PHYSIOGRAPHY OF KLAMATH MOUNTAINS 157 
Contemporaneous Neocene deposits are now found at all ele- 
vations in the Klamath Mountains, up to four thousand feet, and 
in such relations that it is clear that differential elevation of the 
region has occurred since their deposition. Probably some of 
these disturbances were coincident in time with the faulting that 
has been described as occurring in the Great Basin. In the 
interior of the Klamath group, faulting on ascale comparable to 
that of the Great Basin has not yet been clearly recognized, 
though many minor faults occur that perhaps coincide in time. 
Sharp flexures, as that along the western border of Scott valley, 
occur, some of which may be traced for many miles, but there 
are no well established extensive fault lines. 
DEVELOPMENT OF THE PRESENT DRAINAGE. 
During middle or late Neocene times there existed among the 
Klamath Mountains and along their southern and eastern borders 
extensive series or systems of lakes that-have left their deposits 
in unmistakable evidence. These deposits rest conformably upon 
those of later Cretaceous, in such a manner that they have not 
always been distinguished. 
During the period which intervened between the deposition of 
these two series of strata—the Eocene—we are left to infer that 
there was unrestrained erosion and aereal reduction throughout 
the region, covering indeed the long interval between the close 
of the Chico and the opening of the Ione, to the effects of which 
those of the Ione itself were added. Whatever traces there may 
be, therefore, of an ancient peneplain in the Klamath Mountains, 
it must doubtless be in part referred to this time. The fact 
should be emphasized that the drainage of the Klamath Moun- 
tains is westward, and it has probably remained so since Cre- 
taceous time. There is no drainage that can properly be called 
eastward from these mountains, while the streams leading to 
the west derive their waters even from the eastern limits of the 
group, and probably during the Neocene period it was much the 
same. The canyons, or river channels of the period had been 
developed approximately to their present length and are fairly 
