Geologic units in Hancock county, Tennessee

Additional scientific data in this geographic area

Rome Formation (Cambrian) at surface, covers 15 % 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.

Chickamauga Group (Ordovician) at surface, covers 13 % of this area

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

Maynardville Limestone, Nolichucky Shale, Honaker Dolomite, Maryville Limestone, Rogersville Shale, Rutledge Limestone, Pumpkin Valley Shale (Cambrian) at surface, covers 10 % 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.

Copper Ridge Dolomite (Ordovician) at surface, covers 7 % 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.

Conasauga Group (Cambrian) at surface, covers 7 % 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.

Longview Dolomite and Chepultepec Dolomite (Ordovician) at surface, covers 6 % 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.

Pennington Formation (Mississippian) at surface, covers 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.

Jonesboro Limestone, Newala Formation, Mascot Dolomite, Kingsport Formation, Longview Dolomite, and Chepultepec Dolomite (Ordovician) at surface, covers 5 % 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.

Newman Limestone (Mississippian) at surface, covers 5 % 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.

Rockwood Formation and Clinch Sandstone (Silurian) at surface, covers 5 % 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.

Chattanooga Shale (Mississippian and Devonian) at surface, covers 4 % 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)

Newala Formation, including Mascot Dolomite and Kingsport Formation (Ordovician) at surface, covers 4 % 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.

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 3 % 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.

Maynardville Limestone (Cambrian) at surface, covers 2 % 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.

Grainger Formation (Mississippian) at surface, covers 2 % 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.

Martinsburg Shale, including Reedsville Shale and Unnamed Limestone Unit (Ordovician) at surface, covers 2 % of this area

Martinsburg Shale - Bluish-gray, calcareous clay shale, weathers yellowish-brown; with thin beds of nodular gray, fossiliferous limestone; thin layers of metabentonite near base. Thickness about 1,000 feet. Incluldes Reedsville Shale - Greenish-gray calcareous shale. Thickness 200 to 400 feet. and Unnamed Limestone Unit - Medium-grained, fossiliferous, gray limestone, shaly in part. Thickness as much as 600 feet.

Juniata Formation (Ordovician) at surface, covers 1 % of this area

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

Maryville Limestone, Rogersville Shale, Rutledge Limestone (Cambrian) at surface, covers 0.7 % 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.

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.

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.

Pumpkin Valley Shale (Cambrian) at surface, covers 0.3 % of this area

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

Chepultepec and Copper Ridge Formations (Cambrian-Ordovician) at surface, covers 0.2 % 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).

Hardy Creek Limestone through Dot Limestone (Ordovician) at surface, covers 0.2 % 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.

Clinch Sandstone (Silurian) at surface, covers < 0.1 % of this area

Clean, white, well-sorted sandstone; locally gray siltstone and shale. Average thickness about 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).

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.

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.

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

Knox Group (Safford, 1869). Dolostone, limestone, and sandstone. Dolostone, light- to medium-gray, very-fine- to fine-grained, locally with pink streaks in the upper part; and very-light-gray to dark-gray and brownish-gray, medium- to coarse-grained, locally argillaceous dolostone near the base of the unit; greenish-gray shale partings locally present; chert is abundant in some parts of the unit. Limestone, blue gray to dark-blue-gray, very-fine- to coarse-grained, locally sandy. Sandstone, gray to brown, fine- to medium-grained. Limestone is dominant in the eastern thrust belts. The Knox Group ranges from 2000 feet in Southwest Virginia to 3560 feet in thickness to the east in Washington County (Bartlett and Webb, 1971). The Knox includes the Mascot, Kingsport, Chepultepec, and Copper Ridge Dolomites and the Maynardville Formation.

