Valentine Formation  search
BTChronostratigraphic Units
 .Phanerozoic
 ..Cenozoic
 ...Neogene
 ....Pliocene
 .....Valentine Formation
RTNebraska
 Kansas
 South Dakota
 Ogallala Formation
SNIn Ogallala Group. Composed largely of unconsolidated layers of greenish silty marl sand and very few local lenses of diatomaceous marl and light bluish-gray volcanic ash. In W Kansas, NW Nebraska, and SW South Dakota.