164 the coastal plain formations of cecil county 



Tile Eocene, 

 the aquia formation. 



The Aquia formation is the only representative of Eocene deposits 

 in Cecil county. It is confined in its distribution to the extreme 

 southeastern portion of the region, and is so largely buried beneath 

 Pleistocene deposits, that only a small portion of it is visible. The 

 name of the formation is derived from Aquia Creek, one of the tribu- 

 taries of the Potomac river in Virginia, for in that area, the forma- 

 tion is found typically developed. The Aquia formation lies un- 

 confcrmably on the underlying Monmouth, and is overlain uncon- 

 formably by beds belonging to the Columbia group. 



The materials making up the deposits consist of sand and green- 

 sand. The color of fresh exposures varies from a brownish to a 

 greenish tint, and certain of them have a very decided green tone. 

 This color, however, changes to a brown on weathering. 



The most western outcrop of the Aquia formation of any import- 

 ance is in the valley a mile north of Eredericktown. There the for- 

 mation is a slightly cemented glauconitic sand, and in fresh exposures 

 has a somewhat streaked and mottled appearance, due to the mixing 

 of grayish-green and reddish-brown sand. The thickness of the expo- 

 sure is about 35 feet and it is underlain by ]\Ionmouth and overlain by 

 coarse cross-bedded Columbia sand and gravel. The outcrop shows 

 quite continuously from this point down the valley to the Sassafras 

 river. 



Along the river to the east and west of Eredericktown there is a 

 continuous outcrop of Aquia varying from 15 to 20 feet in thickness. 

 The best exposures are in the town, where it is found to be very 

 similar in appearance to the deposit just described although it does 

 not contain as much iron. East of Eredericktown the amount of 

 glauconitic and calcareous matter seems to increase and the character 

 of the Aquia formation changes so as to resemble what may be de- 

 scribed as a pepper and salt appearance. In the stream-cut west of 

 Duffy Creek there is a fair exposure of a light greenish-brown sand 

 which is very slightly cemented and full of white concretionary 



