Klamath Mountains, California — Hershey. 145 
before the gorge was cut down to nearly one-half of its pres- 
ent depth. The stream flowing from the lakelet was a large 
one, carrying the combined waters of Cofifee and Union creeks, 
but as it was nearly free from sediment, its erosive power was 
not great. Hence, it probably occupied a longer time in mak- 
ing the cut which drained the lake, than in doing an equal 
amount of work since, but it has done so much more work 
since that it is quite safe to place the destruction of the lake- 
let farther back than one-half of the time since the maximum 
extension of the Union creek glacier. 
That the lakelet disappeared long ago is also evidenced by 
the changes that have since occurred in the basin. Over the 
silt there is a deposit of coarse gravel and boulders made by 
Coffee creek after the destruction of the lake. The creek has 
excavated a new trench through this gravel and the underly- 
ing silt, leaving remnants of them on its northern side. This 
latest trench is several times as wide as the stream and is 
floored by a sort of modern alluvial plain. Compare this com- 
plex histor}^ with that of the glacial lake basins near the heads 
of the glaciated valleys. The latter are so fresh that in no 
case observed has a large one been drained by the cutting of a 
gorge through the rock barrier below. Some of these lakelets 
are held by barriers of till. In my former paper on the ancient 
glaciers of this region I have given a number of facts proving 
the comparative recency of most of the glacial action in these 
mountains and I will not repeat them. 
The stream which drained the lakelet under discussion 
was a much larger one than those flowing from the existing 
lakelets, and may be expected to have eroded the outlet more 
rapidly, but making due allowance for this factor, I still think 
that the lake basin should not yet be completely drained if this 
lake did not originate long anterior to those now existing in 
the higher valleys. 
A comparison of the changes which have occurred in this 
lake basin since the destruction of the lakelet, and of the 
amount of gorge-cutting since that event, with the changes 
which have occurred near the head of the glaciated valleys 
since the disappearance of the Pleistocene glaciers, leads to 
the conclusions that the final draining of the lakelet preceded 
the end of the glaciation. If the premise that the elephant 
