74 THE CANADIAN NATURALIST. [Vol. vi. 



have yet been found. The 340 feet of limestone underlying the 

 shale, represent the Guelph, Niagara and Clinton formations, and 

 the red and blue shales beneath these belong to the Medina for- 

 mation. By referring to the account of a boring at Barton, near 

 Hamilton, it will be seen that these shales have there a total 

 thickness of about 600 feet. (Beporb for 1866, page 251.) 



It will be noticed that the Onondaga formation, as shewn in 

 the borings of Goderich and its vicinity, consists of several hun- 

 dred feet of limestone, chiefly magnesian, underlaid by two or 

 three hundred feet of red and blue shales, which carry rock-salt 

 at their base. These are succeeded, in descending order, by the 

 magnesian limestones of the Guelph, Niagara and Clinton for- 

 mations, which rest upon the red shales of the Medina, as seen 

 in the Southampton and Waterloo borings. We have the follow- 

 ing succession in going downwards : 



1. Limestones of the Onondaga or Salina formation, j 



2. Ked and blue shales of the same. 



3. Limestones of the Guelph and Niagara formations. 



4. Ked and blue shales of the Medina formation. 



On account of the resemblances in color between the upper and 

 lower couples of the above series mistakes may easily occur, as at 

 Southampton, where the strata of 3 and 4 were supposed to be 

 those of 1 and 2. Such errors, which have caused the expend- 

 iture of considerable sums of money at Southampton, Port Elgin, 

 and Waterloo, would be avoided by a careful study of the dis- 

 tribution of the various geological formations of this region, as 

 described in the Geology of Canada. The accuracy with which 

 the limits of the various formations throuGjhout this region were 

 traced out by Mr. Alex. Murray, has received repeated confirma- 

 tion in the course of the various explorations for oil and salt 

 which have been made within the past few years. 



As regards the possible extent of the salt-bearing area now 

 under consideration, I take the liberty of quoting the following 

 passage from my Beport for 1866, page 271 : — 



With regard to the probabilities of obtaining salt wells by 

 other borings in this region, it is to be remarked that the thick- 

 ness of the deposit of salt traversed in the Goderich well may 

 warrant us in expecting that its area may be considerable ; though 

 whether its greatest extent will be inland, or beneath the waters 

 of the lake, can only be known by experiment. It has already 

 been explained that salt deposits have been formed in basins 



