Geologic units in Claiborne county, Tennessee

Additional scientific data in this geographic area

Longview Dolomite and Chepultepec Dolomite (Ordovician) at surface, covers 19 % of this area

Longview Dolomite - Siliceous, gray, fine-grained, medium-bedded dolomite; interbeds of gray limestone in upper part. Thickness about 300 feet; and Chepultepec Dolomite - Light-gray, fine-grained, well-bedded dolomite, moderately cherty; fine-grained limestone locally in upper part; quartz sandstone beds at base. Thickness about 800 feet.

Copper Ridge Dolomite (Ordovician) at surface, covers 15 % of this area

Coarse, dark-gray, knotty dolomite, asphaltic in places; with much gray, medium-grained, well- bedded dolomite; abundant chert; cryptozoans typical. Thickness about 1,000 feet.

Chickamauga Group (Ordovician) at surface, covers 14 % of this area

In the northwest predominantly a limestone sequence about 2,000 feet thick. Becomes progressively more clastic and thicker to the southeast.

Newala Formation, including Mascot Dolomite and Kingsport Formation (Ordovician) at surface, covers 9 % of this area

Newala Formation includes 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; and Kingsport Formation - Gray, fine-grained, sparingly cherty dolomite with basal dense, gray limestone sequence. Thickness about 250 feet.

Jonesboro Limestone, Newala Formation, Mascot Dolomite, Kingsport Formation, Longview Dolomite, and Chepultepec Dolomite (Ordovician) at surface, covers 7 % of this area

Jonesboro Limestone - Dark bluish-gray, ribboned (silt and dolomite) limestone; numerous interbeds of dark-gray dolomite; quartz sandstone at base. Erosional unconformity at top. Thickness about 2,000 feet; Newala Formation inlcuding 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; and Kingsport Formation - Gray, fine-grained, sparingly cherty dolomite with basal dense, gray limestone sequence. Thickness about 250 feet; Longview Dolomite - Siliceous, gray, fine-grained, medium-bedded dolomite; interbeds of gray limestone in upper part. Thickness about 300 feet; Chepultepec Dolomite - Light-gray, fine-grained, well-bedded dolomite, moderately cherty; fine-grained limestone locally in upper part; quartz sandstone beds at base. Thickness about 800 feet.

Slatestone Formation (Pennsylvanian) at surface, covers 6 % of this area

Shale, sandstone, siltstone, and several important coals; from Jellico coal to Poplar Creek coal. Thickness 500 to 650 feet.

Crab Orchard Mountains and Gizzard Groups (Pennsylvanian) at surface, covers 4 % of this area

Sandstone, conglomerate, siltstone, shale, and thin coal beds. Thickness 1,200 to 1,400 feet.

Rockwood Formation and Clinch Sandstone (Silurian) at surface, covers 3 % of this area

Rockwood Formation - Brown to maroon shale, thin gray siltstone and sandstone, and thin lenticular layers of oolitic and fossiliferous red hematite. Thickness 350 to 550 feet; Clinch Sandstone - Clean, white, well-sorted sandstone; locally gray siltstone and shale. Average thickness about 600 feet.

Crooked Fork Group, including Wartburg Sandstone, Glenmary Shale, Coalfield Sandstone, Burnt Mill Shale, Crossville Sandstone, Dorton Shale (Pennsylvanian) at surface, covers 3 % of this area

