oval or nearly semicircular curve ; pos-- 
 tero-basal border prominent, and somewhat narrowly rounded; anal margin obliquely 
 truncated above, so as to form with the slope in front of the beaks an angle of nearly 
 
 * Since writing the above, I have again examined the type-species, and find that it agrees so nearly with Ci/i>riin<-i-i.i 
 that, so far as they show, there would seem to bo no satisfactory reason for separating it. 
 
TO JUNCTION OP GRAND AND GREEN RIVERS. 129 
 
 90; surface ornamented by about thirty small, simple, radiating costa?, all of which 
 appear to be continued to the beaks. 
 
 Height, 0.27 inch; breadth, 0.23 inch; convexity, 0.22 inch. 
 
 There may be fine concentric markings on well-preserved specimens of this species, 
 though none are visible on that from which the above description is made out The 
 radiating costge are small, regular, and about equal to the grooves between. They 
 are moderately well denned, but seem to become gradually obsolete toward the anterior 
 and posterior dorsal margins. It is a neat little shell, presenting a regular cordate out- 
 line as seen from the anterior or posterior side. 
 
 Locality and position. Rio de la Plata; base of upper member of the New Mexican 
 Cretaceous series. 
 
 GASTEROPODA. 
 Genus ACTION, Montft. 
 
 ACTJEON INTERCALARIS, Meek. 
 Plate II, figs. 4 a, b, c. 
 
 Shell small, narrow-subovate, or subfusiform ; spire rather elevated; volutions five 
 to five and a half, compressed-convex, increasing gradually in breadth, and more 
 rapidly in height; last one a little produced below, and forming about half the entire 
 length; suture well defined; aperture narrow-subovate, very acutely angular above; 
 surface marked by fine, slightly-impressed, punctured striae, about twelve of which may 
 be counted on the second turn. 
 
 Length, about 0.40 inch; breadth, 0.21 inch ; apical angle nearly regular or a little 
 convex, divergence about 35. 
 
 The only specimen of this species in the collection has the lower part of the aper- 
 ture and a portion of the columella broken away. The aperture, however, was evi- 
 dently quite narrow, and the columella somewhat tortuous, with apparently one oblique 
 fold below the middle. The fine, punctate, revolving grooves are not more than from 
 one-third to one-half as wide as the spaces between on the second whorl, and can 
 scarcely be seen without the aid of a magnifier. 
 
 This shell is more nearly allied to A. subelliptica (Meek and Hayden), from the 
 Fort Pierre Group (Cretaceous formation No. 4) of the Upper Missouri section, 
 than any other with which I am acquainted. It may be readily distinguished from 
 that species, however, by the much greater elevation of its spire in proportion to the 
 length of its body-whorl, being in this respect about intermediate between A. subelliptica 
 and A. attenuata (M. & H.), but quite distinct from them both. 
 
 Locality and position. Same as last. 
 
 Genus ANCHURA, Conrad. 
 ANCHURA ? NEWBERRYI, Meek. 
 
 Plate II, fig. 5. 
 
 Shell of medium size, thin, fusiform; spire moderately elevated; volutions six, dis- 
 tinctly convex, increasing rather rapidly in size; suture well defined. Surface orna- 
 17 s F 
 
130 EXPLORING EXPEDITION FROM SANTA F15 
 
 mented by revolving lines, two of which, on the body-whorl, become so much larger 
 than the others as to form small carina-. Of these two carin;r, the upper only is seen 
 on the second turn, where it is much reduced in size; and, on those above, it is not 
 distinguishable from the other revolving lines. Marks of growth obscure; aperture 
 unknown; lip extended into a long appendage, the form of which cannot be determined 
 from the specimen examined. 
 
 Length, exclusive of the beak, 0.65 inch: breadth of body- whorl, exclusive of the 
 lip, 0.37 inch; apical angle slightly convex, divergence about 40. 
 
 The collection contains but a single specimen of this species, and it is unfortunately 
 so firmly imbedded in the hard matrix that it is impossible to work out the labial 
 appendage. It evidently extends out, however, at least as much as 0.5o inch from the 
 axis of the shell; and as its lower margin (which is thickened and a little reflexed) is 
 seen to curve downward, it is probable that there are two salient points to the lip, one 
 of which curves a little downward and the other upward. The lower margin of the lip 
 can be seen to extend out to /of fig. 5, plate 2. 
 
 The body-whorl contracts into the beak below, but the latter is broken from the 
 specimen, so that its form and length cannot be determined. Some eight or nine of the 
 revolving lines may be counted on the upper turns, and about twenty (including the two 
 caringe) on the body-whorl. Half of those on the under side of the body-volution are 
 larger than any of those above the carinse, while between each two of them there are 
 one or two smaller lines. 
 
 In size and general appearance, this species (at least as seen with the lip concealed 
 in the matrix) bears some resemblance to A. AHKT'ICIUHI, Kvans & Shumard (sp.), hut 
 has a less-elevated spire, and differs in being destitute of vertical costac. In the latter 
 character, it is more nearly like A. sttlifa'rix, Meek & Haydeu, from which it may be 
 readily distinguished by its two revolving cariiuv on the body-whorl It may be an 
 Ajinn'has, and have to be called Aporrhas Newberryi. 
 
 Locality ami jioxifion. Same as last. 
 
 CEPHALOPODA/ 
 
 Genus BACULITES, Lam. 
 BACULITES ANCEPS, var. OBTTJSUS.* 
 
 Plato II, figs. 1 a, b, c, d, c, f, g, h. 
 
 Baculites ancvps, Lamarck (1822), An. Sans Vert., vii, 648. D'Orbiguy ( 1835), Tab. des Oph., 75; anil (1840) Paleont. 
 
 FT. Terr. Cr<;t., i, 565, plate 139, tigs. 1, 7. Rocinor, Texas, 41C.; and (]-">) Kivid. von Texas, :!ti, tal'. ii, tigs. :; 
 
 a, b, c, &c.; and of many others. 
 Huciilitet vcrtebralis, Defrance (1816), Diet. Sci. Nat., Snpp., iii, 168 ; and of some others, but not of Lamarck. 
 
 The collection under examination contains a number of specimens agreeing 
 almost exactly in size, form, and surface-undulations with those figured under the name 
 of Ji. (Dtri'jts by Dr. F. Roemer, in his beautiful work on the Cretaceous rocks and fos- 
 sils of Texas. As Dr. Roemer gives' no enlarged figures showing the details of the 
 septa of the Texas specimens, however, we have no means of determining whether or 
 
 * Originally I had not used the variety-name oblimnx in connection with this shell ; but I ha\ e applied t hat name, to 
 this form in the I'pper Missouri I'atieontolngy, now in the, press ( November 'J, 1*7.")). and add it hero in rcviHing the 
 MS. of this report. 
 
TO JUNCTION OK (1IJAND AND GREEN RIVERS. 131 
 
 not they agree witlitlio.se of the forms under consideration, though it is probable they 
 will be found to present essentially tlie same characters. It is, therefore, chiefly owing 
 to the probable identity of our specimens with those investigated by this distinguished 
 author (who doubtless had an opportunity to make direct comparisons witli authentic 
 European examples of Lanark's species) that those under examination are here 
 referred provisionally to l>. aiin-ps. 
 
 As I have had an opportunity to examine but two authentic specimens of B. anceps 
 from foreign localities, and these were mere fragments, I have no means of knowing 
 to what extent that species varies in form and internal characters. It is worthy of 
 remark, however, that the two fragments of It. aiiccpK here alluded to, as well as tlie 
 figures of that species given by Professor Mronn in his Lethtsa Geognostica, and those 
 given by d'Orbigny in his Pu/roi/tohgie franc.ais, although agreeing very nearly in 
 form and surface-undulations, all differ from our New Mexican specimens, as well as 
 from those figured by Dr. Roemer, in being rather distinctly carinated on the dorsal side. 
 Again, on comparing the septa of the two European specimens of B. anceps mentioned 
 above with d'Orbigny's enlarged figure of the same, it was found that they agree quite 
 nearly in all their essential characters, while they both present rather marked differ- 
 ences from those of the New Mexican forms. 
 
 These differences consist not merely in the greater obtuseness of all the smaller 
 divisions of tlie septa-lobes of the specimens under examination, but also in the form 
 and mode of branching of the lobes themselves, as may be seen by reference to the 
 figures given on plate II. I strongly suspect these differences to be of specific impor- 
 tance; but, without other means of comparison than those now available, it is difficult 
 to determine whether this is the case or not. 
 
 It will be observed that the figures on plate II represent two rather marked varie- 
 ties, some of the specimens being more slender and less compressed than others, and 
 provided with obtuse, nearly circular, nodes, instead of transversely-elongated, arcuate 
 undulations, as in the more compressed forms. A careful study of the whole series of 
 specimens, however, shows that there are intermediate; gradations between these two 
 forms, while the septa present almost precisely the same characters throughout the 
 entire series. 
 
 These two extremes of form bear very nearly the same relations to each other that 
 B. asper of Morton does to Iris B. carinatus, which forms they also very closely resem- 
 ble in their external characters, excepting that neither of them is ever carinated on the 
 dorsal side, as in the typical B. carinatus of Morton. Dr. Roemer suggests that the 
 latter is probably not distinct from B. anceps of Lamarck; and Mr. Gabb, who 
 examined Dr. Morton's typical specimens, has arrived at the conclusion that not only 
 that form (./>'. carht(tttis), but B. asper also, are merely' varieties of B. anceps* (See 
 Proceedings of the Academy of Natural Sciences of Philadelphia for November, 1861.) 
 Without expressing an}- decided opinion in regard to this latter conclusion (not 
 having seen the specimens upon which it is based), 1 would remark that the figures ot 
 the septa of B. car-hint nx and II. ax/in- given by Mr. Gabb, seem to present some rather 
 marked differences from those of B. aneeps, though it is not improbable that there may 
 
 * Our figures 2 a and 2 b, on plate II, represent a section and a septum of B. anceps of Europe, for comparison. 
 
