18 Dr Hibbert on the Discovery of the Fossil Elk. 



flowed, and, in the course of ages, had succeeded by this 

 accumulation of earthy matter in excluding the water from 

 these hollows, as well as in changing the course, or narrowing 

 the bed of the river by which these lakes communicated with 

 each other, and with the sea on the west. But another cause 

 besides this will be found in most instances to have assisted in 

 levelling the land, and as no one has more clearly explained 

 this cause than Dr MacCulloch,* it would be an injustice to him 

 not to o-iye it in his own words. " Many fresh water shells," 

 he observes, " breed in lakes, and even in the shallowest and 

 smallest pools ; and as their death and reproduction is very 

 rapid in many cases, a considerable addition of solid matter is 

 made to that which is brought in from the rocks and soil 

 which the feeding waters act on in their courses. Such shells, 

 therefore, produce calcareous beds, which are never, or rarely 

 at least, much consolidated, but are known by the name of 

 marl. This marl also varies in character, as the shells may 

 have disappeared entirely, or it may be further intermixed 

 with the clay or the sand introduced by the rivers." 



The shell marl, which is accumulated in the low sites of 

 ground near the Peel River, is of a milk-white colour, also, 

 when dried, very light and porous. All the shelly parts are in 

 such a comminuted state, and so mixed up with clay or sand, 

 that I could not find a specimen in which the organic structure 

 of the animals to which the marl owes its origin was preserv- 

 ed. The bones of the elk are said to be found about six to 

 ten feet deep in this marl, and mixed along with them, particu- 

 larly in the more superficial strata, are the remains of nume- 

 rous aquatic plants, as of willows, ferns, reeds, &c. indicative 

 of the ancient marshes which succeeded to the levelling of the 

 land, and to which the elks appear to have resorted. In the 

 upper beds the calcareous matter gradually lessens, showing 

 that the gradual extinction of the race of fresh water shells 

 kept pace with the filling up of the lake. A stratum of sand, 

 the pure and nearly unmixed debris of the neighbouring hills, 



* Article Organic Remains in Dr Brewster's Encyclopaedia, vol. xv. 

 p. 726 - 



