Californian Metainorphic Formations. — Hcrshey. 239 
DISCUSSION OF THE AGE OF THE KLAMATH SCHIST SERIES. 
The common association of serpentine with the Abrams 
formation suggests that the peridotyte was intruded into the 
slates and that the schists represent contact zones of meta- 
morphism about it, and are merely altered portions of the De- 
vono-Carboniferous series or the Bragdon slates. To this hy- 
pothesis there are two fatal objections. • 
1. The original or unaltered sedimentary formations of the 
schist series, the Devono-Carboniferous series and the Bragdon 
slate series were of a similar character petrographically (and 
might be expected to yield like products under like conditions 
of metamorphism) hut the sequence of the strata was different. 
No amount of metamorphism could have converted the Brag- 
don slates or any portion of the known Devono-Carboniferous 
into a series as the mica, graphite and hornblende schists. That 
layer of graphitic schist is extremely important in this connec- 
tion. By means of it and the nearly purely siliceous layers 
outcropping as apparent large glassy quartz veins, we are able 
to determine that the mica schist everywhere in the Klamath re- 
gion represents the same portion of the original sedimentary 
series, and the hornblende schist always a certain higher portion 
while the recognized Devono-Carboniferous nowhere contains 
representatives of this portion of the original sediments and the 
Bragdon series is so very different as to be quite out of the 
question. 
2. Along several lines in the Klamath region the Devono- 
Carboniferous and the schist series are in contact and "dikes'" 
or narrow belts of serpentine appear along these lines. On 
Hay Fork mountain in southern Trinity county, a narrow belt 
of the serpentine is bounded on the west as usual by mica schist, 
followed by the graphite and hornblende schists. On the east 
it is bounded by a belt of the characteristic schistose slate (cut 
by greenstone dikes) of the Devono-Carboniferous. Now, if 
the mica schist is an altered portion of the Devono-Carbonifer- 
ous and due to the intrusion of peridotyte, why was the met- 
amorphic action so very much more intense on one side of the 
dike than on the other ? These conditions are exactly repeated 
along the boundary between the undoubted Devono-Carbonifer- 
ous and the schist series in the vicinity of Cecilville and the 
King Solomon mine in southwestern Siskiyon countv, except 
