River Junction, lower beds [Tampa Limestone] (Oligocene to of the United States)

Where: Gadsden County, Florida (30.7° N, 84.8° W: paleocoordinates 31.0° N, 79.9° W)

• coordinate based on nearby landmark

• outcrop-level geographic resolution

When: Tampa Limestone Member (Arcadia Formation), Chattian to Chattian (28.1 - 20.4 Ma)

• LITHOSTRATIGRAPHY: Formerly referred to as the Tampa Limestone. Scott et al. (2001) assign the Tampa to the rank of member and place it in the Arcadia Formation. AGE: Mansfield suggests age equivalencies (based primarily on faunal similarities) with the Chipola Fm., the Trent Marl of North Carolina, and the Anguilla Fm. of Anguilla. Placed here into the Chattian-Aquitanian on the basis of most recent chronostratigraphy.

• member-level stratigraphic resolution

Environment/lithology: shallow subtidal; lithified, white, sandy, cherty/siliceous limestone

• Sand size quartz grains and an abundance of freshwater molluscs in the Tampa Limestone indicate nearshore deposition.
• The Tampa LS member of the Arcadia Fm. is more quartz sand rich and poorer in calcium carbonate than the underlying Suwannee LS. Fossils are often preserved via silicification and can be found in fully replaced, partially replaced or unaltered states. From several localities, a buff to dirty limestone matrix is reported, speckled with quartz sand grains of medium size.

Size class: macrofossils

Preservation: cast, mold/impression, permineralized, replaced with silica

Collection methods: collections from multiple beds in the lower section of the River Junction outcrop.

Primary reference: W. C. Mansfield. 1937. Molluscs of the Tampa and Suwannee Limestones. Geological Bulletin, State of Florida Department of Conservation 15:1-334 [A. Miller/C. Ferguson/P. Wagner]more details

Purpose of describing collection: taxonomic analysis

PaleoDB collection 61111: authorized by Arnold Miller, entered by Chad Ferguson on 29.05.2006

Creative Commons license: CC BY (attribution)

Taxonomic list

• Occurrence based data only
Gastropoda
 Neogastropoda - Muricidae
Rapana vaughani Mansfield 1937 murex snail
Bivalvia
 Mytilida - Mytilidae
"Modiolus (Botula) cinnamomeus" = Botula cinnamomeus
"Modiolus (Botula) cinnamomeus" = Botula cinnamomeus Lamarck 1819 mussel
 Pholadida - Corbulidae
 Cardiida - Cyrenidae
 Cardiida - Veneridae
"Antigona (Artena) ? shepardi" = Artena
"Antigona (Artena) ? shepardi" = Artena venus clam
 Cardiida - Cardiidae
"Cardium (Trachycardium) ? hernandoense" = Trachycardium, "Cardium (Trachycardium) ? brooksvillense" = Trachycardium
"Cardium (Trachycardium) ? hernandoense" = Trachycardium cockle
"Cardium (Trachycardium) ? brooksvillense" = Trachycardium cockle
subspecies: conjunctionense
 Cardiida - Tellinidae