154 F. M. ANDERSON 
proved whether the beds occurring along the western slope of 
the Cascades should be regarded as the western margin of 
deposits underlying the Klamath Lakes, or belong to an inde- 
pendent body. It seems almost certain, however, that the basin 
of the Klamath Lakes must contain similar deposits, and that the 
Neocene drainage of the same basin was westward, and therefore 
that there was at least a connection with the deposits of Rogue 
River valley. Probably the connection was closer than one of 
mere drainage. But in any case it yet remains to be seen by 
which channel these waters reached the sea. If the outlet was 
by the present course of the Klamath, it must have traversed a 
mountainous country for at least one hundred miles, crossing 
masses of eruptive rocks like so many barricades, and the present 
dimensions of the canyon seem hardly proportional to the time 
and the volume of water that should have been discharged. 
On the other hand, an alternative but little less difficult 
remains in supposing the outlet was through the Rogue River 
valley. Still, as we have said, the Rogue River valley is a 
structural depression dating at least from late Cretaceous time ; 
and this fact lends a strong degree of probability for an outlet 
through this channel. Furthermore, the Cretaceous deposits of 
the Rogue River valley, as well as the older formations upon 
which they rest, show a broad line of terracing similar to that 
described by Mr. Diller in the upper Sacramento valley. This 
could only have been done in the presence of a body of water 
in post-Chico times, or by the reducing action of a large stream. 
It seems most probable, therefore, that the Neocene drainage of 
the upper Klamath basin was through the Rogue River valley, 
and that more recently it has been diverted to the present chan- 
nel of the Klamath. 
Overlying the Ione deposits, if there are such in the valley of 
the Klamath Lakes, are lake deposits apparently of a younger 
age. Possibly they may represent those of the Lahontan epoch 
described by Russell.t. They consist for the most part of white 
diatomaceous and clayey beds extending far to the south, east, 
t Monograph X/, U. S. Geol. Surv., p. 143 et. seg. 
