ICE-SHEET EROSION IN NEW YORK 71 



its walls are buried under drift, while 6 or 7 miles south from the Ontario 

 shore the entire valley is hidden from view. The Sodus valley lies in 

 direct line with the axis of the Seneca valley, and it is not a forced as- 

 sumption that the Senecan river flowed through the Sodus valley, and 

 that the Keukan, Flintian, and Canandaiguan rivers, lying westward, 

 were tributary to the Senecan, probably bending eastward along the 

 strike of the less resistant strata (see plate 21 ). The stream in the Mud 

 creek (Ganargua) valley may have turned westward to join the Genesee. 



Eastward from Sodus bay the maps show a series of bays or low ground. 

 In order eastward these are: Port bay, Red creek, Black creek, Blind 

 Sodus bay, and Fairhaven bay. The drift obscures the hard rock geology, 

 but these sags probably indicate buried valleys. The precise correlation 

 of these embayments with the Finger Lakes valleys is, of course, uncer- 

 tain, but test borings will probably show that the Owascan, Skaneatelan, 

 Otiscan, and Onondagan rivers occupied the buried valleys. The Cayu- 

 gan river possibly united with the Senecan. 



Greater glacial lakes. — The story of the later glacial waters has been 

 partially told in other writings* The important fact here is that not 

 only all the glacial drift left by the receding ice in the lower parts of 

 all the Finger Lakes valleys was deposited under w r ater, but that north 

 of the lakes all the drift under about 880 feet elevation was so deposited, 

 either in lake Warren or its successors. In consequence of this fact the 

 glacial debris is much distributed and blended with or buried under the 

 lake deposits, and such morainal topography as shows at all is much 

 subdued. The latter is chiefly kames or knolls of gravel. 



Lake Warren came to extinction by the draining to lower levels through 

 channels in the neighborhood of Syracuse, which carried the water east- 

 ward to the Mohawk valley. These falling waters have collectively been 

 called Hyper-Iroquois. Finall} 7 , with the establishment of the outlet at 

 Rome, came the long-lived lake Iroquois which has left the strong shore 

 phenomena about the Ontario basin. When the ice blockade in the 

 Saint Lawrence valley was finally lifted the region of the Thousand 

 islands was about 40 feet below sealevel, and marine waters, the Ontario 

 gulf, occupied the basin. As an effect of the northward uplifting of 

 the entire region which has occurred since glacial time, and is still in 

 progress.f the Thousand islands have been lifted toward 300 feet, and 



* In addition to references given above, consult papers in the Twentieth, Twenty-first, and 

 Twenty-second Annual Reports of the New York State Geologist. A map of lake Iroquois is in 

 the twentieth report, and one of lake Warren in the twenty-second. 



fG. K. Gilbert: "Recent earth movement in the Great Lakes region." Eighteenth Annual 

 Report U. S. Geol. Survey, p. 604. 



H. L. Fairchild ; " Land-warping in western New York." Bull. Geol. Soc. Am., vol. 10, p. GC. 



