February 21, 1913] 



SCIENCE 



293 



mile north of Blue Lake and Round and 

 Green lakes nine miles east of Syracuse, 

 have basins with low and sloping walls be- 

 cause the rocks are the soft Salina shales. 



These lakes were formerly regarded as 

 mysterious and with their enclosing amphi- 

 theaters were the cause of much specula- 

 tion. Their nature was first announced by 

 G. K. Gilbert and the first geologic de- 

 scription in recognition of their true char- 

 acter was by Quereau.^" 



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 Ontario and 

 the larger Finger lakes, as Cayuga and 

 Seneca, the genesis of which is not entirely 

 clear. The bottoms of these lakes are be- 

 low sea-level, and we do not know what 

 depth of drift lies yet deeper beneath the 

 water. At Watkins a well boring pene- 

 trated 1,200 feet without reaching rock, 

 which shows drift at a depth 600 feet lower 

 than the deepest part of the lake, and 750 

 feet beneath sea-level. 



It seems probable that the valleys of the 

 Finger lakes are blocked on the north, 

 along the drumlin belt, by deep drift fill- 

 ings, which can be determined only by 

 borings at close intervals. That these val- 

 leys were gouged out by ice erosion, even 

 by any number of continental ice sheets, 

 seems to the writer extremely improbable. 

 If they were so deepened, then the basin of 

 Lake Ontario was probably also scooped by 

 ice erosion. But if the Ontario basin is a 



w 1 1 Topography and History of .Jamesville 

 Lake," by E. C. Quereau, Geol. Soe. Am., Bull., 

 Vol. 9, pp. 173-182, 1898. See also illustrated 

 article by Fairchild in the 20th Ann. Eep., N. Y. 

 State Geologist, 1900, pp. 126-129. 



depressed river valley, then the valleys of 

 the Finger lakes must be fairly graded to 

 the bottom of Ontario and be of similar 

 origin. If the Ontario and other basins 

 were excavated by river work and weather- 

 ing, then it must be admitted that there 

 have been great changes in the height and 

 attitude of the land in late geologic time. 

 But such changes are quite certain. It ap- 

 pears probable that the valley-cutting oc- 

 curred during a time of land elevation, and 

 that the Laurentian and the Finger lakes 

 basins are the complex product of land 

 warping, land depression, and of glacial 

 drift filling. Until the later Tertiary and 

 Pleistocene diastrophic movements of the 

 area including New York have been de- 

 termined and the drift-buried valleys 

 mapped by borings the deep lake basins 

 may remain the subject of speculation and 

 dispute. 



GLACIAL LAKE SUCCESSION 



The story of the succession of the glacial 

 waters that laved the receding front of the 

 Laurentian glacier is a dramatic episode in 

 the geologic history. Beginning in small 

 pondlings of water in the heads of the val- 

 leys along the north side of the morainic 

 divide, the lakes were enlarged as the ice 

 barrier receded, and were captured, 

 drained, blended or otherwise affected by 

 changes in outlets. The romantic story can 

 not be satisfactorily told in words alone, 

 but requires cartographic representation, 

 and a series of maps has been constructed 

 to show the better known and more striking 

 changes in the ice recession and the lake 

 succession. 



The control of the glacial waters de- 

 pended on the altitude of the lowest passes 

 affording immediate outflow along with the 

 relation of these passes to some ultimate 

 escape. The watei-s of the Laurentian 

 basin outflow to-day by the St. Lawrence 



