MARYLAND GEOLOGICAL SURVEY 125 



above the surrounding sea as islands. Along the Western Shore the 

 Sunderland advanced steadily up the larger river valleys which had been 

 cut in the Lafayette and converted them into estuaries. As the land 

 continued to sink, waves encroached on the divides. They removed out- 

 liers, cut away the lower courses of drainage ways and diminished consid- 

 erably the areas of Lafayette which had survived the previous epoch of 

 stream erosion. 



The presence of the Sunderland sea cliff which has been preserved in 

 many localities renders the platting of this old shore line much more 

 satisfactory than that of the Lafayette sea. During the maximum subsi- 

 dence the region stood about 220 feet below its present altitude and the 

 Sunderland sea advanced to approximately the position represented in 

 Plate XXVIII. At this time the coast of Maryland had much the ap- 

 pearance of the present shores of Ehode Island and Connecticut. From 

 New Jersey southward to Washington, the sea broke on the rugged rocky 

 coast of the Piedmont Plateau. From the site of Washington to that of 

 Charlotte Hall a long peninsula ran out into the ocean separating the 

 Patuxent and Potomac estuaries. The stream guillies in this headland 

 of Lafayette were drowned and its shore line was irregular and diversified 

 with outliers like that of the Eastern Shore to-day. In this region the 

 waves apparently broke some distance from the shore and rolled in with 

 diminishing force over a long flat to the base of the low scarp at Charlotte 

 Hall. To the northeast Marriott Hill stood out as an island while off 

 the mouth of the Susquehanna river, which at that time resembled the 

 Hudson, the highest points of Elk Feck and Gray's Hill resemble the 

 island clusters which now form so striking a feature in New York harbor. 



In regard to the climate it may be said that the genial warmth of the 

 Pliocene period had come to an end. The huge continental ice-sheet had 

 crept down from the north and terminated not far distant in the high- 

 lands of Xew Jersey and Pennsylvania. Ice floes drifted down the rivers, 

 loaded with boulders and silt from the Piedmont Plateau and the Appa- 

 lachian Mountains beyond, and on melting, scattered this debris along 

 the shore line and over the sea bottom. Of the animal life in Maryland 

 at this time nothing very definite is known, but fossil evidence has shown 



