516 REPORT OF NATIONAL MUSEUM, 1904. 



Triassic. The limestones in the Gray Mountains had been referred by 

 Doctor Trask to the Carboniferous formation. With this reference 

 Whitney agreed. 



The peculiar dome-shaped concentric structure of the granite in the 

 Sierras was dwelt upon with considerable detail, and the curved struc- 

 ture of the sheets regarded as having been produced by the contrac- 

 tion of the material while cooling or solidifying. The Yosemitc 

 Valley itself he thought to be due to a differential movement, the half 

 dome seeming beyond a doubt to have been split asunder in the 

 middle, one-half having gone down in what he calls "the wreck of 

 matter and the crush of worlds.' 1 In other words, he regarded the 

 valley as due to the downward drop of an enormous fault block." 



The first volume of the paleontological reports appeared in 1864. 

 This comprised 243 pages, with 32 full-page plates of fossils, the Car- 

 boniferous and Jurassic being described by F. B. Meek, and the 

 Cretaceous and Triassic by W. M. Gabb. Concerning the work thus 

 far done, Whitney wrote: 6 



Perhaps the most striking result of the survey is the proof we have obtained of 

 the immense development of rocks, equivalent in age to the upper Trias of the Alps, 

 and paleontologically closely allied to the limestones of Hallstadt and Aussee, and 

 the St. Cassian beds, that extremely important and highly fossilliferous division of 

 the Alpine Trias. 



Further on he says: 



Enough (fossils), however, have been found to justify the assertion that the sedi- 

 mentary portion of the great metalliferous belt of the Pacific coast of North America 

 is chiefly made up of rocks of Jurassic and Triassic age. * * * "While we are 

 fully justified in saying that a large portion of the, auriferous rocks of California consist 

 <f metamorphic Triassic ami Jurassic strata, we have not a particle of evidence to 

 uphold the theory * * * that all or even a portion are older than the Carbon- 

 iferous. * * * We are able to state * * * that this metal (gold) occurs in 

 no inconsiderable quantity in metamorphic rocks belonging as high up in series as 

 the Cretaceous. (P. 261.) 



Subsequent to this, apparently W. P. Blake, as geologist of the 

 California State Board of Agriculture, made a claim to having, in 1863, 

 found on the American River a fossil ammonite, which he regarded as 

 establishing the secondary age of the gold-bearing strata. It was 

 claimed by Prof. W. H. Brewer, however, that Blake did not know 

 for a certainty if the specimen was found in place or, indeed, if it 

 were an ammonite or ceratite; also that the fossils were not found so 

 early as the date claimed by Blake (1863). Brewer is very emphatic 

 in his statements to the effect that Whitney was the first to announce 



a Later investigators have been inclined to regard the valley as due merely to river 

 erosion, facilitated by the vertical jointing of the rocks. (See II. W. Turner, Proc. 

 CaliforniaAcademyofScienc.es, Geology, I, No. 9, 1900.) 



& American Journal of Science, XXXVIII, November, 1S64, pp. 256-204. 



<See American Journal of Science, XLII, 1886, p. 114. 



