Rebecca Shoal Dolomite, here named in the subsurface of southeastern FL, includes two newly named tongues: lower Plantation and upper Tavernier. Rebecca Shoal is a subsurface, barrier-reef complex, finely crystalline with numerous vugs, cavities, and caverns. Tavernier Tongue is a brown to cream-colored anhedral dolomite, 239 m thick in the type well. Interfingers with Cedar Keys Formation. Age of the Tavernier is Paleocene, while that of the Plantation Tongue is Late Cretaceous.

Source: GNU records (USGS DDS-6; Reston GNULEX).

Three tongues of the Rebecca Shoal Dolomite, including the newly assigned basal Card Sound Tongue, extend into the lagoonal facies (Cedar Keys and Pine Key Formations). The Tavernier Tongue extends into the lagoon farther than the other two and is the only Tongue to extend into southeastern GA, as it completely encircles the FL peninsula. Thickness varies from 55 ft to more than 800 ft. In a generalized stratigraphic column is shown to underlie the Delray Dolomite. No paleontologic data available to determine the age of the Rebecca Shoal or its three subunits. Earliest appearance of Card Sound Tongue is 100 ft above the Lower Cretaceous. This establishes an early Late Cretaceous age for the lower reef section and through correlation of the Tavernier Tongue with the Cedar Keys Formation, a Paleocene age is suggested for the upper reef section. A late Late Cretaceous age is suggested for the Plantation Tongue through correlation. Reef building extended over a period of approximately 40 million years.

Source: GNU records (USGS DDS-6; Reston GNULEX).