Morrison Formation (AZ*,CO*,KS,MT*,NE,NM*,ND*,OK*,SD*,TX,UT*,WY*)
(alphabetical): Casamero Member (NM), Bluff Sandstone Member (AZ*,CO,NM*,UT*), Brushy Basin Member (AZ*,CO*,NM*,UT*), Bullington Member (NM), Chavez Member (UT*), Fiftymile Member (UT*), Jackpile Sandstone Member (NM*), Prewitt Sandstone Member (NM), Recapture Member (AZ*,CO*,NM*,UT*), Salt Wash Member (AZ*,CO*,NM*,UT*), Stockett Bed (MT), Tidwell Member (AZ*,CO*,NM*,UT*), Unkpapa Sandstone Member (SD*), Westwater Canyon Member (AZ*,CO*,NM*,UT*).
Late Jurassic*; locally Early Cretaceous*
Named from exposures near town of Morrison, Jefferson Co., CO (Eldridge, 1896).
Type locality: Morrison, Jefferson Co., CO.
Type section: along north side of West Alameda Parkway roadcut, 2 mi north of town of Morrison, in SE/4 sec. 23, T. 4 S., R. 70 W., [approx. Lat. 39 deg. 41 min. 08 sec. N., Long. 105 deg. 11 min. 06 sec. W., Morrison 7.5-min quadrangle], Jefferson Co., CO (Waldschmidt and LeRoy, 1944).
Black Mesa basin*
Central Montana uplift*
Green River basin*
Las Vegas-Raton basin*
Montana folded belt*
North Park basin*
Palo Duro basin*
Plateau sedimentary province*
Powder River basin*
San Juan basin*
San Luis basin*
Sierra Grande uplift*
For more information, please contact Nancy Stamm, Geologic Names Committee Secretary.
Asterisk (*) indicates usage by the U.S. Geological Survey. Other usages by state geological surveys.
"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 does not conform with nomenclatural guidelines (CSN, 1933; ACSN, 1961, 1970; NACSN, 1983, 2005). This may be explained within brackets ([ ]).