SECTIONS IN THE EAPPAHANNOCK RIVER VALLEY. 



lor 



VI. Section left hank of Potomac River two and one-quarter miles above 



Pope's Greek, Md. 



Feet 



Miocene. Calvert 



Eocene. Nanjemoy Woodstock 



Potapaco 



Diatomaceous earth 10 



Greensand with fossil casts (Zone 17) 10 



Greensand, somewhat argillaceous (Zone 10) .. 30 



Grayish black argillaceous greensand (Zone 15) 

 with numerous bands of Venericardia poiapa- 

 coensis and other fossils, overlain by a band 

 of concretions 5 



Total 55 



VII. Section of bluff left bank of Potomac River, one mile below Pope's 



Creek, Md. 



Feet Inches 

 Miocene. Calvert Diatomaceous earth 40 



Eocene. Nanjemoy Woodstock Brown glauconitic clay much oxidized in 



places 2 



Band of pinkish-broviTi clay nodules in 



glauconitic clay 6 



Dark glauconitic clay with many fossil 

 casts 4 



Concretions with occasional fossils 6 



Argillaceous greensand with many casts 

 and occasional shells 3 



Concretions with many large specimens 

 of Eercoglossa tuomeyi 6 



Argillaceous greensand with abundant 

 fossils including Meretrix subimpres- 

 sa, Venericardia potapacoensis, Eer- 

 coglossa tuomeyi, Turritella potoma- 

 oensis, Mesalia ohruta, Protocardia 

 lenis, Modiolus alahamensis, Corbula 

 suhengonata, Mitra potomacensis, and 

 many other forms (Zone 17) 6 



Total 56 6 



SECTIONS IN THE RAPPAHANNOCK RIVER VALI,EY. 



The Nanjemoy formation is exposed in many places along the Rappa- 

 hannock River. The finest exposures are in those places where the river in 

 its meanders cuts into the valley bluffs. In such places the bluffs are high 

 and the Nanjemoy strata well exposed in a few places, although the cover- 

 ing of vegetation and the landslides occasionally conceal the undisturbed 

 strata. 



In a cut on the R. F. & P. R. R. between Potomac Creek and Rappa- 

 hannock River about 3i/2 miles north of Fredericksburg, there is an 

 exposure of Nanjemoy and Aquia strata. At the south end of 



