b. Cretaceous Deposits . Fine to very fine muddy sand (lithologic 

 type C) containing Upper Cretaceous fauna was found in outcrop or beneath 

 thin overburden in cores 16, 22, 23, 41, and 42. These cores are grouped 

 in the area between the South Carolina border and Lockwoods Folly Inlet, 

 and are within 10.2 kilometers (5.5 nautical miles) of the shore (Fig. 

 23) . The location of the cores and the depth to the Cretaceous contact 

 indicate that the Cretaceous material corresponds with seismic reflection 

 uni t I . 



Only a few macrofossil fragments were recovered from the cores, 

 probably because of the small area sampled. The Cretaceous mollusk 

 shells that often wash up on nearby beaches (Cooke, 1936) probably come 

 from sea floor exposures of this deposit. Microfossils are abundant in 

 the Cretaceous sediments and consist chiefly of well-preserved foraminif- 

 eral tests (comprising as much as 20 percent of the sediment particles), 

 ostracod carapaces , and echinoid parts . 



The foraminiferal assemblage, which contains a large number of both 

 benthonic and planktonic species, is dominated by Cihicides harpern. 

 Sandidge and Anamatinoides oavoZinensis Curran. Together, these species 

 account for more than half the population. Other common species are 

 Dorothea hulleta (Carsey), Loxistomum plaitum (Carsey), Guembelitria oretacea 

 Cushman, and Hetevohelix ^Zo&uZosa(Ehrenberg) (see App. E for more details) 

 The foraminiferal assemblage as a whole indicates a Late Cretaceous age 

 and deposition probably at mid or outer shelf depths. Seismic reflection 

 records of the deposit show southward-dipping secondary reflectors which 

 indicate that the Cretaceous sediments accumulated by southward prograda- 

 tion. Truncation of these reflectors at the top of the deposit also 

 indicates that, subsequent to deposition, the unit underwent one or more 

 erosional episodes. 



Lithologically, the Cretaceous sediments are relatively homogeneous 

 and typically in the fine to very fine quartz sand size. The dominant 

 constituent is quartz, followed by biogenic calcium carbonate. Other 

 constituents are sparse. 



Samples from core 16 are lithologically different from other Creta- 

 ceous samples. The material is coarser and contains more phosphorite 

 and glauconite. The phosphorite, though sparse in the core sample, is 

 conspicuous because many grains are coarse or very coarse sand size. 

 These large grains are typically almost black, irregular in outline, and 

 often incorporate quartz grains (Fig. 15, a). 



The Upper Cretaceous deposits underlying the inner shelf are probably 

 related to Cretaceous unit A (Brown, Miller, and Swain, 1972) and to the 

 Pee Dee Formation (part of unit A) . The nearest borehole information 

 logged by Brown, Miller, and Swain is OT-15 near Kure Beach where the 

 upper part of unit A is classified as fine sand with calcareous accesso- 

 ries. Swift and Heron (1967) describe the typical Pee Dee lithology 

 from outcrop as a "medium dark-gray (N3), muddy (15 to 50 percent silt 

 and clay) sand." Curran (1968), Brown, Miller, and Swain (1972), and 



54 



