CHAPTER IV 

 GEOLOGY IN THE WHEELER REPORTS 



REPORTS ON THE GREAT BASIN AND PLATEAU PROVINCES 



Gilbert's first season of western work led him rapidly into a region of "mountain intricacies, 

 rigid plateau contours, and desert wastes," as Wheeler described it. The young geologist had 

 to carry on his studies, which were regarded as subsidiary to the main geographical object of the 

 expedition, as well as he could. Naturally and necessarily his work was incomplete. Yet his 

 chief, as if to forestall a reexploration of the region by one of the rival surveys, announced his 

 belief that "the geological matter" gained by Gilbert and bis associates "when supplemented, 

 as it soon will be, by a series of geological maps and paleontological reports, will answer all the 

 present needs of the Government and of the industries of these partially inhabited areas, in 

 which, for years to come, geological or other scientific examinations will find but few localities 

 where sectional industrial interests may be healthfully promoted with economy to them or to 

 the Government." 



The young geologist was under no such illusion. Although his chief credited him with 

 having "aided to give form to the work of the geological parties," it is plainly to be understood 

 from many pages of bis reports that he regarded his journeys as mere reconnaissances. For 

 example, in his first chapter he explicitly states that the Inyo Mountains, one of the larger ranges 

 next east of the southern Sierra Nevada, are "too important and complex to be characterized 

 by our meager data." He felt that it was tantalizing to see 8,000 feet of bedded rocks beauti- 

 fully displayed in bare mountains, near the middle of the oblique California-Nevada boundary 

 fine, and "yet be unable to examine a single stratum." At many points bis observations were 

 regarded as "too cursory to warrant individual mention." He understood that it would be 

 premature to attempt a full discussion of the Great Basin "before the characters of the basin 

 ranges shall have received more thorough study than has been possible for us." But the most 

 emphatic statement concerning the limitations of his work is to be found in a printed "Pref- 

 atory note," dated 1876, which he prefixed to the unbound copies of bis reports on the three 

 seasons of field work, reprinted for personal distribution from Wheeler's Volume III, with the 

 special title: "On the Geology of Portions of Our Western Territory Visited in the Years 1871, 

 1872, and 1873." The note is in part as follows: 



The observations which form the basis of these reports were hurried in the extreme. The writer, for the 

 most part, accompanied field parties which were specially equipped for rapidity of movement and were crowded 

 to the utmost. Moreover, in a country almost unmapped the demand for geographical information was more 

 urgent than that for geological, and all plans and routes were accordingly, and with propriety, shaped to give 

 the topographer the best opportunities consistent with rapidity of movement, while the geologist gleaned what 

 he could by the way. To study the structure of a region under such circumstances was to read a book while 

 its pages were quickly turned by another, and the result was a larger collection of impressions than of facts. 

 That many of these impressions should be erroneous was inevitable, and no one can be more conscious than I 

 of the fallibility of what I have written. Still I am far from counting my labor lost; for the best presentations 

 that have been given of western geology are not free from error, and I certainly have most honorable company 

 in my imperfection. 1 



1 The remainder of the "Prefatory note" is here given, in order that the corrections which it includes may be added to the original Volumo 

 III of the Wheeler Survey by those who possess it uncorrected. 



"More than a year has elapsed since the manuscript left my hands and in that time I have again visited Utah. Partly as the result of my 

 new work, and partly by facts which have been developed by others, I have been induced to change some of my ideas and I avail myself of this 

 occasion to mate a few retractions." 



" On page 132, basalt is erroneously reported to occur near the town of Salina, Utah. 



"On page 44, it is stated that an orographic disturbance occurred in the northeast part of the plateau province 'before the deposition of the C re- 

 taceous.' The unconformity which I ebserved I now know to have arisen after the deposition of the Cretaceous. 



"On page 116, the opinion is expressed that artesian water might be found along the eastern base of the Pahvant range. Mr. Howell has since 

 discovered a fault in the strata of that locality which greatly diminishes the probability. 



"It is asserted on pages 129, 130, and 525 that the San Francisco lava-field is continuous with the great lava-field of New Mexico. The notes of 

 Dr. Loew show that this is not so. 



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