No. 1.] GEOLOGICAL SURVEY OF CANADA. 75 



wliose limits were determined by the geographical surface at the 

 time ; and it is worthy of remark that both here and in New York 

 the salt deposits are connected with a thickening of the Onondao-a 

 formation, which, in its thinner intermediate portion, is appar- 

 ently almost destitute of salt ; a fact suggesting former geographi- 

 cal depressions, in which the two salt bearing portions of the 

 formation may have been deposited. Although it would be un- 

 safe to predict that this development of salt at the base of the 

 Onondaga formation is so widely extended, its thickness at Til- 

 sonburg, St. Mary's, London, and Enniskillen, is such, that it 

 seems probable that farther borings in these localities, where deep 

 wells have already been sunk, may reach saliferous strata capable 

 of yielding valuable brines." 



In confirmation of the first portion of the above extract, we can 

 now point to the existence of salt at Clinton, thirteen miles to the 

 S.E., and at Kincardine, thirty miles N.N.E. of Goderich. These 

 two stations are forty miles apart, and a line connecting them 

 would pass about seven miles to the east of Goderich. It is, 

 therefore, extremely probable that the whole region between Clin- 

 ton and Kincardine will be found underlaid by salt, and may 

 belong to a single basin, whose extent yet remains to be ascer- 

 tained. 



The success of the borings at Goderich and in its vicinity has, 

 as we have seen, led to the sinking of wells for brine, below the 

 salt-bearing horizon. At the same time, other trials have been 

 made in the hope of reaching it, by boring through rocks over- 

 lying those of the Goderich region. For the information of in- 

 quirers, it may therefore be well to recall briefly some of the fads 

 with regard to the nature and thickness of these rocks, of which 

 the details are given in my Report for 1866. It will there be 

 seen that the most recent rocky strata in south-western Ontario 

 are the greenish sandstones of the Portage formation. These 

 pass downwards into hard black slates (the so-called Genessee 

 slates) which, in their turn, rest upon the soft gray strata of the 

 Hamilton formation. This group of sandstone and hard shale, 

 which appears at the surftice at Kettle Point in Bosanquet, and 

 also in Warwick, is generally concealed by the clays of the region ; 

 but from the records of numerous borings, chiefly made in search 

 of petroleum, we have been enabled to determine its thickness in 

 many places. Thus, in a boring at Corunna, on the St. Clair 

 river, near Sarnia, it measures 213 feet; in two borings in Cam- 



