Geologic Map of Tennessee

William D. Hardeman, State Geologist

Tennessee Division of Geology

Published by the Tennessee Division of Geology, 1966, at a scale of
1:250,000. The map was published in a series of four sheets as shown on
the map below.

The explanation on each map included the geologic unit code, formation
name, and a brief description of the geologic units mapped on that
sheet. The gis coverages of the geology are tagged with the geologic
unit codes as used on the published maps. The information published on
the explantaions for each of the geologic map sheets is included below.
Comments regarding differences in on the Explanations between sheets are
not on the published maps and are include in italics.

**West Sheet**

**Gulf Coastal Plain**

Quaternary

Qal Alluvial Deposits Sand, silt, clay, and gravel. In flood plain of
Mississippi River more than 100 feet thick; in smaller streams generally
less than 20 feet thick.

Ql Loess Clayey and sandy silt, gray to brown, massive. Maximum
thickness about 100 feet along bluffs of Mississippi River; thins
eastward. (Minimum mapped thickness 4 feet.)

Quaternary and Tertiary

QT High-level Alluvial Deposits Iron-stained gravel, sand, silt, and
clay; variable in thickness but generally less then 60 feet thick.

Tertiary

Tj Jackson (?) Formation Sand, with layers of gray clay, silt, and
lignite. Exposed only in bluffs along Mississippi River; thickness at
least 60 feet.

Tcw Claiborne and Wilcox Formations Irregularly bedded sand, locally
interbedded with lenses and beds of gray to white clay, silty clay,
lignitic clay, and lignite. Thickness more than 400 feet.

Tm Midway Group

Porters Creek Clay Pale-brown to brownish-gray, massive, blocky clay;
locally contains glauconitic sand. Thickness 130 to 170 feet.

Clayton Formation Glauconitic sand, argillaceous and locally
fossiliferous; at base in Hardeman County is an impure fossiliferous
limestone. Thickness 30 to 70 feet.

Cretaceous

Ko Owl Creek Formation Sandy clay, greenish gray, glauconitic,
fossiliferous; merges northward into unfossiliferous clays and sands.
Thickness 0 to about 40 feet.

Km McNairy Sand Predominantly sand, in places interbedded with silty
light-gray clays. Fine-grained sand at base, locally contains heavy
minerals. Thickness about 300 feet.

Kcc Coon Creek Formation Fossiliferous, micaceous sand, silty and
glauconitic; locally fossiliferous sandy clay at base. Sider­ite
concretions common in upper part. Thickness about 140 feet.

Kd Demopolis Formation Marl and calcareous clay, light-gray,
fossiliferous, locally glauconitic and sandy. Merges northward into
sands mapped as Kcc. Maximum thickness 180 feet.

Ks Sardis Formation Quartz sand and glauconite sand, argillaceous and
locally fossiliferous. (Mapped with Kcc north of Beech River.) Maximum
thickness 70 feet.

Kc Coffee Sand Loose fine-grained sand, light-gray, sparsely
glauconitic, locally interbedded with laminated lig­nitic clay. Thickness
25 to 200 feet; thins northward.

Ke Eutaw Formation Grayish-green sand, fine-grained, glauconitic,
micaceous; interbedded with gray laminated clays which commonly contain
carbonized or silicified wood. (Mapped with Coffee except in Hardin
County and southeastern Decatur County.) Thickness 0 to 180 feet; thins
northward.

Kt Tuscaloosa Formation Poorly sorted, light-gray chert gravel in a
matrix of silt and sand; locally interbedded with sand and clay lenses.
Thickness 0 to 140 feet.

**Western Valley of Tennessee River**

Mississippian

Msw St. Louis Limestone Residuum of nodules and blocks of chert in sandy
clay. (Originally grayish-brown, medium-bedded limestone.) Maximum
preserved thickness about 50 feet.

Warsaw Limestone Residuum of porous chert blocks in sandy clay.
(Originally gray, medium- to coarse-grained, thick- bedded limestone.)
Thickness about 60 feet.

Mfp Fort Payne Formation Bedded chert and calcereous and dolomitic
silicastone; minor coarse-grained limestone and shale. Thin green shale
(Maury) at base. Thickness about 200 feet.

