490 A. W. G. WILSON SHORELINE STUDIES ON ONTAEIO AND ERIE 



the Niagara, and the Saint Lawrence rivers. At these points there is a 

 small but constant current, really a portion of the body current, but much 

 more readily noted than the body current of the main lake. These local 

 currents are too weak to be active transporting agents. In the case of 

 the Detroit river the occurrence of delta deposits at its mouth, although 

 in part undoubtedly due to wave action and other local causes, may be 

 due to the river's ability to transport materials supplied by the waves on 

 lake Saint Clair, the materials being carried down the channel of the 

 river by the current to lake Erie and being deposited in the latter lake as 

 soon as the current is arrested by the lake waters. In the case of the 

 Niagara river the discoloration of the water shows that a small amount 

 of material in a very fine state of division is carried out into lake Ontario. 



Lake 



Ontafiio. 



FiGDRB 6. — Z>j-jft Currents in Lake Ontario 



Two miles off the mouth of the river the coloration has disappeared and 

 the current has become merged with the general drift of the surface 

 waters of the lake. It has also been noted that the outer portion of this 

 current in lake Ontario is shifted by the winds. The waters of the Saint 

 Lawrence where it leaves the lake are clear and practically free from 

 sediment. 



In lakes Erie and Ontario the general study which has been made by 

 the officials of the United States Weather Bureau has shown the existence 

 of a slow general set of the mass of the water toward the outlets. Where, 

 by the action of the wind, surface currents have driven more water to the 

 eastward of the lakes than can well pass through the discharge, there 

 must be more or less of a return current. In the case of these two lakes 



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