Crooked Fork Group - Shale, sandstone, conglomerate, siltstone, and coal; from Poplar Creek coal to top of Rockcastle Conglomerate. Thickness 320 to 455 feet; Wartburg Sandstone - Sandstone, gray to brown, fine- to medium-grained, locally conglomeratic. Poplar Creek coal and thin shale at top. Thickness 0 to 50 feet; Glenmary Shale - Mostly dark-gray to light-brown shale with minor siltstone and sandstone. Thin coal near base locally. Thickness 50 to 150 feet; Coalfield Sandstone - Sandstone, gray to brown, fine- to medium-grained. Thickness 0 to 80 feet; Burnt Mill Shale - Mostly dark-gray to light-brown shale, with minor siltstone. Thin sandstone locally present near base. Hooper coal just above base. Thickness as much as 110 feet; Crossville Sandstone - Sandstone, gray to brown or pink, fine- to medium-grained, thinly and evenly bedded. Thickness 30 to 70 feet; Dorton Shale - Mostly dark-gray to light-brown shale, with minor siltstone and sandstone. Thin coal near top. Rex coal as much as 70 feet above base. Thickness as much as 150 feet.

Maynardville Limestone, Nolichucky Shale, Honaker Dolomite, Maryville Limestone, Rogersville Shale, Rutledge Limestone, Pumpkin Valley Shale (Cambrian) at surface, covers 2 % of this area

Maynardville Limestone - Thick-bedded, bluish-gray, ribboned (silt and dolomite) nodular limestone; light-gray, fine-grained, laminated to thinly bedded, noncherty dolomite in upper part. Thickness 150 to 400 feet; Nolichucky Shale - Pastel-colored (pink, greenish, olive), flaky clay shale; gray, commonly oolitic, shaly limestone lenses; locally stromatolitic limestone layers; thin, blocky siltstone near middle. Thickness 100 feet in the east to 900 feet in the west; Honaker Dolomite - Dark-gray, medium-bedded dolomite with minor dark limestone beds; locally cherty; cryptozoans abundant in places. Thickness about 1,500 feet; Maryville Limestone - Gray, ribboned (silt and dolomite), fine-grained, evenly bedded limestone; intraformational conglomerate and oolitic layers common; clay shale and light-gray dolomite locally. Thickness 300 to 800 feet; Rogersville Shale - Light-green, fissile clay shale; in places limestone (Craig Member) in upper part. Commonly 25 to 80 feet thick; maximum thickness 250 feet; Rutledge Limestone - Medium- to dark-gray, ribboned (silt and dolomite), medium-grained, well-bedded limestone; locally dark-gray, coarse-grained, medium-bedded dolomite in upper part. Thickness 100 to 500 feet; Pumpkin Valley Shale - Dull-brown to maroon shale with numerous interbeds of thin, blocky, and sandy siltstone. Thickness 100 to 600 feet.

Rome Formation (Cambrian) at surface, covers 2 % of this area

Variegated (red, green, yellow) shale and siltstone; gray, fine-grained sandstone in middle and west part of Valley and Ridge; abundant limestone and dolomite in east. Thickness about 2,000 feet.

Indian Bluff Formation (Pennsylvanian) at surface, covers 2 % of this area

Shale, sandstone, siltstone, and thin coal beds; from Pioneer Sandstone Member to Jellico coal. Thickness 150 to 250 feet.

Conasauga Group (Cambrian) at surface, covers 2 % of this area

Mostly shale northwest of a line connecting Knoxville and Tazewell; dominantly dolomite with minor shale southeast of a line from Newport to Kingsport; between these lines it consists of six formations. Thickness about 2,000 feet.

Graves Gap Formation (Pennsylvanian) at surface, covers 1 % of this area

Shale, sandstone, siltstone, and coal; from Windrock coal to top of Pioneer Sandstone. Thickness 200 to 350 feet.

Newman Limestone (Mississippian) at surface, covers 1 % of this area

Gray limestone sequence near Cumberland Plateau; shaly and silty limestone with minor sandstone and shale in the area of Clinch Mountain. Thickness 600 to 3,000 feet.

Chattanooga Shale (Mississippian and Devonian) at surface, covers 1 % of this area

Black carbonaceous shale, fissile. Thickness 100 to 900 feet; about 25 feet on Chilhowee Mountain. (Mapped with Mfp on West-Central and parts of East Central Sheets)

Redoak Mountain Formation (Pennsylvanian) at surface, covers 1 % of this area

Shale, sandstone, siltstone, and several important coals; from Pewee coal to Windrock coal. Thickness 340 to 420 feet.