Chattanooga Shale Black carbonaceous shale, fissile. Thickness 0 to 70
feet. *(Mapped as MDc on East-Central and East sheets.)*

Devonian

D Devonian Formations Characterized by marked north-south facies
variations. Because of pre-Chat­tanooga and/or pre-Cretaceous warping and
erosion, the distribution and thickness of Devonian for­mations is very
irregular.

Pegram Formation Thick-bedded, gray limestone and gray sandstone.
Thickness 0 to 15 feet.

Camden Formation Light-gray novaculitic chert and tripolitic clay; and
minor siliceous limestone. Thickness 0 to about 100 feet.

Harriman Formation Light-gray novaculitic chert and tripolitic clay; and
minor siliceous limestone. (Harriman and Cam­den are differentiated
paleontologically.) Thickness 0 to 50 feet.

Flat Gap Limestone Thick-bedded, coarse-grained limestone, gray with red
and brown grains. Thickness 0 to 55 feet.

Ross Formation Siliceous limestone; gray and variegated shale; and
medium-grained glauconitic limestone. Thick­ness 0 to 75 feet.

Silurian

S Silurian Formations A complete section of Silurian formations is not
common because of pre-Chattanooga and/or pre- Cretaceous erosion. Where
preserved, Silurian formations are remarkably uniform in thickness and
are characteristically light olive-gray to greenish-gray with variable
reddish-brown color in some areas.

Decatur Limestone Thick-bedded, medium- to coarse-grained limestone,
gray with reddish-brown grains. Thickness 0 to 70 feet.

Brownsport Group

Lobelville Formation Shale with thin beds of limestone. Thickness 0 to
40 feet.

Bob Limestone Thick-bedded, medium-grained limestone, locally oolitic.
Thickness 0 to 25 feet.

Beech River Formation Shale with thin beds of limestone. Thickness 0 to
60 feet.

Wayne Group

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, 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.

Brassfield Limestone Thin-bedded cherty limestone, locally glauconitic.
Thickness 0 to 20 feet.

Ordovician

O

Richmond Group

Mannie Shale Shale with thin beds of argillaceous limestone. Thickness 0
to 20 feet.

Fernvale Limestone Thick-bedded, coarse-grained limestone with
vari-colored grains. Thickness 0 to 20 feet.

Nashville Group

Hermitage Formation Gray shale and thin-bedded to laminated, sandy and
argillaceous limestone. Maximum exposed thickness 80 feet.

**West-Central Sheet**

**Highland Rim and Cumberland Plateau**

Quaternary

Qal Alluvial Deposits Sand, silt, clay, and gravel. As much as 60 feet
thick in flood plains of Tennessee and Cumberland Rivers; in smaller
streams generally less than 20 feet thick.

Quaternary and Ter.tiary

QT High-Level Alluvial Deposits Iron-stained gravel, sand, silt, and
clay; variable in thickness but generally less than 60 feet thick.

Cretaceous

Kc Coffee Sand Loose fine-grained sand, light-gray, sparsely
glauconitic; locally interbedded with laminated lig­nitic clay. Maximum
preserved thickness about 40 feet.

Ke Eutaw Formation Grayish-green sand, fine-grained, glauconitic,
micaceous; interbedded with gray laminated clays which commonly contain
carbonized or silicified wood. Maximum preserved thickness 80 feet;
absent to the north.

Kt Tuscaloosa Formation Poorly sorted, light-gray chert gravel in a
matrix of silt and sand; locally interbedded with sand and clay lenses.
Thickness 0 to 150 feet.

Pennsylvanian

Pco Crab Orchard Mountains Group Only the lowest formation of the group,
the Sewanee Conglomerate, is preserved in the area of this sheet.
Sewanee is gray to brown, medium- to coarse-grained conglomeratic
sandstone, with a thin zone of ferruginous quartz- and shale-pebble
conglomerate at base. Maximum preserved thickness 35 feet.

Pg Gizzard Group Sandstone, conglomeratic sandstone, siltstone, shale,
and minor coal. Thickness 100 to 200 feet.

Warren Point Sandstone Gray to brown sandstone and minor conglomeratic
sandstone. Thickness 60 to 160 feet.

Raccoon Mountain Formation Siltstone, sandstone, shale, and minor coal.
Thickness 0 to 65 feet.

