The informal Chattahoochee formation of Gillon (1982) is here named the Horton Formation of the Helen Group in the Helen thrust sheet in GA and NC. It consists of an interlayered sequence of argillaceous and feldspathic metasandstone and metasiltstone (locally sulphidic), schist, and amphibolite. It is gradational to the southeast with the Nacoochee Formation and is conformable to the northwest with the Robertstown Formation, both of the Helen Group. Age is tentatively Late Proterozoic to early Paleozoic.
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 ([ ]).