50 Mr. Wright on The Micro- Fauna of the Boulder Clay, &c. 



it usually contains few Foraminifera, and would be characteristic 

 of deposits formed near exposed sea coasts, as such situations 

 are not favourable for marine forms of life. 



Reference may be made to the slow downward movement of 

 glaciers by gravity, and that when they terminated in the sea, 

 as they frequently did in the Arctic regions, they sooner or 

 later broke off into large masses, floating away as icebergs, 

 carrying with them any stones or other material which they 

 had accumulated in their course. As ice when submerged 

 beneath the sea diminishes far more rapidly than when in air, 

 so the bergs quickly melted away, depositing their burden over 

 the floor of the ocean ; and to this cause, as also to the action 

 of shore ice, may be largely attributed the formation of boulder 

 clay. 



Should at any future time the sea bed between Labrador and 

 Greenland be raised above the sea, one can readily imagine 

 such a place to present a very similar appearance to that which 

 we now find in boulder clay. There would be rock fragments 

 and stones striated and scored by ice action, with shells more or 

 less broken, and other material which had been dropped there 

 by bergs floating southward from Arctic places. With these 

 would be found associated mud and stones from the wearing of 

 rocks in the vicinity, and also marine organisms that lived 

 at the place. 



