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NEW YORK STATE MUSEUM 



mentary but positive beaches, deltas and weak erosion planes [pi. 

 33]. Then it was itself extinguished by another waning of the ice 

 barrier in the region of Syracuse. 



11 The singular and apparently contradictory relation ill alti- 

 tude of the stream channels southwest of Syracuse may be explained 

 by supposing that the Marcellus-Cedarvale valley was blocked by 

 entrapped ice (probably drift-buried) during the time when the Van- 

 uxem waters existed but that the subsequent melting of the ice 

 opened the pass for sub-Warren flow at an altitude inferior to the 

 Vanuxem outflow. The great channels and cataracts southwest and 

 southeast of Syracuse with altitudes under the Warren plane received 

 at least their final expression by its outflow and down draining. 



12 The sub-Warren (or hyper-Iroquois) waters must have low- 

 ered somewhat spasmodically, that is, rapidly as new outlets were 

 suddenly found and slowly as the longer-lived outlets were being 

 excavated. Only one decided pause has been registered in dis- 

 covered beaches, that of Lake Dana, 700 feet [pi. 40]. The only 

 strong channel that can be correlated in altitude with the Dana plane 

 is the Marcellus-Cedarvale channel. To make this effective requires 

 the assumption that the ice barrier lay northeastward so as to 

 leave the north and south Marcellus (Ninemile creek) valley 

 open. 



13 The well developed river channel leading east from Fairport 

 to Lyons [pi. 3] apparently represents an episode of proglacial drain- 

 age distinct from that which produced the Victor-Phelps channel 

 series. It is supposed that this northern channel was cut or at 

 least given its present form by proglacial river flow during a sub- 

 Dana or hyper-Iroquois stage. Apparently it is the lowest and 

 latest channel cut by glacial stream flow in western New York, 

 correlating with the low passes through Syracuse. The hypotheti- 

 cal lake which overflowed by the Fairport channel extended west- 

 ward from the Rochester district, with altitude only 30 or 40 feet 

 higher than its successor, Lake Iroquois. This lake is named Lake 

 Dawson, after Dr George M. Dawson [pi. 41]. 



14 Niagara falls and Lake Erie came into existence while the 

 falling hyper-Iroquois waters were recutting the lower channels, 

 under 600 feet, at Syracuse, and later the channel leading east from 

 Fairport, near Rochester. The emergence of the Niagara escarp- 

 ment at Lockport and Lewiston above the lowering waters produced 

 a barrier which confined the western waters to the Erie basin [see 

 P- 3o]- 



