Ratcliffe interval (informal) in Charles Formation of Madison Group (ND-subsurface)
Informal. The rank or lithologic term should not be capitalized.
Middle Mississippian (Visean; late Osagean to Meramecian)
Named from Socony Central Le duc Del Rio Ratcliffe No. 1 well, LSD 5-30-1-15, West of 2nd Meridian (W2M), Saskatchewan, Canada (Saskatchewan Geological Society, 1956).
Williston basin
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Asterisk (*) indicates published by U.S. Geological Survey authors.
"No current usage" (†) implies that a name has been abandoned or has fallen into disuse. Former usage and, if known, replacement name given in parentheses ( ).
Slash (/) indicates name conflicts with nomenclatural guidelines (CSN, 1933; ACSN, 1961, 1970; NACSN, 1983, 2005, 2021). May be explained within brackets ([ ]).