St. Marks Formation (FLMIsmk;0)

St. Marks Formation - The Lower Miocene St. Marks Formation, named by Finch (1823), is exposed in Wakulla, Leon and Jefferson Counties on the northwestern flank of the Ocala Platform. It is a white to yellowish gray, poorly to moderately indurated, sandy, fossiliferous (molds and casts) limestone (packstone to wackestone). Mollusk molds and casts are often abundant. The St. Marks Formation makes up the upper part of the FAS in part of the eastern panhandle.

State	Florida
Name	St. Marks Formation
Geologic age	Miocene
Original map label	Tsmk
Primary rock type	limestone
Secondary rock type	sandstone
Other rock types
Lithologic constituents	Major Sedimentary > Clastic > Sandstone (Bed)It is a white to yellowish gray, poorly to moderately indurated, sandy, fossiliferous (molds and casts) limestone (packstone to wackestone). Mollusk molds and casts are often abundant. The St. Marks Formation makes up the upper part of the FAS in part of the eastern panhandle. Sedimentary > Carbonate > Limestone (Bed)It is a white to yellowish gray, poorly to moderately indurated, sandy, fossiliferous (molds and casts) limestone (packstone to wackestone). Mollusk molds and casts are often abundant. The St. Marks Formation makes up the upper part of the FAS in part of the eastern panhandle.
Map references	Scott, T. M., Campbell, K. M., Rupert, F. R., Arthur, J. D., Missimer, T. M., Lloyd, J. M., Yon, J. W., and Duncan, J. G., 2001, Geologic Map of the State of Florida, Florida Geological Survey & Florida Department of Environmental Protection, Map Series 146.
Unit references	Scott, T. M., Campbell, K. M., Rupert, F. R., Arthur, J. D., Missimer, T. M., Lloyd, J. M., Yon, J. W., and Duncan, J. G., 2001, Geologic Map of the State of Florida, Florida Geological Survey & Florida Department of Environmental Protection, Map Series 146. Scott, Thomas M. P.G. #99, Text to Accompany the Geologic Map of Florida, Open-file Report 80, Florida Geological Survey, 2001. Finch, J., 1823, Geological essay on the Tertiary formation in America: American Journal of Science, v. 7, p. 31-43.
Geographic coverage	Jefferson - Leon - Wakulla