KORTII AMERICAN GEOLOGY. 229 



the region where there is iieitlier erosioa nor tlepositioii, bnt transpor- 

 tation only, the shore drift takes the form of a beach, and if the hind 

 is gently inclined a lagoon is separated behind the beach, which is 

 then called a barrier. Points of land are usually eroded by waves, 

 while bays are tilled or partitioned oti' by bars; the waves of a lake 

 thus tend to straighten its shores. Other shore features treated are 

 the delta, whose anatomy as well as morphology is described, and the 

 shore wall, a feature resulting in cold climates from the expansive force 

 of ice. 



The topographic elements constituting shores have sometimes been 

 confused with similar elements of dilferent origin, and the ciiteria for 

 discrimination are therefore discusst'd, A sea-cliff is compared with 

 cliffs resulting from the unequal hardness of strata, from lateral wear 

 by streams, from faulting, etc. Shore terraces are compared with ter- 

 races arising from alternations of hard and soft strata, stream terraces, 

 fault terraces, etc. Barriers and other shore structures constituting 

 ridges are compared with moraines and osars.* 



U. S. Geol. Survey, Filth Auuual Report, pp. 67-123. 



