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SCIENCE 



[N. S. Vol. XXXVII. No. 947 



(246 feet). With that escape blocked the 

 lowest pass is at Rome (460 for the water 

 surface) to the Mohawk-Hudson, and 

 which for many thousands of years was the 

 point of escape of the waters while the ice 

 body lay over the St. Lawrence Valley. 

 The next higher pass is at Chicago, which 

 was occupied by the glacial outflow for a 

 very long time, but to reach this ultimate 

 escape the Ontario-Erie-Huron waters 

 were compelled to cross Michigan by the 

 valley of Grand River. 



The lowest pass leading southward in 

 New 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 Rome were the chan- 

 nels of ultimate escape for the waters of 

 western and central New York until the ice 

 was removed from over Covey Gulf, north 

 of the Adirondaclvs. In immediate control 

 of the waters of central New 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 

 earliest glacial waters in New York were 

 held in the Genesee Valley, and this con- 

 tinued 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 Sen- 

 eca-Cayuga. That for a brief time the 

 Horseheads outlet (Lake Newberry) prob- 

 ably occupied the Genesee Valley, and then 

 for a long time the control was alternately 

 west on the Batavia meridian or east in 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, was eastward 



to the Hudson until the northward flow 

 through Covey Gulf and the Champlain 

 Valley to the Hudson. 



The most extended series of glacial lakes 

 was in the Genesee Valley. This long val- 

 ley, the surviving example of the Pre- 

 pleistocene northward drainage, heads in 

 Pennsylvania, at the terminal moraine, 

 with altitude on the cols over 2,200 feet, 

 and extends across the state to near Roch- 

 ester, where it blends into the Ontario low- 

 land at about 600 feet altitude. The fall 

 of 1,600 feet in a right-line distance of 80 

 miles gave opportunity for many succes- 

 sive!}' 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 corre- 

 lating lake levels have been recognized. 

 Then the drainage was directly into the 

 sea (Gilbert Gulf), and finally into Lake 

 Ontario. In this varied outflow the Gene- 

 see glacial waters were contributed to sev- 

 eral far-separated river systems. Named 

 in order of time these are: (1) Pine creek- 

 Susquehanna; (2) Alleghany-Ohio-Missis- 

 sippi; (3) Canisteo-Chemung-Susque- 

 hanna; (4) Erie basin (Lakes Whittlesey 

 or Warren) -Michigan basin (Lake Chi- 

 cago) -Mississippi; (5) Seneca Valley 

 (Lake Newberry) -Susquehanna; (6) Mo- 

 hawk-Hudson; (7) Champlain-Hudson ; 

 (8) Ocean-level waters direct; (9) Lake 

 Ontario-St. Lawrence. Some of these 

 systems received the Genesee Valley over- 

 flow more than once, or by different im- 

 mediate outflow, making the twenty stages 

 in the drainage history as now understood. 

 It "would seem unlikely that any other val- 

 ley in the world can approach the Genesee 

 in the complexity of its drainage history. 



The series of seventeen maps depict the 

 waning Laurentian ice sheet with the gla- 



