244 ^^^ American Geologist. -^p*''' '^^^'^ 
vono-Carboniferous and schist series of the Klamath region is 
similar to that between the Carboniferous, Cambrian and 
Archaean of the Appalachian region. Upon a superficial survey 
the Abrams mica schist might be classed as Archaean in age. 
However, I do not think it is that old, for the following rea- 
sons : The Archaean complexes of the eastern states are almost 
invariably highly contorted and their original clastic nature to- 
tally destroyed, if, indeed, any parts of them are metamor- 
phosed sedimentaries. As we approach the Pacific coast, the 
supposed Archaean terranes are less contorted, but the original 
planes of deposition are usually not apparent. The series con- 
tains granites, gneisses and schists, but never, so far as I know, 
such an assemblage of formations as the mica, graphite and 
hornblende schists of the Klamath region, and so perfectly pre- 
serving in considerable areas their original stratified structure. 
The general appearance of the series is similar to that of 
the Algonkian formations in the Appalachians, lake Superior 
region and the Black Hills of South Dakota. These Algon- 
kian terranes frequently are but little contorted, lie at compara- 
tively low angles, display evidence of their clastic nature and 
original stratification, and yet are highly crystalline in charac- 
ter. The same is true of the Klamath schist series. 
Opposed to the idea of a Cambro-Silurian age for the 
Klamath schists is the presence in dififerent parts of California 
of known Silurian and Cambrian strata much less metamorphic 
in character. About the northern end of the Sierra Nevada 
mountains Diller has found strata whose fossils indicate a 
Silurian age."^' From the description, these do not appear to be 
greatly more altered than the Carboniferous of the same region 
or the Devono-Carboniferous of the Klamath region. In Inyo 
county, there have been found Lower Cambrian strata, also not 
more metamorphic in character than the Devono-Carboniferous 
of the northern part of the state.f 
Yet, in other parts of the Sierra Nevada region there are 
schists very similar in character to those discussed in this 
paper, notably in the Big Trees area.'l It is usually implied 
that these schists are only more altered portions of the Car- 
* Descriptive text of the Lassen peak folio, U, S. Geol. Atlas. 
t Am. Jour. Sci., vol. xlix, 2395, p. 141. 
t Seventeenth Annual Report, U. S. Geol. Sur., p. 536. Am. Geol. vol. xiii, 
1894, p. 229. 