Rockwood Formation (Silurian) at surface, covers 1 % of this area

Brown to maroon shale, thin gray siltstone and sandstone, and thin lenticular layers of oolitic and fossiliferous red hematite. Thickness 350 to 550 feet.

Fort Payne Formation (Mississippian) at surface, covers 0.9 % of this area

Bedded chert, calcareous and dolomitic, somewhat crinoidal; and minor shale. Thin green shale (Maury) at base. Thickness about 300 feet.

Pennington Formation (Mississippian) at surface, covers 0.6 % of this area

Highly variegated clay shale distinctive; contains siltstone beds and locally gray, fine-grained sandstone. Thickness 300 to 500 feet near Cumberland Plateau; maximum of about 1,250 feet to the east.

Maynardville Limestone (Cambrian) at surface, covers 0.6 % of this area

Thick-bedded, bluish-gray, ribboned (silt and dolomite) nodular limestone; light-gray, fine-grained, laminated to thinly bedded, noncherty dolomite in upper part. Thickness 150 to 400 feet.

Sneedville Limestone (Devonian to Silurian) at surface, covers 0.6 % of this area

Gray silty limestone and dolomite, minor shale, and fine-grained, greenish-gray sandstone; fossils locally abundant. Thickness 100 to 300 feet.

Juniata Formation (Ordovician) at surface, covers 0.6 % of this area

Maroon, claystone, siltstone, and shale; uniformly bedded; some faint greenish mottling; less calcareous than Sequatchie Formation. Thickness about 300 feet.

Nolichucky Shale (Cambrian) at surface, covers 0.5 % of this area

Pastel-colored (pink, greenish, olive), flaky clay shale; gray, commonly oolitic, shaly limestone lenses; locally stromatolitic limestone layers; thin, blocky siltstone near middle. Thickness 100 feet in the east to 900 feet in the west.

Sequatchie Formation (Ordovician) at surface, covers 0.5 % of this area

Maroon and gray shaly limestone, mottled greenish; with interbeds of olive to maroon calcareous shale and siltstone. Thickness about 300 feet.

Vowell Mountain Formation (Pennsylvanian) at surface, covers 0.4 % of this area

Shale, sandstone, siltstone, and coal; from Frozen Head Sandstone Member to Pewee coal. Thickness 300 to 375 feet.

Rome Formation (Cambrian) at surface, covers 0.4 % of this area

Variegated (red, green, yellow) shale and siltstone with beds of gray, fine-grained sandstone. Maximum exposed thickness 1,500 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 0.4 % 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).

Breathitt Formation, lower part (Pennsylvanian) at surface, covers 0.3 % of this area

lower part which includes Livingston Conglomerate Member of Lee Formation in eastern Rockcastle County

Grainger Formation (Mississippian) at surface, covers 0.3 % of this area

Gray to green shale with siltstone and fine-grained glauconitic sandstone; in some areas quartz-pebble conglomerate. Thickness 500 to 1,000 feet.

Crab Orchard Mounatins and Gizzard Group (Pennsylvanian) at surface, covers 0.1 % of this area

Sandstone, conglomerate, siltstone, shale, and thin coal beds. From top down Crab Orchard Mountains group includes Rockcastle Conglomerate, Vadever Formation, Newton Sandstone, Whitwell Shale, and Sewanee Conglomerate; Gizzard Group includes Signal Point Shale, Warren Point Sandstone, and Raccoon Mountain Formation. Thickness about 1,200 to 1,400 feet.

Cross Mountain Formation (Pennsylvanian) at surface, covers < 0.1 % of this area

Mostly shale, interbedded with sandstone, siltstone, and thin coal beds; base at top of Frozen Head Sandstone. Maximum preserved thickness 270 feet.

