156 The American Geologist. March, 1892 
its being possible at any one point to say, here the Coast Ranges 
end and the Sierras begin. ’’* 
Dr. G. F. Becker, of the U. 8. Geological Survey, follows 
Prof. Whitney in classifying the metamorphic rocks of the Coast 
Ranges as Cretaceous. In his monograph on the Quicksilver 
Deposits are many statements to this effect. The only exception 
he makes is that of the Gavilan range.+ In addition he does not 
deny that older rocks may exist in other parts of the Coast 
Range, and have undergone a second metamorphism at the time of 
the upheaval of the Cretaceous.{ Again he says, ‘‘No fossils 
older than the Knoxville group are known to occur in the Coast 
Ranges, and no known fact suggests the existence of older rocks, 
except the character of the limestone and gneissoid rocks of the 
Gravilan range.”’% In the summary he says, ‘‘Atthe close of the 
Neocomian an upheaval took place with extraordinary violence, 
folding and crushing the rocks, and producing the first ranges 
along the coast of California of which any record remains.” 
As aresult of his study in the Lassen’s Peak district, J. 
Diller would place the dividing line between the Coast Ranges 
and Sierras in a depression of the Auriferous series, between Pitt 
river and the North Fork of Feather river. | 
Many other geologists of prominence have undertaken investi- 
gations in the Coast Ranges, but there seems to have been no pro- 
test made against the generally accepted classification of the 
metamorphic rocks. 
No attempts to get at the true position of these rocks from 
their stratigraphical relation seems to have been made, though 
the merging of the Coast Ranges into the Sierras at both ends 
gives the best opportunity for such an investigation, 
No fossils have been found in rocks which I recognize as be- 
longing to the metamorphic series. An Inoceramus found in the 
sandstones on Alcatraz island was claimed by Prof. Whitney as 
certain proof of the Cretaceous age of the metamorphic rocks 
forming the San Francisco peninsula, on account of lithological 
similarity. This I consider no proof as I have seen the pre- 
Cretaceous rocks in several localities exhibiting so little meta- 
ze Auriferous Gray els, p. 24. 
tGeology of the Quicksilver Deposits, p. 181. 
[Geology of the Quicksilver Deposits, p. 187. 
SGeology of the Quicksilver Deposits, p. 186. 
Geology of Lassen’s Peak District. 
