94 THE PLIOCENE AND PLEISTOCENE DEPOSITS OF MAKYLAND 



about one mile southeast of Queen Anne (Hardesty) in Prince George's 

 county, there is a deposit of carbonaceous matter about 20 feet thick 

 containing plant remains. At times the materials are very much decayed 

 as in the Sunderland. 



In the valleys of the Potomac and Susquehanna rivers the Wicomico 

 formation contains large quantities of ice-borne boulders. These are 

 very conspicuous at the head of the bay and in many of the road cuttings 

 on Capitol Hill, Washington. Ice-borne boulders are also abundant along 

 the lower course of the Potomac river and are frequently met with on 

 the Wicomico surface of the Eastern Shore. 



The Wicomico sea derived its material in much the same way as that 

 of the Sunderland. The waves eroded the borders of the Lafayette and 

 Sunderland formations and re-worked this material with others secured 

 from the older Coastal Plain formations. Wherever the Wicomico sea 

 advanced on uncovered areas of Miocene, Eocene, and Cretaceous depos- 

 its, these were eroded and re-deposited on the sea-floor. At the same 

 time the rivers which drained from the west brought in material from 

 the Piedmont Plateau and Appalachian Mountains. 



At Turkey Point there is a sea cliff cut by the waves of Chesapeake 

 Bay about 75 feet in height. As the greater portion of this consists of 

 the Wicomico formation, it forms one of the most typical sections to be 

 found anywhere in Maryland. 



Section of the "Wicomico Formation at Turkey Point. 



Feet. Inches. 



Sandy clay 10 



Coarse gravel layer, with boulder bed at base 15 



Gravel and clay pebbles, containing black bands 3 



Arkosic sand and coarse gravel 4 



Brownish clay sand 1 



Coarse arkosic sand and clay pebbles, containing black 



bands and spots is 



White clay 1 



Quartz pebbles 3 



Coarse cross-bedded arkosic, reddish-brown sand 15 



Variegated clay 3 



Patapsco formation (Cretaceous) 4 



Total 73 4 



