142 Agricultural Experiment Station, Ithaca, N. Y. 



height reached by the violent storm waves. Since this varies with 

 the exposure, the crest of the beach may vary in height, as we have 

 seen that it varies in width. This 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) ; 



FORMER LAKE 



LEV/EL 



LAKE 



BAR 



LAGOON 



SHORE 



W:^^^^^^^^^^^^^ 



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 



BEACH 



LAKE 





OCK 

 CLIFF 



\,tv><t 



s^^>o 



(xNO 



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 sloping front ; and this descent continues beneath the 

 lake waters. (Fig. 63). 



