Geological Notes on the Sierra Nevada. — Turner. "22i> 
Crystalline Schists. 
Apart from the contact-metamorphic schists and mica 
schists, known to be in part of Jura-Trias and Carboniferous 
age, there are some areas of gneissoid schists, which may be 
much older. One of these is exposed in the canyon of the 
north fork of the Mokelumne river, to the east of the quartzite 
bluff known as Devil's Nose, on the Big Tree atlas sheet. 
These schists consist largely of brown mica and feldspar, but 
carry also at some points abundant quartz, monoclinic and 
rhombic pyroxene, and brown and green hornblende, with ac- 
cessory minerals. The series is cut by numerous granite 
dikes. Only a superficial examination has thus far been made 
of these rocks. 
Grizzly Formation. 
This name has been given by Mr. Diller* to the Grizzly 
quartzite and Taylorville slates in which are limestone lenses, 
from which the following fossils were collected : 
Crinoid stems. Stromatopora. 
Zaphrentis. Syringopora. 
Heliolites. Elalysites catenulatus. 
Orthis. Ormoceras. 
A continuation of the slates of this formation appears in 
the northeast portion of the Downieville sheet, but no Silurian 
rocks are known to enter into the composition of the main 
mass of the range. 
Calaveras Formation. 
A large portion of the sedimentary rocks of the auriferous 
slate seriesconsist of argillite, quartzite and mica-schist, witli 
lenses of limestone. Few determinable fossils have been 
found in these rocks and these chiefly in the limestone lenses- 
Rounded crinoid stems, suggesting the Paleozoic era. have 
been collected at many points by the U. S. Geol. Survey, and 
in addition the following more characteristic fossils: 
Pleurotomaria. Phillipsasl rea. 
Polyphemopsis. Clisiophyllum gabbi. 
Loxonema. Lithbstrotion whitneyi. 
Spirifera. Fusulina cylindrica. 
The limestone at Pence's ranchf containing Productus 
*Text, Lassen peak sheet, and Bull. Geol. Soc. Am., vol. '■'>. p. 376, 
f Geology of California, vol. i. p. 210. 
