1888] MARYLAND ACADEMY OF SCIENCES. 29 



On the Eastern Shore, however, it is much more difficult to 

 recognize the Eocene because of the greater degradation which 

 it has suffered over a large part of the surface, and especially 

 since so much of it is apparently concealed by the sand, loam, 

 p'ravel, and boulders of more recent formations. In Kent 

 County, a few miles north of the Chester river, some of the 

 hills display the mixed green sand below, and gradually become 

 more decidedly siliceous above, until near and on the surflxce 

 they are chiefly made up of the ferruginous sands, like those 

 of the region adjoining the Severn river in Anne Arundel 

 County. In these likewise we find a few of the same fossils as 

 before. Mutilated or worn specimens of Cardita planicosta, 

 CucuUea transversa, TiLrritella Mortoni, Pectunculus stamincus, 

 and Ostrea compressirostra have been found, either loose in the 

 sand or attached to pieces of the ferruginous sandstone which 

 forms broken beds at intervals, and is most perceptible near the 

 ravines. Especially near the heads of the creeks flowing into 

 the Chester river, southwest of Chestertown, and in the ravines 

 adjoining Wharton Creek on the south, and also in those at 

 the sources of Farley Creek, the Eocene beds have been detected 

 with one or more of the species of fossils named above. Prob- 

 ably the best preserved specimens of TurriteUa Mortoni thus 

 far secured from the Eastern Shore have been those from the 

 head of Farley Creek. All the others, as far as they have been 

 examined, were either fragmentary or badly worn. 



Here, as on the Western Shore, the Eocene formation begins 

 at base with aluminous, mixed, dark or greenish marls, which 

 become gradually more sandy above, until the upper member 

 is seen to be composed of ferruginous sand, more or less hard- 

 ened into sandrock, containing the fossils enumerated above. 

 In like manner the whole series of these beds rests upon the 

 sandy marls of the Cretaceous formation, which grow more 

 aluminous and carbonaceous as they are traced below. No 

 precisely drawn boundaries can be given for the entire Eocene 

 formation of Maryland, for its points of contact with other 

 formations are sometimes obscured,- either by being covered up 

 with the deposits of later periods, or else by being mixed with 

 the movable materials derived from underlying beds. Thus 



