is ha: oa oe 
266 Mineralogy and Geology. 
ing. In the geological Report by Dr. Newberry the possibility of 
the gold region being Carboniferous is mentioned. He says: 
“from its relations to the limestone discovered by Dr. Trask near 
the base of Mt. Shasta, and which is of Carboniferous age, one may 
suspect it to belong to that era.”* On p. 29 he observes: “If, a 
seems probable, the fossiliferous limestones of the mountains con- 
nected with Mt. Shasta shall prove to be continuous with the lime- 
stones of the Sierra Nevada referred to above, they will perhaps 
serve as a awe by which to unlock the whole structure and age of 
the great Californian range.” 
In a descriptive notice by the writer of the gold veins and de- 
posits of New Mexico, the following observation occurs: “It is 
remarkable that in one place at least, gold occurs in strata of quart- . 
zose sandstone probably of the age of the Carboniferous, and in 
great ferruginous beds rather than in veins,” 
At the time the foregoing observations were made, it was the - 
commonly accepted opinion that gold bearing rocks in general and 
especially in North America were of Silurian age. To venture to 
rany portion of the California formations to a period more 
recent, and as late as the Carboniferous, was a bold step in advance, 
Lif it was not initiative, it is at least one of the links in the 
e regarded: as characteristic of the rocks of any particular geo- 
logical epoch and that it may be found in formations of any period 
e the conditions are favorable. ’ 
If in opposition to the evidence which has been presented, it 
valley has afforded additional evidence, and yet Mr. Brewer ver 
justly does not positively assert the Carboniferous age of this belt 
southward, but says “all these limestones are of the same litho- 
logical character, and there seems little doubt that all the patches 
are of the Carboniferous age that lie in nearly a direct line from 
pe ote Klamath river to Tahichipi valley a distance of over 
mi 
In the article by Prof. Brewer on the age of the gold-bearing 
rocks of the Pacific coast,§ he controverts the writer's statement 
t the Silurian age of the gold rocks of California has not always 
been assumed, by partially citing paragraphs from 
8 
iy paragraphs, it is 
covery should they [the rocks] actually prove to be Silurian by 
* Pacific d Reports, i, p. 22; 
Rrotectinge Seas Geen i A a 
‘This Journal, xli, May, 1866, p. 362. 
Tid, xlii, July, 1866, p. 116. 
