142 Agricultural Experiment Station, Ithaca, N. Y. 



lieifflit reached bv the violent storm waves. Since this varies with 

 the exposure, the crest of the beacli may vary in height, as we liave 

 seen that it varies in width. Tliis variation amounts to only a 

 few feet, the beach being higher on exposed tlian on sheltered 

 coasts. 



Generally the top of the beach is nearly level (Figs. 59 and 61) ; 



A 



SHORE 



B 

 62.— Cross section of bar : ancient A ; modern B. 



but where accumulations are made off shore, as they sometimes are 

 where streams bring considerably more gravel than the waves can 

 dispose of, a bar is built, and this slopes both ways (see Figs. 60 

 and 62B. Also compare with Figs. 62A and 65). 



Therefore the top of the true beach is a plain of varying width, 

 whose elevation is nearly uniform, both along the shore and at 



^^^JJ^PJSSS!!^'^ "■"■" 



63.— Cross section of beach. 



right angles to it. If it is in the form of a bar, the elevation re- 

 mains nearly uniform in the direction of the length of the bar, 

 but at right angles to this it rapidly descends in both directions. 

 In the beach, the flat topped plain is faced on the lakeward side by 

 a rapidly slojnng front ; and this descent continues beneath the 

 lake waters. (Fig. 63). 



