This is a Paleobiology Database Online Systematics Archive including classification and alpha taxonomy concerning fossil molluscs from the late Mesozoic and early Cenozoic of North America. The classification and synonymy data are intended to be as current as possible as of the time of compilation, but all published opinions were not sought. The data accompany an extensive faunal occurrence data set with the same scope (dominantly the Sohl & Koch Open File Reports, but including many other faunas published by Sohl, Stephenson and other Gulf Coastal Plain workers).