Middle and Lower Parts of Chickamauga Group, including Mocassin Formation, Bays Formation, Sevier Shale, Ottosee Shale, Holston Formation, Lenoir Limestone and Athens Shale (Ordovician) at surface, covers < 0.1 % of this area

Middle and Lower Parts of Chickamauga Group - A sequence of about 1,400 feet of limestone in the northeast, which thickens and becomes more clastic to the southeast and is divided into the formations shown at right. Maximum thickness about 8,000 feet. Includes Mocassin Formation - Maroon calcareous shale, siltstone, and limestone; thin metabentonite layers in upper part; mud cracks, ripple marks common. Thickness 800 to 1,000 feet; (Ob) Bays Formation - Maroon claystone and siltstone, commonly mottled greenish, evenly bedded; to northeast, light- gray to white, thick-bedded sandstone; metabentonite in upper part. Maximum thickness 1,000 feet. (Osv) Sevier Shale - Calcareous, bluish-gray shale, weathers yellowish-brown; with thin gray limestone layers; sandstone, siltstone, and locally conglomerate to the east. Thickness 2,000 to 7,000 feet; (Oo) - Ottosee Shale - Bluish-gray calcareous shale, weathers yellow; with reef lenses of coarsely crystalline reddish fossiliferous limestone ("marble"). Thickness about 1,000 feet; (Oh) - Holston Formation - Pink, gray, and red coarsely crystalline limestone (Holston Marble); in many areas upper part is sandy, crossbedded ferruginous limestone and brown to greenish calcareous shale. Thickness 200 to 600 feet; (Ol) Lenoir Limestone - Nodular, argillaceous, gray limestone; in places basal sedimentary breccia, conglomerate, quartz sand; Mosheim Limestone Member (dense, light- to medium-gray limestone) near base. Thickness 25 to 500 feet; (Oa) Athens Shale - Medium- to dark-gray, calcareous, graptolitic shale; calcareous gray sandstone, siltstone, and locally fine-pebble quartz conglomerate; nodules of shaly limestone near base. Maximum thickness 1,500 feet.

Chepultepec and Copper Ridge Formations (Cambrian-Ordovician) at surface, covers < 0.1 % of this area

Chepultepec Formation (Ulrich, 1911). Dolostone, argillaceous, sandy, light-gray, light-olive-gray, and grayish-brown,very-fine- to coarse-grained. Contains white to light-gray chert nodules and beds; sandstone and dolomitic sand stone lenses and beds; scattered sand grains; minor intraformational conglomerate beds; greenish-gray clay shale partings; and dark-gray, petroliferous dolostone. The Chepultepec ranges from 300 to 850 feet in thick ness (Brent, 1963). Copper Ridge Formation (Ulrich, 1911). Dolostone, generally divisible into a lower olive-brownish-gray to darkgray, medium- to coarse-grained, thick- to massive-bedded dolostone, some of which emits a petroliferous odor on freshly broken surfaces ("stinkstone"); and an upper olive-brownish- gray to light-gray, very-fine- to medium-grained dolostone with minor silty and sandy zones. Olive-black, oolitic chert beds and light-gray to white, chalcedonic chert nodules are present. Similar divisions were described by several geologists including Miller and Brosgé (1954), Miller and Fuller (1954), and Bridge (1956). The Copper Ridge ranges from 415 to 850 feet in thickness. Maynardville Formation (Oder, 1934). Limestone and dolostone. Limestone, locally dolomitic, locally argillaceous, medium- to dark-gray, very-fine- to fine-grained, medium- to thick-bedded, mottled; with argillaceous to dolomitic bands and partings which give the rock a ribbon-banded or straticulate appearance. Dolostone, very-light-gray to dark-gray, light-olive-gray to olive-gray and locally yel low ish-gray or dark-bluish-gray, very-fine- to coarse-grained, finely laminated to thick-bedded (thin-bedded near top of unit distinguishes it from overlying Copper Ridge Formation); with black chert; minor lenses and beds of fi ne- to medium-grained, locally dolomitic sandstone; very-fine-grained, yellowish-gray, argillaceous sand stone; and rounded-pebble conglomerate; all locally present. Generally the limestone is in the lower one third to one-half of the unit and the dolostone is in the upper two-thirds to one-half of the unit, with a transition zone from one to the other. The Maynardville Formation ranges from 60 to 300 feet in thickness, thinning to the east-northeast from Lee County. Thickness variations may be due in part to grouping of the limestone with the underlying Nolichucky Formation or the dolostone with the overlying Copper Ridge, as noted by Derby (1965).

