128 THE ICE AGE IN CANADA. 



surfaces, and sweep it downward, laden with uprooted 

 trees, timber, stones and gravel. The destruction of roads, 

 bridges, and other property, and the tearing up and bury- 

 ing under rubbish of meadows, are sometimes terrific. 

 Fortunately, such freshets occur only at long intervals, 

 but the loss and injury which they cause are long 

 remembered, and the ridges and mounds of debris which 

 they deposit remain as mementoes of their destructive 

 power. Logan has well described* the annual breaking 

 up, or " shove," of the ice on the St. Lawrence, which, 

 though a comparatively quiet phenomenon, piles up ridges 

 of stone where the floes of ice ground. In the Pleistocene 

 period, such ice-freshets and shoves must have been 

 frequent, and it is not unlikely that some of the gravel 

 deposits which are credited to the melting of the 

 continental glacier are due to their agency. 

 4. -BORDAGE ICE. 



4. A special ice agency of some importance is that to 

 which Mr. Chalmers has directed attention on the coast 

 of the bay des Chaleurs.-f* 



Mr. Chalmers describes the rocks of various paleozoic 

 periods, along the south side of the bay des Chaleurs, as 

 presenting a somewhat flat and even surface to a height 

 of 50 to 75 feet above the sea level. A similar appearance 

 is presented by the beds below the sea level along the 

 coasts. He connects this with the action of floating ice, 

 now very evident in the bay. In winter a fixed border 

 of ice is formed along the coast, from two to six feet thick, 

 and extending from the shore for a distance of from half 

 a mile to several miles. The open portion of the bay is 

 generally full of loose floes. 



* Journal Geol. Society. 



t Canadian Record of Science. 



