S$ 
PILOT MTS. 
N 
Esmeralda County, Nevada.—Turner. 267 
CHERT, LIMESTONE AND SHALE. 
SECTION OF THE JURASSIC ROCKS OF THE PILOT MOUNTAINS. 
CHERT 
RED SHALE 
SHALE ANUVESITE 
SHALE 
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The Mesozoic Era. 
Jurassic. The Pilot moun- 
tains are composed of sedi- 
ments which on the western 
side dip rather evenly to the 
south-east at angles of 40°-70 
degrees. As seen in Dunlap 
Canyon at the north base of 
the mountains, the rocks 
lowest down in the series are 
sedimentary breccias, com- 
posed of angular fragments 
of cherty rocks, cemented by 
finer material, then succes- 
sively limestone with fossils, 
shale, limestone and_ shale. 
Still higher lie the thin bed- 
ded chert layers in which the 
Pacific copper mine lode is 
located. The fossils found in 
the lower limestone were re- 
ferred to Prof. J. P. Smith of 
StanfordjUniversity, who de- 
termined the following fos- 
sils: 
Cidaris, sp. undet. 
Terebratula, sp. undet. 
Spiriferina, sp. undet. 
Pentacrinus, sp. undet. 
Entodium cf. meeki Hyatt. 
These appear to indicate 
a lower Jurassic age. 
The Tertiary Era. 
In Tertiary time the Great 
Basin was _ pre-eminently 
characterized by broad lakes, 
flowing streams and _ large 
and numerous volcanoes. As 
evidence of the existence 
of the lakes, we have sand- 
stones, shales and _ lacustral 
