PHVSIOGRAPHY OF KLAMATH MOUNTAINS 159 
course across this fold developing in nearly every case deep and 
narrow canyons, and proving its gradual elevation. The result 
of this action is a type of valley peculiar to this region, namely, 
that of valleys entirely inclosed by mountains and drained 
through deep narrow canyons. The larger basins of the Kla- 
math Mountains include the Rogue River basin and that of 
the Trinity River. Both contain upper Cretaceous and Neo- 
cene deposits, almost or quite conformable, overlain by beds of 
volcanic tuff or lavas. During both of these periods the valley 
of the Klamath Lakes was connected with the Rogue River 
drainage, which condition extended into the latest Tertiary 
times. 
The lake systems of the Neocene were two, that of the 
upper Rogue River (Klamath) basin, and that of the Trinity 
basin. Throughout the Tertiary, volcanic eruptions were in prog- 
ress, and following:this period occurred some of the later flows 
of lava and the formation of beds of volcanic tuff throughout 
the Cascade range and eastward. The latest flows accompanied 
by more or less faulting diverted the drainage of the Klamath 
Lakes from the Rogue River to the Klamath, and accompanying 
movements in a similar manner disturbed the drainage in other 
portions of the Klamath Mountains. 
F. M. ANDERSON. 
BERKELEY, CAL., 
TgOl. 
