The Relation of Mollusks to Fish in Oneida Lake 33 
evidently represent a terminal moraine indicating the point 
at which the Ontarian ice lobe rested at the Lake Dawson 
stage. (Fairchild, 1903, plate 41.) Frenchman and Dun- 
ham Islands appear to be the tops of submerged drumlins, the 
long axes being the same as those of the elevations surround- 
ing the lake. (See the map, Fig. 1.) 
When Lake Ontario was drained to its present level and 
its outlet shifted to the St. Lawrence River, Oneida Lake 
was left as a huge pool. It does not seem possible that this 
Vig. 3. Cross section of Seneca Lake about a mile south of Long Point. 
Horizontal scale 2 inches to the mile. Vertical scale % inch 
= 100 feet. 
lake can be placed in the same class as those of Cayuga, 
Seneca, and other of the Finger Lakes, which are rock bound, 
and were once occupied by preglacial rivers flowing north- 
ward, which eroded the valleys during the long ages preced- 
ing the advance of the ice. Profiles of the two classes of 
2 
