SECTIONS IN THE RAPPAHANNOCK RIVER VALLEY. 109 



On the left bank of the Eappahannock Eiver two and one-half miles 

 above Port Conway, in a bluff 25 to 30 feet in height, some weathered 

 greensand is exposed near the base. The greater portion of the bluff con- 

 sists of Pleistocene materials. 



IV. Section left lank of Rappahannock River, ahout three-quarters of a 



mile above Port Conway. 



Feet 

 Pleistocene Sand, gravel, etc., not well exposed, about. . 15 



Eocene. Nanjemoy Dark green arenaceous glauconitic clay. Fos- 

 sils especially in bed 4 feet thick at base 

 of cliff and in a band 12 to 16 feet above 

 base. The fossils in the lower stratum are 

 as follows : Venericardia potapacoensis, 

 Corbula onisctts, Meretrix lenisf Ostrea 

 Venercardia, sp., Meretrix ovata, Turionilla 

 potomacenfiis, etc. The fossils from the 

 upper zone are Venericardia potapacoensis, 

 Meretrix, Turritella, etc 25 



Total 40 



The Nanjemoy formation outcrops just above Port Conway for a 

 distance of about three-quarters of a mile. In some places it extends to a 

 height of 18 feet above the water. It consists of a compact argillaceous 

 greensand with a few layers of fragile shells principally Venericardia 

 potapacoensis. On the Port Eoyal side the Nanjemoy also outcrops in the 

 river bluff but the exposed thickness is not more than 10 or 12 feet. Shell 

 layers here consist mainly of Venericardia potapacoensis and Turritella sp. 

 Pleistocene materials overlie the Nanjemoy strata on both sides of the river. 



On the south bank of the Eappahannock Eiver between Port Eoyal and 

 the mouth of Mill Creek, Nanjemoy greensand is poorly exposed in several 

 places. 



V. Section left hank of Rappahannock River two miles below Port Conway. 



Feet 

 Pleistocene Sand and gravel 12 



Eocene. Nanjemoy Dark argillaceous greensand containing fossils 



at base 10 



Total 22 



