Pilot Shale  search
BTChronostratigraphic Units
 .Phanerozoic
 ..Paleozoic
 ...Pilot Shale
RTUpper Devonian
 Utah
 Nevada
 Lower Mississippian
SNE Nevada and Utah. Underlies Joana Limestone; overlies Guilmette Formation. Indexed with ages as applicable. Added to Thesaurus in 1989.