Name Pratt Ferry formation proposed for somewhat bituminous calcarenite occurring in layers up to 4 in. or more in thickness in central AL. Total thickness about 8 ft. Underlies black shale of Columbiana formation (new); overlies limestone mapped as Lenoir, but which is faunally similar to Little Oak formation. Name attributed to B.N. Cooper and G.A. Cooper. Age is Middle Ordovician (Mohawkian).
Source: GNU records (USGS DDS-6; Reston GNULEX).
Pratt Ferry reduced in rank and status because of its limited thickness and areal extent. Named used informally here for highly fossiliferous limestone at base of Athens Formation in Bibb Co., AL. Thickness is 10 ft. Age is Middle Ordovician.
Source: GNU records (USGS DDS-6; Reston GNULEX).
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 ([ ]).