Klamath Momitains, California. — Hcrshey. 153 
obtaining for miles along the valley and I consider them of 
the same age. 
The fine gravel and silt in the basin have been mostly re- 
moved by erosion, but near the Couzetti hydraulic mine, there 
is a nearly perpendicular bank of them over 150 feet high. 
Resting on the fine, stratified, boulderless gravel there is a 
glacial moraine. This displays, where cut by the bank, a het- 
erogeneous mixture of rock debris including granite boulders 
embedded in a sandy clay. It is piled up into a low ridge, the 
surface of which is encumbered with great granite erratics. 
A glacier came down a very steep gulch on the northern face 
of Alt. Courtney and upon entering the basin spread out and 
bent eastward or up the valley. The track of the glacier is 
very clear and there is no doubt but that the fine gravel deposit 
was laid down before the maximum extension of the ice. It 
follows that, if my correlation is correct, the alluvial fan at the 
mouth of Crosby gulch was formed at a time preceding the 
maximum extension of the neighboring glaciers. The diffi- 
culty of proving that no long time intervened between the 
completion of the fine gravel deposit in the basin and the gla- 
ciation of the basin is the weak point in the argument which I 
am trying to build up. However, there appears to have been 
no dissection of the fine gravel deposit before its glaciation. 
To bring about this dissection it was not necessary to cut 
through a rock barrier as the rock gorge down stream is en- 
tirely below the level of this fine gravel. All that was needed 
to bring about rapid dissection was the cutting through of the 
barrier of loose material at the lower end of tlie basin which 
must have been quickly effected. Not much rock cutting could 
have been accomplished in the gorge by the time the dissec- 
tion of the fine gravel deposit was well advanced. Therefore, 
I believe that nearly the whole of the gorge cutting has post- 
dated the maximum extension of the glaciers. The cloud- 
burst to which is due the alluvial fan of Crosby creek seems to 
have occurred during the early stages of the glaciation. The 
increased moisture which caused the growth of the glaciers 
favored excessive precipitation in neighboring' regions. The 
system of alluvial fans and associated fine gravels and silts 
was so clearly the product of a set of climatic conditions dif- 
ferent from those which obtained for a long time and which 
