Ecology and Stratigraphy of the Echinoids of the Ocala Limestone (Late Eocene)

Abstract

The Ocala Limestone (Late Eocene) of Florida may be zoned using echinoids. In addition to biostratigraphic zonation, three separate echinoid communities may be recognized utilizing species differing in specimen size and substrate affinity. The communities present are: 1) a community of large echinoids, which are sand-dwellers; 2) a community characterized by mud-dwelling echinoids, as well as a few small species with affinities for a sandy substrate; and 3) a community of sand-dwelling echinoids of large size, the composition of which is different from that of community l. The stratigraphic distribution of these three communities reflect physical changes in the environment of deposition, which may be explained by several hypotheses, but probably reflect a transgressive-regressive sequence.