Lower Pennsylvanian( Morrowan)s ilicified ostracodef aunao ccursj ust above the conformableM ississippian-Pennsylvanian boundaryw ithin the BarnettF ormationi n Texas. The faunac ontainss everal taxa that were previously restricted to the Upper Mississippian and numerous taxa only known from the Lower Pennsylvanian. New taxa proposed include Amphissites (Amphissites) morrowanensis n. sp., Polytylites subrectus n. sp., Kirkbyella (Berdanella) delicata n. sp., Kindlella proscillata n. sp., Libumella walkerorum n. sp., Moorites tumidus n. sp., Leptoderosa rytaina n. gen. and sp., and Cribroconcha prolixa n.sp.