[DATE OF SAMPLING UNKNOWN OR NOT APPLICABLE.] The comparative stratigraphy of 
the mainland coast and islands of northeastern Florida Bay shows that both islands and 
the present coastline initiated from paralic shoreline deposits during an earlier stage of 
the Holocene sea level rise. The present mainland coast is composed of 1.5 to 2 m of 
Holocene sediment over a shallowly submerged Pleistocene limestone surface. This 
build-up initiated from paralic peats and muds from which evolved two basic coastal 
landforms: an east-west trending coastal levee, and several narrow north-south 
trending peninsulas extending into Florida Bay. The coastal levee is characterized by 
basal paralic swamp and marsh sediments overlain by supratidal levee muds. These 
levee mud deposits represent stable, continuous shoreline development during the past 
2,500 yrs. Peninsulas, however, have resulted from supratidal sediments accreting 
over subtidal mud build-ups. Peninsulas have a westward-thinning wedge of paralic peat 
or marsh sediment at the base of their windward (eastern) margins. This wedge is 
interpreted as a remnant of the basal paralic deposit from which the peninsulas 
initiated. Windward shore erosion and leeward progradation have caused peninsulas to 
migrate westward across leeside subtidal deposits. Most of the offshore islands in 
northeastern Florida Bay have a wedge of paralic or marsh sediment at the base of 
their windward margins. Supratidal muds directly overlie this basal wedge along 
portions of the windward side of some islands. This sequence is identical to that of the 
coastal levees, and these portions of islands are interpreted as eroded sections of 
former coastal levees. On the windward margin of other islands, the basal paralic 
sediment wedge is overlain by subtidal sediments, which become thicker to the west, 
and are capped by supratidal muds which thin to the west. This indicates that the 
windward margins of islands, like the peninsulas, have eroded and the islands are 
migrating (prograding) westward. It is concluded that the position of early shorelines 
was defined by pre-existing drainage patterns produced by mangrove-bordered rills, 
along which swamp and marsh sediments accumulated. As the area flooded, these 
deposits persisted and evolved into thin, northwest-southeast trending mangrove 
peninsulas. Subtidal sediments accumulated adjacent to leeward shores, while 
windward shores eroded. With sea level rise and transgression, sections of the 
shoreline were breached, forming islands. These early islands continued to accrete 
leeward muds and erode their windward margins, resulting in the westward migration 
of islands from their point of inception. 
1989 0 
Cottrell, D. J. (1989) Holocene evolution of the northeastern coast and islands of Florida 
Bay. Symp. on Florida Bay: A Subtropical Lagoon. Miami, FL. June, 1987. Bull. Mar. Sci. . 
44(1 ):51 6. 
[ABSTRACT ONLY, DATE OF SAMPLING UNKNOWN OR NOT APPLICABLE.] The 
comparative stratigraphy of the mainland coast and islands of northeastern Florida Bay 
showed that both the islands and the present coastline initiated from paralic shoreline 
deposits during an earlier stage of Holocene sea level rise. The present mainland coast 
is composed of 1.5 to 2 m of Holocene sediment over a shallowly submerged, 
Pleistocene limestone surface. This build-up initiated from paralic peats and muds from 
which evolved two basic coastal features: an east-west trending coastal levee and 
several narrow, north-south trending peninsulas extending into Florida Bay. The coastal 
levee is characterized by basal paralic swamp and marsh sediments overlain by 
supratidal levee muds. These levee mud deposits represent stable, continuous shoreline 
development during the past few thousand years. Peninsulas, however, have resulted 
from supratidal sediments accreting over subtidal mud build-ups. Peninsulas have, at 
the base of their windward (eastern) margins, a westward thinning wedge of paralic 
peat or marsh sediment. This wedge was interpreted as a remnant of the basal paralic 
deposit from which the peninsulas initiated. Windward shore erosion and leeward 
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