Geologic units in Chattooga 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 14 % 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; Middle unit; Shale unit (Cambrian) at surface, covers 13 % 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

Pennsylvanian undifferentiated (Pennsylvanian) at surface, covers 11 % of this area

Pennsylvanian undifferentiated

Red Mountain Formation (Silurian) at surface, covers 9 % of this area

Red Mountain Formation

Chickamauga Group undivided (Ordovician) at surface, covers 8 % of this area

Chickamauga Group undivided

Rome Formation (Cambrian) at surface, covers 5 % of this area

Rome Formation

Chickamauga Group; Upper and Middle Ordovician rocks (Oum) includes Sequatchie Limestone, Murfreesboro Limestone, Ridley Limestone, Moccasin Limestone and Bays Formation. (Ordovician) at surface, covers 5 % of this area

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

Fort Payne Chert (Mississippian) at surface, covers 4 % of this area

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

Mississippian undifferentiated (Mississippian) at surface, covers 2 % of this area

Includes Pennington Shale, Bangor Limestone (except in Floyd County), Hartselle Sandstone, Golconda Formation, Gasper Limestone, Ste. Genevieve Limestone and St. Louis Limestone

Chickamauga Group; Upper and Middle Ordovician Rocks (Omb) includes Moccasin Limestone and Bays Formation (Ordovician) at surface, covers 2 % of this area

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

Newala Limestone (Ordovician) at surface, covers 0.3 % of this area

Newala Limestone

Devonian-Missisippian undivided (Devonian-Mississippian) at surface, covers 0.2 % 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)

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.

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.

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

Medium to dark-gray thick to thin-bedded partly argillaceous, locally fossiliferous limestone. Restricted to the western part of the Valley and Ridge province and Murphrees Valley and Wills Valley anticlines. Locally includes a thin interval of Attalla Chert Conglomerate Member at base. Attalla Chert Conglomerate - conglomerate of pebbles, cobbles, and boulders of chert and rare dolomite and quartzite in a sand-sized matrix; thin beds of gray-green or dusky-red shale common at base.

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.

Sequatchie Formation, Colvin Mountain Sandstone, Greensport Formation undifferentiated (Ordovician) at surface, covers < 0.1 % of this area

Variegated dusky-red and pale-yellowish-orange shale, calcareous mudstone, dolomite, siltstone, and minor sandstone. Mapped in areas of facies transition with the Chickamauga Limestone (Scraper Mountain) and in the structurally complex area at the east end of Dry Creek Mountain.

Sequatchie Formation (Ordovician) at surface, covers < 0.1 % of this area

Light-olive-gray and dusky-red calcareous shale interbedded with light to dark-gray fine to coarse-grained partly bioclastic, argillaceous, locally glauconitic limestone.

Little Oak and Lenoir Limestones undifferentiated (Ordovician) at surface, covers < 0.1 % of this area

Dark-gray argillaceous, fossiliferous medium to thick-bedded limestone; locally contains rare chert in upper part and an interval of fenestral mudstone in lower part (Mosheim Limestone Member of the Lenoir Limestone). Between Siluria and Pelham in Shelby County, the Little Oak and Lenoir Limestones are seperated by a tongue of the Athens Shale.

Bangor and Monteagle Limestones undivided in part (Mississippian) at surface, covers < 0.1 % of this area

Bangor Limestone -- medium-gray bioclastic and oolitic limestone, containing interbeds of dusky-red and olive-green mudstone in upper part. Monteagle Limestone -- light-gray oolitic limestone containing interbedded argillaceous, bioclastic, or dolomitic limestone, dolomite, and medium-gray shale.

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

Medium-bluish-gray fine-grained, thin-bedded argillaceous limestone and interbedded dark-gray shale in varying proportions.

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

Dark-reddish-brown to olive-gray partly fossiliferous, mostly fine-grained sandstone interbedded with siltstone and shale; minor amounts of bioclastic limestone and conglomerate sandstone; includes hematitic beds and beds of ferruginous sandstone, outcrops in northeastern AL are finer grained and include more limestone.

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, absent locally and too thin to map seperately. 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.

Attalla Chert Conglomerate Member of the Chickamauga Limestone (Ordovician) at surface, covers < 0.1 % of this area

Conglomerate of pebbles, cobbles, and boulders of chert and rare dolomite and quartzite in a sand-sized chert and quartz matrix; thin beds of gray-green or dusky-red shale common at base.