50 On the Acid Spri/i^s and Gypsum Deposit)! of the 



It may appear late, on my part, to offer these remarks, 

 considering that the work which has called them forth has now 

 heen nearly four years before the public. My absence from 

 England, in the West Indies, during the interval, and my 

 want of knowledge, in consequence, of the arguments used 

 against Mr Cavendish, require only to be noticed to account 

 for it. 



Lesketh How, Ambleside, 

 April 24, 1849. 



On the Acid Springs and Gypsum Deposits of the Upper Part 

 of the Silurian System {Onondaga Salt Group). By T. S. 

 Hunt, of the Geological Survey of Canada. 



That portion of the upper Silurian system of New York, 

 which has been designated by the geologists of that state the 

 Onondaga Salt Group, is characterised not only by the saline 

 springs to which it owes its name, but also by numerous de- 

 posits of gypsum and spi'ings, which are sour to the taste, 

 and contain free sulphuric acid. The one at Byron, New 

 York, has long been known, and several others have been 

 observed more recently in the same geological district. The 

 same region in Canada affords a remarkable spring of this 

 kind, which, in the course of my official duties, I had occa- 

 sion to examine in the month of October 1847. It is situated 

 in the township of Tuscarora, in the Indian Reserve, about 

 twenty miles north of Port Dover, which is the nearest point 

 on Lake Erie. The water contains a large amount of free 

 sulphuric acid, about 4 parts in 1000, besides sulphates of the 

 alkalies, lime, magnesia, aluminum, and iron in small quan- 

 tities. The proportion of these ingredients is however not 

 constant, as is evident from an analysis made in April 1846, 

 by Professor Croft of King's College, Toronto, which is con- 

 firmed by a partial examination by myself, of a specimen of 

 water brought from the spi'ing in June 1845. 



The specific gravity of the water was much lower, and the 

 amount of foreign ingredients much less, than in that col- 



