FORMATIONS IN CALIFORNIA. 177 



ance which added an important portion of the auriferous shxtes to the 

 Sierra Nevada. The Coast Ranges Ijelong to the same mountain system 

 as the Sierra Nevada. The u[)lieaval mentioned was accompanied or fol- 

 lowed by intense metamorphism, the only event of the kind known to have 

 occurred In tlie history of the Coast Ranges. A great non-conformity 

 exists between tlie metamorphic rocks and the overlying late Cretaceous 

 strata. The Tc^jon formation is shown to be Eocene, as it was regardeil 

 by Conrad, and it is here shown to be absolutely continuous with the 

 Upper Cretaceous The ore deposits have an intimate structural connec- 

 tion with the svstem of fissures along which the upheaval of the ranges 

 took place. So, also, has the distribution of volcanic rocks, the earliest of 

 which probably date from the Pliocene. The ore deposits appear to be 

 contemporaneous with and later than the eruptions and have a more or 

 less intimate chemical relation to them. 



Formattons found in California. — Tlic reader uiay perliaps be glad to l)e reminded 

 of the formations which have hitherto been recognized in California It is 

 not absolutely certain that the Archfean occurs in this State, but, as I 

 pointed out some 3'ears since, the unquestionable occurrence of the Ar- 

 cha3an in Arizona, together with the similarity of the rocks of southeastern 

 California to those of the adjoining territory, makes it highly probable that 

 San Bernardino County is largely Archaean. ^ If so, this formation may 

 enter into the composition of the southern Sierra. The geologists of the 

 fortieth parallel exploration also found the Archaean in central Nevada in 

 its normal relation to the Paleozoic and determined areas close up to the 

 California line in this latitude as Archajan. Their investigations did not 

 extend into California, but they showed that during the Paleozoic a conti- 

 nental area existed west of longitude 117° 30', latitude 40°, and it appears 

 certain that this area must have embraced at least a portion of the great 

 Sierra, which is thus probably composed to a considerable extent of Ar- 

 chaean schists. The Carboniferous was first recognized by Dr. Trask in 

 1854" on the McCloud River. Professor Whitney's party found it near 



I Tenth Census Kepts. U. S., vol. 13, p. 47. 



^Repcrt on the Geology of the Coast Mountains etc., by Dr. John B. Tiask, Senate [of California] 

 Doc. No. 14, 1855, p. 50. 



MON XIII 12 



