354 H. L. FAIRCHILD — GLACIAL LAKES OF WESTERN NEW YORK. 



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The Watkins lake 365 



Seneca valley 365 



Divide and channel 366 



Deltas and water-levels 368 



Lake history 368 



Coalescent waters called lake Newberry 368 



Possible relation to Warren waters 369 



The Ithaca lake 369 



Cayuga valley 369 



Divides and channels 370 



Deltas and water-levels 371 



Location and height 371 



Comparison of terrace levels 372 



Variation in height of terraces 373 



Lake history 373. 



West Danby lake 373 



The main lake 374 



General Statement. 



topography of the "finger lakes'' region. 



To American geologists the geographic features of the " Finger lakes " 

 region are too well known to require extended description. For the pur- 

 pose of this writing it will be sufficient to briefly state the relation of the 

 lakes to the land lying immediately to the southward. These lakes, from 

 Conesus, on the west, to Otisco, on the east, occupy deep valleys of gen- 

 erally north-and-south trend, and of preglacial origin. The valleys all 

 have free drainage northward, but southward they terminate abruptly 

 in the high land which forms the divide between the waters of the Saint 

 Lawrence and the Susquehanna rivers. This elevation is a plateau of 

 Portage-Chemung strata, deeply incised by the river erosion of the long 

 ages preceding the Glacial period. The front of the great ice-sheet lin- 

 gered at the northern limit of this plateau, and lobes of the retreating ice 

 occupied the old north-and-south valleys and left them half filled with 

 frontal moraine drift.* It is this drift which forms the water-parting or 

 col in all these valleys. 



ORIGIN OF THE GLA CIA L LAKES. 



As the glacier-lobes succumbed to the melting and retreated northward 

 the spaces between the ice and the deserted moraines were occupied by 



*A description of the moraines in these valleys is given in Professor Chamberlin's article enti- 

 tled " Terminal Moraine of the Second Glacial Epoch," in the Third Ann. Rep. U. S. Geol. Survey. 