Nolichucky and Maryville Formations, Rogersville Shale, and Rutledge Formation (Cambrian) at surface, covers < 0.1 % of this area

Nolichucky Formation (Campbell, 1894). Shale, siltstone, and limestone. Shale, locally calcareous, light-olive-gray and bluish-gray, fissile, with minor sandstone and dolomite. Siltstone, locally calcareous, yellowish-brown and grayish-orange, thin-bedded. Limestone, argillaceous to glauconitic, medium light-gray to dark-gray and bluish-gray, fine- to coarse-grained; contains oolitic- and flat-pebble conglomerate beds, locally stromatolitic. Shale and siltstone make up 20 to 50 percent of the formation (Derby, 1965). A limestone unit up to 165 feet in thickness is present approximately 100 feet above the base of the Nolichucky in northern Russell County (Miller and Meissner, 1977). The Nolichucky Shale ranges from 440 to 690 feet in thickness in Southwest Virginia but pinches out to the northeast in Giles County. Maryville Formation (Keith, 1895). Limestone, locally dolomitic, silty, medium- to dark-gray and bluish-gray, locally ribbon-banded, generally thick-bedded; with thin shale interbeds and sparse dolostone beds. May be as much as 60 percent oolitic limestone in some areas (Harris and Miller, 1958). The Maryville ranges from 500 to 700 feet in thickness. Rogersville Shale (Campbell, 1894). Shale, silty in part, dark-bluish-gray and dark-greenish-gray, fissile, with minor siltstone, limestone, dolostone, and sandstone. The Rogersville Shale ranges from 60 to 110 feet in thickness. Rutledge Formation (Campbell, 1894). Limestone and dolostone. Limestone, locally dolomitic, silty partings, medium-dark-gray to bluish-gray, thick-bedded, mottled, ribbon- banded, with minor chert. Dolostone, light-olive-gray and dark-gray, fine- to medium-grained, present in the upper part of the formation in eastern Scott County. The formation forms prominent bluffs on the south-side of Clinch River and Copper Creek in Scott and Russell counties. The Rutledge ranges from 215 to 375 feet in thickness. The Maryville Formation, Rogersville Shale, and Rutledge Formation grade from predominantly limestone with subordinate dolostone and shale in southeastern Lee County and southwestern Scott County to limestone with a middle dolostone and thin shale near the Scott County-Russell County line. Northeast of this area the laterally equivalent rocks are predominantly dolostone with subordinate lime stone at the top and bottom and are called the Honaker Formation (Evans and Troensegaard, 1991).

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

Pumpkin Valley Shale and Rome Formation. Pumpkin Valley Shale (Bridge, 1945). Shale, light-greenish-gray to dark-greenish-gray, grayish-brown, and maroon; a few beds of similar colored siltstone; sparse beds of limestone and dolostone. The Pumpkin Valley Shale conformably overlies the Rome Formation. The formation is approximately 350 feet thick. Harris (1964) identified the Pumpkin Valley Shale of Southwest Virginia as a formation within the Conasauga Group; however, because of similar lithologies it is often indistinguishable from the Rome Formation and the two formations commonly are mapped together. Rome Formation (Hayes, 1891). Siltstone, shale, sandstone, dolostone, and limestone. Siltstone and shale, greenish-gray and grayish-red, laminated to thin-bedded. Sandstone, micaceous, locally glauconitic, greenish-gray and reddish-gray, very-fine- to medium-grained, thin-bedded. Dolostone, light- to dark-gray, aphanic to medium-grained, thin-to massive-bedded, with ripple marks and mudcracks. Lime stone, argillaceous, very-light-gray to dark-gray, thin- to medium- bedded. Carbonate rocks range from sparse 1- to 2- feet-thick beds in western Scott County to discontinuous units as much as 50 feet thick which comprise 30 to 40 percent of the formation in western Russell and Washington counties (Evans and Troensegaard, 1991; Bartlett and Webb, 1971). Maximum recorded thickness is 1500 feet in the Clinchport area (Brent, 1963); although this may have included the Pumpkin Valley Shale. A complete thickness has not been determined because the lowermost part of the Rome Formation is normally absent due to faulting.

Juniata, Reedsville, Trenton, and Eggleston Formations (Ordovician) at surface, covers < 0.1 % of this area

Juniata Formation (Darton and Taff, 1896). Siltstone, shale, sandstone, and limestone. Siltstone, shale, and sandstone, locally calcareous, grayish-red, locally fossiliferous; with some interbeds of greenish-gray shale, quartzarenite, and argillaceous limestone. Cycles consisting of a basal, crossbedded quartzarenite with a channeled lower contact; a middle unit of interbedded mudstone and burrowed sandstone; and an upper bioturbated mudstone are commonly present north of New River (Diecchio, 1985). The Juniata Formation ranges from less than 200 to more than 800 feet in thickness. In southwestern Virginia the red, unfossiliferous, and argillaceous Juniata Formation is present in the southeastern belts. It is equivalent to the gray, fossiliferous, and limy Sequatchie Formation of western belts (Thompson, 1970; Dennison and Boucot, 1974). Even though the beds along Clinch Mountain, in Scott County, contain minor amounts of carbonate rock (Harris and Miller, 1958) the majority is grayish- red siltstone, which is typical of the Juniata Formation. Reedsville Shale. Refer to description under Ou. Trenton Limestone. Refer to description under Ou. Eggleston Formation. Refer to description under Ou.

