fragments which are locally abundant. Of these, few are recognizable 

 macrofossils and the majority are microfossils. Remains of the larger 

 organisms consist mostly of small mollusk fragments, barnacle plates, 

 and echinoid parts, particularly spines. The calcareous rock in cores 

 98 and 99 contains abundant casts and molds of mollusks. Outcrops 

 (presumably of this same rock) found off New River Inlet are reported 

 by Lawrence (1975) and Crowson and Riggs (1976) to contain shells of 

 the large Tertiary oyster, Crassostrea gigantissima Finch. 



The more numerous microfauna consist chiefly of foraminifera, by far 

 the most abundant element, ostracods, and bryozoa. The foraminiferal 

 fauna is varied from place to place in species composition and in non- 

 specific characteristics. However, a few elements are near uniquitous 

 and are useful for identifying the deposit. The most important species 

 of this group are Bonion advenim Cushman and Discorbis assulata Cushman. 

 A comprehensive study of the Oligocene foraminifera in the ICONS cores 

 and from onshore samples is planned for publication by the U.S. Geological 

 Survey . 



The distribution and thickness of Oligocene rocks in the North 

 Carolina Coastal Plain are illustrated and discussed in Brown, Miller, 

 and Swain (1972) . They found the characteristic lithology from borehole 

 data to consist chiefly of algal and shell limestone with the original 

 shell material leached out. Locally, there were deposits of sand and 

 calcareous sand. Except for the calcareous sandstone in the cores from 

 New River Inlet, there was little lithologic similarity between the 

 material beneath the inner shelf and the Oligocene unit onshore. However, 

 they note an east-west facies progression and the facies found offshore 

 apparently does not extend much inland of the shoreline of Onslow Bay. 



Coastal plain deposits containing the large Tertiary oyster, 

 Crassostrea gigantissima Finch, have been recognized at several locales 

 on the North Carolina Coastal Plain; these deposits have been variously 

 correlated to the Eocene Castle Hayne Formation or to the Trent Marl 

 Formation of Oligocene or lower Miocene age. In a general study of the 

 oyster communities, Lawrence (1975) reviewed prior work, and added new 

 data on outcrops of these deposits. He found that the localities of 

 oyster-bearing strata form an arcuate belt from Pollocksville through 

 Belgrade to Jacksonville, and shoreward along the westward margin of 

 New River, with deposits extending also along the sublittoral southward 

 of New River Inlet for 5 to 10 kilometers. He concluded that the oyster- 

 bearing deposits which rested on unnamed, well-indurated late Oligocene 

 "shell rock" were also of late Oligocene age and were formed along the 

 northeastern margin of a late Oligocene delta. In this connection, he 

 points out that the areal distribution and unit geometries of sand-rich 

 lithofacies in the unnamed rocks of Oligocene age mapped in this area 

 strongly suggest a prograding delta complex. The inner shelf ICONS data 

 support this conclusion. The internal reflectors in unit III which 

 extends generally south and southeast of Lawrence's study area indicate 

 that the deposit is probably a deltalike progradational sediment body. 

 The consolidated carbonate rock in cores 98 and 99 off New River Inlet 



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