Geologic units in Floyd county, Georgia

Additional scientific data in this geographic area

Knox Group undifferentiated (Ordovician-Cambrian) at surface, covers 26 % of this area

Knox Group undifferentiated

Floyd Shale (Mississippian) at surface, covers 17 % of this area

Includes the Hartselle Sandstone Member (Mh) in Floyd County and an unnamed limestone member (Ml in Floyd County) at the base

Conasauga Group; Upper unit; limestone and shale unit (Cambrian) at surface, covers 15 % of this area

Includes limestone and shale unit (Ccsl). Possible equivalent of the Maryville Limestone and Nolichucky Shale of Tennessee with a dolostone member (Ccd).

Conasauga Group; Middle unit; Shale unit (Cambrian) at surface, covers 7 % of this area

Includes limestone unit (Ccls), possible equivalent of Rutledge Limestone of Tennessee and shale unit (Cc), possible equivalent of Rogersville Shale of Tennessee

Red Mountain Formation (Silurian) at surface, covers 5 % of this area

Red Mountain Formation

Conasauga Group; Middle unit; Limestone unit (Cambrian) at surface, covers 4 % of this area

Includes limestone unit (Ccls), possible equivalent of Rutledge Limestone of Tennessee and shale unit (Cc), possible equivalent of Rogersville Shale of Tennessee

Rome Formation (Cambrian) at surface, covers 4 % of this area

Rome Formation

Fort Payne Shale; Lavender Shale Member (Mississippian) at surface, covers 3 % of this area

Fort Payne Shale (Mfp) with Lavender Shale Member (Mls)

Conasauga Group; Lower unit; shale and sandstone unit (Cambrian) at surface, covers 3 % of this area

Includes shale and sandstone unit (Ccs) with lower dolostone unit (Ccdl). Possible equivalent of Pumpkin Valley Shale of Tennessee

Devonian-Missisippian undivided (Devonian-Mississippian) at surface, covers 3 % of this area

Includes Fort Payne Chert, Chattanooga Shale in Dade Co.; Fort Payne Chert at top, Chattanooga Shale in middle and Armuchee Shale at bottom in all areas except Polk Co. and Dade Co.; Fort Payne Chert, and Armuchee Chert in Polk Co. CHATTANOOGA Shale (Dc)

Conasauga Group; Upper unit; Dolostone member (Cambrian) at surface, covers 2 % of this area

Includes limestone and shale unit (Ccsl). Possible equivalent of the Maryville Limestone and Nolichucky Shale of Tennessee with a dolostone member (Ccd).

Fort Payne Chert (Mississippian) at surface, covers 2 % of this area

Fort Payne Chert (Mfp) with Lavender Shale Member (Mls)

Armuchee Chert (Devonian) at surface, covers 2 % of this area

Armuchee Chert

Chickamauga Group; Upper and Middle Ordovician rocks (Oum) includes Sequatchie Limestone, Murfreesboro Limestone, Ridley Limestone, Moccasin Limestone and Bays Formation. (Ordovician) at surface, covers 1 % of this area

Chickamauga Group; Upper and Middle Ordovician rocks (Oum) includes Sequatchie Limestone, Murfreesboro Limestone, Ridley Limestone, Moccasin Limestone and Bays Formation.

Floyd Shale; Hartselle Sandstone member (Mississippian) at surface, covers 1 % of this area

Hartselle Sandstone member (Mh) in Floyd County

Chickamauga Group; Upper and Middle Ordovician Rocks (Omb) includes Moccasin Limestone and Bays Formation (Ordovician) at surface, covers 0.9 % of this area

Chickamauga Group; Upper and Middle Ordovician Rocks (Omb) includes Moccasin Limestone and Bays Formation.

Pennsylvanian undifferentiated (Pennsylvanian) at surface, covers 0.7 % of this area

Pennsylvanian undifferentiated

Bangor Limestone (Mississippian) at surface, covers 0.6 % of this area

Bangor Limestone

Floyd Shale; unnamed limestone member (Mississippian) at surface, covers 0.5 % of this area

Floyd Shale; unnamed limestone member (Ml in Floyd County) at the base

Shady Dolomite (Cambrian) at surface, covers 0.4 % of this area

Shady Dolomite

Conasauga Group; Maynardville Limestone (Cambrian) at surface, covers 0.4 % of this area

Conasauga Group; Maynardville Limestone

Copper Ridge Dolomite (Cambrian) at surface, covers < 0.1 % of this area

Copper Ridge Dolomite

Conasauga Formation (Cambrian) at surface, covers < 0.1 % of this area

Light to dark-gray finely to coarsely crystalline, medium to thick-bedded dolomite containing minor greenish-gray shale and light-bluish-gray chert. In the Columbiana area of Shelby County, the Conasauga is dominated by thin to medium-bedded, dark-gray dolomitic limestone and minor dark-gray shale. In Bibb County and southwestern Shelby County, the Conasauga consists of medium-bluish-gray fine-grained, thin-bedded argillaceous limestone and interbedded dark-gray shale. In the eastern Valley and Ridge the lower part includes dark-green to pale-olive fossiliferous shale with a few dark-gray limestone interbeds.

Newala Limestone (Ordovician) at surface, covers < 0.1 % of this area

Newala Limestone

Alluvial, coastal and low terrace deposits (Holocene) at surface, covers < 0.1 % of this area

Varicolored fine to coarse quartz sand containing clay lenses and gravel in places. Gravel composed of quartz and chert pebbles and assorted metmorphic and igneous rock fragments in streams near the Piedmont. In areas of the Valley and Ridge province gravel composed of angular to subrounded chert, quartz, and quartzite pebbles. Coastal deposits include fine to medium quartz sand with shell fragments and accessory heavy minerals along Gulf beaches and fine to medium quartz sand, silt, clay, peat, mud and ooze in the Mississippi Sound, Little Lagoon, bays, lakes, streams, and estuaries.

Floyd Shale (Mississippian) at surface, covers < 0.1 % of this area

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.

Red Mountain Formation (Silurian) at surface, covers < 0.1 % of this area

Interbedded yellowish-gray to moderate-red sandstone, siltstone and shale; greenish-gray to moderate-red fossiliferous partly silty and sandy limestone; few thin hematitic beds.

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.

Tuscumbia Limestone and Fort Payne Chert undifferentiated (Mississippian) at surface, covers < 0.1 % of this area

Tuscumbia Limestone -- light to dark-gray fossiliferous and oolitic partly argillaceous and cherty limestone. Apparently present only along part of the northwest limb of the Coosa synclinorium. Fort Payne Chert -- dark-gray to light-gray limestone with abundant irregular light-gray chert nodules and beds. Commonly present below the Fort Payne is greenish-gray to grayish-red phosphatic shale (Maury Formation) which is mapped with the Tuscumbia Limestone and Fort Payne Chert undifferentiated.

Rome Formation (Cambrian) at surface, covers < 0.1 % of this area

Variegated thinly interbedded mudstone, shale, siltstone, and sandstone; limestone and dolomite occur locally. Quartzose sandstone commonly present near top of formation.