192 THE COASTAL PLAIN" FORMATIONS OF CECIL COUNTY 



The hypothesis here advanced is based on and reinforced by many 

 observations along the present shores of the Atlantic Ocean, Chesa- 

 peake Bay, and its estuaries. Each step in the process described 

 above is there illustrated and some of them are met with again and 

 again. 



As one passes along the shores of Chesapeake Bay and of the rivers 

 which flow into it, stream channels are continually met which have 

 arrived at more or less advanced stages in the above mentioned pro- 

 cess. Some are in part converted into lagoons, by bars built across 

 their mouths, others show partial filling by mud washed in from the 

 surrounding country, and still others have reached the advanced 

 stage of swamps or meadows in which various types of vegetation are 

 flourishing. In Virginia, in addition to the usual undergrowth which 

 is found in wet places, the cypress has taken up its abode in these 

 bogs and has converted some of them into cypress swamps. For 

 great stretches along the shore the advance of the sea is indicated 

 by well-washed cliffs while in other places the waves are found de- 

 vouring beds of clay which are situated immediately in front of la- 

 goon swamps and separated therefrom by nothing but a low super- 

 ficial beach. These clay beds invariably lie at and below water-level, 

 are very young in age and evidently pass directly under the beach to 

 connect with the lagoon-clay beyond. This interpretation is made 

 the more certain by the presence of roots in the wave-swept clays 

 which but a short time before belonged to living plants identical with 

 those now flourishing behind the beach, and point to a time not far 

 distant when they also were a part of the lagoon swamp behind a 

 beach situated a little farther seaward. At Chesapeake Beach 

 a ditch has been cut through one of these beaches which shows a con- 

 tinuous deposit of clay from a lagoon swamp passing out under the 

 beach to the Bay beyond. The waves are thus caught, as it were, in 

 the act of eroding the upper portion of the lagoon deposit. 



From a large body of data gained from over a. wide area, it is evi- 

 dent that the erosion which occurred during the interval between 

 the elevation of the Talbot terrace and the present subsidence of the 

 coast was sufficient to permit streams to cut moderately deep valleys 



