124 THE PLIOCENE AND PLEISTOCENE DEPOSITS OF MARYLAND 



feature was to be explained by deformation along the " fall line," but 

 Darton has suggested a more probable cause. He believed that a subma- 

 rine bar was built by the Lafayette approximately in the position now oc- 

 cupied by the Eastern Shore, and that a depression existed between this 

 bar and the main land. When the post-Lafayette uplift took place, this 

 depression was changed to a slough and down this trough the Susque- 

 hanna found its way. A similar state of affairs now exists off the coast 

 of the Carolinas where a great barrier beach cuts off the rivers from 

 direct contact with the ocean. If this coast were to be lifted, Eoanoke 

 river would be deflected southward along the coast and follow the de- 

 pression of Albemarle arid Croatan sounds until a convenient opening 

 could be found through the obstruction to the ocean beyond. It is prob- 

 able that the channel of Chesapeake Bay was not so pronounced during 

 the post-Lafayette uplift as later when the subsequent formations had an 

 opportunity to widen and lengthen this barrier first outlined by the 

 Lafayette sea. 



This interval of erosion was brought to a close when the land sank 

 once more beneath sea-level and permitted the Atlantic ocean to encroach 

 on the valleys which had just been cut and transform them into estuaries. 

 It will be interesting to reproduce as far as possible the appearance of 

 the Coastal Plain during Sunderland time. As far as is known, no Lafay- 

 ette occurs on the Eastern Shore. The formation which caps the divide 

 is Wicomico. This does not prove, however, that there was none at the 

 opening of the Sunderland period for it is probable that erosion, which 

 had not succeeded in carrying it all away from the Western Shore, had 

 been equally unsuccessful in stripping it entirely from the Eastern Shore. 

 If there were remnants of it, or of the underlying Miocene, in that region, 

 the Sunderland sea transformed the lower valley of the Susquehanna 

 river into an early Chesapeake Bay. With the advance of the Sunderland 

 sea, the waves continued the destruction of the Lafayette until toward 

 the close of Sunderland time all traces of it had been carried away from 

 the Eastern Shore, Chesapeake Bay disappeared, and nothing remained 

 to mark the presence of a former land mass over this region except Gray's 

 ITil] and the high Lafayette-capped hilltops of Elk Neck which rose 



