HONEYMAN ON THE HISTORY OF A BOULDER. 323 



When surveying the Precarboniferous rocks of the Pictou Coal 

 Field, in 1869, I found strata to the east of Sutherland's River, 

 about three miles south of the boulder. These dip northerly at a 

 very low angle, and are of the age of the boulder, having the 

 same fossils. It is doubtless from some part of these that the 

 boulder came. Their extension in the direction of their dip would 

 underlie the boulder at no great depth. 



The Homalonotus which I have already referred to is character- 

 istic of the part of the Upper Arisaig Series, which has been deter- 

 mined by Mr. Salter, the late distinguished Paleontologist of H. M. 

 Geological Survey, to be the equivalent of the Aymestry limestone 

 of Wales. There is probably the other member of the upper part 

 of the Upper Arisaig Series in the locality yet undiscovered. So 

 that between Sutherland's River and Marshy Hope* we have pro- 

 bably the whole of the Upper Arisaig Series with the exception of 

 the lowest, or Arisaig Pier portion, which I have regarded as the 

 possible equivalent of the Oneida conglomerate of the United States. 



Our boulder strata and those underlying them, were formed in 

 the bed of the ocean, at ever varying depths, from the detritus of 

 the Crystalline 'rocks of the Lower Arisaig Series, which I have 

 already referred to as underlying the Petraia strata up Barney's 

 River. 



The boulder also tells us that it has undergone great hardships 

 since it was deposited at the bottom of the ocean. When trying to 

 detach a piece of the rock along with the fossils, I found that it 

 would only break at right angles to the line containing the fossils. 

 This tendency is called slaty cleavage, 



Now this indicates that the original strata of the boulder with 

 those underlying it, had been let down deeper than when deposited 

 and subjected to heat as well as hydraulic or other pressure, and 

 had consequently been metamorphosed. The preservation of the 



*At the entrance to the Marshy Hope there is an outcrop of Arisaig A. (May hill 

 sandstone) belonging to the Antigonish Mountain, a Marshy Hope Series. This is 

 overlaid directly by part of the conglomerate of the Merigomish Carboniferous forma- 

 tion. So that along the line of junction of the Precarboniferous and Carboniferous 

 formations of Merigomish, we have an irregularity of a accession corresponding "with 

 that observed in the Pictou Coal Field. Vide ♦* Transactions " 187(>-71. 



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