Type F sediment is distinguished from type A sediment on textural and compositional 

 bases. Type F is finer, often contains a significant quantity of silt, and is less well sorted 

 than type A sand. In addition it contains a distinctively different carbonate composition. 

 Carbonate content generally is less than 20 percent of total sample weight. Calcareous grains 

 are biogenic in origin; ooids and Uthoclasts are absent. The carbonate assemblage is largely 

 derived from moUusks, ecliinoids, and microfauna. None of the macrofaunal fragments 

 display significant black or brown coloration, a feature of coarser deposits in adjacent areas 

 (Pilkey, et al., 1969) and attributed to deposition in a former coastal area. Dominant 

 moUusks in type F sediment are Mulinia lateralis (Say), Abra aequilis (Say), and Corbula 

 spp. The assemblage is generally uniform but abundance of each species is variable. In 

 comparison to type A sand the fauna are not diverse. 



The foraminifera of type F sediment are generally uniform and not diverse in comparison 

 to the type A fauna. The assemblage is dominated by species of Elphidium and varieties of 

 Ammonia beccarii (Linne) which together generally comprise more than 75 percent of the 

 population. Other than the dominant species the only types occurring with any regularity in 

 this sediment are Buccella hannai (Cushman), Florilus atlanticus (Cushman), and 

 Quinqueloculina spp., all in small quantities. 



(3) Type G Sediments. White, ivory, and light tan (10 yr. 7/2) shelly sand and 

 Mulinia shell hash, locally interbedded with fine sand, commonly occur in cores between 

 St. Augustine and Cape Canaveral (Fig. 24). There are also isolated occurrences of these 

 sediments to the north, possibly representing small erosional remnants of the same deposit. 

 A few surface outcrops occur, but this material is largely buried by overlying types A or F 

 sediment and thus is older than these deposits. In cores where type G occurs with type L 

 sediment it is always higher and of younger age. 



Distinctive features of the shelly deposit are the uniform coloration of included shells 

 and predominance of Mulinia lateralis (Say) shell hashes. The general lack of contrasting 

 colors indicates postdepositional loss of distinctive coloration as many of the species present 

 are strongly colored in life. 



Most species of moUuslis in the shelly sand and shell-hash deposits are common to type A 

 sediment; however, several common type A forms are either missing or appear to be 

 considerably less abundant. Ilynassa obsoleta (Say), an intertidal gastropod is commonly 

 found in shell sand and shell hash, but not in other sediments of the study area and is 

 apparently distinctive of shell-hash deposits. Along with the predominance of Mulinia 

 lateralis the occurrence of Ilynassa obsoleta indicates initial deposition in shallow (and 

 probably brackish) water. Anotlier distinctive moUusk present in some samples are 

 thick-bodied shells and fragments of Mercenaria sp. which have been highly bored by 

 sponges and algae. 



In many respects, the uniform light color, presence of abundant Mulinia and occasional 

 semilithification of the shelly sand and shell-hash deposits resemble characteristics of the 



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