132 EXPLORING EXPEDITION FROM SANTA FE 
 
 be intermediate gradations connecting these extremes with Lamarck's species. At any 
 rate, Mr. Gabb's figures of the septa of B. carinatus and B. asper certainly differ so 
 'materially from those of our New Mexican specimens (which, as already stated, are 
 quite constant in their internal characters) as to make it desirable that the latter should 
 be designated by another name (at least as a variety), until all doubts in regard to their 
 relations can be removed by a direct comparison of a good series of specimens of all 
 the forms alluded to. 
 
 Locality and position. Same as preceding. 
 
 Genus PRIONOCYCLUS, Meek. 
 PRIONOCYCLUS ? MACOMBI, Meek. 
 
 Plate II, figs. 3 a, Z>. o, d. 
 
 Shell discoidal ; umbilicus shallow, somewhat less than the diameter of the last 
 whorl from the ventral to the peripheral side, and showing all the inner turns; volu- 
 tions increasing gradually in size, very slightly embracing, compressed so as to be 
 nearly flat on the sides, but rounding into the umbilicus ; periphery rather narrow, 
 nearly flat, and provided with a small mesial carina, which is very slightly waved in 
 outline ; lateral margins of the periphery each having a row of small compressed nodes, 
 arranged one at the termination of each of the costse, with their longer diameters 
 nearly parallel to the peripheral keel ; sides of each turn ornamented by from thirty- 
 six to forty rather obscure, slightly flexuous costae, only every second, third, or fourth 
 one of which extends across to the umbilical margin, where they are usually a little 
 swollen. 
 
 The septa are generally a little crowded in adult shells, and divided into two very 
 unequal principal lobes on each side. Siphonal lobe slightly longer than wide, and 
 ornamented by three branches 011 each side, the two terminal of which are a little 
 larger and much less spreading than the lateral pair, and each ornamented by some five 
 or six sharp digitations along the margins and at the extremity ; while the first pair of 
 principal lateral branches above the terminal ones are of nearly the same form as the 
 latter, but more spreading, and the third pair are smaller, and merely provided with a 
 few digitations; first lateral sinus (dorsal saddle of old nomenclature) as long as the 
 siphonal lobe, but much' wider, and deeply divided intb two unequal parts, of which 
 the one on the siphonal side is larger than the other; each of these principal divisions 
 being ornamented by some four or five short, irregular branchlets, with obtusely digi- 
 tate margins; first lateral lobe longer and slightly wider than the siphonal, and pro- 
 vided with some seven or eight short, rather unequal, merely digitate, and palmately- 
 spreading terminal and lateral branchlets ; second lateral sinus narrower, but as long 
 as the first on the outer or siphonal side, and much shorter on the umbilical, having 
 two short, unequal, digitate, terminal branches at the end, and some three or four short, 
 irregular divisions along the oblique margin of the umbilical side; second lateral lobe 
 small, or scarcely more than twice as large as the auxiliary lobe of the siphonal sinus, 
 and somewhat irregularly bifid, the divisions being short, and, like the lateral margins, 
 more or less digitate. 
 
TO JUNCTION OF GRAND AND GREEN RIVERS. 133 
 
 Greatest diameter of a specimen retaining only a small portion of the non-septate 
 outer whorl, 4.40 inches; greatest convexity of same, 0.95 inch; breadth of umbilicus, 
 l..'>5 inches; breadth of last whorl from the siphonal to the umbilical side, 1.80 inches. 
 
 Young specimens of this species differ materially from the adult ; those not more 
 than an inch or an inch and a half in diameter being destitute of nodes, and provided 
 with a continuous instead of a waved carina. Their costse are also more crowded, 
 more numerous, and curve distinctly forward near the peripheral margins. At this 
 si/<>, the shell closely resembles specimens of Ammonites percarinatus, Hall and Meek, 
 of the same age ; but, as it advances in growth, it assumes quite different external 
 characters, while its septa differ at all ages. 
 
 It seems to be related to a Texas species, described by Dr. Shumard, in the Trans- 
 actions of the St. Louis Academy of Sciences (vol. 1, p. 539), under the name of A. 
 Gmysoncnsis. Dr. Shnmard, however, to whom I sent sketches of it, regarded it as 
 clearly distinct. He wrote that he had seen quite a number of specimens of A. 
 (lni//H'>iir'.iif<is, and that none of them attain more than one-third the size of the form 
 under consideration, while they are always destitute of nodes, and have a more dis- 
 tinctly-waved c;irnia. 
 
 I am far from being satisfied that this shell belongs to the same group as that for 
 which I have, in one of Dr. Hayden's Reports and again in the Upper Missouri Palae- 
 ontology, used the name Prionocydm. It is certainly not a true Ammonites, however, 
 as that genus is restricted to typical forms, but more nearly allied to Prionocydus. 
 
 Named in honor of Capt, J. N. Macomb, of the United States Topographical Engi- 
 neers, commander of the expedition. 
 
 Locality and position. Banks of Canadian; lower part of Middle Cretaceous of 
 New Mexican section. 
 
EXPLORING EXPEDITION FROM SANTA Ffi TO JUNCTION OF GRAND AND GREEN RIVERS. 
 
 DESCRIPTIONS 
 
 OF THE 
 
 CARBONIFEROUS AND TR1ASSIC FOSSILS 
 
 COLLECTED ON THE 
 
 SAN JUAN EXPLORING EXPEDITION UNDER CAPT. J. N. MACOMB, U. S. ENGINEERS. 
 
 BY 
 
 J. S. NEWBERRY. 
 
 GKOLOGIST OF THE EXPEDITION. 
 
DESCRIPTIONS OF FOSSILS. 
 
 HY J. s. KKWBKRRT. 
 DELTODUS MERCUREI, Newb. 
 
 Plate III, iigs. 1, I". 
 
 Teeth of medium size, thick and strong, cuneiform or spatulate in outline, strongly 
 arched in both senses, broader end uniformly rounded, lateral margins thickened and 
 rounded over, on one side depressed, on the other raised into a prominent marginal 
 ridge, which is separated from the central portion of the crown by a relatively deep 
 and narrow sulcus; whole surface of crown finely punctate, especially in the sulcus, 
 and gently undulate. This is quite unlike any Coal-Measure Deltodus hitherto dis- 
 covered. In its general proportions and appearance, it is perhaps most like D. spatula- 
 iits, N. & W., from the Mountain limestone of Illinois; but in the present species the 
 marginal sulcus is much deeper and more conspicuous, and the granulation of the sur- 
 face finer. 
 
 Formation and locality. Coal-Measures ; Santa FC", New Mexico. 
 
 PTYCITOWS WIIIPPLEI, Marcou. 
 
 Plate III, figs. 2-2'. 
 
 
 
 Teeth varying in form according to their places in the mouth; largest, conical in 
 profile ; the central cone" rounded above and on the lateral and posterior faces, expanded 
 below into a flattened, subquadrate base; summit of crown marked with a few distinct, 
 acute, transverse folds of enamel; anterior face covered with reticulate, radiating, raised 
 lines, as in Pt. Mortoni; upper surface of margins of base finely and reticulately 
 wrinkled; tuberosity of base small, subquadrate, with a broad sulcus, having an 
 antero-posterior direction; the smaller teeth are rel||fvely broader and lower, elliptical 
 or subtrigonal in outline; the central cone marked with a few coarse interrupted ridges. 
 
 This is the most conical tooth of the genus, the central cone being considerably 
 higher and narrower than in Pt. altior, Ag. The other known American species, Pt. 
 Mortoni, has also a decidedly conical form, in that respect differing from the European 
 species, but wants the transverse folds so characteristic of the flattened, quadrate spe- 
 cies of the Old World. 
 
 In the specimen figured by M. Marcou, the crown is worn smooth, the folds being 
 all gone. It is also more angular than those now figured; but the general resemblance 
 is so strong that I do not hesitate to consider them the same. 
 18 s F 
 
138 EXPLORING EXPEDITION FROM SANTA FE 
 
 Formation and locality. The horizon at which the teeth of Ptyclwdiis 
 occur in the Cretaceous rocks of New Mexico is, according to my observations, very 
 clearly defined. It is below the middle of the series, generally within a hundred feet 
 of the yellow Lower Cretaceous leaf-bearing sandstones. 
 
 The rock containing them is a sandy, ferruginous limestone, lying in thin bands 
 divided by layers of dark calcareous (often bituminous) shale. The associate fossils 
 are Lamna Texana, Gryphcca Pitclteri, Ostrca htgitlris, 0. uniformis, Inoceramus prollc- 
 maticus, I. f rat/His, Ammonites percarinatus, A. Macombii, Scapliitcs larrifonnis, &c. 
 
 The Ostrea of which M. Marcou speaks as occurring with Pt. Wliipplei is not 0. 
 conf/esta, as he supposes, but 0. luyulris of Conrad. Tlie- place of 0. com/esta is a little 
 higher in the series, (injplifca Pitcheri is found a few feet below. 
 
 Of all these species, specimens were obtained on the banks of the Canadian at 
 Galisteo, at the ford of the Chama, and at the Pagosa. 
 
 ATHYRIS SUBTILITA, Hall, sp. 
 
 Wherever we found Carboniferous rocks in the West, we were sure to meet with 
 this wide-spread fossil. On the Colorado, west of the San Francisco Mountains, at the 
 junction of the Grand and Green Rivers, in the Sierra la Plata, at Santa Fc', and at Pecos, 
 it is abundant. At all these places, the most common form of the Coal-Measures in the 
 valley of the Mississippi is most numerously represented ; there, as here, varying some- 
 what in size, apparently accordingly as it was well or ill fed. 
 
