The Andy Mountain Formation of the informal Roosterville group, here named, is in the Austell-Frolona antiform, west-central Georgia. Consists of garnet-muscovite-quartz schist and quartzite containing local horizons of gneiss. Stratigraphically overlies but structurally underlies the New Georgia Group (new name); stratigraphically underlies the Bill Arp Formation (new name), but folding has placed it structurally over the Bill Arp and the intrusive Austell Gneiss. Age is Proterozoic.
Type locality: Andy Mountain, 1.5 mi west of Winston, Winston 7.5-min quadrangle, Douglas Co., west-central GA. Named from Andy Mountain.

Source: US geologic names lexicon (USGS Bull. 1565, p. 11).

The Andy Mountain Formation is here assigned to the Sandy Springs Group (western belt). It conformably overlies the Dog River Formation and stratigraphically underlies the Bill Arp Formation. Age is Late Proterozoic and (or) early Paleozoic.

Source: GNU records (USGS DDS-6; Reston GNULEX).

The Andy Mountain Formation of Abrams and McConnell (1981), assigned to the Sandy Springs Group by McConnell and Abrams (1984), is here abandoned because it is partly the same unit as the Chattahoochee Palisades Quartzite of the Sandy Springs Group, and partly the same as the Canton Schist of Bayley (1928), also here abandoned. Canton rocks now referred to as the Cherokee alteration zone of the Ropes Creek Metabasalt.

Source: GNU records (USGS DDS-6; Reston GNULEX).