1848.] GESNER ON THE GYPSUM OF NOVA SCOTIA. 129 



tion, beyond a tendency of plates of talc and mica to arrange them- 

 selves along the planes of cleavage : but as on these planes there 

 would be the least resistance to their intrusion or formation, this may 

 have been a subsequent operation, and should not alter our opinion 

 of the cause of the cleavage. 



Thus all our observations and deductions ultimately converge to 

 the conclusion that the cleavage must be attributed to pressure caused 

 by the elevation of great masses of rock under conditions of w^hich 

 we are ignorant. And if to this conclusion it should be objected that 

 no similar results can be produced by experiment, I reply that we 

 have never tried the experiment with a power at all to be compared 

 to that employed ; and that this may be one of many cases where 

 our attempts to imitate the operations of nature fail, owing to the 

 feebleness of our means, and the shortness of the period during which 

 we can employ them. 



November 15, 1848. 



The following communications were read : — 



1. On the Gypsu7n o/Nova Scotia. 

 By Abraham Gesner, For. Mem. G.S. 



(In a letter to Sir Charles Lyell.) 



Since my return to Nova Scotia I have had an opportunity of ex- 

 amining several places the geology of which had been unexplored. 

 I scarcely need say that at the time of your visit to this country I 

 had based my opinions in regard to the position of the gypsiferous 

 sandstones and coal-measures of Nova Scotia upon the facts that I 

 was then acquainted with, and the views of those who had worked in 

 the same field. The declarations also that have been often made in 

 reference to the situation of the gypsiferous strata of England had, I 

 must say, diverted my attention from the subject to which you have 

 since fully adverted. 



I feel it now but just and honourable to state, that subsequent ob- 

 servations have convinced me that the order of succession which you 

 have laid down in your remarks in the Proceedings of the Geological 

 Society, and in your Travels in America, in reference to the above 

 rock series, is correct. In a new work now in course of publication, 

 on the Industrial Resources of this Province, I have adverted to this 

 subject, and have given my reasons for renouncing my former opinions 

 in this matter, and I doubt not that in the gratification this acknow- 

 ledgment will afford you, on my part I shall receive as much indul- 

 gence as the case deserves ; nor need I add, that even in the advancing 

 state of the science similar errors will occur, especially in cases in- 

 volved in more or less obscurity. In reference to the question, which, 

 so far as I am concerned, is now no longer at issue, I will add a 



