Geologic units in Macon county, Tennessee

Fort Payne Formation and Chattanooga Shale (Mississippian) at surface, covers 76 % of this area

Fort Payne Formation - Bedded chert; calcareous and dolomitic silicastone; minor limestone and shale; scattered lenses of crinoidal limestone. Thin green shale (Maury) at base. Average thickness about 250 feet (475 in Wells Creek area); and Chattanooga Shale - Black carbonaceous shale, fissile. Thickness 0 to 70 feet; average about 20 feet. (Mapped as MDc on East-Central and East sheets)

Ordovician [units] including Richmond Group (which includes Mannie Shale, Fernvale Limestone, Sequatchie Formation, and Arnheim Formation), the Maysville Group (which includes Leipers Formation), the Eden Group (which includes Inman Formation), and the Nashville Group (which includes Catheys Formation). (Ordovician) at surface, covers 17 % of this area

Ordovician [units] including Richmond Group (which includes Mannie Shale - Olive-gray shale. Thickness 0 to 20 feet; Fernvale Limestone - Massive, coarsely crystalline, gray limestone with varicolored grains. Thickness 0 to 50 feet; Sequatchie Formation - Olive-gray and greenish-gray shale, mudstone, and argillaceous limestone; dolomitic, laminated, and sandy. Thickness 0 to 100 feet; and Arnheim Formation Nodular, shaly, gray limestone. Thickness 0 to 20 feet; the Maysville Group (which includes Leipers Formation - Nodular, shaly limestone; fine- to coarse-grained limestone; and phosphatic calcarenite locally. Thickness 0 to 150 feet); the Eden Group (which includes the Inman Formation - Thin-bedded to laminated, fine-grained, gray limestone with shale partings. Thickness 0 to 50 feet); and the Nashville Group (which includes Catheys Formation - Nodular, shaly limestone; fine- to coarse-grained limestone; phosphatic calcarenite; and light-gray cryptograined limestone. Thickness 50 to 175 feet.)

Sequatchie Formation, Leipers Formation, Inman Formation and Catheys Formation (Ordovician) at surface, covers 2 % of this area

Sequatchie Formation - Greenish-gray calcareous shale, mudstone, and argillaceous limestone; dolomitic, laminated, and sandy. Thickness 0 to 165 feet; Leipers Formation - Nodular, shaly limestone and fine- to coarse-grained limestone. Thickness 0 to 150 feet; Inman Formation - Thin-bedded to laminated, fine-grained, greenish-gray limestone interbedded with red and green calcareous shale beds. Thickness 0 to 50 feet. (Present only in Sequatchie Valley.); and Catheys Formation - Nodular, shaly, thin- to medium-bedded limestone and fine- to coarse-grained limestone. Thickness 125 to 400 feet.

Silurian Formations, including Decatur Limestone, Brownsport Group (Lobelville Formation, Bob Limestone, Beech River Formation), Wayne Group (Dixon Formation, Lego Formation, Waldron Shale, Laurel Limestone, Osgood Formation) and Brassfield Limestone (Silurian) at surface, covers 2 % of this area

Silurian Formations - Characteristically light olive-gray to greenish-gray, with variable reddish-brown color in some areas. Individual formations are generally uniform in thickness, except where truncated by pre- Chattanooga erosion. Most formations are slightly thicker (than indicated) in Wells Creek Basin. Includes Decatur Limestone- Thick-bedded, medium- to coarse-grained limestone, gray with reddish-brown grains. Thickness 0 to 70 feet; Brownsport Group (which includes Lobelville Formation - Shale with thin beds of limestone. Thickness 0 to 30 feet; Bob Limestone - Thick-bedded, medium-grained limestone, locally oolitic. Thickness 0 to 25 feet; and Beech River Formation - Shale with thin beds of limestone. Thickness 0 to 60 feet); Wayne Group (which includes Dixon Formation - Green and reddish-brown argillaceous limestone, shale, and mudstone. Thickness 0 to 40 feet; Lego Limestone - Even-bedded, olive-gray limestone with scattered reddish-brown grains. Thickness 0 to 30 feet; Waldron Shale - Greenish-gray fossiliferous shale. Thickness 0 to 5 feet; Laurel Limestone - Even-bedded, olive-gray limestone with scattered reddish-brown grains. Thickness 0 to 30 feet; Osgood Formation - Greenish- and reddish-gray shale and argillaceous limestone. Thickness 0 to 15 feet); and Brassfield Limestone - Thin-bedded cherty limestone, locally glauconitic. Thickness 0 to 50 feet; generally about 20 feet.

Nashville Group; Bigby-Cannon Limestone and Hermitage Formation (Ordovician) at surface, covers 1 % of this area

Nashville Group - Bigby-Cannon Limestone - Brownish-gray phosphatic calcarenite and light-gray to brownish-gray, cryptograined to medium- grained, even-bedded limestone. Thickness 50 to 125 feet; and Hermitage Formation - Thin-bedded to laminated, sandy and argillaceous limestone with shale; nodular shaly limestone; coquina; and phosphatic calcarenite. Thickness 50 to 100 feet.

St. Louis Limestone and Warsaw Limestone (Mississippian) at surface, covers 0.7 % 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.

Renfro and Muldraugh Members of Borden Formation and Fort Payne Formation, undivided (Mississippian) at surface, covers 0.4 % of this area

Renfro and Muldraugh Members of Borden Formation and Fort Payne Formation, undivided

New Albany, Chattanooga, and Ohio Shales, Boyle Dolomite (Limestone), and Sellersburg Limestone, undivided (Devonian to Mississippian) at surface, covers < 0.1 % of this area

New Albany, Chattanooga, and Ohio Shales, Boyle Dolomite (Limestone), and Sellersburg Limestone, undivided

Salem, Warsaw, and Harrodsburg Limestones, undivided (Mississippian) at surface, covers < 0.1 % of this area

Salem, Warsaw, and Harrodsburg Limestones, undivided

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

Fort Payne Formation - Calcareous and dolomitic silicastone; contains bedded chert, cherty limestone, and shale; scattered crinoidal limestone lenses. Thin green shale (Maury) at base. Thickness 100 to 275 feet.; and Chattanooga Shale - Black carbonaceous shale, fissile. Thickness 20 to 30 feet in most areas. (Mapped as MDc in Flynn Creek structure, where it is about 200 feet thick.) (Also mapped as MDc on the East Sheet)

Laurel Dolomite, Osgood Formation, and Brassfield Dolomite, undivided (Silurian) at surface, covers < 0.1 % of this area

Laurel Dolomite, Osgood Formation, and Brassfield Dolomite, undivided

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 100 to 280 feet; and Warsaw Limestone - Coarse-grained, gray, crossbedded limestone; somewhat shaly in the northeast. Thickness 40 to 150 feet.

Cumberland Formation and Leipers and Catheys (?) Limestones, undivided (Ordovician) at surface, covers < 0.1 % of this area

Cumberland Formation and Leipers and Catheys (?) Limestones, undivided; in southernmost Kentucky

Laurel Limestone, Osgood Formation, and Brassfield Formation (Silurian) at surface, covers < 0.1 % of this area

Laurel Limestone - Dolomitic limestone, mottled yellowish-gray to yellowish-green, fine-grained. Thickness 0 to 10 feet. (Present only in Macon County); Osgood Formation - Grayish-green shale. Thickness 0 to 10 feet. (Present only in Macon County.); and Brassfield Formation - Olive-gray, fine-grained cherty limestone to the north, merging into olive-gray calcareous shale to the south. Thickness 60 to 130 feet. (Present only in Sequatchie Valley.)