Ludlow Member  search
BTChronostratigraphic Units
 .Phanerozoic
 ..Cenozoic
 ...Paleogene
 ....Paleocene
 .....Ludlow Member
RTMontana
 North Dakota
 South Dakota
 Fort Union Formation
SNIn Fort Union Formation. NW and N South Dakota, NE Montana and SW North Dakota. Added to Thesaurus in 1989.