148 PHYSIOGRAPHY AND GEOLOGY OF THE COASTAL PLAIN PROVINCE. 



Feet 

 Band of small pebbles in matrix of white sand 



containing some white and pink clay 4 



Pink to yellow to gray sand containing con- 

 siderable clay 8 



Sandy yellow to gray clay 6 



Miocene. St. :\Iary"s Layer of indurated shell marl with Pecten 



the dominant genus 5^4 



Shell layer 20 



Gray sand with few fossils 5 



Blue clayey sand slightly fossiliferous (to 



water) 7 



Total 801/2 



At Eocky Point, opposite the west end of Jamestown Island, beneath a 

 covering of Pleistocene about 18 to 20 feet in thickness, there is a 12-foot 

 indurated fossiliferous stratum. The shells are firmly consolidated, forming 

 a hard rock which has fallen in great masses and covers the beach. The cal- 

 careous material has been removed in some cases forming a porous rock com- 

 posed of sand molds and casts. Melina, Pecten eboreus ( ?) and Balanus 

 are the common forms. Beneath the hard layer there is a bed of loose buff 

 sand containing some fossils. The shell bed seems to represent part of the 

 thicker shell layer described in previous sections while the buff sand repre- 

 sents the blue slightly fossiliferous sand exposed at the preceding localities. 



V. Section right hanJc of James River just belovj Scotland ^¥]larf. 



Feet 

 Pleistocene Yellowish-brown sand with some small peb- 

 bles 13 



Miocene. St. INIary's Shell marl, the same layer as that at Rocky 



Point, though less firmly indurated and 

 not so thick. Fragments of this rock strew 

 the beach. Where the rock is not consoli- 

 dated the shells are present, but are exceed- 

 ingly rotten 7 



Buff sand with few fossils 2 



^lateri.Tl concealed by wash, to water 10 



Total 32 



In the right bank of the James Eiver, % mile above mouth of C'obham 

 Creek, the Miocene shell bed which is so prominently exposed in the Clare- 

 mont and Dillard's AVharf bluffs and at Eocky Point and Scotland, outcrops, 

 reaching a height of about 12 feet above the water. Only the lower part of 

 the bed seems to be present and the entire thickness is only about 5 feet. The 

 Pleistocene cover consists almost entirely of sand with few small pebbles and 

 some drab clay. Beneath the shell stratum a little buff sand appears but most 



