J. W. Spencer — Duration of Niagara Falls. 471 



1 0. Relationship of the Falls to Geological Time. 



All attempts to reduce geological time to terms of years are 

 most difficult, but the Niagara river seemed to be an easy chro- 

 nometer to read, and yet we see that utterances even this 

 year are vastly farther from the mark than those made fifty 

 years ago — the clock had not kept mean time throughout its 

 existence. After this attempt at regulating the chronometer, 

 investigators will doubtless carry the determinations to greater 

 accuracy, but for the present I can offer this geological com- 

 pensation. The Niagara seems a stepping stone back to the ice 

 age. What is the connection between the river and the Pleis- 

 tocene phenomena ? 



The Lake epoch is an after or late phase of the Glacial, and 

 Niagara came into existence long subsequent to the commence- 

 ment of the lakes. If we take the differential elevation of 

 the deserted beaches, and treat them as absolute uplifts in the 

 Niagara district, with the mean rate of rise in the earlier por- 

 tion of the lake epoch as in the later, then the appearance of 

 Warren water in the Erie basin was about 60 per cent* longer 

 ago than the age of Niagara river; or about 50,000 years ago. 

 The earlier rate of deformation was not greater than that dur- 

 ing the Niagara episode as shown by the deformation of the 

 beaches but it may have been slower, so that from 50,000 to 

 60,000 years ago Warren water covered more or less of the 

 Erie basin. Before the birth of Niagara river, by several 

 thousand years, there was open water extending from the Erie 

 basin far into the Ontario and all the upper lakes were open 

 water with a strait at Nippissing, but the northeastern limits 

 are not known, and although they do not affect the age of 

 Niagara, yet they leave an open question as to the end of the 

 ice age, in case of those who do not regard the advent of the 

 lakes as its termination. Certainly, if not before the Iroquois 

 episode, at its close the ice age had ended so far as the whole 

 lake region and St. Lawrence valley is concerned ; and the end 

 ■of the Iroquois episode was about 14,000 years ago. To 

 attempt to place the end of the ice age at either 50,000 or 

 14,000 years ago, or between, would be to base the conclusions 

 upon opinions and conjectures not so far settled by the incom- 

 pletely written history of the lakes, whose age in terms of the 

 falls may be inferred. The determination of the end of the 

 ice age will be in terms of the lake history. 



* The beaches show an elevation in the Niagara district (accompanied by 

 deformation) amounting to 940 feet above tide, of which 5*73 feet have been 

 raised since the birth of the Niagara river. 



