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Ii4 NEW YORK STATE MUSEUM 
In the southern Finger lakes region of south-central New York 
there are numerous postglacial gorges, a few of the best knowr 
ones being: Watkins and Havana glens near the southern end of 
Seneca lake, Taughannock gorge on the west side of Cayuga lake 
and in northern Tompkins county, and the gorges of Butternut 
(Enfield), Fall, Six Mile, and Buttermilk creeks in the vicinity of 
Ithaca. These gorges all contain waterfalls and have been cut 
into Devonic shales or sandy shales by streams which have been 
either partly or wholly diverted from their preglacial courses due 
to heavy drift filling. In some cases, as at Watkins and Taughan- 
nock, the main north-south Seneca and Cayuga-valleys were scoured 
and somewhat deepened by ice erosion, while in all cases the tribu- 
tary channels were heavily drift filled, thus accounting for the 
frequent postglacial diversion of these streams which were forced 
to cut new channels into the steep slopes facing the main valleys. 
Watkins glen is several miles long, often very narrow, and with 
a maximum depth of over 300 feet. Taughannock gorge, which is 
one and a quarter miles long and with greatest depth of about 350 
feet, has in it Taughannock falls whose height is 215 feet and which 
takes rank as the highest true waterfall in New York State (see 
frontispiece). Fall creek gorge, on the north side of Cornell 
campus, is about a mile long and with greatest depth of about 200 
feet, and contains Triphammer and Ithaca falls. The Butternut 
creek (Enfield) gorge is two miles long and with maximum depth 
of over 300 feet. 
In Chautauqua county there are numerous gorges or so-called 
gulfs which have been cut through the steep front or escarpment 
of the western border of the Southwestern plateau province. A 
fine example is the gulf south of Westfield, which is several miles 
long and from 300 to 400 feet deep. These are also postglacial 
channels which have been worn into the soft Devonic shales. The 
steepness of the shale escarpment here, as in the case of Tug hill, 
was more than likely produced by ice erosion, while the preglacial 
north-flowing streams had their channels partially or completely 
filled with glacial debris so that the streams now often flow in 
postglacial channels. The conditions are here very similar to those 
of the Finger lakes region already described. 
Length of time since the Ice age. Estimates of the duration 
of the glacial epoch by the most able students of the subject vary 
from 500,000 to 1,500,000 years, these estimates being based on 
such criteria as amount of erosion and weathering of the earliest 
till sheets (in Mississippi valley), times necessary for the various 
