Geologic units in Coosa county, Alabama

Elkahatchee Quartz Diorite Gneiss (Precambrian to Paleozoic) at surface, covers 22 % of this area

Mesocratic to melanocratic, fine to coarse-grained, massive to strongly foliated, locally sheared quartz diorite gneiss.

Higgins Ferry Group; Roscoelite-graphite-quartz schist and graphitic quartzite (Precambrian to Paleozoic) at surface, covers 10 % of this area

Higgins Ferry Group; Roscoelite-graphite-quartz schist and graphitic quartzite

Hatchet Creek Group; Pinchoulee Gneiss (Precambrian to Paleozoic) at surface, covers 10 % of this area

Medium to fine-grained migmatitic, locally garnetiferous biotite-feldspar gneiss, commonly saturated with granitic pods.

Higgins Ferry Group (Precambrian to Paleozoic) at surface, covers 10 % of this area

Thinly layered coarse to fine-grained biotite-feldspar-quartz gneiss, sericite-feldspar-muscovite schist, +/- biotite +/- garnet-muscovite schist, and biotite-garnet feldspathic gneiss; locally common pegmatites.

Wedowee Group; Wedowee Group undifferentiated (Precambrian to Paleozoic) at surface, covers 8 % of this area

Wedowee Group undifferentiated includes the Cragford Phyllite and Cutnose Gneiss. Cragford Phyllite -- interbedded fine-grained graphite-chlorite-sericite schist and phyllite, garnet-sericite schist and phyllite, graphite-quartz-sericite phyllite, locally feldspathic biotite gneiss, calc-silicate rock, and quartzite. Cutnose Gneiss -- cyclically interbedded fine-grained quartz-biotite feldspathic gneiss, graphite-chlorite-sericite schist, locally thin interbeds of graphite-quartz-sericite phyllite, and quartzite. Rocks in the area northeast of Clanton in Chilton and Coosa Counties that are here assigned to the Wedowee Group also have been interpreted as part of the Higgins Ferry Group.

Talladega Group; Lay Dam Formation (Silurian?-Devonian) at surface, covers 7 % of this area

Interbedded dark-green phyllite, medium-gray to light-brown and black metasiltstone, dark-green feldspathic metagraywacke, and light-gray and dark-gray medium to coarse-grained arkosic quartzite and metaconglomerate; graphitic phyllite common in upper part. In Cleburne and Calhoun Counties, rocks mapped as the Lay Dam include the Abel Gap Formation of Bearce (1973) and consist of interbedded greenish-gray metasiltstone and quartzite, black phyllitic metasiltstone, medium-gray to greenish-gray arkosic quartzite, and dark-gray pyritic quartzite. In Clay Chounty the upper part of the Lay Dam includes black graphitic sericite phyllite and slate reportedly containing plant fossils (Erin Slate Member).

Rockford Granite (Precambrian to Paleozoic) at surface, covers 6 % of this area

Leucocratic granite, granodiorite, and trondhjemite; locally well foliated, numerous pegmatites. Includes unnamed granitoids in Chilton County.

Talladega Group; Jemison Chert and Chulafinnee Schist undifferentiated (Silurian?-Devonian) at surface, covers 5 % of this area

Grayish-white to yellowish-orange massive, thick-bedded, fine-grained, locally argillaceous, locally fossiliferous metachert and light to dark-greenish-gray fine to medium-grained fissile quartz-sericite-chlorite phyllite and schist which locally includes thin chlorite phyllite and quartzose phyllite beds.

Hatchet Creek Group; Hanover Schist (Precambrian to Paleozoic) at surface, covers 4 % of this area

Coarse to fine-grained feldspathic biotite-sericite-quartz-muscovite schist, commonly containing staurolite, garnet, and locally sillimanite in northeastern outcrop areas includes zones of aluminous graphite schist, hornblende quartzite, garnet quartzite, and rare amphibolite. Schist commonly retrograded to sericite-garnet-quartz schist. Numerous granitic pegmatites.

Hissop Granite (Precambrian to Paleozoic) at surface, covers 3 % of this area

Mesocratic to leucocratic, strongly lineated granite to granodiorite.

Hillabee Greenstone (Paleozoic) at surface, covers 3 % of this area

Pale-green to light-olive-brown massive, fine-grained greenstone interbedded locally with well-foliated mafic phyllite.

Mitchell Dam Amphibolite (Precambrian to Paleozoic) at surface, covers 3 % of this area

Dark-green to black fine to coarse-grained, thin-layered to massive hornblende-actinolite amphibolite; includes all amphibolite associated with the Higgins Ferry and Hatchet Creek Groups.

Emuckfaw Group; Emuckfaw Group undifferentiated in part (Precambrian to Paleozoic) at surface, covers 2 % of this area

Interbedded muscovite +/- garnet-biotite schist, metagraywacke, calc-silicate rock, and quartzite; rare thin amphibolite. Includes thin layers of aluminous graphitic schist. Locally sheared to mylonite schist.

Kahatchee Mountain Group; Kalona Quartzite Member of Wash Creek Slate (Precambrian?-Cambrian?) at surface, covers 2 % of this area

Light-brown to light-gray coarse-grained, feldspathic quartzite and metaconglomerate in lower part of Wash Creek Slate.

