108 PHYSIOGRAPHY AND GEOLOGY OF THE COASTAL PLAIN PROVINCE, 



me cut a few feet of Potomac arkosic sand appears overlain by Eocene 

 greensand. In the centre of the cut the Nanjemoy clay is exposed. At a 

 few places along the base the Eocene is dark green and unweathered but 

 for the most part it is weathered to lighter shades, and more or less mottled 

 with buff. The cut is about 35 feet deep, 



I, Section left hank of Rappahannock River at Hopyard. 



Feet 

 Pleistocene Yellow sand and gravel 12 



Eocene. Nanjemoy and Aqiiia Aigillaceoiis greensand 35-40 



Total 52 



Above the wharf the upper part of the bluff is 

 not well exposed. Near tlie base the follow- 

 ing Aquia fossils were obtained: Turritella 

 mortoni, Area (?), Crassatellites, Meretrix, 

 Ostrea compressirostra , Corbula. Below the 

 wharf a few hundred yards and near the top 

 of the Eocene several thin layers of Nanjemoy 

 fossils occur. The principal form is Vener- 

 icardia potapacoensis. This is the first ap- 

 pearance of the Nanjemoy formation on the 

 Rappahannock River. The fossiliferous ma- 

 terial is a clay rather than a sand although 

 it is somewhat arenaceous. Many of the shells 

 in this place are waterworn. 



II. Section rigid bank of Rappahannock River, two and one-half miles 



below Hopyard. 



Eocene. Nanjemoy and Aquia Tlie bluff is about 40 to 50 feet high. Not well 



exposed except near base where about 10 

 feet of fossiliferous Eocene greensand out- 

 crops in which are Turritella mortoni, Mere- 

 trix subimpressa, Crassatellites alaeformis 

 and Lunatia marylandica. The Nanjemoy 

 is undoubtedly present in the concealed por- 

 tion of the bluff. 



III. Section right bank of Rappahannock River one and one-half miles 



below the mouth of Mount Creek. 



Feet 

 Pleistocene Coarse yellow sand and gravel 30 



Eocene. Nanjemoy Dark green finely arenaceous and micaceous 



clay. Fossils occur in the lower 6 feet. 

 Venericardia potapacoensis, Meretrix sub- 

 impressa, Corbula oniscus are abundant. 

 The fossils are broken and water-worn and 

 in this respect resemble the layer at Hop- 

 yard containing Venericardia potapacoen- 

 sis. It is probably the same horizon.... 18 



Total 48 