Lee Formation (Mississippian to Pennsylvanian) at surface, covers < 0.1 % of this area

Lee Formation

Pumpkin Valley Shale (Cambrian) at surface, covers < 0.1 % of this area

Dull-brown to maroon shale with numerous interbeds of thin, blocky, and sandy siltstone. Thickness 100 to 600 feet.

Mascot and Kingsport Dolomites (Ordovician) at surface, covers < 0.1 % of this area

Mascot Dolomite (Rodgers, 1943). Dolostone and limestone. Dolostone, nearly white or very-light- to medium gray with red- to pink-streaks, very-fine- to fine-grained; with subordinate medium- to coarse-grained dolostone; thin green shale partings; sandstone lenses to 1-foot thick; and grayish red and dark-gray dolostones; all locally present. Dense, gray limestone is in the lower half and chert is present locally. Unconformable (locally angular) upper contact. The Mascot Dolomite ranges from 330 to 640 feet in thickness. Kingsport Dolomite (Rodgers, 1943). Dolostone and limestone. Dolostone, very-light-gray to dark-gray and light- to dark-brown, fine- to coarse-grained; with white chert; thin green shale partings; sandstone lenses; and scattered sand grains. Fine-grained limestone is locally present. The Kingsport Dolostone ranges from 100 to 350 feet in thickness. The Longview Limestone of previous reports is included in the Kingsport (Harris, 1969).

Maryville Limestone, Rogersville Shale, Rutledge Limestone (Cambrian) at surface, covers < 0.1 % of this area

Maryville Limestone - Gray, ribboned (silt and dolomite), fine-grained, evenly bedded limestone; intraformational conglomerate and oolitic layers common; clay shale and light-gray dolomite locally. Thickness 300 to 800 feet; Rogersville Shale - Light-green, fissile clay shale; in places limestone (Craig Member) in upper part. Commonly 25 to 80 feet thick; maximum thickness 250 feet; Rutledge Limestone - Medium- to dark-gray, ribboned (silt and dolomite), medium-grained, well-bedded limestone; locally dark-gray, coarse-grained, medium-bedded dolomite in upper part. Thickness 100 to 500 feet.

Hardy Creek Limestone through Dot Limestone (Ordovician) at surface, covers < 0.1 % of this area

