Rocks of Southern California.—Hershey. 281 
degree of alteration is fully as great as that of the Pelona 
schist series. Its relations to the latter are not known and can- 
not even be conjectured. It is curiously associated with the 
eneiss series and small patches of brown schist like the San 
Emedio series occur in the gneiss area south of Pelona moun- 
tain, but what may be their significance I cannot say. I should 
like to place it in the interval between the Algonkian and the 
Mesozoic, (and in the Santa Lucia range it has been classed as 
Carboniferous for no very good reason,) but it has the same 
claims for a pre-Cambrian age as the Pelona schists. Its age 
remains one of the interesting problems of the older crystalline 
rocks. 
The gneisses, schists, granites and limestone of this Fraser 
mountain region were first discovered by the members of 
‘Whitney’s survey and have since been reported on by Dr. H. 
W. Fairbanks, but no attempt was made to classify them. 
THE MESOZOIC GRANITES. 
Near the head of the Tick canon, there is a long, narrow, 
east-west dike of white, medium-grained, very acid granite, 
composed of quartz and feldspar, with no appreciable quanti- 
ties of biotite or hornblende. It is intruded in gneiss and being 
unsheared, strongly contrasts with it. North of the divide, in 
the basin of Mint creek, there is a small batholith several miles 
in diameter, Of a very light colored, unsheared, muscovite 
granite, intrusive in the gneiss series. About the main mass 
are apophyses of similar granite cutting through the gneisses 
on the south, and the schists on the north. It is composed of 
quartz, a straw-yellow, varying to light pink feldspar, and mica, 
of which white pearly muscovite is conspicuous; but there are 
no appreciable quantities of biotite or hornblende. 
The mountain range directly north of the Sierra Pelona 
has soil of a uniform light yellowish color suggesting granite. 
Further west the same range, the Sierra de la Liebre becomes 
streaked suggesting the gneiss series. The Tehachapai range 
is almost exclusively granite which near the western end is 
of the light pink, very acid variety. Alamo mountain in Ven- 
tura county is partly composed of a darker, more basic gran- 
ite and this in Piru canon is overlaid by a great thickness of 
dark olive Cretaceous shales, probably Knoxville, with a very 
coarse basal breccia-conglomerate, 500 feet thick. 
