CHARACTER OF THE SHORELlNEiS 473 



raphy of the pre-Glacial cycle, modified it is true by glacial scouring. In 

 larger part they were bordered by morainic materials of different types 

 and by lacustrine deposits. 



The initial shorelines would be nneven and irregular, and the materials 

 bordering these shores would be of very diverse character — hard rock, 

 almost equally hard clay, soft shales, and softer sands and gravels. 

 Prominent headlands would be formed by some drumltns and moraines, 

 while elsewhere low sand flats would be formed by some glacial sand 

 plain, or long narrow points by the partial submergence of cuesta ridges. 



Features oe the present Shores 

 lake ontario 



Shore-cliffs. — At the present time there are many places where the 

 lake shore is bordered by a sea-cliff cut in glacial debris or in bedrock. 

 In the great majority of cases there is a beach of shingle and sand between 

 the base of the cliff and the water ; still there are some localities where the 

 water reaches to the foot of the cliff. As the shores are visited from year 

 to year, the conditions have been found to vary. The periodical fluctua- 

 tions in the water level, apparently due to variations in the annual rain- 

 fall over the whole basin of the Great lakes, may in part be responsible 

 for some of these changes. In some 5rears there are quite extensive 

 stretches on the north shore of lake Ontario, where the waves attack the 

 very foot of the sea-cliffs. At the present time (1908) the only localities 

 where the water when quiet reaches to the base of the cliffs occur along 

 the shore at several places west of Lome Park, where the sea-cliffs are cut 

 in Medina shales. 



The beaches around the shores of lake Erie are characteristically wider 

 and of gentler slope than those on lake Ontario ; probably this is because 

 lake Erie beaches are more frequently sand beaches, while on Ontario 

 gravels predominate. Erie is also a much shallower lake and of greater 

 area than Ontario, and its waves would be modified and more easily 

 influenced by bottom conditions. 



While in its initial stages the shoreline of lake Ontario was very uneven, 

 the subsequent operation of shore processes has tended to reduce the 

 smaller irregularities and to straighten all shorelines. We accordingly 

 find that headlands have been reduced, spits and bars have been built 

 across the intervening bays, more or less completely closing them, and a 

 nearly continuous beach of loose waste has been formed. 



Bay-bars and spits at the east end of the lake. — South of the mouth 

 of Stony creek, at the east end of lake Ontario, for about 21 miles there 



