450 Spencer — Deformation of Iroquois Beach and 



only to account for the rocky barrier holding the lake above 

 the sea, but to account for all of the barrier across the St. 

 Lawrence valley closing the ancient basin of Ontario to a depth 

 of nearly 500 feet below sea level.* 



In the Iroquois Beach no shells have been found. Only the 

 remains of mammoth, elk and beaver have been met with.f 

 Consequently, the question arises as to the freshness of the 

 waters. Not far from the eastern end of Lake Ontario, the 

 remains of a whale were found at 450 feet above the sea — at an 

 elevation which would admit of the free access of oceanic waters 

 into the Ontario basing Still no other marine or fresh- water 

 fossils have been found in the beaches. It therefore ap- 

 pears to me that the absence of such organisms speaks no 

 more in favor of fresh water conditions than of brackish or 

 even salt when the Iroquois shores were being formed ; and 

 does not preclude the idea of free communications with the 

 sea any more than when the whale came landward in waters 

 200 feet higher than the present lake surface. Indeed, I look 

 upon the Ontario -St. Lawrence valley, during the Iroquois 

 episode, as resembling the Gulf of Obi, which is a sheet of 

 water from 40 to 60 miles wide, and 600 to 700 miles long, 

 into which so much fresh water is discharging as to render 

 even the Arctic Sea for sixty miles beyond the mouth of the 

 gulf so fresh as to be almost potable,§ and sufficiently fresh to 

 destroy marine life. 



The only dam that has been hypothecated as filling the St. 

 Lawrence valley is that of a glacier. As the Iroquois Beach was 

 at sea level, no dam ought to be required to hold up the water, 

 but at most only to keep out the sea. However, I have fol- 

 lowed the beach for sixty miles within the margin of the 

 hypothecated barrier without finding the traces of an ending 

 of the old shore markings upon the confines of the Adirondack 

 wilderness. Even the coincidence of the shallow and small 

 channel, discovered by Mr. Gilbert, connecting the Iroquois 

 waters with the sea, by the Mohawk valley, or of the broader 

 and lower valley of Lake Champlain, does not prove the neces- 

 sity of a former barrier across the St. Lawrence valley any 

 more than the narrow channels among the gigantic islands 

 north of Hudson Bay would prove the former presence of a dam 

 holding in the waters of that bay, were the whole country ele- 

 vated. For a glacial dam to exist across the Adironclacks, even 



* See Origin of the Basins of the Great Lakes, by .T. W. Spencer, Q. J. G-. S., 

 vol. xlvi, Part 4. 1890. 



f Col. G. C. Grant of Hamilton has recently found other vertebrate remains, 

 but not yet determined. 



% Sir W. Dawson. Can. Nat., vol. x, p. 385. The remains are in the Redpath 

 Museum at Montreal. 



§ Nordenskjold in "Voyage of the Vega," p. 140. 