 In the extreme upper Carboniferous or Permian beds, an Atliyris is common which 
 has sometimes been considered as distinct from those obtained below, for it is usually 
 larger and more ventricose than the prevailing type of Coal-Measure specimens. It 
 may possibly be a distinct species, but it is true that in many places in the Coal- 
 Measures A. sMilita is found, assuming precisely the same form and reaching an 
 equal size.. It will, therefore, be impossible to make two species of them until some 
 internal characters are found which can serve to distinguish them. 
 
 SPIRIFER CAMERATUS, Morton. 
 
 This shell is common in the limestone of the Carboniferous series at all points in 
 the route of our expedition where these rocks are exposed. Of the large number col- 
 lected in New Mexico and Utah, and a very much larger number examined, all exhibit 
 nearly the same character, the prevailing type as regards size and markings closely 
 resembling that figured by Professor Hall in Captain Stansbury's Report under the 
 name of S. triplicates. Specimens collected in Eastern Kansas and others obtained 
 from the banks of the Colorado are absolutely undistinguishable. The larger shell, 
 considered by Mr. Davidson identical with 8. striatus of Martin, is nowhere met with 
 in New Mexico or Utah. It is abundant in the mountain limestone of Illinois and 
 .Missouri, but I have never seen it from the Coal-Measures. Considering the marked 
 difference in form and position of these two shells, it is difficult to resist the conviction 
 that if the European palaeontologists could study what the}- regard as American 
 representatives of 8. str'talux in great numbers as the}- occur in place, they would con- 
 sider them as forming two distinct species. 
 
TO JUNCTION OF GRAND AND GREEN RIVERS. 139 
 
 Sl'IRIFER (TUIGONOTEETA '?) TfiXANUS, Mock. 
 
 Plate III, figs. 5, 5", and 5 b . 
 Spii-ifer (Trigunotnta!) Tetanus, Meek (1871), I'rocecd. Acad. Nat. Sci. Phila., xviii, 179. 
 
 Shell scarce! v attaining a medium size, very gibbous in the adult, varying from 
 subquadrate or subglobose to longitudinally-subovate, the widest part being generally 
 in advance of the middle, and the length greater than the breadth ; hinge-line short, 
 or in young individuals scarcely equaling the breadth of the valves, and in the adult 
 often proportionally very decidedly shorter, sometimes obtusely angular at the extrem- 
 ities, while in the more gibbous individuals its extremities do not project beyond the 
 lateral slopes ; anterior margin often somewhat emarginate in the middle. Dorsal 
 valve truncato-suborbicular or subquadrate, and moderately convex ; beak incurved, 
 with a narrow area, but not prominent; mesial elevation commencing as a small simple 
 plication at the beak, but rapidly widening and becoming more prominent and angular, 
 with on each side several small costa 1 , which divide so as to form altogether twelve to 
 sixteen at the front ; lateral slopes having at the beak each two or three plications or 
 costs?, which farther forward divide so as to form as many fascicles of three each, or 
 about nine on each side of the mesial fold. Ventral valve more gibbous than the other, 
 and more strongly arched than the other from the beak to the front ; beak very promi- 
 nent in the adult, always strongly incurved over the hinge; cardinal area moderate, 
 well denned, and extending to the extremities of the hinge without narrowing strongly 
 laterally, rather distinctly arched with the beak ; foramen slightly wider at the hinge 
 than high, open nearly or quite to the apex, a-nd provided with a distinct linear mar- 
 ginal furrow on each side ; mesial sinus angular, and commencing very small at the 
 beak, and widening and deepening rapidly to the front, where it terminates in a 
 strongly-curved triangular projection fitting into a corresponding sinus in the margin 
 of the other valve ; surface as in the dorsal valve, the costaj within the sinus being 
 smaller than those on the lateral slopes, and numbering about sixteen to twenty; fine, 
 rather obscure, undulating strire, and, near the front and lateral margins, a few stronger 
 marks of growth traverse the valves, parallel to the free margins ; while numerous 
 small, rather scattering, but regularly-disposed granules, apparently the remaining 
 bases of minute spines, may be seen over the whole surface of well-preserved speci- 
 mens, which also sometimes show traces of very fine radiating striae. 
 
 Length of one of the largest specimens seen, 1 inch; breadth of same, about 0.98 
 inch; convexity, 0.90 inch ; length of hinge, 0.72 inch. Smaller specimens are propor- 
 tionally less gibbous, shorter, wider, and provided with a proportionally somewhat 
 longer hinge. 
 
 Small specimens of this species resemble a little the more gibbous varieties of 
 S. cameratus, with a very short hinge ; but, in the adult, the valves become propor- 
 tionally more elongated anteriorly, and more gibbous, and the beak of the ventral 
 valve is so narrow, so much produced and incurved, as to present the appearance of 
 a Pentamcrus. Its distinctly-granulated and minutely-striated surface, however, will 
 always serve to distinguish, even the specimens with the most extended hinge-line, 
 from the most gibbous varieties of S. camcratufi, with a short hinge. Its granular sur- 
 
140 EXPLORING EXPEDITION FROM SANTA FE 
 
 face leads me to suspect that it may possibly be a Spirifcrina; but as I have not been 
 .able to see any certain indications of punctures, I hardly feel warranted in referring it 
 to that group, I have not, however, given it an examination by the aid of higher 
 power than a strong hand-magnifier. Should a more thorough examination reveal the 
 usual punctate structure, and the internal septum of that group, it will of course have 
 to be called Spiriferina Texana. 
 
 Compared with foreign forms, this shell seems to be most nearly like the extremely 
 narrow and elongated variety of S. dnplicatus, Phillips, as illustrated by Mr. Davidson's 
 figure 8, Plate IV, Monogr. British Carboniferous Brachiopoda. It is much more 
 gibbons, however, with decidedly more prominent and more angular mesial sinus ; 
 while its surface-granulations and minute stria 1 serve to distinguish it. Although its 
 mesial fold has a very angular appearance, a careful examination shows it to be very 
 slightly flattened, or sometimes even marked by a linear furrow along its crest ; and 
 there is sometimes also a slightly more prominent line along the middle of the angular 
 sinus of the other valve. 
 
 Locality and position. The type-specimen was found, by Mr. H. 11. Roessler, asso- 
 ciated with Coal-Measure fossils in Young County, Texas. Dr. Newberry also has 
 specimens from the northwest corner of Jack County, west fork of Trinity River, Texas. 
 I have never seen it from any locality north or east of Texas. (F. B. M.) 
 
 PHODUCTUS NODOSUS, Newb. 
 
 Plato III, figs. 3-3 d. 
 
 This fine Productus, first collected on a former expedition, and described in my 
 report to Lieutenant Ives (Colorado Expedition, Geology, p. 124, plate 1, figs. 7- 
 7 ), we found in large numbers at Santa Fd, and in many localities along our route 
 quite to the. Colorado. Indeed, it is perhaps as common as any other species of the 
 genus in Western New Mexico and Southern Utah. 
 
 The figures now given of it will convey a much better impression of its true char- 
 acter than 'those before published. From these it will be seen that, with a near 
 approach in form and markings to P. corn and P. (cqiticostatus, it is distinguished from 
 these and other species by the single line of conspicuous nodes, the bases of large 
 spines, which mark the median line of the ventral valve. In some specimens a corre- 
 sponding line of tubercles marks the dorsal valve; but they are always less distinctly 
 marked and are often entirely wanting. 
 
 Figures 3 c and 3 d show a somewhat remarkable variation in the length of the 
 cardinal border, but the wings are usually quite short, as in figures 3 I and 3 c. 
 
 PLEUROTOMA.RIA EXCELSA, Newb. 
 
 Plate III, figs. 4, 4. 
 
 Shell large, long-conical in outline, higher than broad; .whorls flattened out- 
 wardly above and below, having an angular section, the lower ones projecting consid- 
 erably beyond the upper, giving the shell a shouldered appearance ; surface smooth, 
 or marked with fine lines of growth. Height, 3.2 inches. Breadth, 2.6 inches. In its 
 
TO JUNCTION OF GRAND AND GREEN RIVERS. 141 
 
 large size and character of surface, this shell approaches P. Missouricnslx, Swallow, but 
 is apparently something smaller and more elongated in outline. In P. Missouriemis 
 the width of the base is greater than the height, while in our species the reverse is true. 
 In the Missouri "specimen, which I saw in the hands of Governor Gilpin before it was 
 described, the whorls are so fitted together as to produce smooth and somewhat con- 
 cave sides; while in P. excclsa they are shouldered, and the outline of the sides is 
 straight or slightly convex. 
 
 Formation and locality. Upper part of the Carboniferous formation, in the canon 
 of Grand River, near its junction with Green River, Southern Utah. 
 
 LAMNA TEXANA, Roem. 
 
 Lamna Ttxatia, Roomer, Krcido v. Texas, p. 21, taf. 1, fig. 7. 
 
 Found in company with Ptycliodus Whipplci on the banks of the Canadian, at 
 Galisteo, and at the Pagosa in the "fish-bed" near the base of the Middle Cretaceous 
 series. 
 
 OXYHHINA MANTELLI, Agass. 
 
 Ojryrhiua Maiitclli, Ag., Roi'iner, Krcidc v. Texas, p. 2U, taf. 1, fig. 6. 
 
 This species occurs in the fish-bed of the Middle Cretaceous (No. 2 of Meek and 
 Hayden's section) at the Pagosa. It is somewhat doubtful, however, whether it is 
 really identical with that described by Agassiz. Probably more material will show 
 that it is distinct. 
 
 OTOZAMITES MACOMBII, Newb. 
 
 Plato IV, figs. 1, 2 ; Plate VI, figs. 5, 5. 
 
 Frond pinnate, pinna} opposite or subalternate, approximate or imbricated, entire, 
 sessile ; lower ones small, reniform, or circular; upper large, oblong, rounded, or trun- 
 cated at the extremity ; base nearly as broad as apex, very slightly auricled and 
 rounded at upper and lower angles, attached to rachis by two-thirds to three-fourths 
 of entire breadth; nerves numerous, fine, but distinct, equal, forked, radiating from 
 the attached portion of the base to all parts of the lateral and apical margins ; rachis 
 slender, smooth, or finely striated longitudinally. 
 