Mississippian

Mp Pennington Formation Reddish and greenish shale and siltstone;
fine-grained dolomite; and minor fragmental and oolitic limestone.
Thickness 240 to 360 feet.

Mbh Bangor Limestone Dark brownish-gray limestone, thick-bedded.
Thickness 100 to 250 feet.

Hartselle Formation Thin-bedded, fine-grained sandstone and
greenish-gray shale interbedded with coarse limestone. Thickness 0 to 60
feet.

Mm Monteagle Limestone Fragmental and oolitic limestone, light-gray; and
fine-grained, brownish-gray limestone. Thickness 180 to 350 feet.

Msg St. Genevieve Limestone Gray limestone, slightly oolitic and cherty,
with some green shale and fine-grained sandstone. Max­imum preserved
thickness 70 feet. (In Western Highland Rim area only.)

Msw St. Louis Limestone Fine-grained, brownish-gray limestone, dolomitic
and cherty. Thickness 100 to 280 feet.

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

Mfp 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).

Chattanooga Shale Black carbonaceous shale, fissile. Thickness 0 to 70
feet; average about 20 feet. *(Mapped as MDc on East-Central and East
sheets)*

**Central Basin and Western Valley of Tennessee River**

Devonian

D Devonian Formations Characterized by marked north-south facies
variations and by very irregular distribution. Individual formations are
not uniform in thickness and have been truncated by pre-Chattanooga
erosion.

Pegram Formation Thick-bedded, gray limestone and gray sandstone.
Thickness 0 to 30 feet.

Camden Formation Light-gray novaculitic chert and tripolitic clay; and
minor siliceous limestone. Thickness 0 to about 100 feet.

Harriman Formation Light-gray novaculitic chert and tripolitic clay; and
minor siliceous limestone. (Harriman and Cam­den are differentiated
paleontologically.) Thickness 0 to 50 feet.

Flat Gap Limestone Thick-bedded, coarse-grained limestone, gray with red
and brown grains. Thickness 0 to 13 feet.

Ross Formation Siliceous limestone; gray and variegated shale; and
medium-grained glauconitic limestone. Thick­ness 0 to 75 feet.

Silurian

S 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.

Decatur Limestone Thick-bedded, medium- to coarse-grained limestone,
gray with reddish-brown grains. Thickness 0 to 70 feet.

Brownsport Group

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.

Beech River Formation Shale with thin beds of limestone. Thickness 0 to
60 feet.

Wayne Group

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.

Brassfield Limestone Thin-bedded cherty limestone, locally glauconitic.
Thickness 0 to 50 feet; generally about 20 feet.

**Western Valley of Tennessee River and Wells Creek Basin Structure**

Ordovician

> O Ordovician formations
>
> Mannie Shale Shale with thin beds of argillaceous limestone. Thickness
> 0 to 20 feet.

Fernvale Limestone Thick-bedded, coarse-grained, gray limestone with
varicolored grains. Thickness 0 to 30 feet.

Hermitage Formation Gray shale and thin-bedded to laminated, sandy and
argillaceous limestone. About 200 to 300 feet thick in Wells Creek
Basin; only about 80 feet exposed in Western Valley.

Carters, Lebanon, Ridley, Pierce,

and Murfreesboro Limestones Thin- to thick-bedded, cryptograined to
coarse-grained, yellowish-brown to olive-gray limestones. Thickness
about 1,000 feet. (Not exposed in Western Valley.)

OCk Wells Creek Dolomite Yellowish-gray and light olive-gray dolomite

and Knox Group withthin partings of grayish-green shale, and pale-
orange to yellowish-gray limestone; thin- to thick-bedded, micrograined
to coarse-grained. Present only in Wells Creek Basin. Exposed thickness
at least 600 feet. *(Also mapped with Onc on East-Central Sheet)*

Central Basin

Ou Ordovicion

Richmond Group

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.

Arnheim Formation Nodular, shaly, gray limestone. Thickness 0 to 20
feet.

Maysville Group

Leipers Formation Nodular, shaly limestone; fine- to coarse-grained
limestone; and phosphatic calcarenite locally. Thickness 0 to 150 feet.

Eden Group

Inman Formation Thin-bedded to laminated, fine-grained, gray limestone
with shale partings. Thickness 0 to 50 feet.

