482 



/. C. B RANKER 



and throw the beach sands and all floating material alternately 

 right and left. 



In the diagram the waves are represented as being equal dis- 

 tances apart, the shore has a regular curve and the cusps are 



Fig. i. — Diagram illustrating the formation of beach cusps. The concentric lines 

 represent two sets of wave crests. The heavy line is the curve of a beach which, with 

 these waves, would yield cusps of uniform size. 



uniformly spaced. Such regularity is not to be expected in 

 nature. The waves are not so evenly spaced, the depth of the 

 water varies near the shore, and the waves do not all strike the 

 shore at the same angle. 



Fig. 2. — Diagram illustrating the formation of cusps of different sizes upon a 

 straight beach D E. If D C were the beach line, these waves would produce cusps 

 of uniform size. 



In Fig. 2 the waves are represented as breaking upon a. 

 straight beach. If the water off shore were of a uniform depth 

 and the waves were evenly spaced the cusps in this case would, 

 for obvious reasons, be further and further apart from left to 