 The outline of the entire frond is linear-lanceolate; different ones varying much in 
 breadth and in the spacing of the pinnules. At first sight, they seem to resemble closely 
 those of several of the Cycads of the Oolite, Wealden, and Chalk, but on more careful 
 examination they will be found to present characters widely different. The oblong or 
 quadrate truncated pinnules, increasing in length from the base upward, at once sug- 
 gest the species of Nilssonia and Ptcropliylliim,tQ whfch I have alluded, such as P. majus, 
 P. minus, P. Schaumlerf/ense, Nilssonia compta, &c., but the nervation (fine, equal, fork- 
 ing nerves, radiating from the attached portion of the base to all parts of the lateral 
 and terminal margins,) and the mode of attachment to the rachis each pinnule being 
 distinctly separated from the others, the base slightly auricled, with rounded lobes 
 exclude it from both the preceding genera as at present constitiited, and associate it 
 with that group of Zamitcs (Brorig.) which form Fr. Uraun's gemis Otozamitcs (Oto- 
 pteris, L. & II.). From all known species of that genus, it is, however, somewhat 
 
142 EXPLORING EXPEDITION FROM SANTA FE 
 
 widely separated by its general habit; yet, if the nervation and mode of insertion on 
 the racing of the pinnules afford good characters for generic classification, it must be 
 grouped with these. 
 
 By Unger and Goeppert the genus Oto/samites is not recognized, and our fossil 
 would be classed by them in Zamites. Brongniart, however, claims that the section of 
 Zamites represented by Otozamiti's, Br., including species differing much among them- 
 selves, it is true, biit having in common important botanical characters, may be very 
 properly regarded as forming a natural generic group. 
 
 As this species is distinctly new, it affords no very reliable evidence by which to 
 judge of the age of the formation in which it is found, and yet it was with very lively 
 pleasure that I discovered this and the associate Cycad in the copper-mines of New 
 Mexico. Extremely few fossils had been found at this horizon, although I had sought 
 them most carefully over a large area in which the red sandstones and shales are 
 exposed. On finding in the old copper-mine at Abiquiu great numbers of fossil plants, . 
 I was more than pleased, and when upon examination they proved to be Cycads, 
 plants most characteristic of the Triassic and Jurassic rocks in the Old World, I felt 
 that we had here new and important evidence that the criteria of palaeontology may 
 be trusted. 
 
 Among the Cycads of the Old World, the species most nearly allied to Oto. J\Ia- 
 comlii is perhaps 0. obtusa, Lind. & Hutt. (vol. 2, p. 128), from the Lias of England, 
 and yet it will be seen on comparison of the two species that they are quite distinctly 
 separated. 
 
 The discovery of this species by Mr. Remond in Sonora, associated with well- 
 marked Triassic fossils, is a fact of great scientific value, and of very special interest 
 to me, as it proves that the entire thickness of the gypsiferous red sandstones and 
 marls of New Mexico, on and west of the Rio Grande, is made up of strata as old as 
 the Trias. There is no doubt of the existence of Jurassic rocks in the Rocky Mount- 
 ain region; but, so far as yet known, they do not occur on any part of the route fol- 
 lowed by M. Marcou, and where he claims to have discovered them. 
 
 The plant-beds of the Moqui villages and Abiquiu are overlain by the yellow 
 sandstones of the Cretaceous formation, and angiospermous leaves were found by us 
 in a number of localities within five or ten feet of the underlying red marls. On the 
 east flank of the Rocky Mountains, in some places, as at Cold Spring, on the Santa Fe 
 road, I found a series of calcareous strata interposed between the Gypsum formation 
 and the Cretaceous sandstones, and these, since holding the place and having the 
 lithological character of the beds found by Dr. llayden a little farther north, contain- 
 ing Jurassic fossils, are probably, of that age. It is, however, true at the present 
 time that no Jurassic plants have been found on this continent. 
 
 Formation and locality. Triassic strata: Abiquiu, New Mexico; Los Bronces, Sonora 
 (Mr. Remond); Yaki River, Sonora (Mr. Hartley). 
 
 ZAMITES OCCIDENTALS, Newb. 
 
 Plate V, figs. 1, 1", 2. 
 
 Frond petioled, linear-lanceolate; pinnules springing from the rachis at an 
 angle of about 45, rigid, coriaceous, closely approximated, linear in outline, 6-15 
 
TO JUNCTION OF GRAND AND GREEN RIVERS. 143 
 
 lines long, rounded or subacute at extremity, very slightly constricted at base; 
 nerves fine, parallel, scarcely visible ; rachis strong, chaffy. 
 
 In the form and attachment of the pinnules, this species approaches those grouped 
 by Fr. Braun under the name of Ptewsamites, in which the pinnules are usually 
 linear and obtuse, and are attached to the rachis by the entire breadth of the base, 
 which is not constricted. In the upper pinmiles of our plant, however, the bases are 
 very distinctly narrowed, and the attachment is sensibly oblique. 
 
 There is no described species of Zamitcs for which this will be likely to be mis- 
 t;iken, nor does it clearly fall into any of the groups of the genus which have been 
 established. With the lance-leaved species (Podozamitcs Fr. Braun), such as Z. din- 
 tans, Z. lanccolatus, Z. loididatos, Z. falcatus, &c., it seems to have very little in common, 
 while from the group represented by Z. Fcnconis, Z. pectinatus, Z. Taxinus, &c. 
 (Pteroxamites Fr. Braun), in which the folioles are inserted by all their uncontracted 
 bases, it is separated by the slight though distinct expansion and 'constriction of the 
 bases of the leaves. It would, therefore,-seem to be a sort of connecting link between 
 the groups with auricled and those with simple folioles. It approaches, however, 
 nearest to that group of species described by Goeppert and Dunker (Z. Dunkerianum 
 Gopp, Z. Humboldtianum, Dunk., Z.^ Lydlianiim Dunk., &c.) from the Wealden, 
 included by these authors in Pterophyllum, but by Brongniart in Zamites, and perhaps 
 nearest of all to Ptcr. Saxonlcum, Reich. (Gaea, v. Saxon., p. 134, t. 4, f. 14; 
 Gopp., "Flora des Quadersandsteins in Schlesien", in Nova Acta Acad. Leop. Carol. 
 Ca?s. Nat. GUI-., Oct., 1847, p. 362, taf. xxxviii, fig. 13), from the Quadersandstone 
 (Cretaceous) of Saxony. 
 
 Formation and locality. Top of Triassic series; Copper-mines near Abiquiu, New 
 Mexico. 
 
 PECOPTERIS BULLATUS, Bunbury. 
 
 Plate VI, figs. 1, 1". 
 
 Among the specimens collected by Mr. Remond at Los Bronces, Sonora, are 
 several of a Pccopteris in fruit, which is apparently identical with that first described 
 by Bunbury from the coal-strata of Richmond, Virginia, and subsequently found by 
 Professor Emmons in North Carolina. This species is considered by Professor Heer 
 as identical with Pecopteris Stutgardtensis, Brong., one of the most characteristic 
 plants of the European Trias. 
 
 Without more material, it woidd be presumption to attempt to decide this question ; 
 but that the plant before us is identical with that found in the Triassic strata of 
 Virginia and North Carolina there is little doubt, and it therefore becomes an impor- 
 tant connecting link between the eastern and the western exposures of Triassic, strata, 
 
 Formation (Did locality. Triassic rocks; Los Bronces and on Yaki River 
 Sonora (Messrs. Remond and Hartley). 
 
 PECOPTKRIS MEXICANA, Newb. 
 
 Plato VI, figs. 9, 2. 
 
 Frond bi- or tripinnate, small; pinna; elongated, narrow, linear, acute; pinnules 
 ovate, acute or subacute, sometimes falcate ; nervules delicate and few, simple or 
 
144 EXPLORING EXPEDITION FROM SANTA Fl 
 
 once-forked ; sori from 1 to 5 on basal portion of pinnules, seated on the nerves, and 
 apparently covered with an indusium. 
 
 This is an exceedingly neat and pretty species, quite distinct from-any other with 
 which I am familiar. The plant was evidently small, and the fronds very delicate 
 and membranous. 
 
 In common with most of the smaller Mesozoic species of the genus, it had long, 
 narrow, riband-like pinna-, and pinnules more or less falcate. In the form of the 
 pinnules, the plant resembles Pecopteris+Wliitbiensis, but the nervation is less crowded, 
 the pinnae more elongated, and in size the one is biit a miniature of the other. 
 
 Formation and locality. Triassic shales ; at the Coal-mines of Los Bronrcs, 
 Sonora (Mr. Remond). 
 
 PECOPTERIS FALCATUS, Emmons. 
 
 Plato VI, fig. 3. 
 
 This is evidently the plant described by Professor Emmons (Geol. N. Carolina, 
 p. 327, fig. 9) as the fertile frond of his P. falcatus. No specimens of the barren 
 frond occur in the collection; but the resemblance of the plant before us to that 
 represented in the figure to which I have referred will be apparent to any observer. 
 
 Professor Heer considers P. falcatus of Emmons as identical with Laccoptcris 
 f/crminans Goep. (Gatt. Foss. Pflanz. liv. 1 and 2, plate vi, fig. 8) from the Keuper of 
 Bayreuth ; and he is probably correct in that -conclusion, but the want of sterile 
 fronds in the collection made by Mr. Remond leaves this question as it was, and we 
 are now only able to identify, by means of this and the other species common to 
 these widely-separated localities, the plant-beds of Sonora with the Trias of North 
 Carolina and Richmond. 
 
 Formation and locality. Los Bronces, Sonora (Mr. Remond). 
 
 PTEROPHYLLUM FRAGILE, Newb. 
 
 Plate VI, figs. C and f.. 
 
