FLORIDA GEOLOGICAL SURVEY


Tamiami Formation

 Lithology of the Lower- to mid Pliocene
(Missimer, 2002) Tamiami Formation
(Mansfield, 1939) is difficult to characterize due
to the large number of sediment facies it
contains. These facies occur over a large region
of southern Florida and represent a complex set
of depositional environments (Berndt et al.,
1998). The Tamiami Formation consists of a
wide range of mixed carbonate/siliciclastics
(sandy limestone, sand and clay with varying
percentages of phosphate grains) and shell beds
that are subdivided as members (e.g., Ochopee
Limestone Member) south of the study area
(Missimer, 1993). The Tamiami Formation is
unconformably overlain by the Caloosahatchee
Formation and overlies the Peace River
Formation either conformably or
unconformably.

 Where present in the study area, the Tamiami
Formation is part of the IAS/ICU and SAS
(Bemdt et al., 1998). A semi-regionally
extensive clay layer within the Tamiami
Formation comprises the top of the IAS/ICU,
whereas the uppermost higher permeability
sediments are hydraulically connected with the
SAS.

 Sands and finer-grained facies probably
represent deposition in a regressing Tamiami sea
in the brackish water of a lagoon or bay (DuBar,
1962). Deposition of the shell beds are most
likely the result of storms and processes
occurring in shallow coastal waters (Missimer,
2001). Phosphatic quartz sand facies containing
giant barnacles and echinoids exposed along
Alligator Creek and in pits near Acline
(Charlotte County) are thought to represent
deposition in a shallow water, nearshore
environment (DuBar, 1962).

Cypresshead Formation

 The Upper Pliocene Cypresshead Formation
(Huddlestun, 1988) is composed entirely of
siliciclastics, predominantly quartz and clay
minerals (Scott, 1992b; Berndt et al., 1998). It
consists of characteristically mottled reddish


brown to reddish orange, unconsolidated to
poorly consolidated, fine to very coarse grained,
clean to clayey sands (Scott, 2001), some of
which are cross bedded. Discoid quartz pebbles
and mica are also often present. Clay beds are
generally thin and discontinuous. Overall, the
clay content varies from trace amounts to more
than 50 percent, averaging 10-20 percent (Scott,
1992b). Due to weathering, the clays are often
altered to kaolinite. Davis et al. (2001) describe
three lithozones within the unit, which are based
on color, sedimentary structures and varying
proportions of siliciclastics. Original fossil
material is not present in the sediment but poorly
preserved casts and molds of mollusks and
burrow structures are occasionally present
(Scott, 2001).

 The Cypresshead Formation occurs in the
central uplands of the Florida peninsula south
into Highlands County (Arthur, 1993; Scott et
al., 2001). Exposure of the formation generally
occurs above 100 ft. (30.4 m) MSL (Scott,
1992b, 2001). In the northern half of the study
area, the unit lies unconformably on Eocene
carbonates, whereas in the southern half it
unconformably overlies Hawthorn Group
sediments. The Cypresshead Formation can be
readily distinguished from the Hawthorn Group
because the younger unit is non-phosphatic,
contains prominent horizontal bedding and cross
bedding, is largely nonfossiliferous and contains
burrow and bioturbation structures (Huddlestun,
1988). Along the Lake Wales Ridge, the SAS is
comprised of sediments from the Cypresshead
Formation and undifferentiated sediments (Scott,
1992b). Huddlestun (1988) suggests that the
depositional environment was coastal marine
(see also discussion of Figure 7 on p. 15).

Caloosahatchee Formation

 The Caloosahatchee Formation was first
recognized by Heilprin (1887) as a Pliocene
formation he called the "Floridan Beds." Dall
(1887) also considered the deposits Pliocene and
described many of the fossils; he referred to
them as the Caloosahatchee Beds or Marls.
Scott (1992c) includes sediments informally
referred to as the Bermont formation within the