Usage:
Morrow Group (AR,OK)
Morrow Supergroup (IA)
Morrow Sandstone (CO,TX)
[?] Morrow Formation (CO,KS,MO,NM,NE,OK)
(See also Morrowan Series.)
Subunits:
SUPERGROUP STATUS: Caseyville Formation (IA).
Geologic age:
Early Pennsylvanian (Morrowan)
Type section, locality, area and/or origin of name:
Named from Morrow, Washington Co., AR (Adams and Ulrich, 1904).
Reference section (Morrow Series): Ardmore basin, OK.
AAPG geologic province:
Arkoma basin
For more information, please contact Nancy Stamm, Geologic Names Committee Secretary.
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 ([ ]).