Talladega Group; Lay Dam Formation, unnamed diamictite facies (Silurian?-Devonian) at surface, covers 1 % of this area

Unnamed diamictite facies of Lay Day Formation in Coosa and Chilton Counties consists of cobbles and boulders of carbonate, pelitic rocks, quartzite, chert, felsic plutonic rocks, and gneiss in a metagraywacke matrix.

Zana Granite (Precambrian to Paleozoic) at surface, covers 0.9 % of this area

Quartz monzonite to granite with strong gneissic texture, cut by small pegmatites and aplite dikes, generally elongate; semiconcordant to foliation of country rock.

Parkwood Formation and Floyd Shale undifferentiated (Pennsylvanian-Mississippian) at surface, covers 0.8 % of this area

Parkwood Formation -- Interbedded medium to dark-gray shale and light to medium-gray sandstone; locally contains dusky-red and grayish-green mudstone, argillaceous limestone, and clayey coal. Floyd Shale -- Dark-gray shale, sideritic in part; thin beds of sandstone, limestone and chert are locally present; beds of partly bioclastic, partly argillaceous limestone are abundant in parts of Calhoun and Cherokee Counties.

Kowaliga Gneiss (Precambrian to Paleozoic) at surface, covers 0.6 % of this area

Coarse-grained granodiorite to quartz monzonite with large plagioclase augen; generally shared among margins.

Talladega Group; Butting Ram Sandstone (Silurian?-Devonian) at surface, covers 0.5 % of this area

White to light-bluish-gray medium to coarse-grained, locally conglomeratic thick-bedded quartzose sandstone. Possible Devonian fossils.

Kahatchee Mountain Group; Wash Creek Slate (Precambrian?-Cambrian?) at surface, covers 0.5 % of this area

Grayish-green to black micaceous, partly carbonaceous to graphitic slate and metasiltstone containing interbedded light-gray to light-brown fine to coarse-grained metasandstone.

Sylacauga Marble Group; Jumbo Dolomite (Cambrian?-Ordovician?) at surface, covers 0.5 % of this area

Light to medium-gray thin to thick-bedded dolomite marble; contains intraclast-bearing dolomite, locally sandy in middle part.

Newala Limestone (Ordovician) at surface, covers 0.4 % of this area

Light to dark-gray thick-bedded micritic and peloidal limestone and minor dolomite.

Kahatchee Mountain Group; Stumps Creek Formation (Precambrian?-Cambrian?) at surface, covers 0.3 % of this area

Grayish-green micaceous metasiltstone and minor phyllite; grayish-green fine to medium-grained pyritic metasandstone in middle to upper part.

Hillabee Greenstone, unnamed dacite unit (Paleozoic) at surface, covers 0.2 % of this area

Unnamed unit comprised of masses of well-foliated quartz dacite.

Wedowee Group; Hackneyville Schist (Precambrian to Paleozoic) at surface, covers 0.1 % of this area

Medium to coarse-grained quartz-plagioclase +/- almandine +/- kyanite +/- biotite-muscovite schist, graphite-muscovite-quartz schist, and quartzite containing biotite. Large porphyroblasts of muscovite, andalusite and/or chiastrolite common. Rocks in the areas between Goodwater in Coosa County and Millerville in Clay County that are here assigned to the Hackneyville Schist also have been interpreted as part of the Higgins Ferry Group.

Higgins Ferry Group; Garnet quartzite (garnetite) and garnitiferous altered mafic rock (Precambrian to Paleozoic) at surface, covers 0.1 % of this area

Higgins Ferry Group; Garnet quartzite (garnetite) and garnitiferous altered mafic rock.

Sylacauga Marble Group; Fayetteville Phyllite (Cambrian?-Ordovician?) at surface, covers < 0.1 % of this area

Dusky-red and medium-gray phyllite and slate interlayered with light-brown to light-gray feldspathic metasiltstone, fine-grained metasandstone and dolomite marble.

Sylacauga Marble Group; Shelvin Rock Church Formation (Cambrian?-Ordovician?) at surface, covers < 0.1 % of this area

Moderate-pink to light-gray calcite and locally dolomite marble.

Sylacauga Marble Group; Gooch Branch Chert (Cambrian?-Ordovician?) at surface, covers < 0.1 % of this area

Light-gray to light-brown dolomite marble associated with abundant light-gray to white massive to moderately foliated metachert.

Ultramafic rock (Precambrian to Paleozoic) at surface, covers < 0.1 % of this area

Ultramafic pods and sheets, principally enstatite-hypersthene pyroxenite with hornblende and actinolite alteration assemblages.

High terrace deposits (Pleistocene) at surface, covers < 0.1 % of this area

Varicolored lenticular beds of poorly sorted sand, ferruginous sand, silt, clay, and gravelly sand. Sand consists primarily of very fine to very coarse poorly sorted quartz grains; gravel composed of quartz, quartzite, and chert pebbles.

Kahatchee Mountain Group; Waxahatchee Slate (Precambrian?-Cambrian?) at surface, covers < 0.1 % of this area

Dark-gray to grayish-green thin-bedded, micaceous metasiltstone, slate, and fine-grained quartzite.

Kahatchee Mountain Group; Brewer Phyllite (Precambrian?-Cambrian?) at surface, covers < 0.1 % of this area

Dusky-red micaceous slate and phyllite, locally containing interbedded micaceous arkosic quartzite and metasiltstone; locally at the base is interbedded calcite and dolomite marble.