lagoon deposit which accumulated under environmental conditions that 

 were unfavorable for most marine animals. 



Coarse quartz sand of type D sediment probably represents deposition 

 at different times during the Quaternary. Part of these sediments seem 

 to be closely related to type E material, differing mostly in a smaller 

 shell content. This difference may be due only to minor differences in 

 depositional environment from place to place, or to episodes of post- 

 depositional leaching or preferential sorting which locally altered the 

 original character of the deposit. A second group of quartz sands 

 (classed as type D material) is judged to be closely related to type A 

 sand because it also forms part of the modem surficial sediment deposits 

 and contains similar fauna. This aspect of type D material is identified 

 on the core logs (App. B) as a "shelf facies" deposit. 



The shelf facies sands also include all type A sediments. They are 

 judged to be the most recent of the Quaternary sediments and are, for 

 the most part, wholly modern because they represent the ongoing nearshore 

 and shelf sedimentation processes. Locally, however, the deposits may 

 have been initiated during the last stages of the transgression at a sea 

 level somewhat lower than present. Shelf facies deposits overlie large 

 areas of the inner shelf floor and shoreface zone, and probably comprise 

 the bulk of the material in the shoal complex off Cape Fear and lesser 

 shoal features elsewhere. 



Faunal elements in the shelf facies sands are mostly compatible with 

 the inner shelf and existing nearshore environments. Reworked or detrital 

 faunal components occur frequently but can usually be discriminated from 

 the more modem elements. The modem fauna consist primarily of mollusks, 

 echinoids, and foraminifera. Many of the mollusks are larval or juvenile 

 forms; large mollusk shells are rare. Common mollusks found in adult form 

 are small species with shells generally less than 25 millimeters (1 inch) 

 long. Of these. Caecum ■putcheltian Stimpson and Ervitia aonaentriaa (Holmes) 

 are most common; others occurring frequently are Parvilucina multitineata 

 (Tuomey and Holmes), Crassinella tunulata Conrad, and Tellina cf. T. 

 sybaritiaa Dall. 



Foraminifera in shelf facies sediments vary in frequency from rare to 

 abundant. The assemblages in many instances contain reworked and detrital 

 tests derived from substrate deposits. Where they are clearly exotic, 

 such as the Oligocene fauna which are common detrital and reworked ele- 

 ments in surface sediments, the assemblages can be readily differentiated 

 from the more modern types. Those derived from late Tertiary and Quater- 

 nary substrate deposits are not usually separable. Although it is 

 probable that such displaced material is present in substantial amounts 

 locally, the general consistency from place to place in the more common 

 species suggests they are representative of the modem shelf floor 

 assemblage. 



Studies of southeastern Atlantic shelf foraminifera have shown the 

 existence of distinct inner, mid, and outer shelf assemblages (Wilcoxon, 



62 



