80 PHYSIOGRAPHY AND GEOLOGY OF THE COASTAL PLAIN PROVINCE. 



II. Section below Point of Rocks. 



Feet 

 Pleistocene Argillaceous loam Avith gravel at base 10 



Eocene. Aquia Weathered glauconitic argillaceous sand 



exposed 12 



Concealed 6 



Lower Cretaceous. Patuxent Arkosic sand with scattered pebbles 10 



Total 34 



The last exposures of the Potomac Group on the Appomattox Eiver 

 are about three miles above City Point at a locality known as Figs Wharf 

 where from 10 to 15 feet of coarse arkosic sand apparently of Patuxent age 

 is overlain with from 10 to 20 feet of Aquia greensand. 



SECTIONS ALONG THE RICHMOND, FREDERICKSBURG AND POTOMAC RAILROAD. 



A large number of sections showing Potomac outcrops are to be seen 

 along the line of the R. F. & P. R. R. between Alexandria and Fredericks- 

 burg of which the following are the more representative : 



I. Section in cut one-half mile 7iorth of Accotinh. 



Feet 



Pleistocene Ferruginous sand and gravel 10 



Lower Cretaceous. Patuxent Cross-bedded arkosic gray sands more or less 



lithified with occasional balls of greenish 

 hackly clay 40 



Total 50 



II. Section in cut just norili, of Accoiink. 



Feet 



Pleistocene Ferruginous gravel with boulders 2-5 



Lower Cretaceous. Patuxent Brownish sandy clay with plant fragments.. .. 0-6 



Cross-bedded coarse gray arkosic sand 5 



Very sandy brownish clay 2-3 



Total 9-19 



III. Section in second cut south of Accotink. 



Feet 

 Pleistocene Sand and gravel with cobbles and boulders up 



to 3 feet in diameter 2-10 



Lower Cretaceous. Patuxent Coarse arkosic cross-bedded sands with clay pel- 

 lets 10-15 



Iron crusts 6 ins. 



Greenish black clay 4-6 



Total 17-31 



