134 PHYSIOGRAPHY AND GEOLOGY OF THE COASTAL PLAIN PROVINCE. 



IV. Section left hank of Rappnhannocl- River, one-half mile above Carters 



Wharf. 



Feet 

 Pleistocene Yellow and red coarse sand and gravel. Peb- 



bles not exceeding a few inches in size. 



Numerous large boulders 10 



Miocene. Calvert Pink and white clay 4 



Sand colored, various shades of red, pink, 



yellow, and gray 25 



Argillaceous sand, dark greenish-gray, where 

 unweathered, light greenish-gray where 



weathered 32 



Ferruginous fossiliferous sand layer with 



Pecten Venus, Dosinia, Turritella, etc. ... 6 in. 



Dark green arenaceous clay 10 



Dark green argillaceous sand 9 



Ferruginous fossiliferous sand layer 6 



Dark green clay 5 



Dark green argillaceous sand 22 



Diatomaceous clay, white when dry 18 



Total 1411^ 



The above section resembles very closely the Nomini Cliffs and seems to 

 represent the same horizon. The fossil layers mentioned contain only very 

 decayed fossils. This is principally because the face of the blufE is very much 

 weathered. It is probable that by digging into the fresh material good 

 specimens could be obtained. The purest diatomaceous earth is contained 

 in the lower 18 feet but it is probable that diatoms occur in the layers 

 higher up. Slight differences in the sand and clay content cause the bluff 

 to have a banded appearance. A few large mammalian vertebrae were 

 observed about half way up the bluff. The exposure is a very striking one 

 and furnishes an excellent section of the Rappahannock River Calvert 

 materials. 



A series of bluffs not so high or well exposed extends from the preced- 

 ing section down stream for about 3 miles. The diatomaceous portion may 

 be traced the entire distance with scarcely any variation in level showing 

 that the Miocene beds are very nearly horizontal. 



V. Section right bank of Rappahannock River at Tappahannock. 



Feet 

 Pleistocene Loam grading down into sand with an inter- 

 mixture of gravel 10-15 



Unconformity 



Miocene. Calvert Dark greenish-gray to olive green argillaceous 



clay, lighter in color where weathered 5-10 



Total 25 



