OPEN FILE REPORT NO. 80


 Huddlestun (1993) recognized a tripartite subdivision in the type area of the Suwannee
Limestone in northwestern peninsular Florida and proposed the Ellaville Limestone,
Suwannacoochee Dolostone and Suwannee Limestone. In the panhandle, west of the Gulf
Trough, Huddlestun (1993) recognized the Marianna Limestone and an undifferentiated
residuum as the Oligocene sediments extending into Florida's panhandle from Georgia.
Huddlestun (1993) also recognized Bucatunna Formation, Florala Limestone, Bridgeboro
Limestone and an unnamed marl in Okaloosa and Walton Counties.
 Bryan (1991, 1993) provides a better framework for the recognition of the various facies
within the Lower Oligocene sediments. Within this framework, the Ellaville Limestone,
Suwannacoochee Dolostone and Suwannee Limestone occur within his Florida Platform
Association east and south of the Gulf Trough. West of the Gulf Trough in the Florida
panhandle (Bryan's Eastern Gulf Shelf Association), Bryan (1991) recognized the Bumpnose
Limestone, Marianna Limestone, Bridgeboro Limestone, Florala Limestone, Suwannee
Limestone, Byram Marl and Bucatunna Formation.
 The limited data available, the occurrence of thin beds of some of these units and the
questionable occurrence of other units made mapping the Lower Oligocene sediments in the
central panhandle problematic. The approach selected by FGS geologists was to combine the
units into several mappable units appropriate for the scale of the present map. These mappable
units include: undifferentiated Oligocene sediments composed of the Bumpnose Limestone,
Marianna Limestone, Bridgeboro Limestone, Florala Limestone, Suwannee Limestone, thin beds
of the Byram Marl and Bucatunna Formation and undifferentiated Oligocene residuum (see
Huddlestun [1993] for a discussion of the origin of the residuum).
 The Lower Oligocene sediments of peninsular Florida are mapped as the Suwannee
Limestone and are not subdivided into the Ellaville Limestone, Suwannacoochee Dolostone and
Suwannee Limestone. This mapping convention was adopted by FGS geologists due to the
limited data on the areal distribution of the Ellaville Limestone and Suwannacoochee Dolostone.

 Ts Suwannee Limestone Peninsular Lower Oligocene carbonates crop out on the
northwestern, northeastern and southwestern flanks of the Ocala Platform. The Suwannee
Limestone is absent from the eastern side of the Ocala Platform due to erosion, nondeposition or
both, an area referred to as Orange Island (Bryan, 1991).
 The Suwannee Limestone, originally named by Cooke and Mansfield (1936), consists of
a white to cream, poorly to well indurated, fossiliferous, vuggy to moldic limestone (grainstone
and packstone). The dolomitized parts of the Suwannee Limestone are gray, tan, light brown to
moderate brown, moderately to well indurated, finely to coarsely crystalline, dolostone with
limited occurrences of fossiliferous (molds and casts) beds. Silicified limestone is common in
Suwannee Limestone. Fossils present in the Suwannee Limestone include mollusks,
foraminifers, corals and echinoids.

 Tsm Undifferentiated Lower Oligocene Sediments The undifferentiated Lower
Oligocene sediments of the central panhandle consist of white to cream-colored, poorly to well
indurated, variably fossiliferous limestones (grainstone, packstone, wackestone and mudstone).
Glauconite occurs in some sediments. Siliciclastics form a minor component in some sediments.
Thin beds of siliciclastics (Byram Marl and Buccatuna Formation) are included in the