Nashville Group

Catheys Formation Nodular, shaly limestone; fine- to coarse-grained
limestone; phosphatic calcarenite; and light-gray cryptograined
limestone. Thickness 50 to 175 feet.

Obh 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.

Hermitage Formation Thin-bedded to laminated, sandy and argillaceous
limestone with shale; nodular shaly limestone; coquina; and phosphatic
calcarenite. Thickness 50 to 100 feet.

Stones River Group

Oca Carters Limestone Fine-grained, yellowish-brown limestone;
thin-bedded in upper part; thicker bedded and very slightly cherty with
scattered mottlings of magnesian limestone in lower part. Contains thin
bento­nite beds. Thickness 50 to 100 feet.

Olb Lebanon Limestone Thin-bedded, gray limestone with calcareous shale
partings. Thickness 80 to 100 feet.

Ord Ridley Limestone Thick-bedded, brownish-gray limestone,
fine-grained, with minor mottlings of magnesian lime­stone; slightly
cherty. Thickness 90 to 150 feet.

Opm Pierce Limestone Gray, thin-bedded limestone with shale partings.
Thickness 25 feet.

Murfreesboro Limestone Thick-bedded, dark-gray, fine-grained limestone,
with mottlings of magnesian limestone; some­what cherty in upper part.
Maximum exposed thickness 70 feet.

**Howell Structure**

Obr Ordovician Breccia Angular to subrounded fragments of limestone
ranging in size from a fraction of an inch to several feet.

**East-Central Sheet**

**Cumberland Plateau, Highland Rim, and Central Basin**

Quaternary

Qal Alluvial Deposits Sand, silt, clay and gravel. Mapped only in valley
of Cumberland River and in Elk Valley. Thick­ness generally less than 30
feet.

Pennsylvanian

Pcm Cross Mountain Formation Mostly shale, interbedded with sandstone,
siltstone, and thin coal beds; base at top of Frozen Head Sandstone.
Maximum preserved thickness 554 feet.

Pvm Vowell Mountain Formation Shale, sandstone, siltstone, and coal;
from Frozen Head Sandstone Member to Pewee coal. Thick­ness 230 to 375
feet.

Prm Redoak Mountain Formation Shale, sandstone, silicastone, and several
important coals; from Pewee coal to Windrock coal. Thickness 340 to 420
feet.

Pgg Graves Gap Formation Shale, sandstone, siltstone, and coal; from
Windrock coal to top of Pioneer Sandstone. Thickness 275 to 385 feet.

Pib Indian Bluff Formation Shale, sandstone, siltstone, and thin coal
beds; from Pioneer Sandstone Member to Jellico coal. Thickness 150 to
415 feet.

Psl Slatestone Formation Shale, sandstone, siltstone, and several
important coals; from Jellico coal to Poplar Creek coal. Thickness 500
to 720 feet.

Pcf 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.

Pco 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.

Pr 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.

Pg Gizzard Group Shale, siltstone, sandstone, and conglomerate; from
base of Sewannee Conglomerate to top of Mis­sissippian. Thickness 0 to
520 feet.

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.

Pcg Crab Orchard Mountains

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

Pf Fentress Formation Mostly dark-gray to light-brown shale, with minor
siltstone and sandstone. Wilder coal near mid­dle. Laterally equivalent
to entire Gizzard Group and all of Crab Orchard Mountains Group below
Rockcastle Conglomerate. Thickness as much as 340 feet.

Mississippian

Mp Pennington Formation Reddish and greenish shale and siltstone;
fine-grained dolomite; dark-gray limestone; and thin-bed­ded sandstone.
Persistent dolomite bed at base. Thickness 150 to 400 feet.

Mbh Bangor Limestone Dark brownish-gray limestone, thick-bedded.
Thickness 70 to 400 feet.

Hartselle Formation Thin-bedded, fine-grained sandstone interbedded with
gray shale; with oolitic and coarse-grained limestone beds locally.
Thickness 0 to 80 feet.

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

Msw St. Louis Limestone Fine-grained, brownish-gray limestone, dolomitic
and cherty. Thickness 80 to 160 feet.

Warsaw Limestone Mainly medium- to coarse-grained, gray limestone,
crossbedded. Includes much calcareous sand­stone and shale to the north.
Thickness 100 to 130 feet.

