362 Whitney’s Geology of California. 
begin atthe north, since in that direction the first fossils were 
found. 
At Bass’ Ranch, near Pitt river, (about lat. 40° 45! N.), there 
isa large development of the limestone formation of the Sierras. 
It is highly altered and forms several hills of considerable alti- 
tude. Dr. Trask first noticed fossils in these limestones, and 
mentions the locality in his Report of 1855, where he refers 
them correctly to the Carboniferous; but the material was too 
incomplete for a satisfactory conclusion. Placer mines occur 10 
the region but not in the immediate vicinity, and the relation of 
these limestones to the true auriferous rocks, and to the chain of 
Paleontological Report, (plates 1 and 2). These species number 
ed fourteen, of which only four or five were referred to species 
ore known. number of* others were too imperfectly 
auriferous slates. These, though imperfect, were considered 
identical with those of Bass Ranch. Other fossils, also 1mpe? 
fect, but apparently of the same age, have since been ound 
near Genesee Valley, in a similar rock. All these limestones 
0 
proved, but we are led to infer that they are so from their char- 
acter, from the fossils found near Genesee Valley, and from thelr 
n. 
In the same year, Triassic fossils were found in several places 
east of the Sierra Nevada, in the (then) territory of Nevada. 
hitney, near Dayton, and by 
essrs. Gorham, Blake and R. H : eae 
the Humboldt mining region, omfray in several localits 
i 
