ABSTRACT

Samples of the Salt Mountain Limestone (Paleocene) from Jackson, Alabama, have yielded a diverse nannoplankton flora. Preservation varies greatly between species. Some forms are well-preserved whereas others have been subjected to extensive dissolution and/or recrystallization. Placoliths are generally well-preserved, but the centers of many specimens are obscured by petaloid overgrowths. Many specimens also bear sparry extensions of isolated shield elements.

The presence of Discoaster mohleri, and the absence of recognizable specimens of Heliolithus riedeli, places the Salt Mountain Limestone within the Discoaster mohleri Zone. This indicates that the Salt Mountain Limestone is older than the Nanafalia Formation which has been placed in the Heliolithus riedeli Zone (Bramlette and Sullivan, 1961). Toulmin (1940) suggested that the Salt Mountain Limestone was an offshore facies equivalent of the Ostrea thrisae beds of the Nanafalia Formation.