Geologic units in Walker county, Georgia

Additional scientific data in this geographic area

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

Knox Group undifferentiated

Pennsylvanian undifferentiated (Pennsylvanian) at surface, covers 16 % of this area

Pennsylvanian undifferentiated

Chickamauga Group undivided (Ordovician) at surface, covers 12 % of this area

Chickamauga Group undivided

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

Red Mountain Formation

Rome Formation (Cambrian) at surface, covers 8 % of this area

Rome Formation

Mississippian undifferentiated (Mississippian) at surface, covers 8 % 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

Newala Limestone (Ordovician) at surface, covers 7 % of this area

Newala Limestone

Fort Payne Chert (Mississippian) at surface, covers 5 % of this area

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

Chickamauga Group; Upper and Middle Ordovician Rocks (Omb) includes Moccasin Limestone and Bays Formation (Ordovician) at surface, covers 3 % of this area

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

Floyd Shale (Mississippian) at surface, covers 2 % 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; Upper and Middle Ordovician rocks (Oum) includes Sequatchie Limestone, Murfreesboro Limestone, Ridley Limestone, Moccasin Limestone and Bays Formation. (Ordovician) at surface, covers 2 % of this area

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

Conasauga Group; Upper unit; limestone and shale unit (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).

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

Conasauga Group; Maynardville Limestone

Conasauga Group; Middle unit; Shale unit (Cambrian) at surface, covers 0.3 % 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

Devonian-Missisippian undivided (Devonian-Mississippian) at surface, covers < 0.1 % 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)

Lookout Sandstone; Sewanee Sandstone (Pennsylvanian) at surface, covers < 0.1 % of this area

Lookout Sandstone; Sewanee Sandstone

Gizzard Group, including Signal Point Shale, Warren Point Sandstone, and Raccoon Mountain Formation (Pennsylvanian) at surface, covers < 0.1 % of this area

Gizzard Group - Shale, siltstone, sandstone, and conglomerate; from base of Sewannee Conglomerate to top of Mississippian. Thickness 0 to 520 feet, including Signal Point Shale - Mostly dark-gray to light-brown shale, with minor siltstone. Wilder coal near top. Thickness 0 to 180 feet, average about 60 feet; Warren Point Sandstone - Sandstone and conglomeratic sandstone, gray to brown, fine- to medium-grained, locally interbedded with shale containing coal. Thickness 0 to 300 feet, thins from southeast to northwest, average thickness about 100 feet; Raccoon Mountain Formation - Shale, siltstone, and sandstone. Bon Air coal near top; White Oak and Sale Creek coals near base. Thickness 0 to 260 feet.

Crab Orchard Mountains Group, including Rockcastle Conglomerate, Vandever Formation, Newton Sandstone, Whitwell Shale, and Sewanee Conglomerate (Pennsylvanian) at surface, covers < 0.1 % of this area

Crab Orchard Mountains Group - Conglomerate, sandstone, siltstone, shale, and coal; from top of Rockcastle Conglomerate to base of Sewanee Conglomerate. Thickness 200 to 950 feet; including Rockcastle Conglomerate - Conglomeratic sandstone and sandstone, gray to brown, fine- to coarse-grained. Thin coal-bearing shale locally present near middle. Thickness 150 to 220 feet; Vandever Formation - Mostly shale and siltstone, dark-gray to light-brown; conglomerate or sandstone in middle to south. Lantana and Morgan Springs coals near base and top. Thickness as much as 450 feet, average about 300 feet; Newton Sandstone - Sandstone, gray to brown or pink, fine- to medium-grained, locally conglomeratic. Thickness as much as 200 feet; average about 90 feet; Whitwell Shale - Mostly dark-gray to light-brown shale, with minor siltstone; locally middle part is sandstone. Richland coal near base; Sewanee coal in upper part. Thickness as much as 220 feet, average about 75 feet; Sewanee Conglomerate - Conglomeratic sandstone and sandstone, gray to brown, fine- to coarse-grained. Thickness as much as 200 feet, average about 100 feet.

Pennington Formation (Mississippian) at surface, covers < 0.1 % of this area

Highly variegated clay shale, distinctive; contains siltstone and locally gray, fine-grained sandstone. Thickness 400 to 700 feet.

Monteagle Limestone (Mississippian) at surface, covers < 0.1 % of this area

Mainly fragmental and oolitic, light-gray limestone; blocky bryozoan chert weathers from base. Thickness 180 to 300 feet.

St. Louis Limestone and Warsaw Limestone (Mississippian) at surface, covers < 0.1 % of this area

St. Louis Limestone - Fine-grained, brownish-gray limestone, dolomitic and cherty. Thickness 80 to 160 feet.; and Warsaw Limestone - Mainly medium- to coarse-grained, gray limestone, crossbedded. Includes much calcareous sandstone and shale to the north. Thickness 100 to 130 feet.

Fort Payne Formation (Mississippian) at surface, covers < 0.1 % of this area

Bedded chert, calcareous and dolomitic, somewhat crinoidal; and minor shale. Thin green shale (Maury) at base. Average thickness about 200 feet.

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

Brown to maroon shale, thin gray siltstone and sandstone, and thin lenticular layers of oolitic and fossiliferous red hematite. Thickness 200 to 800 feet.

Chickamauga Group, includes Upper part of Chickamauga Group (Reedsville Shale, and Unnamed limestone unit) and Middle and Lower part of Chickamauga Group (Moccasin Formation, Bays Formation, Ottosee Shale, Holston Formation, Lenoir Limestone, Athens Shale, and Sevier Shale) (Ordovician) at surface, covers < 0.1 % of this area

In the northwest part of the Valley and Ridge a predominantly limestone sequence about 2,000 feet thick. Becomes progressively more clastic and thicker to the southeast, including Upper part of Chickamauga Group (Reedsville Shale- Greenish-gray calcareous shale. Thickness 0 to 400 feet, and Unnamed Limestone Unit - Medium-grained, fossiliferous, gray limestone, shaly in part. Thickness as much as 600 feet ) and.Middle and lower parts of Chickamauga Group (Omlc).

Unnamed (upper part of Knox Group), including Newala Formation, Mascot Dolomite, Kingsport Formation, Longview Dolomite, and Chepultepec Dolomite (Ordovician) at surface, covers < 0.1 % of this area

(Onc) Unnamed (upper part of the Knox Group), including the (On) Newala Formation; (Oma) Mascot Dolomite - Light-gray, fine-grained, well-bedded cherty dolomite; mottled (red and green) dolomite characteristic; interbeds of bluish-gray limestone in upper part; chert-matrix quartz sandstone at base. Erosional unconformity at top. Thickness 350 to 800 feet; (Ok) Kingsport Formation - Gray, fine-grained, sparingly cherty dolomite with basal dense, gray limestone sequence. Thickness about 250 feet. and (Olc) Unnamed (middle part of the Knox Group), including (Olv) Longview Dolomite - Siliceous, gray, fine-grained, medium-bedded dolomite; interbeds of gray limestone in upper part. Thickness about 300 feet; (Oc) Chepultepec Dolomite - Light-gray, fine-grained, well-bedded dolomite, moderately cherty; fine-grained limestone locally in upper part; quartz sandstone beds at base. Average thickness about 800 feet.