38 THE ICE AGE IN CANADA. 



frost. The boulder-clay usually rests directly on striated 

 rock-surfaces; but I have observed in Cape Breton a 

 peaty or brown coal deposit, with branches of coniferous 

 trees, which underlies it, and in other places there are 

 deposits of rolled gravel under the boulder-clay. At the 

 Glen brick-work, near Montreal, a peculiar modified 

 boulder-clay occurs, consisting of very irregularly bedded 

 sand and gravel, with many large boulders, and only thin 

 layers of clay. 



The stones of the boulder-clay are often scratched, and 

 ground into those peculiar wedge-shapes so characteristic 

 of ice-worked stones. Very abundant examples of this 

 occur at Montreal and in its vicinity. 



At Isle Verte, Eiviere du Loup, Murray Bay, Quebec, 

 St. Nicholas, Little Metis, etc., the boulder-clay is fos- 

 siliferous, containing especially Leda glacialis, and often 

 having boulders and large stones covered with Balanus 

 Hameri and with Bryozoa, evidencing that they have for 

 some time quietly reposed in the sea bottom before being 

 buried in the clay. This is indeed the usual condition of 

 the boulder-clay in the lower part of tlie St. Lawrence 

 river.* Further up, in the vicinity of Montreal, it has 

 not been observed to contain fossils, but it presents 

 equally unequivocal evidence of sub-aqueous origin in the 

 low state of oxidation of the iron in the blue clay, which 

 becomes brown when exposed to the weather, and in the 

 brightness of the iron pyrites contained in some of the 

 glaciated stones, as well as in the presence of rounded and 



* Upham admits (Proc. Brit. Nit. Soy., 1888) that sea shells exist 

 in the boulder-clay of Massachusetts ; but his explanation that they 

 have been pushed up by glaciers is quite inadmissible, more especially 

 as they are not of more boreal types than those of Massachusetts bay 

 at present. 



