CONODONTS FROM THE MINERAL WELLS FOSSIL PARK (LATE PENNSYLVANIAN), NORTH-CENTRAL TEXAS

The Mineral Wells Fossil Park is a public park located at an abandoned borrow pit that serves the public as a scientific site of interest and for the collection of diverse marine Pennsylvanian fossils. While the strata are generally considered to be within the Salesville Formation, no definitive correlation has been made. Two measured sections were collected within the park and processed for conodonts. The lowermost dark-gray clay shales yield small to intermediate-sized conodonts while the overlying gray to brown shales yield no conodonts. The conodont fauna recovered is limited to the genus Idiognathodus and the species I. turbatus, I. swadei, I. sulciferus, I. eccentricus, and I. corrugatus. This fauna correlates to faunas collected locally from the Dog Bend Limestone interval of Lower Salesville Formation. The Fossil Park likely represents a more restricted muddier overall environment, as it lacks cleaner water genera like Adetognathus and Hindeodus. Advanced forms of Idiognathodus (I. cancellosus, I. biliratus, and I. pseudocarinatus) are recovered from nearby exposures of the Upper Salesville Formation but are not recovered at the Fossil Park. The Mineral Wells Fossil Park represents a large exposure of the lower shale in the Salesville Formation. The lower Salesville is correlated with the Midcontinent Hertha Cyclothem while the upper Salesville is correlated with the Midcontinent Swope Cyclothem. It has been proposed that the first appearance of I. turbatus should be used as the marker of the base of the global Kasimovian Stage of the Pennsylvanian; therefore, the Mineral Wells Fossil Park would be considered Kasimovian in age.