Mfp 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.

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)*

Silurian

S 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.)

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.)

Ordovician

Ou 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.)

Catheys Formation Nodular, shaly, thin- to medium-bedded limestone and
fine- to coarse-grained limestone. Thickness 125 to 400 feet.

Obh Bigby-Cannon Limestone Dark- to light-gray, dense to medium-grained,
medium- and even-bedded limestone. Thickness 80 to 150 feet.

Hermitage Formation Gray, fine-grained, thin-bedded to laminated, sandy
and argillaceous limestone; shale, weathers yellowish-brown; and
nodular, shaly limestone. Thickness 50 to 100 feet.

Oca Carters Limestone Fine-grained, yellowish-brown limestone;
thin-bedded in upper part; thicker bedded and very slightly cherty with
scattered mottlings of magnesian limestone in lower part. Contains thin
bento­nite beds. Thickness 60 to 250 feet.

Olb Lebanon Limestone Thin-bedded limestone, gray to yellowish-brown,
slightly dolomitic, with thin calcareous shale partings. Thickness about
100 feet.

Ord Ridley Limestone Medium- to very thick-bedded, fine- to
medium-grained, gray dolomitic limestone, with prominent greenish-gray
calcareous shale and shaly limestone unit in middle. Thickness 200 to
275 feet.

Opm Pierce and Murfreesboro Limestones Medium- to very thick-bedded,
fine-grained, gray limestone; thin-bedded, nodular and shaly,
greenish-gray limestone in places. Thickness 200 to 500 feet.

Onc Wells Creek Formation Gray limestone and dolomite, with angular
chert blocks and fragments; and minor shale, mottled red and green,
calcareous. Thickness 0 to 50 feet. (Present only in Sequatchie Valley.)

Knox Group (above Copper

Ridge Dolomite) Gray, cherty dolomite and limestone, fine- to
medium-grained. Maximum exposed thickness in Sequatchie Valley 600 feet.

*(Units in Onc are alos mapped as OCk on the West-Central Sheet)*

**Flynn Creek Structure**

Obr Ordovician Breccia Limestone and dolomite fragments ranging in size
from a fraction of an inch to several feet.

**Cumberland Plateau and Valley and Ridge**

MDSO Mississippian, Silurian, Devonian, Structurally complex area
containing all or portions

and Ordovician Formations of the Newman, Fort Payne, Chattanooga,
Rockwood, and Sequatchie formations.

Mississippian

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

Mn Newman Limestone Gray limestone sequence near Cumberland Plateau and
on Whiteoak Mountain. Shaly limestone, shale, siltstone, and sandstone
on Chilhowee Mountain. Thickness about 700 feet.

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

Mgg Greasy Cove Formation Gray argillaceous limestone, calcareous shale,
siltstone, and fine-grained sandstone. Equivalent to Newman Limestone.
Maximum preserved thickness about 400 feet.

Mg Grainger Formation Gray to green shale with siltstone and
fine-grained glauconitic sandstone; in some areas quartz-peb­ble
conglomerate. Thickness about 1,200 feet.

Mississippian and Devonian

MDc Chattanooga Shale Black carbonaceous shale, fissile. Thickness 20 to
30 feet in most areas; thickens abruptly to about 100 feet near east
edge of sheet. *(Mapped with Mfp on West-Central sheet)*

Silurian

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

Clinch Sandstone Clean, white, well-sorted sandstone; locally gray
siltstone and shale. Combined Rockwood and Clinch thicknesses about 700
feet.

Ordovician

Os Sequatchie Formation Maroon and gray shaly limestone, mottled
greenish; with interbeds of calcareous, olive to maroon shale and
siltstone. Average thickness about 200 feet.

Och Chickamauga Group 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.

Upper part of Chickamauga Group

Reedsville Shale Greenish-gray calcareous shale. Thickness 0 to 400
feet.

Unnamed Limestone Unit Medium-grained, fossiliferous, gray limestone,
shaly in part. Thickness as much as 600 feet.

Omlc Middle and Lower Parts of

Chickamauga Group A sequence of about 1,400 feet of limestone in the
northwest part of Valley and Ridge, which thick­ens and becomes more
clastic to the southeast and is divided into the formations shown at
right. Maximum thickness about 7,000 feet.

