26 THE CANADIAN NATURALIST. [Vol. vi. 



especially the case at the base of cliffs or prominent outcrops, 

 whence a large quantity of material would be easily derived. In 

 other cases material travelled from a distance largely predomi- 

 nates. Throughout the valley of the Lower St. Lawrence, the 

 gneiss and other hard metamorphic rocks of the Laurentian hills 

 to the north-east are very abundant, and in boulders of large size 

 and much rounded. Occasional instances also occur where boulders 

 have been transported to the northwards ; but these are compara- 

 tively rare. I have mentioned some examples of this in Acadian 

 Geology, p. 61. Similar instances are mentioned in the Geology 

 of Canada, page 893. 



Though the boulder clay often presents a somewhat widely ex- 

 tended and uniform sheet, yet it may be stated to till up all small 

 valleys and depressions, and to be thin or absent on ridges and 

 rising grounds. The boulders which it contains are also by no 

 means uniformly dispersed. Where it is cut through by rivers, 

 or denuded by the action of the sea, ridges of boulders often 

 appear to be included in it. Those on the Ottawa referred to in 

 the " Geology of Canada," page 895, are very good illustrations, 

 and I have observed the same ftict on the Lower St. Lawrence 

 and on the coast of Nova Scotia. It is also observable that these 

 lines and groups of boulders are often not of local material, but of 

 rocks from distant localities, and that a number of the same kind 

 seem often to have been deposited together in one group. 



Loose boulders are often found upon the surface, and some- 

 times in great numbers. In some instances these may represent 

 beds of boulder clay removed by denudation. In other cases they 

 may have been derived from the overlying members of the forma- 

 tion, or may have been deposited on the surface, without any 

 covering of clay or gravel. In "Acadian Geology," p. 64, I 

 have illustrated the manner in which large stones, sometimes 8 

 feet or more in diameter, are moved by the coast ice and some- 

 times deposited on the surftice of soft mud, and I have had ooca- 

 don to verify the observations of the same kind made by Admiral 

 Bayfield, and quoted by Sir C. Lyell in the " Priociples of Geol- 

 ogy." Lastly, on certain high grounds there are large loose 

 boulders, which have probably been moved to their present posi- 

 tions by means of land ice or glaciers. 



The Bouider-clay not only presents, as above stated, indications 

 of successive beds, but it occasionally contains surfaces on which 

 lie laro:e boulders striated and polished on the upper surface, in 