 Plant apparently delicate and fragile; midrib of frond slender and weak; pinnules 
 oblong on the center of the frond, quadrangular above and below; summit squarely 
 truncated; base attached to the rachis by its entire width; nerves fine, straight, simple, 
 parallel. 
 
 The figure now given of the central part of the frond is taken from the only spe- 
 cimen which shows distinctly the nervation and other diagnostic characters of the 
 species. In this the midrib is very delicate, and the pinnules are given off at a right 
 angle. The other figure (G a ), which represents the base of a frond, is taken from a 
 specimen which may belong to another species, as the nervation is nearly obliterated, 
 and the pinnules are given off at an acute angle. I have thought it probable, however, 
 that this latter peculiarity was simply due to their position near the base of the frond. 
 With this exception, there is no tangible difference. Should this be found to be a con- 
 stant feature, however, it would make it necessary to establish a new species on the 
 specimen represented in fig. 6. 
 
 Formation ami locality. Triassic strata; Los Bronces, Sonora, Mexico. 
 
TO JUNCTION OF GRAND AND GREEN RIVERS. 145 
 
 PTEROPHYLLUM EOBUSTUM, Newb. 
 
 Plato VI, tig. 7. 
 
 
 
 Leaf large, G inches or more in width; pinna 1 strap-shaped, 3 inches in length; 
 buses expanded and* coalescing; summit truncated or abruptly rounded; nervation 
 delicate; nerves simple, parallel with the border of the pinna?,. 
 
 Two specimens of this singular plant are contained in the collection made by Mr. 
 Remond, both imperfect, but both exhibiting the same characters. These are so pecul- 
 iar that, without the evidence of ttco specimens, I would have said we had here simply 
 a frond of Tcemopteris torn into strips, with an accidental but striking regularity. It 
 seems hardly probable, however, though not impossible, that we should find in this 
 small collection two fronds torn in precisely the same way. Besides this, the curvature 
 of the sides of the divisions, where they coalesce at the base, is almost too regular to 
 be the result of accident. They are also too uniform in width to be the effect of 
 mechanical force. I have thought best, therefore, to describe this provisionally as a 
 distinct species of PterophyUum. 
 
 Formation and locality. Triassic strata ; Los Bronces, Sonora. 
 
 PODOZAMITES CRASSIFOLIA, Newl). 
 Plate VI, fig. 10. 
 
 Plant large and strong; pinna3 long-elliptical or spatulate in form, thick and 
 coriaceous; nervation strong, but somewhat obscured by the thickness of the paren- 
 chyma; nerves parallel with the border, converging at both extremities of the pinnae; 
 a more distinct nerve traverses the central line. 
 
 Only detached pinme of this plant are contained in the collection made by Mr. 
 Remond, but of these there are quite a number. By their large size and thickness, 
 they are greatly different from those of any species of Podozamites hitherto described, 
 and the distinct median nerve which they show presents a feature not common, if 
 even known, in this genus. It is, therefore, possible that more complete specimens 
 will -show it to have characters which should be given generic value. 
 
 Formation and locality. Triassic strata; Los Bronces, Sonora. 
 
 ALETHOPTEKIS WHITNEYI, Newb. 
 
 Plate VII, figs. 1,1", I 1 '. 
 
 Frond pinnate or bipinnate ; pinnules of lower portion large, 2-3 inches long, 
 narrowed above, broad below ; the lower half of the base attached to, and decurrent 
 on, the rachis ; the upper half detached and snbcordate ; upper pinnules shorter, be- 
 coming at last elliptical and even orbicular ; nervation crowded ; midrib strong ; lat- 
 eral nerves fine and numerous, given off at nearly a right angle, simple or once forked. 
 
 The specimens of this plant are too fragmentary and imperfect to permit a full 
 
 and complete description of it. Enough remains, however, to show that it was a 
 
 strongly-marked species, and one quite distinct from any before described from this 
 
 horizon. That portion of the frond contained in the collection made by Mr. Remond 
 
 19 SP 
 
146 EXPLORING EXPEDITION FROM SANTA FE 
 
 gives the impression of a large and strong plant, much more like some species from 
 the Goal-formation than any hitherto found in the Triassic or Jurassic rocks. The 
 detachment of the upper half of the base of the pinnules from the racliis is a feature 
 so peculiar that it will serve to distinguish it at a glance. At first sight, this would 
 seem to be accidental; but each of the pinnules of the larger specimens contained in 
 the collection before us shows it to exist in precisely the same degree, so that we must 
 conclude it to be a constant character. 
 
 This species is named in honor of Prof. J. D. Whitney, to whom I am indebted 
 for the opportunity of examining the Triassic plants collected by Mr. Remond. 
 
 Formation and locality Triassic strata; Los Bronces, Sonora (Mr. Remond). 
 
 CAMPTOPTERIS RKMONDI, Newb. 
 
 Plate VII, fitfs. 2, 2". 
 
 Frond digito-pinnate or spirally discoid, from one to two feet in diameter, con- 
 sisting of twenty or more pinna' radiating from a common center, and extended in the 
 same plane. The longest pinnae are one foot in length and one and one-half to two 
 inches wide in their central and broadest portions. By the lower fourth of their length 
 they are united ; above they are free, lanceolate in outline, with margins obtusely 
 dentate or crenate. The central nerve of each pinna is strong and flat. From this 
 the secondary nerves spring at a subacute angle, curve gently upward at their extrem- 
 ities, and terminate in the crenations of the border. The tertiary nervation is very 
 delicate, filling all the spaces between the secondary nerves with a somewhat irregu- 
 lar polygonal reticulation. 
 
 This remarkable fern evidently belongs to the same genus with that figured by 
 Schimper in his I'aleontoloyic Vfgdale (plate xlii, fig. 4) under the name of Camp- 
 topteris serrata, and it seems to me highly probable to the same genus as Goeppert's 
 Thaumatopteris Munsteri. It is specifically, however, quite distinct from both of these; 
 the fronds being larger, the pinnae broader and united by a greater portion of their 
 length, and the dentition of the margins being shallower and more rounded. The 
 nervation of Camptopteris serrata is not given, but in our plant it is very distinctly 
 shown. It consists of a series of secondary nerves springing from the midrib at an 
 angle little less than a right angle. These are gently arched upward, and terminate 
 in the denticles of the border. The interval between them is filled with a polygonal 
 network of rounded or quadrangular 'meshes, inside of which is a finer network, hav- 
 ing the same general character, the meshes being four-, five-, or six-angled. This is 
 also the nervation of Thaumatopteris, and since one plant, as shown by its peculiar form 
 of frond, is genetically identical with the typical species of Camptopteris, and its ner- 
 vation can hardly be distinguished from that of Thaumatopteris, it tends to link these 
 two genera together. I should also mention that on one of the specimens brought by 
 Mr. Remond from Sonora besides the expanded pinnae of Camptopteris, we have one 
 spirally folded precisely like that figured by Goeppert (Gattungen, plate 1, fig. 3). 
 
 The discovery of this plant in the coal-strata of Los Bronces is a matter of no 
 little geological interest, as no species of Camptopteris had been before discovered on 
 this continent. It also adds to the strength of the evidence of the Triassic age of the 
 
TO JUNCTION OF GRAND AND GKEEN KlVEItS. 147 
 
 Los Bronces coal, as the two species of Camptopteris C. serrata and C. (fuertifolia 
 are both from the Upper Trias of Bayrenth. 
 
 The collection of Mr. Reniond contains a large number of specimens of Caniji- 
 foptcris, although these are very much broken up ; two of the more complete are now 
 figured. These show the form of the radiate, almost peltate frond, the character of the 
 margins, and nervation of the pinnae. 
 
 Formation and locality. Triassic strata ; Los Bronces, Sonora, Mexico. 
 
 T.ENIOPTKRIS KLEGANS, Newb. 
 Plate VIII, fig. 1. 
 
 Frond broadly spatulate or elliptical in outline ; median nerve prominent and 
 roughened; lateral nerves remarkably strong, uniform, parallel, simple, issuing from 
 the median nerve at an acute angle. They are straight below, but near the summit 
 of the frond are gently arched upward. 
 
 This fern will be distinguished at a glance from any of its associates by its 
 remarkably strong and clear 'nervation. Fragments only of the frond are contained 
 in the collection, so that we are unable to indicate its exact form ; but the portions 
 seen lead to the inference that when complete it was broadly spatulate or elliptical. 
 Among all the great group of the Tfcnioptcridfe, there is none, so far as I know, which 
 has a nervation so distinctly-marked and exact as this one. 
 
 Formation and locality. Triassic beds of Los Bronces, Mexico. 
 
 TYENIOPTEKIS GLOSSOPTEROIUES, Newb. 
 
 Plato VIII, tigs. 2, 2". 
 
 I'Yond simple, spatulate in outline, one foot or more in length, two inches in 
 width at the broadest part. The base is long-wedge-shaped. The median nerve is 
 very strong and smooth ; the lateral nerves relatively sparse and distinct, given off at 
 an acute angle, dividing near the base, and more or less inosculating above to form 
 elongated and irregular meshes. 
 
 In their general aspect, the fronds of this fern bear considerable resemblance to 
 Tfeniopteris marantacea, so common in the Trias of Kurope; but in that species the frond 
 is supposed to be pinnate, while in this it is unquestionably simple. The nerves in 
 our plant are also finer and anastomose much more frequently. It seems to me, how- 
 ever, that we have not sufficient ground for separating these plants generically, and I, 
 therefore, for the present, consider them simply as distinct species of the same genus. 
 Of the figures now published, fig. 2 represents the summit of the frond; fig. 2 a the base. 
 
 Formation and locality. Triassic strata of Los Bronces, Sonora, Mexico. 
 
 TJENIOPTERIS MAGNIFOLIA, Rogers. 
 
 Plate VIII, figs. 3, 4. 
 
