Fusulinidae of the Winchell Formation (Pennsylvanian), North-Central Texas

The Winchell Formation is the thickest and best exposed limestone unit in the Canyon Group and separates the Wolf Mountain Shale from the Placid Shale in the Canyon type area. The Canyon type area is included in the southernmost portion of the index map of Palo Pinto, Stephens and Wise counties. Northeastward of the Brazos River the Winchell Limestone grades laterally into shale and sandstone, leaving the overlying Placid Shale resting directly on the underlying Wolf Mountain Shale. Study of the Fusulinidae of the Winchell Formation in Palo Pinto, Stephens, and Wise counties, Texas, reveals the presence of six species in nine collections from nine localities: Triticites ohioensis Thompson, T. oryziformis Newell, T. primarius Merchant & Keroher, T. heroyi n. sp., T. ferayi n. sp., and T. winchellensis n. sp. The fauna is most closely comparable to that of the Mid-Missourian Series, indicating equivalency in age with the Pennsylvania standard section strata of the Mid-Continent region. Although T. ferayi n. sp. is suggestive of species appearing in Late Virgilian and Early Permian rocks, its relations with other Missourian species require its inclusion within the Mid-Missourian Series.