Moccasin 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, well-jointed claystone and siltstone, commonly
mottled greenish, evenly bedded; light- gray sandstone beds and
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.

Ock Knox Group

Onc

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.

Olc

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.

Ccr Copper Ridge Dolomite 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.

**Valley and Ridge and Unaka Mountains**

Cambrian

Cc Conasauga Group Mostly shale northwest of a line connecting Etowah
and Bearden (Knoxville); to the east it consists of the six formations
at right. Thickness about 2,000 feet.

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

Ccl

Cn 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 500 feet in the east to 900 feet in the west.

Cmr Maryville, Rogersville, and

Rutledge Formations Maryvile and Rutledge are gray limestone, in part
oolitic, with gray dolomite locally. Rogersville is green clay shale.
Thickness 400 to 1,000 feet.

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

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

Cs Shady Dolomite Light-gray dolomite and thinly bedded limestone with
much shaly gray limestone and calcareous gray shale. Thickness about
1,000 feet.

Chilhowee Group

Che Hesse Sandstone White, vitreous quartzite, medium- to
coarse-grained, occurs in massive ledges; Helenmode Mem­ber at top is
gray to greenish sandstone and shale. Thickness about 600 feet.

Cmu Murray Shale Shale, silty, sandy, dull-green to brown, micaceous.
Thickness about 500 feet.

Cnb Nebo Sandstone Medium-bedded, fine-grained, white vitreous
quartzite, in part feldspathic. Thickness 250 feet.

Cni Nichols Shale Olive-gray to green, silty and sandy, micaceous shale
and siltstone; local lenses of fine-grained feldspathic quartzite.
Thickness about 700 feet.

Cch Cochran Conglomerate Quartz-pebble conglomerate, gray pebbly arkose,
siltstone and shale; irregular bedding, scour fea­tures, crossbedding
common; maroon micaceous arkose and shale near middle and base.
Thickness about 1,200 feet.

Precambrian

pCw Walden Creek Group The formations at right, other than the Sandsuck,
are applicable mainly in the region of the Great Smoky Mountains.
Thickness about 8,000 feet.

pCss Sandsuck Formation Olive-green and gray, argillaceous, micaceous
shale with coarse feldspathic sandstone and quartz- pebble conglomerate.
Thickness about 2,000 feet.

Wilhite Formation Gray to green siltstone and slate with interbeds of
pebble conglomerate, sandstone, and quartzite. Thickness about 4,000
feet.

Shields Formation Massive conglomerate, sandstone, argillaceous slate;
conglomerate (pebbles of various rock types) characteristic. Thickness
about 1,500 feet.

Licklog Formation Feldspathic sandstone, greenish phyllite, and
bluish-gray slate. Thickness about 1,500 feet.

pCg Great Smoky Group Characterized by very massive layers of coarse
graywacke and arkose. The formations at right have been mapped only in
the region of the Great Smoky Mountains. Near Ducktown, in ascending
order, the Copperhill, Hughes Gap, Hothouse, and Dean Formations are
recognized. Thickness 14,000 to about 40,000 feet.

Anakeesta Formation Dark-gray, bluish-gray, and black slate with
dark-gray interbeds of fine-grained sandstone. Thick­ness 3,000 to 4,500
feet.

Thunderhead Sandstone Coarse, gray feldspathic sandstone, graywacke, and
conglomerate; occurs in massive ledges; graded bedding and blue quartz
characteristic. Thickness 5,500 to 6,300 feet.

Elkmont Sandstone Coarse to fine, gray feldspathic sandstone, graywacke,
and fine conglomerate; generally finer grained beds in lower part;
graded bedding typical. Thickness 1,000 to 8,000 feet.

Paleozoic (?)

ig Intrusive Igneous Rocks Metadiorite and metagabbro in Polk County,
intrude Great Smoky Group.

**East Sheet**

**Cumberland Plateau, Valley and Ridge, and Unaka Mountains**

Pennsylvanian

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

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

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

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

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

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

Pcf Crooked Fork Group Shale, sandstone, siltstone, and thin coal beds;
from top down group includes Poplar Creek coal, Wartburg Sandstone,
Glenmary Shale, Coalfield Sandstone, Burnt Mill Shale, Crossville
Sand­stone, and Dorton Shale. Thickness 200 to 450 feet.

