138 PHYSIOGRAPHY AND GEOLOGY OF THE COASTAL PLAIN PROVINCE. 

 SECTIONS IN THE PAMUNKEY AND CHICKAHOMINY RIVER VALLEYS. 



There are few good exposures of the Calvert formation along either of 

 these streams due to the low bluffs and the swamps that border the streams 

 throughout so great a portion of their courses. Enough exposures are 

 known, however, to prove the continued distribution of the Calvert along 

 their valleys in Hanover, Henrico, ISTew Kent, and Charles City counties. 



At the road crossing of Stony Eun, li/^ miles southeast of Ashland, 10 

 feet of fossiliferous blue clay belonging to the Calvert is exposed resting 

 directly on the crystalline rocks. One mile south of that point at crossing of 

 Ashland-Kichmond road and the Chickahominy Eiver similar material about 

 15 feet in thickness appears on the north side of the stream between the 

 crystalline rock and Pleistocene gravels and sand. On same road 1 mile 

 south of the Chickahominy Eiver the Calvert formation is again exposed. 



The Calvert, consisting of drab to blue clay and sandy clay, is exposed 

 in many places along Totopotomy Creek, in the valley of the Chickahominy 

 near Mechanicsville, and near Gaines Mill. 



Section in railroad cut and river hanh at Ramancol-e on the Pamunl'ey 



River, four miles west of West Point. 



Feet 

 Pleistocene Brown and mottled (red and drab) clay loam 



interbedded with many layers of coarse sand 

 containing thin bands of pea gravel 20-25 



Miocene. Calvert Buff-colored, fine-grained sand with certain por- 

 tions slightly indurated 30-35 



Blue sand containing extremely fragile fossils 25 



Total 85 



SECTIONS IN THE JAMES RIVER VALLEY. 



The Calvert formation is exposed in few places along the James Eiver 

 though it can be frequently seen along the small tributaries. In Eich- 

 mond it is exposed in numerous places but best along Shockoe Creek near 

 the Eichmond Locomotive Works. It consists of more or less impure 

 diatomaceous earth overlying Eocene greensand and overlain by Pleisto- 

 cene gravels and loam. The total thickness exposed is 40 to 50 feet. 

 Many species of diatoms have been described from this bed and it contains 

 also some imprints of molluscan shells and vertebrate remains. Most 

 remarkable, however, are leaf remains found in the upper portion. 



