In Brevard Comity tlie Hawthorn beds are described as light green to greenish gray sandy 

 marl with streaks of green clay, phosphatic radiolarian clay, black and brown phosphorite, 

 and thin beds of phosphatic sandy limestone (Brown, et al., 1962). Under the northern half 

 of Brevard County, Hawthorn beds are 10 to 25 feet thick in the area west of Banana River, 

 and possibly thicker under the coast and inner Continental Shelf, In Duval and Nassau 

 Counties, Hawthorn beds are reported to bfr 450 feet thick in wells near Jacksonville and 

 Fernandina. The beds consist of greenish calcareous phosphatic sandy clay and clayey sand 

 with lenses of limestone and dolomite (Leve, 1961a, b). 



Late Miocene and Pliocene deposits of the study area are heterogeneous and consist of 

 beds and lenses of shells, sand, calcareous clay, clay, phosphatic pebbles and limestone. Most 

 of these units have not been sufficiently studied in the Atlantic coastal area to be correlated 

 or to determine age relationships and they are generally undifferentiated in coastal well logs. 

 Presumably Miocene sections of these deposits are referable to Choctawhatchee Stage 

 sedimentation. 



Various marine formations in the Florida peninsula have at one time or another been 

 assigned to the Pliocene but most have subsequently been ascribed to late Miocene or 

 Pleistocene deposition. Akers (1972) has recently assigned a Pliocene age to late 

 Choctawhatchee Stage sediments. The existence of a marine sedimentary unit of PUocene 

 age under the Florida Atlantic inner Continental Shelf based on data obtained^or this study 

 is discussed later in this report. 



The most important Pleistocene deposit of the Florida Atlantic coast is the Anast^ia 

 Formation. Locally the Anastasia Formation outcrops along the shore and nearshore and 

 forms the core of the Atlantic ridge north of Boca Raton where it grades southward into the 

 Miami Formation. Tentative correlation of tlie Anastasia with one or more Pleistocene 

 interglacial stages has been made by various workers but no definitive assignment is now 

 possible. Lithologically, the Anastasia Formation is composed of a loosely cemented sandy 

 coquina consisting primarily of moUusk shells. 

 6. Coastal Morphology' and Development. 



The Atlantic coast of north Florida is a low relief, low elevation, coastal plain surface 

 overlain by relict Pleistocene terraces and beach ridges. Geomorphology of the area has been 

 recently interpreted by White (1970), who states that surface morphology is shaped 

 primarily by the preservation of rehct Pleistocene strand lines and offshore profiles and 

 secondarily by modification of these features through differential surface erosion and 

 solution collapse. 



The term Atlantic Coastal Ridge is applied to the series of relict beach ridges and bars 

 that extend from Georgia on the north to south of Miami. In the study area, the Atlantic 

 Coastal Ridge is nearly parallel to the modern coastline and displays an overall decrease in 

 lagoon and beach ridge width from north of Daytona to Canaveral Peninsula. Indian River, 

 an open water lagoon at Cape Canaveral, ends and becomes an elevated valley just north of 



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