Fountain Formation  search
BTChronostratigraphic Units
 .Phanerozoic
 ..Paleozoic
 ...upper Paleozoic
 ....Fountain Formation
RTPermian
 Pennsylvanian
 Wyoming
 Colorado
SNPennsylvanian and Permian. E Colorado and SE Wyoming. Indexed with ages as applicable. Added to Thesaurus in 1985.