 This species is abundantly represented in the collection made at Los Bronces by 
 
 Mr. Remond, and is perhaps the most important connecting link between the Triassic 
 
 beds of Sonora and those of North Carolina and Virginia. It may be recognized at 
 
148 EXPLORING EXPEDITION FROM SANTA FE, ETC. 
 
 once by the remarkably fine, uniform, parallel, simple veins given off at rig] it angles 
 from the midrib. None of the specimens obtained in Sonora rival in size the huge 
 fronds obtained from the coal-beds of Richmond; but it is nevertheless the largest 
 Sonora species, and the largest specimens are fully equal to the average of those found 
 in Virginia. 
 
 There are in the collection of Mr. Remond many simple, narrow fronds, in which 
 the nervation is similar to that described above, and the only difference I can discover 
 between these and the larger ones is in the greater relative width of the rachis in the 
 narrow fronds. It is frequently as broad as in the larger ones, and is seen to be scaled 
 or chaffy toward the base. These narrow fronds are contracted in width, and are more 
 or less waved or ruffled. Possibly these may represent another species, but the differ- 
 ence between the two forms seems hardly sufficient to justify me in considering them 
 distinct. 
 
 JEANPAULIA EADIATA, Newb. 
 
 Plate VIII, fig. C. 
 
 Fronds radiating from a common center and apparently forming a whorl. Each 
 subdivision has a wedge-shaped outline and is several times dichotomously branched. 
 The laciniae are nearly straight, flat, and marked by continuous parallel veins. 
 
 Detached portions of this plant could hardly be distinguished from Jeanpaulia 
 Munsteriana, Ung., from the Rhsetic beds of Bayreuth, as will be seen by the figure 
 now published. The subdivisions of the fronds, or perhaps the distinct fronds, are, 
 however, narrower and straighter than in that species. 
 
 A large number of specimens of this plant occur in Mr. Remond's collection, and 
 some of them possibly represent the European species, being stronger and having 
 the sub-divisions more curved than in the specimen figured. 
 
 It will be regarded as an interesting fact that a well-marked species of Jeanpaulia 
 is found in the Triassic of Sonora, and I have also to add that I have in my hands 
 specimens which indicate the existence of another species of this genus, closely allied 
 to, if not identical with, J. Munsteriana in the Triassic coal-formation of China. They 
 were collected by Prof. R. Pumpelly. I have seen, too, a large and strong species, 
 perhaps new, from the coal-basin of Richmond, Va., whence it was brought by Prof. 
 D. S. Martin. 
 
PLA.TE I. 
 
 Page. 
 FlG. 1. OSTREA LUGUBIIIS 123 
 
 1 a. Under valve attached to a piece of rock, and showing the inside, -with the muscular impression. 
 
 1 6. Outside view of an upper valve of same. 
 
 1 c. Outside view of an under valve, showing the scar of attachment, which is unusually small. 
 
 1 d. Inside view of another specimen. 
 
 Fir,. 2. OSTREA UXIFORMIS 124 
 
 2 a. Inside view of an under valve. 
 2 6. Outside of same. 
 
 2 c. Lateral view of same. 
 
 FlG. 3. EXOGYRA COLUMBEI.I.A f. - 124 
 
 3 a. Outside of under valve, from a wax cast taken in a mould left in the matrix. 
 3 6. An internal cast of an under valve. 
 
 3 c. Side view of same. 
 
 3d. An internal cast left in the rock, of the inside of the upper valve. 
 FIG. 4. ANOMIA NITIDA 125 
 
 4 a. View of an upper valve, with only a portion of the shell attached to the cast. 
 
 4 b. An outline side view of the same. 
 
 FlG. 5. Pl.ICATULA ARKXAKIA !'<<> 
 
 5 a. An internal cast of the under valve. 
 56. Outside of the upper valve. 
 
 5 c. A side view of same. 
 
 FlG. 6. IKOCKRAMUS FRAGII.I8 127 
 
 FIG. 7. CAPROTINA BIOORNIS - 126 
 
 7 a. A view of one of the valves. 
 
 7 6. The two valves together. 
 
 FlG. 8. CVPRIMERIA? CRASSA 128 
 
 8 a. Outside of a right valve. 
 
 S 6. An internal cast of the same valve, showing the muscular and pallial impressions and a cast of the 
 
 hinge. 
 
 8 c. Hinge of the right valve. 
 8 <?. An anterior view. 
 
PALAE ONTOLO &Y of" 
 Capt. Macombs Expls. 
 
 CRETACEOUS FOSSILS. 
 
 Plate I. 
 
 FB.MMk.acl. 
 
 T. Sinclair J< Son. Eih.PMa. 
 
II. 
 
 Page. 
 
 FIG. 1. BACULITES ANCEPS ? : 130 
 
 1 a. Side view. 
 
 1 b. An antisjphonal view. 
 
 1 c. A section of same. 
 
 1 d. A sept'iim of same. 
 
 1 e. A more slender, less compressed individual, with rounded nodes instead of transverse rostai. 
 
 I/. An antisiphonal view of same. 
 
 1 g. An enlarged septum of the same. 
 
 1 h. Transverse section of the same. 
 
 Km. 2. BACULITES ANCEPS, after D'Orbigny, for comparison 
 
 2 a. Transverse section. 
 
 2 ft. A septum. 
 
 FIG. 3. PKIONOCYCLUS ' MACOMDI 1 ;{ 2 
 
 3 a. Side view. 
 
 3 ft. An antisipbonal view. 
 
 Jc. A septum of the game, enlarged. 
 
 3rf. An autisiphoual view of a very small specimen. 
 
 FIG. 4. ACTION INTERCALARIS 1 -'.' 
 
 4 a. View showiug the aperture, which is imperfect in the specimen figured. 
 4 6. A back view of the same specimen. 
 
 4 o. Surface-stria;, enlarged. 
 
 FIG. 5. ANCHURA ? NEWBERR YI 12r> 
 
 FIG. 6. CARDIUM BELLULUM 128 
 
 6 a. Side view. 
 
 6 ft. Anterior view (the left valve being restored). 
 
 FlG. 7. CUASSATELLA SHU.MARDI 127 
 
 7 a. View of a specimen, with the lower part of the valves imperfect. 
 7 b. Cardinal \ iew of the same. 
 
 7 c. An internal cast of a larger specimen. 
 FIG. 8. Ax UNDETERMINED BIVALVE, from the fame rock as fig. 7. 
 
PALEONTOLOGY of 
 Capt. Macomb-s Expls. 
 
 CRETACEOUS FOSSILS. 
 
 Plate II. 
 
 E V .. . 
 
 T Sinclair iSori.V. 
 
PLA.TE III. 
 
 Pace. 
 
 FIG. 1. Deltodus Mereurii, Newb., upper surface 137 
 
 la. " " Newb., side view 137 
 
 Coal- Measures, Santa F6", N. Mex. 
 
 FIG. 2. I'tycliofliix Whipiild, Marcou, upper surface 137 
 
 2a. " Marcou, side view 137 
 
 26. " Marcou, anterior face 137 
 
 Se-2/. " " Marcou, side and front view of small teeth 137 
 
 Middle Cretaceous, Pagosa, Southwestern Colorado. 
 
 FIG. 3. Product UK r.odoms, Newb., ventral valve 140 
 
 Ha. " " Newb., side view 140 
 
 3fc,3c. " " Newb., specimen with narrow hinge 140 
 
 'id. " " Nowb., specimen with broail hingo 140 
 
 Coal Measures, Santa Fe, N. Mex. 
 
 FIG. 4. Pleurolomaria excelsa, Newb., side view 
 
 4a. " " Newb., basal aspect 140 
 
 Carboniferous strata, Canon of Colorado River, Southeastern Utah. 
 
 FlO. 5. Spirifer Texanns, Meek, side view, natural size 
 
 f>a. A dorsal view of same specimen, showing cardinal area and foramen 130 
 
 .Vi. A ventral view of a larger specimen, showing the deep angular mesial sinus 139 
 
PALEONTOLOGY of CARBONIFEROUS ft CRETACEOUS FOSSILS. 
 
 l-'h Expi.-. ^ ^ 
 
 Plate III. 
 
 2f 
 
 
 2c 
 
 4a 
 
 \. 
 
 
 T SmcUit lSon.Elh.PMla. 
 
FLA.TJU 
 
 Page. 
 
 KKJ. l,a. Otozamile* Maoombii, Newb., Copper-mines, near Abiquin, N. Mox 141 
 
 3,4. Branch of conifer, Copper-mines, near Abiquiu, N. Mex 109 
 
 4. Branch of conifer (Braekgfbyllxmf), Copper-mines, near Abiqnin, N. Mex 109 
 
Capt. J.N.Macomb, Rxp. in New Mexico 8-U(ah. 
 
 Plate IV. 
 
 T. Sinclair & Son. Uti. Phila. 
 
FLA.TE 
 
 Fio. 1 , '<!. Zamilcs occidentalis, Newb 142 
 
 la. Newb., pinua! enlarged, Upper Trias, Copper mines, Abiquiu, N. Mex 14i 
 
 3. Olozamitet Macombii, Newb., Upper Trias, Copper-mines, Abiquin, N. Mex 141 
 
 4. Branch of conifer (PaehypJiyUiim f), Upper Trias, Copper-mines, Abiqnin, N. Mcx (i!) 
 
 5. Cone of conifer (PacJiyi>liyllum "), Upper Trias, Copper-mines, Abiquin, N. Mex (!9 
 
Capt. J.N.Macomb, Kxp. in Now Mexico R-Utah. 
 
 Plate V. 
 
 T- Sinclair & Son. Eft.. Ph.Ua. 
 
PLA.TE VI. 
 
 Page. 
 
