154 H. L. FAIRCHILD PLEISTOCENE GEOLOGY OF NEW YORK STATE 



such lakes have already been obliterated, mostly changed into swamps by 

 marl and peat accumulation or by detrital filling, and the existing lakes 

 are doomed to similar ultimate extinction either by filling or draining. 



The Finger Lakes probably owe their origin in part, at least in their 

 upper levels, to drift barriers. 



Cataract lakes. — The most singular and interesting lakes in the State 

 lie in the courses of ancient ice-border rivers. These occupy the plunge 

 basins of extinct cataracts. Niagara today illustrates the method in 

 production of a basin or bowl by the excavating work of a large cataract. 

 If Niagara Biver were to be diverted above the fall so as to extinguish 

 the cataract, a rock basin holding a lake would probably be left in the 

 amphitheater oeneath what is now the "Horseshoe" Falls. South and 

 east of Syracuse the predecessors of Niagara Eiver plunged over cliffs of 

 the Onondaga limestone in their eastward flow and produced several 

 plunge basins that hold lakes, two of which outrival Niagara. 



The James ville Lake, 4 miles southeast of Syracuse, is a circle of 

 emerald green water about one-eighth mile in diameter and 60 feet deep, 

 lying in a half -circle amphitheater with perpendicular rock walls 160 

 feet high. Two and one-half miles east of Jamesville Lake, across the 

 Butternut Valley, is Blue Lake, resting in a cataract basin and rock 

 amphitheater, equaling the Jamesville in dimensions, but not so sym- 

 metrical. White Lake, one-half mile north of Blue Lake, and Bound 

 and Green lakes, 9 miles east of Syracuse, have basins with low and 

 sloping walls because the rocks are the soft Salina shales. 



These lakes were formerly regarded as mysterious, and with their in- 

 closing amphitheaters were the cause of much speculation. Their nature 

 was first announced by G. K. Gilbert and the first geologic description 

 in recognition of their true character was by Quereau. 10 



These cataract lakes are very remarkable features, and representing as 

 they do an ancient drainage of the Great Lakes area, held at high levels 

 by the glacier front, they have a scientific and educational value not yet 

 appreciated. 



Lakes of complex origin. — This title is intended to include Lake On- 

 tario and the larger Finger lakes, as Cayuga and Seneca, the genesis of 

 which is not entirely clear. The bottoms of these lakes are below sea- 

 level, and we do not know what depth of drift lies yet deeper beneath the 

 water. At Watkins a well boring penetrated 1,200 feet without reaching 



111 E. C. Quereau : Topography and history of Jamesville Lake. Bull. Geol. Soc. 

 America, vol. 9, 1898, pp. 173-182. 



See also illustrated article by Fairchild in the Twentieth Ann. Rept. New York 

 State Geologist, 1900, pp. 126-129. 



