ABUNDANCE, ORIENTATION, AND DISTRIBUTION ANALYSIS OF CORAL FOSSILS IN A DEVONIAN BIOSTROME AT THE FALLS OF THE OHIO, CLARKSVILLE INDIANA

The Jeffersonville Limestone at the Falls of the Ohio in Clarksville Indiana, contains one of the most extensively exposed middle Devonian biostromes in the world. This community is composed of primarily solitary and colonial corals and stromatoporoids. Until now, the only in-depth paleoecological study performed at this location was published in 1967 by D.L. Kissling and J.A. Lineback. In that work, a portion of the coral beds were divided into 100 one square foot sectors within 10 by 10 feet quadrats. They then recorded the positions, sizes, and shapes of tabulate corals and sponge specimens larger than four centimeters onto a field map. They also generated azimuth estimates by measuring the bearing of the axes of branching Favositid corals and calculated an average. Their abundances and distributions were calculated using surface area measurements, rather than numbers per unit area.

Since it has been more than fifty years since Kissling and Lineback published their work, this study will present an update on their findings, focusing in the northeast corner of the exposed Coral Zone. The current research utilized transect sampling to document fossil location, identification, length, width, and compass bearing. Data were collected for every specimen encountered along the transect that was one centimeter or larger for a total of 2,340 intact specimens over 81 meters of transect. The compass bearings of each taxon were analyzed, as well as their position on the fossil beds and in relationship to other organisms. Trends in distribution were examined by identifying patterns in taxa along each transect and in the study area as a whole. Abundances were determined by the number of fossils recorded, as well as by calculating the surface area of each type of organism in order to directly compare this study to that of Kissling and Lineback.

Together, these analyses will provide a comprehensive interpretation of the Coral Zone at the Falls of the Ohio. The ultimate goal of this research is to recognize evidence of relationships within the preserved fauna, that could reveal the paleoecological and paleoenvironmental parameters of this ancient biostrome.