282 The American Geologist. ^i^^- 1^04. 
the bottoms of the mature hanging tributary valleys; that 
these gorges, being drift-filled, antedate the last ice advance ; 
that they are broader and deeper, hence required longer time 
to form than the post-Glacial gorges ; and that, where they 
enter the main valleys, their rock bottoms are above lake level.* 
They therefore resemble hanging valleys, since their bottoms 
are in some cases, as Taughannock, about 400 feet above the 
main valley bottom one-half mile distant. Since we have no 
data proving what their bottom slope actually is, though it 
seems evident that their slope is very steep, and possibly great 
enough to carry them down to the main valley axis, it may 
not be proper to consider them hanging valleys. If the inter- 
pretation of hanging valleys is warranted, which I doubt, then 
the tributary valleys to Seneca and Cayuga lakes are double 
hanging valleys, — an upper mature hanging valley and a 
lower hanging gorge valley. 
The Post-Glacial Gorges: Incidentally, in the above dis- 
cussion, the main facts of the relation of the post-Glacial 
gorges to the condition of hanging valleys and buried gorges 
have been stated. The rare beauty of the gorges and falls 
of the Finger Lake region, indicated by the wide reputation 
of Watkins Glen, which is but one of many, is a result of 
this relation. The great number of gorges and waterfalls, 
and their wide reputation, warrant a specific restatement of 
their cause. 
Coming to the edge of the steepened slope of the main 
valleys, after a fairly quiet course, along a moderate grade 
in the mature hanging tributary valleys, the water finds itself 
forced to tumble down the steepened slope either to the valley 
floor or to lake level. Hundreds of streams, large and small, 
have this condition thrust upon them. With cutting power 
accelerated by the increased slope, the streams have set to 
work on their task with excellent result. They have cut deeply 
into the shale strata, and here and there have crossed the 
buried gorges, revealing their presence by the sudden broad- 
ening of the valley wherever a stream moves from its post- 
Glacial gorge in shale to one of the drift-filled buried valleys 
* While a large mass of data has been gathered bearing on the buried gorge 
problem, the work has not progressed far enough to warrant an attempt to 
discuss it here, excepting in so far as it has a bearing ou the question in hand. 