 Fid. 1. Pecopteri* lullatiis, Bunbury 14 ;! 
 
 la. " " Bunbury, pinnules with sori, Trias, Los Bronces, Sonora 143 
 
 2. Aletliopteri* Mcx\ca.na, Newb 143 
 
 2u. " " Newb., pinna bearing fruit, Los Bronces, Sonora 143 
 
 :!. Pecopteris falcatus, Emnious, in fruit, Los Bronces, Sonora 144 
 
 4. Frond of undetermined fern in fruit, Los Brouces, Sonora < 
 
 5. OtozamUes Macambti, Newb., Los Uronces, Sonora 141 
 
 (>, 60. Pteropliyllum dtlicatiiliim, Newb., Los Bronces, Sonora 144 
 
 7. Pterophyllum robustitm, Xewb., Los Brouces, Souora 14"> 
 
 8. Podozamites crassifolia, Newb., Los Brouces, Sonora '- 
 
 !). Branch of conifer (PadiyphyUum?), Copper-mines, Abiquiu, N. ^lex 09 
 
 10. Branch of conifer ( Palyssia ?), Los Bronces, Sonora 145 
 
dipt .J.N.MaCOmb, Kx|>. in -Vow Mexico 8- Utah . 
 
 Plate V}. 
 
 T. Sinclair & 
 
PLATE VII 
 
 Page 
 
 . 1. Aletlioptrrix ll'liiliieyi, Newb.,. upper portion of frond 14") 
 
 In. Lower portion of frond 14"- 
 
 16. " Summit of frond, Los Bronces, Sonoi a 145 
 
 2. Camptoptrris /i'cio(7i, Newb., central portion of frond 14C> 
 
 .'. " Portion of pinos, ahowiog nervailoo, LoeUronces'Sonora 14(i 
 
Capt. J.N. Ma comb, Kxp. in New Mexico 
 
 Plate VII. 
 
 T. Sinclair !. Son. lift. Bull. 
 
Page. 
 
 Fit;. 1. Tieuiopteris elegant, Newb., Los Bronces, Sonora 
 
 2, 2a. T(fioptens glossopteroides, Newb., Los Bronces, Sonora 
 
 :!. Taniopteris magnifolia, Rogers, Los Bronces, Sonora 
 
 4. Taniopteris magnifolia var. ?, Los Bronces, Sonora . . 
 
 5. Tairiopteri* sp ?, in fruit ; summit of frond, Los Bronces, Sonora 
 
 6. Jeanpaalin railiata, Newb., Los Bronces, Sonora 
 
Capt. J. N. Macomb, Kxp. in New Mexico 8-Utnh. 
 
 Plate. VIH. 
 
 T Sinclair i Son. lift. Fkilo . 
 
INDEX. 
 
 A. p "R e - 
 
 At >ii] 11 iu ' r > 
 
 Abiquia copper-mines 67 
 
 Peak '''I' 
 
 Arl;iM)ii inttsrcalaris 129 
 
 Alctliopteris Mexiciina, (Plato VI.) 
 
 Serlii 18 
 
 Whitneyi II-"' 
 
 Allorisma 98 
 
 Ainimmik's 33,51,52,77,91,99,102,107,1*5 
 
 Anrliurii Ntnvberryi 128 
 
 Aiiiii.:is 76,80,81 
 
 Aiiniilaria sphenophylloidea 18 
 
 Am >ii i in nitida 125 
 
 Aporrhais 99 
 
 Aquarius Mountains 55, GO 
 
 Araucariii excelsa 49 
 
 Arcliu'oeidaris 16,21,47 
 
 Arkansas basin 25 
 
 Arroyo Seco 69, 70 
 
 Artemesiiw . 5 
 
 Atbyris 19,21,43, 45,40, 9(5, 98, 99, 138 
 
 Atrypha 60 
 
 Avit-.iila 47 
 
 Aximis 19,20,47 
 
 A/.tcc Mountains 60 
 
 B. 
 
 Baculitt-H 72,99,102 
 
 anceps 130 
 
 " Ba<i Lands" cif tbo Missouri 26 
 
 Nebraska 27 
 
 Bakevellia 19,20,21,47 
 
 Basalt 26,32,52 
 
 Boar's Ears 85,103 
 
 Bellerophon 19, 20, 21; 47 
 
 Black Hills 29,57 
 
 Bracbypliyllnm 69 
 
 Buttes in Canon Colorado 69 
 
 west ofNaciuiieuto Mountain 112 
 
 near San Juan River 103, 104 
 
 Cabezou 1 
 
 Catamites 45,49 
 
 Camptopteris Reuioudi 146 
 
 Canon of Grand River 97 
 
 Green River 97 
 
 Largo .' 6,64,109 
 
 Pintado 90,92 
 
 Canons 1)7 
 
 Caprotina bioornis 126 
 
 Carboniferous rocks 15, 18,63,97, 106 
 
 Carboniferous sorics 10, 
 
 .-n in in it of 
 
 strata 16,17,19,42, 
 
 CiU'dium bellulmn 
 
 Casa Colorado 
 
 Cataract Creek 
 
 Cephalopoda 
 
 Cerbat Mountains 
 
 Cerrillos, mines of the 
 
 Cerro del Navajo 
 
 Chalk formation 
 
 Chalchnitl 
 
 Chaina 5, 
 
 Clionetes 
 
 Ciiiiarron River ? t 
 
 Circeopsis 
 
 Clu 
 
 Page. 
 22, (W 
 
 95 
 
 46,66 
 128 
 
 92 
 
 98 
 130 
 
 55,59 
 
 40,41 
 73 
 24 
 41 
 
 65,70 
 19 
 
 24,25 
 52 
 
 lay 19,24 
 
 Coal 17,39,98 
 
 Coal-plants, Kansas 17 
 
 Coal-Measures, Illinois 17 
 
 Kansas 16,17 
 
 Missouri , 16 
 
 Santa Fe' 46 
 
 Cobro eg 
 
 Cogswell, Lieut. M 7 
 
 Colorado River 53 
 
 basiu 53,55,83,93 
 
 Canon 37,42,53,93 
 
 Cbiquito 56 
 
 Mountains 59,64,84 
 
 plateau 54,60,62,94 
 
 Conglomerate 27,29 81 
 
 Conifers, Abiquiu copper-mines 69 
 
 Copper, old placer 40 
 
 Abiquiu 67 
 
 Los Cerrillos 41 
 
 Rocky Mountains 59 
 
 Hauta F6 37 
 
 Cottou wood Creek 18 
 
 Spring 30,31 
 
 Cordaites 45 
 
 Crassatolla .Shiiinardi 127 
 
 Creston, the ' 107 
 
 Cretaceous formation 22, 25, 50, 63, 75, 77, 110 
 
 Upper 32, 50, 71, 84, 108, 121 
 
 Lower 16, 24, 32, 50, 63, 121 
 
 Middle 16,32,71,121 
 
 rocks 24,76 
 
 sandstone '_':>,:!( 
 
 Cuchillo 66 
 
 Cyprimeria crassa 128 
 
150 
 
 INDEX. 
 
 D. 
 
 Deltodus Morcurei 
 
 Dinunock, C. H 
 
 Divide, High 
 
 between Rio Grande and Sau Juan 
 Dorsey, Mr 
 
 137 
 7 
 
 78 
 
 ... 74 
 7 
 Dragoon Creek ................................... 18,19 
 
 Drift ............................................ 81 
 
 E. 
 Echinoderms .................... . ............ -. 18 
 
 Eighteen-Mile Ridge ............................. 27 
 
 El Vtulo do los Padres ................. ........... 6 
 
 Enchanted Spring ................................ 30 
 
 Enos, Lieut. H.M ................................ 
 
 Eroded buttes... ........................ 92,96,97,107 
 
 monuments .............................. 94 
 
 Erosion ........................ 28,32,37,50,67,73,112 
 
 of Colorado plateau ...................... 84 
 
 Exogyra columbella ............................. 124 
 
 F. 
 Fish-teeth ................. ..................... 51,108 
 
 Fisher, F. P ..................................... 7 
 
 Fissure, volcanic ....................... ......... 32 
 
 foot-hills ....................................... 72,73 
 
 Fort Union ...................................... 34 
 
 Fossil plants .............................. 29,32,33,69 
 
 Fossils, Carboniferous ............................ 18, 19 
 
 Cretaceous ............................... 32, 33 
 
 Jurassic ................................. 29 
 
 Permian ................................ 19,47 
 
 Fugulina ....................................... 18 
 
 G. 
 Galisteo ........................................ 38,51 
 
 Creek ................................... 38,48 
 
 Gallinas Mountain .............. ..... ............ 34 
 
 Gasteropoda action ............................ 12J 
 
 Gold of Galisteo Creek .......................... 39,40 
 
 Los Cerrillos ............................. 41 
 
 Placer Mountains ....................... 39 
 
 Rocky Mountains ...................... 59 
 
 Santa Fd ................................ 37 
 
 Grand River ..................................... 96 
 
 Granite ........................................ 27,81 
 
 of Santa F6 .............................. 37 
 
 Great Central Plateau ............................ 30,50 
 
 Green River ....... ............................. 97 
 
 Gres-bigarre' ..................................... 22 
 
 Gryphea Pitcher! ............ 33,51,52,71,88,99,104,115 
 
 Guajelotes ....................................... 90 
 
 GulfofMexico .................................. 24 
 
 Gypsum formation ......................... 21, 47, 49, 92 
 
 its parallelism ................. 21 
 
 H. 
 
 llalyinenites .................................... 77 
 
 High Divide ..................................... 78 
 
 High Prairie ..................................... 22 
 
 I. 
 Indian ornaments ............................... 41 
 
 Inoceramus ........................ 51,52,77,87,99,107 
 
 Crispii ............................... 33 
 
 fragilis ........................... 33,72,127 
 
 problematicus ...... 33,52,71,72,108,115,127 
 
 Iron, magnetic . 
 
 of Los Cerrillos 
 
 Rocky Mountains . 
 old placer 
 
 Pag*. 
 
 41 
 
 40 
 
 59 
 
 40 
 
 ore 19,31 
 
 J. 
 
