(125 to 250 millimeters or 3.0 to 2.0 phi) and the well -sorted character 

 indicate these deposits are poorly suited for nourishment of most beaches 

 in the area. 



The most suitable sand for beach fill should be in the medium to 

 coarse size range (0.250 to 1.00 millimeter or 2.0 to 0.0 phi) which 

 corresponds to the size of the natural beach sediment. Potentially 

 suitable sand found in cores of the study area has been of the medium 

 to coarse type D facies which typically occurs as a relatively thin 

 discontinuous blanket deposit on the shelf floor. In addition, at least 

 one area of Frying Pan shoals near cores 58, 61, and 62 contains medium 

 to coarse sand. 



The bulk of the Frying Pan shoal material appears to be fine sand, 

 but due to the draft of the coring vessel few cores were taken from this 

 area; consequently, there may be other suitable deposits within the shoal 

 complex. It is pertinent to note that the single coarse sand facies in 

 Frying Pan shoals was found near the western end of some linear transverse 

 depressions which may have been created and subsequently maintained by 

 strong tidal or storm-driven currents. The coarser sand deposits in this 

 locale may be the result of winnowing of the finer material by these cur- 

 rents. This suggests that similar topographic features in the shoal area 

 are promising for further exploration. 



Type E sediment often contains medium to fine quartz sand and a few 

 usable sand deposits of this material were located. However, the large 

 shell content, which often exceeds 50 percent in volume, and the frequent 

 presence of silt and clay make most of the type E material of marginal 

 quality for beach fill. It is also commonly buried under unsuitable 

 overburden and tends to occur in discontinuous patches which makes 

 recovery difficult. 



Type G calcareous rocks and sediment occur widely in southern Onslow 

 Beach and in part of Long Bay. In many places, this deposit is exposed 

 or covered by only a thin overburden, making it readily accessible for 

 dredging. As previously discussed, it is unclear whether the occurrences 

 of unconsolidated type G material represent a naturally unconsolidated 

 material or disaggregation during the coring process. In either event, 

 it is probable that large quantities of granular sediment could be 

 dredged from the area. However, since there are well-consolidated 

 ledges throughout, detailed surveys with a dense net of probe or drill 

 holes would be necessary to delineate the recoverable material. 



The suitability of the calcareous granular sediment for beach fill 

 is questionable. Its coarseness and abundance of granule and pebble- 

 size fragments are undesirable for a recreational beach. In addition, 

 being almost entirely composed of calcium carbonate, it is chemically 

 and mechanically less durable than quartz and could degrade rapidly or 

 form cemented crusts when placed in the beach environment. It would, 

 however, probably be suitable for purely protective beaches or as core 

 material for beaches or armored structures . 



