208 THE CANADIAN NATURALIST. [Vol. X. 



Lake OntMrio of about 125 feet, without the possibility of an 

 adjacent buried channel through the range of hills, through 

 which the Mohawk valley is cut. The Onondaga basin, then, 

 appears to have been originated by a river extending from the 

 Adirondack mountains westward, and emptying into the Ontario 

 basin northward of the Cayuo-a lake, forming alons; the course 

 the basin, now occupied by drift material and Onondaga lake, 

 and perhaps that also of Oneida lake. 



Most of the other lakes of central New York, especially those 

 Iiaving a more or less meridional direction, lie in great valleys, 

 and are only closed up ancient river valleys. All of these lakes, 

 except two, Seneca and Cayuga, are at a considerable elevation. 

 One of the deepest of these elevated lakes is Skeneateles (613 

 feet above Lake Ontario, and 320 feet deep). This lake, and 

 Owasco lake, have northern modern outlets over rocky barriers. 

 They lie in valleys several hundred feet deep (300 feet or more) 

 and evidently emptied into the Susquehanna river in some for- 

 mer geological times. The valleys of these lakes as well as 

 several river valleys in the region now having northern outlets 

 (such as those of Onondaga, and Bntiernut creeks) all radiate 

 from adjacent or common points as they extend northward, 

 evidently shewing a former southern discharge. However, it is 

 exceedingly difficult to determine how much of the valleys are of 

 Presrlacial, and how much of Intero:lacial or Posts^lacial date, for 

 there are evidently three periods of erosion — the valleys produced 

 in Interglacial and Modern epochs coinciding. 



Thus far no apparent outlet of the great ancient Ontario basin 

 has presented itself. One other route at first appeared possible 

 — hy the Se7ieca Lake, Chemung and Susquehanmr Rivers. The 

 features favoring this suggestion are : the greatest depth of Lake 

 Ontario north of Seneca lake ; the depth of Seneca lake, which 

 is 612 feet (423 feet below the level of Lake Ontario) : the 

 direct continuity of Seneca lake valley with that of the Chemung, 

 at Elmira, and of the latter valley with that of the Susquehanna, 

 at Sayre. The valley of Chemung above Elmira is much smaller 

 than the portion below, which joins it at a considerable angle, 

 but this portion of the river just above Elmira is more modern 

 than the Preglacial course of the Chemung, which from Corning 

 passed directly to Seneca valley at Horse Heads. One thing is 

 certain, the Ontario basin as it was emerging from the last sub- 

 sidence of the ice age, flowed by the route indicated and lingered 