 Jeanpaulia Munsteriana 148 
 
 radiata 148 
 
 Jeinez 46,67,117 
 
 Jurassic formation 21,28,51,69 
 
 fossils 16,22,29 
 
 Labyrinth Canon 95 
 
 Creek 98 
 
 Lagiina de los Cavallos 5,72 
 
 I. Hiiu'lli branchial a 123 
 
 Lamna 33,99, 141 
 
 Las Orejas del Oso 85,103 
 
 Vegas 34 
 
 La Teiiejal 92 
 
 Lava Plain 38 
 
 Lead 37,39,41 
 
 Leda 19 
 
 Lepidodendrou 46 
 
 Lias 22 
 
 Limestone 26, 33 
 
 Fusiilina 16 
 
 maguesian 19,21,22 
 
 tufaceous 28 
 
 Lizards 90 
 
 Llano Estacado 48, 51 
 
 Los Cafiones til) 
 
 Cerrillon 41 
 
 Lower Colorado Mountains 58 
 
 Permian formation 20 
 
 M. 
 
 Manzanita 71 
 
 Marl 21,32,112 
 
 variegated 48 
 
 Marues irisdes 22 
 
 McNee's Creek 31 
 
 Meek, F. B 119 
 
 30, 4H 
 
 above the Chaina 
 
 broken 
 
 High 
 
 Great White 
 
 69 
 
 78 
 
 73 
 
 103 
 
 Verde H3, 85, 100, 107 
 
 Mesas of Navajo and San Juan 63, (M, 10:5 
 
 Mines, copper 07 
 
 gold . 40 
 
 silver 41 
 
 Mogollon Mountains 55, 57, 58 
 
 Monotis Hawni 19,21,46 
 
 Mormon Spring 99 
 
 Mountains drained by Animas 81 
 
 Mount Taylor 55, 114 
 
 Murchisonia 19, 47 
 
 Muschelkalk 22 
 
 Myaliua 19,21,47,98 
 
INDEX. 
 
 151 
 
 N. Page. 
 
 Nacimiento Mountain 7,37,50,67,102, 109,112,114 
 
 Nautilus 19,45,51,77,99 
 
 Navajo Spring 71 
 
 Needles, The 10:?, 107 
 
 Network of canons 97 
 
 Neuropteris llexuosa 18 
 
 hirsiitu 18 
 
 Newberry, Dr. J. S 1,7,9,135 
 
 O. 
 
 Ojo del Cuerbo 90 
 
 Ojo Verde 5,93 
 
 Ojos Heriondos 86 
 
 Old placer M>, 40 
 
 Oolite 22 
 
 Orejas del Oso 85, 103 
 
 Orthis 45 
 
 Orthiniiia 21,43,45.98 
 
 Ostrea congesta 33, 72, 77, 87, 99, 115 
 
 elegantula 33 
 
 lugubris 52,77,107,123 
 
 nniforinis 124 
 
 Otozainites 69,141,142 
 
 Macoinbii 141 
 
 Oxyrhina 33,141 
 
 P. 
 
 Pachyphyllnin 69 
 
 Pagosa 5,74,77 
 
 Palyssia 69 
 
 Pawneo Fork 22 
 
 Pecopteris arboresceus 18, 49 
 
 bnllatns 143 
 
 falcatna i 144 
 
 Mexicaua 143 
 
 Stutgurdtensis 69 
 
 Pecos 49 
 
 Pernio-carhoniftToiis group 20 
 
 I'feiffer, AlBert H 5,67,68,69 
 
 Piedra Parada 77 
 
 Placer Mountains 38 
 
 Plateau west of Rocky Mountains 54 
 
 Plateaus bordering Canon Largo 109 
 
 Platyceras 45 
 
 Plenrophorona 19,20,47 
 
 Pleurotoiuaria 98, 140 
 
 Plicatula areuaria 126 
 
 Podozamites crassifolia , 145 
 
 Pope's Well 51 
 
 Porphyry 26,27,41,52,76,77,81 
 
 Prioncyclus Macombii 132, 133 
 
 Productus 19, 21, 43, 45, 46, 58, 98, 99, 140 
 
 Puerco 7 
 
 Q. 
 
 Quartz 26,27,37,41 
 
 Quercup !t!) 
 
 R. 
 
 Rabbit-Ear Buttes 31 
 
 Rain-fall 40 
 
 Raton Mountains 25,28 
 
 Red beds 47,56 
 
 Red Fork of Canadian 31,32 
 
 Page. 
 
 Reservoirs 89 
 
 Retzia mormon i 43 
 
 Rhynchonella 21,45 
 
 Rio de la Plata 81 
 
 los Mancos 85 
 
 Pinos 79 
 
 Dolores 86 
 
 Florido 79 
 
 Grande 5 
 
 Navajo 73 
 
 Piedra 77, 78 
 
 Rito Blanco 74, 76 
 
 Rock Corral 37 
 
 Rocks, jointed 77 
 
 bright-colored 68, 90, 92 
 
 Rocky Mountain system 55 
 
 Mountains, time of elevation of the 57 
 
 Ruins at Abiqnin 69 
 
 Labyrinth Canon.'. 95 
 
 in San Juan Valley 109 
 
 on the Animas 80 
 
 Dolores 88 
 
 Sage-plain 67', 83, 85, 89 
 
 Saliferous group 48 
 
 Salix Meekii 24,31,32,87,99 
 
 Sandia Mountain 56, 77 
 
 Sand-hills 27 
 
 Sandstone 24, 26, 33 
 
 San Francisco Mountains 55,60 
 
 San Juan 5,74,75,101,106 
 
 San Juan River 106 
 
 San Jos6 Spring 7 
 
 San Mateo 55, 56, 60 
 
 Santa Fe" 5,34,36 
 
 geology of 36,37 
 
 minerals of 38, 39 
 
 Mountains 37, 38, 50, 65 
 
 Santo Domingo 118 
 
 Sarcobatus 90 
 
 Saurian bones 91 
 
 Scaphites Warreni 72,121 
 
 Scoria 28,52 
 
 Section of rocks at breaks of Red River 33 
 
 btitt.es west of Nacimiento 
 
 Mountain 112 
 
 Canon Colorado.... 95 
 
 Pintado 91 
 
 Largo Ill 
 
 camp 34 104 
 
 Captain Pope's Well 52 
 
 Cedar Spring 30 
 
 Cerro Gordo 46 
 
 Colorado Valley 99 
 
 Clift's at Moqui villages 105 
 
 Creston 108 
 
 crossing of Arkansas 27 
 
 Enchanted Spring... 29 
 
 gorge of Santa F<5 River 45 
 
 Labyrinth Creek 98 
 
 Middle Spring of Cimarron 28 
 
 Pawnee Fork 24 
 
152 
 
 INDEX. 
 
 Page. 
 86 
 43 
 48 
 71 
 48 
 
 Section of rocks at Rio Dolores 
 
 Santa F6 
 
 San Jos6 
 
 in the Valley of the Cluima 
 
 Pl'COS 
 
 Sierra Abajo 6, 55, 62, 90, 100 
 
 delos Finos 76,79,80 
 
 de la Plata 5, 56, 7(i, 80, 82, 84, 88 
 
 del Navajo 73,76,77 
 
 el Wanico 66 
 
 La Sal 55,62,85,88,80,93 
 
 La Late 55 
 
 Madre 56,62 
 
 San Juan 75, 76 
 
 San Miguel 56,88,90 
 
 Tucane 55,62 
 
 Sigillaria Menardi - 18 
 
 Silicitied wood 38,110 
 
 SilverofLos Corrillos 1 41 
 
 Sierra do la Plata 81,82 
 
 Rocky Mountains. 
 
 Santa F6 
 
 Simon sou. Major 
 
 Siredon 
 
 Smoky Hill Fork 
 
 Smoky Hills 
 
 Spanish Trail 
 
 Speuophylliim dentatnm . 
 
 59 
 
 37 
 
 6 
 
 90 
 
 22 
 
 24 
 
 6 
 
 18 
 
 Spirifer 43,45,46,60,96,98,99,138,13!) 
 
 Surouara 88 
 
 T. 
 
 Table-lands skirting Rocky Mountains 34 
 
 Taeniopteris 69 
 
 elegans 147 
 
 glossopteroides 147 
 
 magnifolia 147 
 
 Tertiary basin of the Arkansas 24 
 
 fossils 25 
 
 strata 25, 26, 28, 30, 31, 3G, 39, 52 
 
 at Jemez... 11<> 
 
 Pago. 
 
 ThautnatoptcrLs 14(> 
 
 Tierra Blanca '->0 
 
 Mnria 73,77 
 
 Trap 27, 31, 73, 77, nl 
 
 plateaus 34, 117 
 
 butt.es and mesas near Raton Mountains 31 
 
 Triassie formation 47, (>'.!, si, 102 
 
 rooks of Lower San Juan 103 
 
 Turquoise 41 
 
 U. 
 
 Union, Fort 
 
 Upper Colorado 53 
 
 Peimian formation ... 
 magnrsian limestone. 
 
 20 
 21 
 
 V. 
 
 Vada del Chaina ('-7,71 
 
 Vail, Mr 
 
 Valdez, Neponocino 5 
 
 Valles, The 'l~ 
 
 Valley of the Animas 76, HP, si 
 
 Arkansas 22, 28 
 
 Canadian 32, 34 
 
 Cimarron 28, 30 
 
 Little Colorado 63 
 
 Pecos 48 
 
 View from High Divide 78 
 
 of country bordering San Juan 103 
 
 Volcanic action 25, 31, 34, 38, 52, (50, 61 , 62 
 
 Voltzia 4H, 69 
 
 W. 
 
 Walchia 4-i, 49 
 
 Walnut Ureck 21,22 
 
 Wasatch Mountains :,.\i;i> 
 
 Water-supply 89,90,92 
 
 /amites oncidentalis 142 
 
 5 7744 
 
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 1^3 Report of the exploring expedition from 
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