Geologic units in Polk county, Georgia

Additional scientific data in this geographic area

Knox Group undifferentiated (Ordovician-Cambrian) at surface, covers 45 % of this area

Knox Group undifferentiated

Newala Limestone (Ordovician) at surface, covers 19 % of this area

Newala Limestone

Chickamauga Group; Middle Ordovician rocks; Rockmart Slate (Middle Ordovician) at surface, covers 15 % of this area

Chickamauga Group; Middle Ordovician rocks; Rockmart Slate

Phyllite and Quartzite (Precambrian-Paleozoic) at surface, covers 15 % of this area

Phyllite and Quartzite

Frog Mountain (Devonian) at surface, covers 2 % of this area

Frog Mountain

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

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

Conasauga Group; Middle unit; Shale unit (Cambrian) at surface, covers 1 % 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

Conasauga Group; Upper unit; Dolostone member (Cambrian) at surface, covers 0.8 % 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).

Floyd Shale (Mississippian) at surface, covers 0.5 % of this area

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

Chickamauga Group; Middle Ordovician rocks; Lenoir Limestone (Middle Ordovician) at surface, covers 0.2 % of this area

Chickamauga Group; Middle Ordovician rocks; Lenoir Limestone

Shady Dolomite (Cambrian) at surface, covers 0.2 % of this area

Shady Dolomite

Rome Formation (Cambrian) at surface, covers 0.2 % of this area

Rome Formation

Armuchee Chert (Devonian) at surface, covers < 0.1 % of this area

Armuchee Chert

Conasauga Group; Lower unit; shale and sandstone unit (Cambrian) at surface, covers < 0.1 % of this area

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

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.

Knox Group undifferentiated in part (Ordovician-Cambrian) at surface, covers < 0.1 % of this area

Light-gray to light-brown locally sandy dolomite, dolomitic limestone, and limestone; characterized by abundant light-colored chert.