LACUSTRINE CLAYS. 209 
Chenango valley.* Little of inference was there drawn from the presence 
of massive beds of fine clays underlying the gravels throughout the val- 
ley. They are of such depth and apparent continuity as to suggest a 
single and contemporaneous origin. The gravels, on the other hand, 
overlie the clays abruptly, show a high gradient, and kames and kame 
terraces at short intervals from Deansville to Binghamton were made in 
the presence of glacial ice. The case is similar for the Unadilla valley, 
though little study has been given to it. The writer has information of 
a bed of more than 800 feet of clay at Leonardsville, in the Unadilla 
valley, 10 miles south of the col at Richfield Junction. At the col, rock 
is reported at a depth of 30 feet. These facts, compared with the rapid 
ascent of the rock bottom to the surface in the Chenango-Susquehanna 
confluence at Binghamton, suggest that there may be long and shallow 
rock basins in these valleys similar to that east of Utica. Much addi- 
tional study would be needful to prove this, but in any case the clays 
point to a depression much earlier than the Champlain, so fully described 
by Chamberlin and Leverett for the west and indicated by Shaler and 
Woodworth for southern New England.f 
SUMMARY 
The lower Mohawk and a corresponding valley to the westward are 
considered as subsequent in character, having been initiated by head- 
ward cutting from the ancient Hudson and Saint Lawrence valleys, along 
the strike of soft beds to the col located by Chamberlin at Little Falls. 
The Adirondack streams consequent on Paleozoic topography were thus 
diverted and the Susquehanna streams were beheaded. West of Little 
Falls the rock floor descends toward lake Ontario, but not uniformly, a 
buried rock basin nearly 150 feet in depth lying east of Utica. The 
present arrangement is due to glacial and aqueo-glacial erosion at Little 
Falls, and to aggrading from Rome eastward by glacial materials. The 
westward flow of the lower Mohawk glacier is confirmed by striation at 
Amsterdam. 
The drift deposits west of Little Falls are largely composed of deltas 
and benches whose altitudes indicate approximately a waterlevel of 600 
feet. Thisis believed to represent a lacustrine stage in which the waters 
had fallen below the Warren level and below Fairchild’s Geneva beach, 
but had not yet subsided to the Iroquois plane. The dam is thought to 
have been at Little Falls, and of a composite nature. the sill of gneiss 
* Glacial flood deposits in Chenango valley. Bull. Geol. Soe. Am., vol. 8, pp. 27-29. 
+ N.S. Shaler, J. B. Woodworth, and C. F. Marbut: The glacial brick clays of Rhode Island and 
southeastern Massachusetts. Seventeenth Ann. Rep. U.S. Geol. Surv., pp. 951-1004. 
