236 The American Geologist. "^i'"^- ^^^2- 
The eastern schist belt emerges from beneath the Creta- 
ceous sandstones and shales in the Sacramento valley west of 
Ono, with a width of eight miles and gradually increases as 
it advances northward to a maximum of about twelve miles 
west of Scott valley. Southward from the Trinity river, the 
pre-Paleozoic area is occupied chiefly by the Abrams mica 
schist, the hornblende schist being confined to narrow strips, 
but northward from the Trinity river, the hornblende schist 
spreads out and finally nearly excludes the mica schist as in 
the valley of the South Fork of the Salmon river. Still farth- 
er north, in the mountains west of Scott valley, the mica schist 
has again asserted its supremacy. 
The structure within the schist belt is somewhat obscure, 
but it is certain that there is no sharp folding of the schists as 
in the areas of newer and less rigid formations. At one time 
I thought I saw evidences of two narrow anticlines in the schist 
area south of the Trinity river, but now I am less confident of 
that conclusion. It appears to me rather that the schists have 
been elevated to unequal bights in irregular areas without the 
formation of any clearly anticlinal or other symmetrical types 
of structure. Mapping, considered in relation to the present 
topography, is developing the situation and shape of some of 
the structurally depressed and elevated areas of the schists and 
little more can be said about them at present. 
The space between the two schist belts has a width south 
of the Trinity river of about twenty-four miles and northward 
in approaching the Klamath river increases to about thirty five 
miles. It is occupied mainly by the Paleozoic series, although 
somewhat west of the center there is a narrow belt of Mesozoic 
rocks, consisting of the Clear Creek volcanic series and the 
Bragdon slate series. The Paleozoic series is difficult of sep- 
aration into its constituent members because of its comparative 
uniformity of character throughout, but the presence of Uppef 
Carboniferous fossils just cast of the Mesozoic belt as found 
by the writer at Patterson's on New river in western Trinity 
coimty, and by Mr. James Storrs* (an assistant of Mr, Diller) 
near Harrison gulch in western Shasta county, makes it evi- 
dent that the Mesozoic series rests upon the upper members of 
the Paleozoic series. 
* Bulletin of the V. S. Geol. Survey, No. 196, Series F, Geography, 31, p. 64. 
