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Rocks of Southern California—Hershey. 275 
to its termination eastward where it approaches Antelope val- 
ley, a distance of about 20 miles and with an average width 
of about 4 miles, is composed of a single series of schists, 
mostly mica schists. There are no granite intrusives and few 
dikes of any kind. Strikes and dips are locally varied, but as 
a whole the strike seems to be prevailingly east-west and the 
general dip northerly at angles of 10 to 40 degrees, averaging 
between 20 and 30 degrees. Going up the mountain on the 
south side, due north from the Mitchell ranch in Mint canon, 
the following succession was made out: 
1. The lower slopes, in places extending up two-thirds of the 
way, are composed of a uniformly light yellowish, coarse, 
' granular mica schist of muscovite and quartz. The mica is less 
abundant than in a typical mica-schist and the general appear- 
ance of the rock suggests an approach to the gneissic structure, 
although it is certainly a different formation than the gneisses 
on the south. The estimated exposed thickness is 2000 feet. 
It seems in general to dip into the mountain and to pass under 
the darker schists of the summit, which it grades into by inter- 
stratification. 
2. A more varied and more typically schistose series of mica 
schists of a prevailingly dark color, much being a dark lead- 
gray, which may be nearly black underground. These schists 
are coarse and granular, but muscovite is abundant. The gen- 
eral appearance of the series is quite unlike the Calaveras 
schists of the Sierra Nevada region, but remarkably like the 
Abrams mica schist of the Klamath region. 
At various places along the crest of the Sierra Pelona are 
masses of micaceous blue limestone schist identical in charac- 
ter with the limestone schists of the Abrams formation. They 
have a regular, thin-bedded structure like lamination, appar- 
ently representing original bedding. In places they are beau- 
tifully contorted. 
At other horizons are thin-bedded, quartzytes, retaining 
sufficient of the original structure to make their detrital origin 
unquestionable. One small knob is composed wholly of 
quartzyte debris. 
The mountain is traversed by narrow bands of a green, 
fine granular rock which, when unaltered, seems to be a chlor- 
itic schist, but in many places it is altered to dull pink talc 
