THE SUCCESSION OF DEPOSITS. 63 



and gravel with Saxicava and other shells;* while, in a 

 depression above this, at a height of 550 feet, sea-shells 

 occur in clay and sand, and there is a distinct beach at 

 about 615 to 625 feet.-f- Even on the top of the Mountain, 

 at a height of about 700 feet, large travelled Laurentian 

 boulders occur, lying loose and without any boulder-clay. 

 On the lower St. Lawrence, below Quebec, the series of 

 terraces is generally very distinctly marked, and for the 

 most part the lower ones are cut into the boulder and 

 Leda clays, which are here of great thickness. I give 

 below rough measurements of the series as they occur at 

 Les Eboulements, Little Mai bay and Murray bay, where 

 they are very well displayed. I may remark in general, 

 with respect to these terraces, that the physical conditions 

 at the time when they were cut nnist have been much 

 the same with those which exist at present, the appear- 

 ances presented being very similar to those which would 

 occur were the present beach to be elevated. 



Comparisons of the older and modern terraces may be 

 made at many places on the lower St. Lawrence. At 

 Little Metis, where I have had good opportunities of 

 studying their appearances, the coast is fringed with a 

 broad belt of boulders, wholly covered at high tide, but 

 exposed at low tide, and occupying in many places a 

 breadth of thirty to fifty paces, within which the boulders 

 are packed very closely. They vary in size from nine to 

 ten feet in diameter downward, and consist principally of 

 orthoclase gneiss, Labradorite rock and other crystalline 

 rocks from the Laurentian of the north shore, here about 

 thirty-five miles distant at the nearest point. With 



* The beach at Cote des Neiges is that described by Sir C. Lyell 

 in his travels in N. America. 



t Dr. F. D. Adams and Baron de Geer. 



