346 THE CANADIAN NA'ttJRALIST. [Vol. Til. 



of the ice, when forced by tide or wind across the bed, would soon 

 destroy them. I have observed the more elevated portions of an 

 oyster bed, over which ice had been thus forced. Several inches 

 ot the surface of the bed, including all the living oysters, had 

 been driven before the ice, and the shells and oysters so re- 

 moved, had been deposited in a miniature moraine on the slope 

 of the bed, where the water was sufficiently deep to allow the ice 

 to pass over it. This crushing and grinding process would de- 

 stroy many of the oysters; some would be crushed and broken, 

 others smothered in the moraine. The gradual silting up oi 

 the river would prevent the running of the ice, and the oyster 

 beds would, in time, be covered, as we now find them. Deposits 

 of oyster shells (covered with mud), twenty feet in depth, are 

 found in rivers, in the deepest parts of which there are not now 

 fourteen feet of water." 



'* Oysters thrive on muddy bottoms, but they will not liv^e if 

 imbedded in mud: many oyster beds have been destroyed by 

 mud alone. The annual fishinsr of ovster beds, if not carried to 

 excess, improves them. In the process of fishing the surface of 

 the bed is broken up, the shells and oysters lifted out of the mud, 

 and a supply of material (cultch) aiForded such as the oyster S2)at 

 requires, and without which it must perish." 



" Oysters upon natural beds are seldom, if ever, killed by frost. 

 I have known oysters to thrive upon a hard stony bottom, not- 

 withstanding that the ice rested upon them once in every twenty- 

 four hours throughout the winter. Some of these oysters grew 

 adherent to a small flat rock about ei^ht inches in thickness. 

 The oysters on the top of the rock were killed when they attained 

 their second years' growth, I think, by pressure, as those on its 

 edges were never injured by ice or cold." 



'' Oj'ster beds in rivers in which sawdust is thrown in large 

 quantities would probably be injured by it. The sawdust would, 

 I think, be carried by the current over the beds, and the rough- 

 ness of their surface would detain some of it. The interstices 

 between the shells and oysters would probably become filled with 

 sawdust and mud. Mud and decomposing sawdust constitute a 

 most offensive compound." 



" The area of productive oyster beds in the Dominion is com- 

 paratively limited, and altogether inadequate to supply the 

 demand for oysters which is now enormous, and which is increas- 

 ing every year. ITnless the existing beds be protected and ini- 



