Chautauqua Grape Belt. 



141 



The reason why these beaches are being built is that the supply 

 of gravel is greater than the waves are able to remove. In some 

 cases the supply comes mainly from the rocky headlands, in others 



60.— Present bar formation at Silver Creek. 



from streams. Where it can not all be ground down to a fine clay, 

 that can be carried off shore and dropped to the bottom, it accumu- 

 lates as beach gravel ; and so, year by year, the beaches encroach 







S^.'i-srr'iS^ts^SsiE 











. - < .- 



61.— Present beach of Lake Erie, north of Dunkirk. 



upon the lake. The crest of the beach, which may be ten feet 

 above the lake level, represents the highest point to which the lake 

 waves can reach and bear gravel : in other words it represents the 