Hardy Creek, Ben Hur, Woodway, Hurricane Bridge, Martin Creek, Rob Camp, Poteet, and Dot Limestones (Lee County). Hardy Creek Limestone (Miller and Fuller, 1947). Limestone, light-olive-gray to olive-gray, light- to medium-gray, and brown, micrograined, 1- to 2-inch-thick beds, even-bedded; with interbedded yellowish-gray, argillaceous, limestone; and light-olive-gray, aphanic limestone. Olive-black chert nodules locally abundant. The Hardy Creek Limestone ranges from 75 to 150 feet in thickness. Ben Hur Limestone (Miller and Brosgé, 1950). Limestone, argillaceous, yellowish-gray, light-olive-gray, light-brown, and light-gray, micrograined, thin-bedded; some beds composed of fossil detritus in middle of unit; and some beds of coarsegrained limestone. The Ben Hur Limestone ranges from 95 to 165 feet in thickness. Woodway Limestone (Miller and Brosgé, 1950). Limestone, light-olive-gray to olive-gray and light-brownish-gray to brownish-gray, micrograined, thin-bedded, even-bedded; interbedded with olive-gray to olive-black, medium-grained, wavy-bedded limestone; and sparse zones of argillaceous limestone. Thin limestone beds composed of fossils locally abundant at base of unit. Locally abundant olive-black chert nodules. The Woodway Limestone ranges from 240 to 400 feet in thickness. Hurricane Bridge Limestone (Miller and Brosgé, 1950). Limestone, light-gray and light-olive-gray to olive-gray, thin-bedded, micrograined, yellowish-gray; with intervals of interbedded grayish-red, argillaceous, micrograined limestone; and light-olive-gray, thick-bedded, micrograined limestone. Dark-gray chert zones locally present. The Hurricane Bridge Limestone ranges from 200 to 370 feet in thickness. Martin Creek Limestone (Miller and Brosgé, 1950). Limestone, light-olive-gray to dark-olive-gray, locally with abundant fossil fragments, me ium-grained; and light-olive gray to dark-olive-gray, micrograined limestone; with locally abundant olive-black chert nodules. A fine- to coarse-grained limestone that is a maximum 35 feet thick is locally present. Locally the dark colored, medium-grained limestone emits a petroliferous odor when broken. The Martin Creek Limestone ranges from 40 to 180 feet in thickness. Rob Camp Limestone (Miller and Brosgé, 1950). Limestone, light-olive-gray, thin- to massive-bedded, micrograined, with patches of white calcite ("birds-eyes") and very sparse chert nodules. The Rob Camp Limestone ranges from discontinuous (where cut out by post-depositional erosion) to a maximum 150 feet in thickness (Miller and Brosgé, 1954). Poteet Limestone (Miller and Brosgé, 1950). Limestone, grades from light-olive-gray and medium-gray, micrograined limestone; interbedded with argillaceous, yellowish-gray, micrograined limestone in the southwest; to dark-gray, medium grained limestone; overlain by interbedded light-olive-gray, micrograined limestone, and argillaceous limestone in the northeast. Locally abundant olive-black chert nodules. Generally thin- to medium-bedded. The Poteet Limestone ranges from 45 to 110 feet in thickness. Dot Limestone (Miller and Brosgé, 1950). Limestone, dolomite, and shale. Limestone, light-olive-gray, micrograined, thin- to medium-bedded, locally dolomitic. Dolostone, argillaceous, conglomeratic (pebbles and cobbles derived from underlying dolomite and chert), grayish-red, yellowish-gray, and very-light- to medium-gray, micro-grained, grades into overlying limestone. Shale, dolomitic to calcareous, very light-to light-gray, interbedded with limestone and dolomite beds. One or more chert zones may be locally present near top of unit. Generally lower contact is represented by an unconformity overlain by the conglomeratic dolomites. The Dot Limestone ranges from 70 to 220 feet in thickness.

Hancock, Rose Hill, and Clinch Formations (Silurian) at surface, covers < 0.1 % of this area

