Casper Formation  search
BTChronostratigraphic Units
 .Phanerozoic
 ..Paleozoic
 ...Casper Formation
RTPermian
 Pennsylvanian
 Wyoming
SNPennsylvanian and Permian. Includes all beds from top of Madison Group to base of Permian (Opeche Shale) red shales. In SE Wyoming. Indexed with ages as applicable.