108 TPIE PLIOCENE AND PLEISTOCENE DEPOSITS OP MARYLAND 



found not only along the exposed shore, but also passing up the estuaries 

 to their heads. The materials which compose it are extremely variable, 

 depending not only on the detritus directly surrendered to the sea by the 

 land, but also on the currents which sweep along the shore. Along an 

 unbroken coast the material has largely a local character, while near river 

 mouths the terrace is composed of debris contributed from the entire river 

 basin. Where the waves are weak, partially decayed material is torn 

 from the bank and redeposited practically unharmed on the surface of 

 the terrace, and continues, unchecked, its process of decay. 



In addition to building a terrace, the waves are cutting a sea cliff along 

 their coast line, the height of this cliff depending not so much on the 

 force of the breakers as on the relief of the land against which the waves 

 beat. A low coast line yields a low sea cliff and a high coast line the 

 reverse, and the one passes into the other as often and as suddenly as the 

 topography changes, so that as one sails along the shore of Chesapeake 

 Bay, high cliffs and low bluffs are passed in succession. The subaqueous 

 terrace and the wave-cut cliff are important features and should be sought 

 for whenever other terrace surfaces are investigated. The terrace is never 

 absent, but with varying width wraps about the present coast line like a 

 contour about a hill. The wave-cut cliff is not so constant for when the 

 shore is low, it may sink to insignificance or may disappear altogether. 

 In addition to these features, bars, spits, and other formations of this 

 character are frequently met with. Along the Atlantic coast of Mary- 

 land similar features are present, although the shore line is modified by 

 the presence of extensive barrier beaches thrown up by the more powerful 

 waves of the ocean. The subaqueous platform is here more extensive 

 and characteristic than within the confines of Chesapeake Bay. It 

 extends out with a gentle slope to the 100-fathom line at a distance of 

 about 100 miles from the shore. 



Were the present coast line to be elevated, the subaqueous platform 



which is How building would appear as a well -de fined terrace of variable 



width, with a surface gently sloping toward the water. This surface 



would fringe the entire Atlantic and Bay shore as well as that of the 



iaries. The sen cliff would at first be sharp and easily distinguished, 



