180 THE COASTAL PLAIN FORMATIONS OF CECIL COUNTY 



race is everywhere present and may be found not only along the 

 exposed shores but also passing up the estuaries to their heads. The 

 materials which compose them are extremely variable. Along the 

 unbroken coast the detritus has a local character, while near river 

 mouths, the terrace is composed of the debris contributed from the 

 river basin. 



In addition to building a terrace, the waves of the Atlantic and 

 the Chesapeake are cutting a sea-cliff along their coast-line. The 

 height of this cliff depends not only on the force of the breakers but 

 also on the relief of the land against which the waves beat. A low 

 coast-line yields a low sea-cliff, and a bold coast-line, a high one, and 

 each passes into the other as often and as rapidly as the topography 

 changes, so that as one travels along the shore of Chesapeake Bay 

 high cliffs and low depressions are passed successively. The wave- 

 built terraces and the wave-cut cliffs are important features along the 

 entire extent of the Bay shore, and should be sought for wherever 

 other terrace surfaces are studied. It must, however, be borne in 

 mind that there are places along the Bay shore where the sea-cliff is 

 absent, or so low that it does not form a conspicuous feature in the 

 topography. In addition to these features, bars, spits and other wave 

 and current-built formations of a similar character are frequently 

 met with. 



If the present coast-line should be elevated, the submerged plat- 

 form which is now forming would appear as a well-defined terrace of 

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

 surface would fringe the entire Atlantic and Bay shores as well as 

 those of all the estuaries. The sea-cliff would at first be sharp and 

 easily distinguished, but as time passed, the least conspicuous portions 

 would gradually yield to the levelling influences of erosion, such as 

 soil-creep, plant roots and cultivation, and might gradually disappear 

 altogether. Erosion would also destroy in large measure the original 

 continuity of the formation, but as long as portions of it remained, 

 the old surface could be reconstructed and the history of its origin 

 determined. 



If the topographic and geologic features which are associated with 



