156 H. L. FAIRCHILD PLEISTOCENE GEOLOGY OF NEW YORK STATE 



tario-Erie-Huron waters were compelled to cross Michigan by the valley 

 of Grand Biver. 



The lowest pass leading southward in Xew York is at Horseheads. the 

 head of the Seneca Valley, leading to the Chemung- Susquehanna, with 

 altitude of 900 feet. These three outlets — Horseheads, Grand Valley 

 (Michigan) and Borne — were the channels of ultimate escape for the 

 waters of western and central Xew York until the ice was removed from 

 over Covey Gulf, north of the Adirondacks. In immediate control of 

 the waters of central Yew York, the Seneca-Cayuga depression and the 

 Genesee Basin, there were two localities, the salient or highland on the 

 Batavia meridian and the highland in the Syracuse District. The ear- 

 liest glacial waters in Yew York were held in the Genesee Valley, and 

 this continued for a long time as a distinct basin, with several successive 

 outlets. 



When we consider the glacial lakes and drainage in chronologic order 

 we find that the earlier waters were confined in two separate basins, the 

 Genesee and the Seneca-Cayuga ; that for a brief time Lake Newberry 

 ( the Horseheads outlet ) probably occupied the Genesee Valley, and then 

 for a long time the control was alternately west on the Batavia meridian 

 or east on the Syracuse District. Then, when the ice-front weakened on 

 the Batavia salient, the westward control was across Michigan (Lake 

 Warren level). All the later flow subsequent to Lake Warren wa- east- 

 ward to the Hudson until the northward flow through Covey Gulf to the 

 Champlain Valley and the Hudson. 



The most extended series of glacial lakes was in the Genesee Valley. 

 This long valley, the surviving example of the pre-Pleistocene northward 

 drainage, heads in Pennsylvania, at the terniinal moraine, with altitude 

 on the cols over 2.200 feet, and extends across the State to near Boches- 

 ter. where it blends into the Ontario lowland at about 600 feet altitude. 

 The fall of 1.600 feet in a right-line distance of SO miles gave oppor- 

 tunity for many successively lower outlets and water planes as the ice 

 released passes on the east or west borders of the basin. Probably the 

 glacial lake history of the Genesee Valley is more complicated than is 

 now known, but no less than eighteen distinct outlets, with correlating 

 lake levels, have been recognized. Later the drainage was directly into 

 the sea (Gilbert Gulf), and finally into Lake Ontario. In this varied 

 outflow the Genesee glacial waters were contributed to several far-sepa- 

 rated river systems. Yarned in order of time, these are : ( 1 ) Pine Creek- 

 Susquehanna : (2) Allegany-Ohio-Mississippi: (3) Cani-teo-Chemung- 

 Susquehanna : (4) Erie Basin (lakes Whittlesey or Warren (-Michigan 

 Basin (Lake Chicago) -Mississippi : 5 S :ieca Valley (Lake Yewberry)- 



