1881.] *^^^ [Spencer. 



described on previous pages points to every condition necessary to indicate 

 its depth as being sufficiently great to empty Lake Huron, altliough the 

 actual measurement (on the north-east side of the channel) has only 

 reached to 200 feet below the surface of Lake Erie, with a bottom com- 

 posed of soft shales. There now remains one other question to be an- 

 swered, but certainly one of no greater moment than the ancient connection 

 between Lakes Erie and Octario — the outlet of Lake Ontario. 



Dr. Newberry, at times a glacialist, finally appears to advocate the glacial 

 excavation of the lakes after their courses had been determined by river 

 action. Various writers for the last twenty years have referred to the deep 

 buried channel near Lake Onondaga, more than 400 feet below its surface, 

 as indicating the former outlet of Lake Ontario by this route, and down the 

 Mohawk to the Hudson river. This course will not answer, as the Geo- 

 logical Survey of Pennsylvania has shown, for at Little Falls, Herkimer 

 county, the Mohawk flows over metamorphic rock. Various fluvialists 

 refer some buried route by the St. Lawrence. This seems scarcely possible, 

 as that great river flows over hard rocks at various points for 200 miles east- 

 ward of Lake Ontario, unless the outlet existed somewhere between Kings- 

 ton in Canada, and Oswego in New York, and continued in a buried course 

 through crystalline rocks (in part) to eastward of Montreal. The north- 

 eastern portion of Lake Ontario is very shallow, and the deepest channel 

 points to the south- eastward extremity of the lake. 



At the present time the writer knows nothing positively of the most 

 probable outlet, as that by the Mohawk will not answer. Yet he will pre- 

 dict that its outlet will be found as certainly as the one between Lakes 

 Erie and Ontario, of which there was no clue, or even suggestion until 

 working up the origin of the Dundas valley. One other route presents 

 itself, but as positive proof is not at hand, I will defer theorizing. 



The Geological Survey of Pennsylvania has shown that many of the 

 water courses, emptying southward at the present time, formerly emptied 

 to the northward. In New York, we find most of the small lakes of narrow 

 but long dimensions having their axis in a meridional direction. Also, 

 these waters are generally along some stream flowing northward into Lake 

 Ontario even at the present time. Though the bottoms of these lakes are 

 frequently below the sea level, yet in no case, that I am aware of, are they 

 nearly as deep as Lake Ontario. Doubtless these small lakes were former 

 expansions of the rivers running into Lake Ontario in Preglacial times, and 

 owe to ice, simply, the closing of their outlets by drift. 



No local land oscillations apparent. I agree with Mr. Carll that there 

 are no indications of local oscillations in the region of our lower great 

 lakes, at least to account for any changes in the drainage systems. It 

 has been a popular idea that the coast of New England, even at the present 

 time, is sinking. If so, any changes must be very slow, for Mr. Henry 

 Mitchell, of the United States Coast Survey, shows (in appendix 8 of re- 

 port for 1877), that the whole north-eastern coast of the United States has 

 undergone no change of level during the last hundred years. 



