Science, Geology and Physics 



before the birth of Niagara in even the Ontario basin, and that 1895 

 under no circumstances could there have been any hydrostatic p "" 1- 

 obstruction to the Ontario basin since before the birth of Niagara 

 Falls. 



Spencer, Joseph William Winthrop. Duration of Niagara 



Falls and the history of the great lakes. 2d ed. (Ann. rep'ts of the 

 com'rs of the state reserv. at Niagara. Albany: 1895. 126pp.) 

 Geological survey of the Great Lakes, 1881 — 1894. 



Spencer, Joseph William Winthrop. The duration of Niagara 

 Falls and the history of the great lakes. (/n N. Y. (state) Assembly 

 Docs. 118thsess. 1895. No. 90 app.) 



Taylor, Frank Bursley. Changes of level in the region of the 1895 

 great lakes in recent geological time. (Am. jour, sci., Jan., 1895. Taylor 

 Ser. 3. 49:69-71.) 



As a measure of the duration of postglacial time, therefore, 

 I do not see how the gorge can have any value worth men- 

 tioning. But without meeting this demand, it goes far enough to 

 show that postglacial time must have been much longer than the 

 current estimate. , . . There is considerable evidence to 

 show that the greater Niagara had another earlier period of post- 

 glacial activity, during which it cut out the gorge from Lewiston 

 to Foster's flat. . . . Thus the great cataract has been 

 intermittent in its activity. It has had two active periods, 

 separated by the long, almost indefinitely long, period during 

 which the falls of the smaller stream carried on the work. 



Taylor, Frank Bursley. Niagara and the Great Lakes. (Am. 

 jour, sci., Apr., 1895. 149:249-270.) 



The author takes a position between the theories of Spencer and 

 Upham. 



In the recent papers of Professor J. W. Spencer and Mr. 

 Warren Upham, the post-glacial history of the Great Lakes has 

 been ably told according to two very different ideas of the cause 

 of Pleistocene change. Prof. Spencer on the one hand levels all 

 the higher abandoned beaches with the sea, and does not distinctly 



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