Hancock Formation (Keith, 1896). Dolomite, limestone, and sandstone. Dolomite, locally calcareous, locally siliceous, light-olive-gray and light-to dark-gray, aphanic to fine-grained, finely-laminated to massive-bedded, locally stromatolitic and vuggy. Lime stone, medium- to dark-gray and bluish-gray, aphanic to fine-grained, laminated to thickbedded, ribbon-banded, mottled, locally emits petroliferous odor when broken. Sandstone, locally calcareous, generally quartzose, medium-grained to pebbly and conglomeratic locally at base of formation; and fine- to medium-grained sandstone locally interbedded with limestone. The formation grades from dolomite with minor limestone and a basal sandstone in southwestern Lee County (Cayuga Dolomite of Miller and Fuller, 1954) to limestone with an underlying or interbedded dolomite with sandstone partings, and a basal sandstone to the northeast and east (Harris and Miller, 1958; Miller and Roen, 1971). The Hancock Formation ranges from 75 to 225 feet in thickness and correlates with the Tonoloway Limestone. Rose Hill Formation . Refer to description under Skrt. Clinch Formation (Safford, 1856). Quartzarenite and shale. Quartzarenite, very-light gray, olive-gray, and brownish- gray with local grayish-red beds, very-fine-grained to very-coarse-grained with local conglomeratic zones, thin- to thick-bedded with thin, green ish-gray and dark-gray shale beds and partings in upper part. Shale, light-olive-gray to gray ish-green; with thin, very fine- to fine-grained sandstone interbeds in the lower one-third to one-quarter of the unit. Erosional unconformity at base of unit identified in northern Lee County (Mill er and Roen, 1973). The Clinch Formation ranges from 220 to 330 feet in thickness. The Division of Mineral Resources uses the name Clinch Formation for exposures in Lee, Wise, and Scott counties where the lower Silurian rocks include the lower Hagan Shale Member and the upper Poor Valley Ridge Sand stone Member. The name Tuscarora Formation is used for the lower Silurianquartzitic sandstone unit in all areas northward in the Valley and Ridge of Virginia, including the Clinch Mountain area where the name Clinch Formation was first used, because of similarity between the Tuscarora and the rocks on Clinch Mountain. In the past many geologists used the name Clinch Sandstone in the southern part of the Valley and Ridge of Virginia and the name Tuscarora Formation in the northern part of the Valley and Ridge of Virginia (Butts, 1940) for essentially the same group of quartzitic sandstones. Dennison and Boucot (1974) and Mill er (1976) described the facies change of the lower Silurian Clinch Sandstone of Southwest Virginia from quartzitic sandstones in the Clinch Mountain belt in Scott and Wise Counties to sandstones and shales in the Lee, southwestern Wise, and western Scott counties area.

Sequatchie Formation, Reedsville Shale, Trenton Limestone, Eggleston Formation (Ordovician) at surface, covers < 0.1 % of this area

Sequatchie Formation (Ulrich, 1913). Siltstone, limestone, and shale. Siltstone, calcareous, medium-gray to grayish-red, maroon, and green, even and wavy thin-beds. Limestone, argillaceous, gray, greenish-gray, and grayish-red to dusky-red, nodular, in 1-inch to 3-feet thick planar beds. Shale, grayish-red. Percentage of each lithotype varies throughout the lateral and vertical extent of the formation. The Sequatchie Formation ranges from 250 to 440 feet in thickness. Laterally equivalent to the Juniata Formation. Reedsville Shale (Ulrich, 1911). Shale, siltstone, and minor limestone. Shale, locally silty, calcareous, yellowish gray, grayish-olive, greenish-gray, and medium-gray. Siltstone, calcareous, greenish-gray to olive-gray, in 1- to 2-inch thick planar beds. Limestone, medium- to dark-gray, fine- to coarse-grained, fossiliferous, in 6-inch thick beds; and silty to argillaceous, medium-light-gray to medium-dark-gray and olive-gray, micrograined to medium-grained limestone, generally in 1- to 2-inch thick planar beds. A few very-fine grained sandstone beds are present within the unit. The shales are predominant throughout most of southwestern Virginia (Miller and Brosgé, 1954; Miller and Fuller, 1954). Siltstones and limestones are subordinate to and interbedded with the shales. The Reedsville Shale ranges from 275 feet in Lee County to approximately 1000 feet in Frederick County. It is equivalent to the upper Martinsburg of previous reports in western Virginia and is conformable with the underlying Trenton Limestone and Dolly Ridge Formation. Trenton Limestone (Vanuxem, 1838). Limestone, medium-light-gray to dark-gray and brownish-gray, micrograined to medium-grained, fossiliferous, thin- to medium-bedded, wavy- to platy-bedded with grayish-yellow and dark-gray shale partings, minor olive-black chert nodules; and one bentonite bed noted in western Scott County (Harris and Miller, 1958). (See Eggleston Formation description for additional discussion of the bentonite beds). Locally some of the dark-colored beds emit a petroliferous odor when broken. The Trenton Limestone ranges from 300 to 600 feet in thickness. Eggleston Formation (Matthews, 1934). Mudstone, siltstone, limestone, and bentonite. Mudstone and siltstone, light-gray, greenish-gray and yellowish-gray, locally contains gray and white mottled calcite patches and stringers. Limestone, light-olive-gray to olive-gray and light-brown, aphanic to medium-grained, thin-bedded; with argillaceous, yellowish-gray, micrograined to medium-grained limestone. Two thick (1-3 feet), greenish-gray, bentonite beds in upper part of unit. Olive-black chert nodules are locally present. Mudstone is dominant in lower and locally in upper part; light-olive-gray to olive-gray limestone is dominant in middle part of unit. The Eggleston Formation ranges from 125 to 180 feet in thickness. Haynes (1992) reported on three K-bentonite beds in the Trenton and Eggleston Limestones and the Moccasin Formation in the Valley and Ridge Province of southwest Virginia. The uppermost K-bentonite bed has not been correlated regionally and is known locally as the V-7. The lower two K-bentonite beds have been identified from regional correlations as the Deicke K-bentonite overlain by the Millbrig K-bentonite.

