FLORIDA GEOLOGICAL SURVEY


Figure 14. Selected diagnostic Suwannee Limestone fossils. Top row left: Fallotella (Dictyoconus)
cookei (bar = 1 mm; from Rupert, 1989), right: Rhyncholampus gouldii (bar = 2.5 cm, photo
courtesy of Sean Roberts). Bottom row left: Discorinopsis gunteri (bar = 2 mm; Cooke, 1945),
right: milliolid (bar = 1 mm; photo courtesy Jonathan Bryan).


comprising the base of the Tampa Member
(Arcadia Formation) in parts of northern and
central Pinellas County, south-central
Hillsborough County and eastern Polk County.
In other areas, lack of phosphate sand in the
Suwannee Limestone distinguishes it from
overlying phosphatic (i.e., non-Tampa Member)
Hawthorn Group sediments. South of the study
area, however, Suwannee Limestone carbonates
include minor occurrences of blackened
(possibly francolite) discontinuity surfaces
(Missimer, 2002).

 The northern extent of the Suwannee
Limestone occurs in Citrus County based on
isolated outcrops and discontinuous borehole
data. The approximate northern limit of laterally
continuous Suwannee Limestone, however,
occurs in southernmost Citrus County (Plates 41


and 42). In the eastern region, the subcrop limit
occurs beneath the Lake Wales Ridge. In
Highlands County, the eastern extent of the unit
is uncertain and denoted with a dashed line
(Plates 41 and 42). Two wells east of the line
contain limited thicknesses of the Suwannee
Limestone; however, nearby wells deep enough
to have encountered the unit do not contain it.
This suggests the two wells represent outliers.
Maximum elevation of the unit exceeds 75 ft
(22.9 m) MSL in parts of Hillsborough and Polk
Counties as well as along the Brooksville Ridge,
while in the southern region, depths exceed -825
ft (-251.5 m) MSL (Plate 41). Maximum
thickness of the Suwannee Limestone in the
study area exceeds 450 ft (137.2 m) in south-
central Charlotte County (Plate 42).

 Evidence supporting previously identified