Rocks of Southern California.—Hershey. 277 
partly converted into schist. These may be fragments of a 
newer schist series than the Pelona series, but I fear the evi- 
dence is deceptive and the phenomena due to alteration of the 
yellow schists by a Tertiary deposit once resting on them. 
The schists of Pelona mountain are equally metamorphosed 
throughout and show regional and in nowise local or contact 
metamorphism. They were altered to about their present de- 
gree long anterior to the intrusion of the neighboring Meso- 
zoic granites. 
So strongly have I been impressed by the similarity in lith- 
ology and sequence of the dark member of the Pelona schists 
and the Abrams mica schist, and their marked dissimilarity 
from any schists observed anywhere else in California, that i 
propose to correlate them tentatively. The Salmon hornblende 
schist proper is absent in southern California. During the 
past summer, Prof. A. C. Lawson, while reconnoitering the 
area of the hornblende schist in Siskiyou county, suggested 
that its chemical composition and remarkable uniformity 
throughout a great thickness indicate that it was originally a 
fine water-laid volcanic ash rather than the ordinary shale or 
slate which I had maintained as its pre-metamorphic con- 
dition ; and thereupon I remembered that the lower portion of 
the formation in the Bully Choop region has a structure very 
suggestive of highly altered squeezed or sheared tuffs such as 
are common in a later volcanic series of the Klamath region. 
If the hornblende schist was originally a tuff as is probable, 
it may have been more local in development than the associated 
mica schist and perhaps no great body of it was formed in 
southern California. It is also possible that it was developed 
in the Pelona region but has been destroyed by erosion; the 
attitude of the schists is such that it is due above any portion 
of the mountain; the very highest strata exposed are those 
which in the north are the transition beds. 
The coars2 yellow schists forming the lower member of the 
Pelona series have not been identified in the Klamath region. 
So far as known their horizon is not due at the surface as the 
Abrams schists have nowhere been sufficiently elevated and 
eroded. We, therefore, probably have in southern California 
older rocks than any known in the northern part of the state. 
