ABSTRACT

Silurian chitinozoans have previously been described from four wells in north-central Florida. These wells have also been previously correlated with each other as well as with known Silurian sections. The youngest assemblage is Ludlovian in age; the oldest is of Upper Llandoverian age.

Outcrop samples were collected from the Silurian Red Mountain Formation in Alabama and Georgia. This formation has been dated as Llandoverian on the basis of megafossil evidence. Four Red Mountain Formation sections are divided into biostratigraphic zones on the basis of chitinozoan assemblages.

Attempts at correlating the well and outcrop samples based on the frequency of chitinozoan taxa proved unsuccessful because only a few taxa are abundant throughout the sections. Instead, correlations are made on the first or last occurrence of certain taxa. A comparison of the assemblages in the oldest (Upper Llandoverian) Florida well section and the youngest (Upper Llandoverian) Red Mountain Formation section indicates that they have only two taxa in common. A comparison between the other portions of the Florida and Alabama-Georgia sections was not feasible due to the age differences.

The general aspect of the Florida assemblages is quite different from the ones in Georgia and Alabama. It is concluded that the sections in Georgia and Alabama are of different ages than those in Florida. The rocks are not different faunal facies of isochronous strata since chitinozoans are planktonic and are therefore not lithofacies dependent.

One problem encountered in this study was that three of the wells did not penetrate very deeply into Silurian strata. Three of the Florida wells only penetrated the Upper Silurian and only one went as deep as the Lower Silurian. Future work in correlating the Silurian rocks from these three states must depend on new wells being drilled to greater depths. Only in this way can a more complete Silurian section be determined in Florida.

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