120 THE PLIOCENE AND PLEISTOCENE DEPOSITS OF MARYLAND 



the others ? In dealing with the Wicomico formation, the same objection 

 is met with as was confronted in trying to apply this explanation to the 

 Sunderland. There is no opposing bank on the east to confine the river 

 which is supposed to have built up the Wicomico terrace. It remains 

 then to apply the explanation to the Talbot terrace. This formation is 

 deposited for the most part between higher ground. Were these elevated 

 borders river banks ? 9 



A flood plain of the dimensions of the Talbot terrace would require a 

 long time for its formation. As the material which composes the sur- 

 rounding Wicomico formation is soft, tributary streams which would 

 enter the main river system would have had an opportunity to completely 

 destroy the plain surface of this terrace before that of the Talbot could 

 have been developed to its present dimensions. In other words, an ad- 

 vanced system of dendritic drainage would have been developed on the 

 Wicomico surface. In the chapter on Physiography of the Eegion, the 

 author was careful to explain that these various terraces were not dis- 

 sected except along their margins. This is particularly well shown on 

 the Eastern Shore where the surface of the Wicomico formation is prac- 

 tically undrained over large areas although the drainage lines are more 

 conspicuous along the borders. The time which must have elapsed in 

 order to have the Talbot terrace below formed as a flood plain of a river 

 system would have been sufficient to completely drain and in a large 

 measure destroy the surface of the Wicomico formation. This has not 

 been accomplished. It is, therefore, believed that an estuary existed dur- 

 ing Talbot time and that the waves which beat along the shore of this 

 estuary kept the streams cut back at their mouths, and although a den- 

 dritic type of drainage started to develop, it had apparently not pro- 

 ceeded far because of the constant shortening of the river valleys. An- 

 other argument against the flood plain hypothesis is that sufficient time 

 would have elapsed to have permitted the complete destruction of the 

 scarp-line by subaerial erosion. With the advance of the dendritic drain- 

 age systems, the scarp-line would have blended with the terrace beneath. 



"Typical marine Pleistocene terraces containing marine invertebrate fossils 

 are extensively developed on the coast of Greenland. They are described and 

 illustrated by White & Schuchert, Bull. Geol. Soc. Araer., vol. ix, p. 348, 1898. 