Moccasin or Bays Formation through Blackford Formation (Ordovician) at surface, covers < 0.1 % of this area

Moccasin Formation, Bays Formation, Unit C, Unit B, and Unit A. Moccasin Formation (Campbell, 1894). Mudstone, shale, imestone, and sandstone. Mudstone and shale, dusky-red to dark-reddish-brown, calcareous, ripple-marks, and mud cracks common. Limestone, light-olive-gray, weathers very-light gray, aphanic with "birds-eyes", locally fossiliferous. The limestone generally is the middle member of the Moccasin southwest of Giles County. In eastern Giles County and northeastward a thin medium-grained, gray sandstone occurs near the base of the Moccasin. The thickness ranges from 0 in northern Alleghany County to about 600 feet in Scott County. Bays Formation (Keith, 1895). Siltstone, sandstone, mudstone, and limestone. Siltstone, grayish-red, olive- to light-olive-gray, locally calcareous, sandy in part. Sandstone, light-gray to yellowish-gray, fine- to very-coarse-grained, locally conglomeratic, calcareous. Mudstone, grayish-red, olive- to light-olive-gray, mudcracks common. Limestone, grayish-red to light-olive-gray, aphanic. Five distinct K-bentonites reported by Hergenroder (1966). Contacts are conformable except perhaps in Botetourt, Roanoke, and Montgomery counties. Thickness ranges from 105 feet north of Wytheville to 890 feet near Daleville in Botetourt County. From Scott and Washington counties to Highland County and northwest of the Pulaski and North Mountain faults, a multitude of stratigraphic names have been applied to the rocks between the Bays or Moccasin (above) and the Beekmantown or Knox (below). The lack of detailed geologic mapping, except in Scott and Giles counties, the restricted area of the two major stratigraphic studies (Cooper and Prouty, 1943; Kay, 1956), and the general disagreement as to mappability and correlation of units makes it impossible to apply specific stratigraphic nomenclature at this time. Therefore, the rocks are described as three packages of lithologies (from youngest to oldest): Unit C, Unit B, and Unit A. Unit C. Limestone, medium- to dark-gray, aphanic to fine-grained with thin, medium- to coarse-grained beds, argillaceous, nodular to planar-bedded, locally very fossiliferous. The following names have been applied to Unit C: Witten, Bowen, Wardell, Gratton, Benbolt, Chatham Hill, Wassum, Rich Valley, Athens, Ottesee, Liberty Hall, Fetzer, and Giesler. Unit B. Limestone, light- to dark-gray, aphanic to coarsegrained, black and gray chert nodules, carbonate mound buildups. This unit is characterized by grainstone with interbedded micrite and chert. The overlying Unit C is very argillaceous and lacks chert. The following names have been applied to Unit B: Wardell, Gratton, Benbolt, Lincolnshire, Big Valley, McGlone, McGraw, Five Oaks, Peery, Ward Cove, Rockdell, Rye Cove, Effna, Whitesburg, Holston, Pearisburg, and Tumbez. Unit A. Dolostone, light- to medium-gray, fine-grained, locally conglomeratic, cherty. Limestone, medium- to dark gray, fine-grained, locally cherty. Shale, light-gray to dusky red. A basal chert-dolomite conglomerate with clasts as much as cobble size is locally present on the unconformity surface. The following names have been applied to Unit A: Blackford, Elway, Tumbez, Lurich (lower part), and "basal clastics".

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).

Upper and Middle Ordovician Formations Undivided (Ordovician) at surface, covers < 0.1 % of this area

Includes: Oun, Ous, Ou, Om, Okpl, Oeln, Oml, Ols.

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

Some landslides with intact stratigraphic units in Giles County area. Includes: Dsu, Skrt, Sm. (Shrc?)