PLEISTOCENE LAKE WITH FIVE OUTLETS. 473 



of water would need a barrier to the north as well as to the east. The 

 drainage of the lake, at all stages from the Ridgeway beach downward, was 

 to the northeast, and beneath a greater mass of ice than in the case of the 

 Algonquin or the Iroquois water; but above the Ridgeway beach,''^ at the 

 Maumee level,f there were outlets across Ohio and Illinois, if a lake it were. 

 The difficulties are increasing. 



The shore markings occurring at Kalamazoo, at about 900 feet above tide, 

 represent a sheet of water having at least five outlets across Ohio and Illi- 

 nois. Again, the sea-cliffs of the Ontario peninsula, at from 1,200 to 1,425 

 feet and more, and the beaches now found up to 1,689 feet, would demand 

 great dams toward the south and west as well as toward the north. But 

 such dams could scarcely have existed with open waters carving out sea- 

 cliffs and terraces on the high peninsula of Ontario, and also leaving records 

 200 miles southward. It should be noted that gravel deposits of the so-called 

 kame and osar structures occur at all high levels ; but of these I do not take 

 cognizance. 



The drainage of the high country, such as the Genesee valley, with ter- 

 races up to 1,900 feet gr more, and of the " terminal moraine," up to 2,680 

 feet, was toward the north without obstruction. 



Ascending now to Potter county, we find the gravel ridge at 2,660 feet, 

 on the very edge of the highest knob of the "terminal moraine." This high 

 point could not have stood out of the ice as a Greenland " nunatak," with a 

 lake around it, for it is at the margin of the drift, and glaciers do not de- 

 posit their terminal detritus within the ice, but at their very margins. It 

 seems impossible to conceive a glacial mass retaining a lake about this flat- 

 tened knob, even if the country were submerged to almost sea-level. There 

 are other similar deposits on adjacent summits. Again, had a glacier ex- 

 isted on the top or on the southern side of this "morainic" ridge, which is a 

 water-shed, its melting ice must have carried great quantities of drift into 

 the valleys toward the south, which neither Mr. Lewis nor I have seen. But 

 the drainage was toward the north, into the hypothetical glacier, which, if it 

 permitted sub-glacial drainage, could scarcely have formed lakes. 



Conclusions. 



Under these conditions, fairly stated I think, whether is it easier to accept 

 a great subsidence of the continent, to nearly 2,700 feet in western Pennsyl- 

 vania, or account for the phenomena by glacial dams formed on land vastly 

 lower toward the north? Indeed, the great deformation of the lake resrions 



*"High Level Shores in the Region of the Great Lakes and their Deformation," by J.W. Spencer : 

 Am. Journ. Sci., vol. XLI, 1891, p. 207. 

 flbid., p. 208. ^ 



LXIX— Bull. Geoi-. Soc. Am , Voi,. 2, 1890. 



