226 The American Geologist. -^p^''- i^^^- 
about it was of a rather desultory character, hardly calculated 
to give one a comprehensive and correct knowledge of its geol- 
ogy. The present writer has been engaged in prospecting 
for the precious metals in the Klamath region for nearly 
two years, during which many sections of the territory have 
been traversed and although there was not carried on a sys- 
tematic study of any particular geological problems, it has 
resulted, it is believed, in the accumulation of sufficient knowl- 
edge of the structural relations of the formations of that re- 
gion to make possible a classification of the metamorphic rocks. 
DESCRIPTION OF FORMATIOXS. 
The pre-Cretaceous rocks of the entire Klamath mountain 
region (aside from the eruptives occurring in batholiths and 
dikes and unquestionably of an intrusive character) may be 
classified into seven great formations as in the following table 
which represents their structural positions although not nec- 
essarily their age relations : 
I. The Upper Slates or Bragdon formation. 
The Greenstone or Clear Creek formation. 
The Lower Slate Series 
The Hornblende Schist or Salmon formation. 
The Mica Schist or Abrams formation. 
The Serpentine or Trinity formation. 
The Gabbro or Tamarack formation. 
The structural relations and age of the serpentine consti- 
tute the great problem in the geolog}" of the Klamath region. 
In the Coast range region a petrographically similar serpen- 
tine is an altered peridotyte, unquestionably intrusive in the 
Franciscan series, of an age at least not earlier than the 
Jurassic ; but in the Klamath region I cannot find the same 
evidences of the serpentine being intrusive in the metamorphic 
sedimentaries. The subject is a complex one, and requires 
further field work for its solution ; hence, in this paper I shall 
confine. my attention to the schists, slates and associated forma- 
tions. 
The Abraiits 'mica schist. — Large bodies of schists of a 
prominently micaceous character are not of common occur- 
rence in the rocks of the Klamath region except as constitut- 
ing a single well-defined formation, for which from its relations 
to neighboring terranes being best worked out in the upper 
