LAKE DANA ONONDAGA VALLEY 57 



The height of the rock sill at the intake is practically that of the tops 

 of tlie ridges, and averages 691 feet. The limestone exposed at the north- 

 ern angle of the channel head will average about 700 feet elevation. 



The correlation of the Geneva beach with this channel at Marcellus 

 is wholly theoretical. Only uncertain evidences of the Geneva Beach 

 water have been seen east of the Seneca valley, but doubtless because no 

 serious search has been made. However, our knowledge of the problem 

 is sufficient, with the aid of the topographic sheets (partly unpublished) 

 of the critical region in the vicinity of Syracuse, to give great confidence 

 in the accuracy of this correlation. It is desirable to have a distinctive 

 name for this important stage of the hyper-Iroquois waters, and it is 

 proposed to name it after the eminent man who led American geologists 

 in the adoption of the glacial theory and in making glaciology a branch 

 of geologic science, and to call it lake Dana. 



The extent of this lake remains to be determined, but it probabl}' oc- 

 cupied the area of lake Warren, diminished by a fall of about 180 feet. 

 This will carry it westward throughout the Erie basin, but not into the 

 Huron basin. Search should be made for faint evidences 180 ± feet 

 under Warren level. 



Tvake Dana existed many years, perhaps a century, or several centuries ] 

 yet, as compared with lake Warren, it had a brief life. It came to its 

 close by the melting away of the ice-front from the district between 

 Marcellus and Syracuse sufficient to allow eastward escape of the h3'per- 

 Iroquois waters through a lower pass than the Cedarvale channel. 



Onondaga Valley 



This valley was the basin of a glacial lake with early outlet southward 

 through the depression occupied by the Tull}^ lakes. The valley has a 

 length, from Syracuse to Tully, of about fifteen miles, and is much more 

 irregular in form than the other north-and-south preglacial valleys. A 

 wide branch on the west, the South Onondaga valley, carries the west 

 branch of the Onondaga creek. A heavy moraine heads the valley and 

 extends from the divide at the Tully lakes northward for two miles. 

 The Onondaga creek rises some miles west of the valley, which it enters 

 by a ravine at the north end of the moraine filling. Like all the drift 

 at the heads of these eastern valle3^s, the moraine is very gravell}^, and 

 the hills are really kames. Tlie head of the divide is not a swamp col, 

 but an area of knolls, with only indefinite channels, being in this regard 

 like the divides at the head of Ca^aiga inlet, Keuka, Canandaiga, Hem- 

 lock, and Warsaw valleys. The water-parting was originally north of 

 all the Tully lakes, which naturally drained south. The elevation of 



