widespread deposit on the inner slielf between Cape Canaveral and Palm Beach deseribed by 

 Meisburger and Duane (1971) and Field and Duane (1974). There are essential differences, 

 especially the rarity of hthification and the absence of ooUtes and pelletoid calcareous 

 particles which are common features of most t}'pe E sediment. Further study may show tliat 

 these two units are time equivalents as tliey seem to occupy a similar stratigraphic niche. 



Foraminiferal assemblages in the Mulinia shell hash and associated shelly sand and fine 

 quartz sand are variable. Elphidium and Quinqueloculina are generally important genera, 

 whereas Hanzawaia is rarely so; in several places a distinctive suite containing abundant 

 Elphidium gunteri (Cole) occurs. Most mollusks and foraminifera in type G deposits indicate 

 deposition in a shallow nearshore or marginal marine environment. The variability in the 

 assemblage plus Uthologic differences suggest that the deposit as a whole probably contains 

 several facies. 



A more detailed study of the mollusks and foraminifera may produce a clearer definition 

 of these facies and indicate distinct time breaks between some of the units. However, in 

 terms of the scope of this study and wide core spacing in the area of occurrence it seems 

 more practical to treat the interbedded shell hash, shell sand, and sand as a single unit. 



(4) Type L Sediment. Type L sediment is a white to hght gray (2.5 yr. N8 to N7), 

 fine to medium foraminifera-rich quartz sand and is restricted in areal distribution and 

 stratigraphic position. It is locally exposed at the surface and commonly overlies type M 

 sediments. Faunal analysis of this sediment indicates it is a late Tertiary deposit (App. C). 



Detrital fraction of type L sediment is composed principally of quartz and phosphorite 

 (Fig. 25). Quartz grains are generally fine to medium in size but very coarse-size grains occur 

 frequently. Tlie grains are well rounded and polished. With the exception of phosphorite 

 grains, accessory minerals are rare. Phosphorite abundance varies but is always less than 10 

 percent of the total sediment; most grains are rounded and highly polished although platy 

 grains are common. 



Carbonate content of type L sediments is between 25 and 75 percent by weight. 

 Constituents are mainly foraminifera; most other contributors are echinoids and ostracods. 

 Fine silt and clay in type L sediments appear to be degraded biogenic carbonate, in contrast 

 to the terrigenous fines in types F and G deposits. Individual biogenic grains in type L 

 sediment display evidence of secondary calcification and recrystallization. 



Only a few macrofaunal specimens have been found in type L sediment. These include 

 occasional barnacle plates, sharks teeth and fragments of the pelecypod Amusium mortoni 

 (Ravenel). A single valve of Placunanomia plicata (Tuomey and Holmes) and a few valves 

 and fragments of Chlamys comparilis (Toumey and Holmes) complete the list. AH of these 

 species have been reported in Tertiary strata of the Atlantic Coastal Plain. 



In contrast to the sparse macrofauna, type L sediment contains an abundant and diverse 

 microfauna dominated by Cibicides spp. with either planktonic species or species of 

 Textularia of secondary importance. Occasional layers in the type L sediment, sampled by 

 only one or two cores, contain an anomalous microfauna indicating that there may be 

 several biofacies associated with this deposit; however, none seem to be widespread. 



52 