Breathitt Formation, middle part (Pennsylvanian) at surface, covers < 0.1 % of this area

Breathitt Formation, middle part

Mississippian Formations Undivided (Mississippian) at surface, covers < 0.1 % of this area

Pennington Group, Bluefield Formation, Greenbrier Limestone, Maccrady Shale, and Price Formation; includes Newman Limestone, Fort Payne Chert, and Grainger Formation in western Lee County. Refer to individual units for descriptions.

Chattanooga Shale and Wildcat Valley Sandstone (Devonian-Mississippian) at surface, covers < 0.1 % of this area

Chattanooga Shale (Hayes, 1891). Shale, siltstone, and sandstone. Shale, carbonaceous, grayish-black to black, fissile to platy, thin- to thick-laminated, locally fossiliferous and pyritic, locally contains phosphatic nodules in the upper part, locally has strong petroliferous odor (Henika, 1988); with beds and zones of medium-gray to greenish-gray, locally silty shale. Siltstone, light-gray to grayish-black, laminated to thick-bedded, locally wavy- and ripple-bedded. Sandstone, light-gray, very-fine-grained. Grayish-black to black, carbonaceous shale comprises 100 percent of the formation in western Lee County and is predominant in the formation throughout southwest Virginia. The Chattanooga Shale uncomformably overlies the Silurian Hancock Formation throughout most of Lee County and the lower Devonian Wildcat Valley Sandstone to the northeast. The Chattanooga Shale ranges in thickness from 200 feet in western Lee County (Englund, 1964) to 1870 feet in northwestern Russell County (Meissner and Miller, 1981). Roen and others (1964) and Kepferle and others (1981) discussed divisions of the Chattanooga Shale and correlation with other units. Wildcat Valley Sandstone (Miller, Harris, and Roen, 1964). Sandstone, limestone, and shale. Sandstone, locally calcareous, locally quartzose, light-gray, grayish-orange, and dark-yellowish-brown, very-fine- to coarse-grained, thin- to massive-bedded, fossiliferous, friable, locally glauconitic; with chert nodules and beds. Locally dark-reddish-brown ironstone replaces sandstone. Limestone, gray, pinkish-gray, and light-brownish-gray, coarse-grained, thick- to massive bedded, sandy, locally present. Shale, yellowish-green to gray, locally present. Where the Wildcat Valley Sandstone is present it uncomformably overlies the Silurian Hancock Formation. The Wildcat Valley Sandstone is absent throughout most of Lee County (Englund, 1964; Harris, 1965; Miller and Roen, 1973) but reaches a maximum of 60 feet in thickness to the northeast (Lower Devonian sandstone of Harris and Miller, 1963).