380 Whitney’s Geology of California. 
the diggings in several cases. We expect most interesting Te- 
sults from a careful study of the vertebrate remains, which we 
trust they will receive. , 
Farther north, where the lava has flowed over extensive flats 
and slopes in sheets rather than in streams, the gravel is often 
worked beneath the beds. For reasons obvious to the reader, 
range of hills, called the Gopher Hills. The first is rather reg 
ular, and claims have been located in regular sequence for some 
twelve miles in length, the direction of the productive part of 
the lode being about N. 30° W., the claims curving to the north- 
ward as it goes west. The other line is more irregular and the 
tem ber. 
At present the two principal mines at Copperopolis are the 
“Union” and “Keystone,” both of which are opened on an €X- 
tensive scale, and have sent large quantities of ore to market. 
bons gem = rie rie 2 — At the latest accounts the low- 
est levels had reac a depth of he mine 
continued still to be rich, aoe 
‘te ore 1s copper pyrites, more or less mixed with irot 
pyrites, the latter in some of the mines greatly reducing the per 
