Chapter VII 



SCIENCE, GEOLOGY AND PHYSICS 



1789 



McCaUSLIN, Robert. An account of an earthy substance found near 1789 

 the Falls of Niagara and vulgarly called the spray of the falls : together McCaushn 

 with some remarks on the falls. (Trans. Am. Philos. Soc. 1 793. 

 3:17-24.) 



This paper was read before the American Philosophical Society on 

 October 1 6, 1 789. The author, who resided at the Falls from I 774 

 to 1 783, was one of the earliest observers of the recession of the Falls. 

 After describing the escarpment at Queenston he says: 



It is universally believed that the cataract was originally at this 

 ridge, and that it has by degrees worn away and broke down the 

 rock for the space of these six or seven miles. Some have supposed 

 that from these appearances, conjectures might be formed of the 

 age of this part of the world. To enter upon such a calculation, 

 it would previously be necessary to ascertain how much the fall 

 had retired in a hundred years, or any other certain period. 

 Suppose that we were even in possession of such a fact, still the 

 conclusions drawn from it would be liable to the greatest uncer- 

 tainty, as it is evident that the space of rock broke down and 

 worn away in a certain number of years would not always be the 

 same. The more or less hardness and brittleness of the rock in 

 different parts; the greater or less severity of the frosts in differ- 

 ent years; and the quantities of water that flowed at different 

 periods in the cataract of the river, would all occasion consider- 

 able variations. This retrocession of the Falls does not by any 

 means go on so quickly as some have imagined. During nine 

 years that I have remained at Niagara, very few pieces of the 



495 