Pcg Crab Orchard Mountains

and Gizzard Groups 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.

Mississippian

Mp Pennington Formation 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.

Mgg Greasy Cove Formation Gray, argillaceous limestone, calcareous
shale, siltstone, and fine-grained sandstone. Equivalent to Newman
Limestone. Maximum preserved thickness about 400 feet.

Grainger Formation Gray to green shale with siltstone and fine-grained
glauconitic sandstone; in some areas quartz-peb­ble conglomerate.
Thickness about 1,200 feet.

Mn Newman Limestone 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.

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

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

Mississippian and Devonian

MDc Chattanooga Shale 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)*

Devonian and Silurian

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

Silurian

Src

Sr 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.

Sc Clinch Sandstone Clean, white, well-sorted sandstone; locally gray
siltstone and shale. Average thickness about 600 feet.

**Northwestern Valley and Ridge**

Ordovician

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

OCk Knox Group Siliceous, well-bedded dolomite and magnesian limestone
in the central and northwest belts of the Valley. To the southeast, much
dark limestone is present and the rocks are only sparsely cherty.
Thickness about 3,000 feet.

Cambrian

Cc Conasauga Group 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.

**Southeastern Valley and Ridge and Unaka Mountains**

Upper Part of Chickamauga Group

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

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

Omb 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.

Reedsville Shale Greenish-gray calcareous shale. Thickness 200 to 400
feet.

Unnamed Limestone Unit Medium-grained, fossiliferous, gray limestone,
shaly in part. Thickness as much as 600 feet.

Omic Middle and Lower Parts of A sequence of about 1,400 feet of
limestone in

Chickamauga Group 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.

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.

OCk Knox Group

Onc

Ojb 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.

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.

Olc

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. Thickness about 800 feet.

Ccr Copper Ridge Dolomite 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.

Ccc Conococheague Limestone Well-bedded, ribboned (silt and dolomite),
dark-gray limestone; interbeds of fine-grained, light- to dark-gray
dolomite; sparingly cherty; cryptozoans typical. Thickness about 1,500
feet.

Cc Conasauga Group

Ccl

Ccu

Cmn 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.

Cn 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.

Chk Honaker Dolomite Dark-gray, medium-bedded dolomite with minor dark
limestone beds; locally cherty; cryptozoans abundant in places.
Thickness about 1,500 feet.

Cmr

Cm 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.

Crg 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.

Crt 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.

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

Cr Rome Foundation 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.

Cs Shady Dolomite Light-gray, well-bedded dolomite with thin- to
medium-bedded gray limestone; yellowish-brown residual clays with
"jasperoid" diagnostic. Thickness about 1,000 feet.

Cchi Chilhowee Group Conformable sequence of dominantly clastic
sediments. Thickness 3,000 to 7,500 feet.

Ce Erwin Formation White, vitreous quartzite, massive, with interbeds of
dark-green silty and sandy shale, minor silt­stone, and very fine-grained
sandstone. Thickness 1,000 to 1,500 feet.

Che Hesse Sandstone White, vitreous quartzite, medium- to
coarse-grained, occurs in massive ledges; Helenmode Mem­ber at top is
gray to greenish sandstone and shale. Thickness about 600 feet.

Cmu Murray Shale Shale, silty, sandy, dull-green to brown, micaceous.
Thickness about 500 feet.

Cnb Nebo Sandstone Medium-bedded, fine-grained, white, vitreous
quartzite, in part feldspathic. Thickness 250 feet.

Cni Nichols Shale Olive-gray to green, silty and sandy, micaceous shale
and siltstone; local lenses of fine-grained feldspathic quartzite.
Thickness about 700 feet.

Cch Cochran Conglomerate Quartz-pebble conglomerate, gray pebbly arkose,
siltstone and shale; irregular bedding, scour fea­tures, crossbedding
common; maroon micaceous arkose and shale near middle and base.
Thickness about 1,200 feet.

Ch Hampton Formation Dark greenish-gray, silty and sandy, micaceous
shale; numerous layers of medium-grained, felds­pathic, thinly bedded
sandstone. Thickness 500 to 2,000 feet.

Cu Unicoi Formation Sequence of gray feldspathic sandstone, arkose,
conglomerate, graywacke, siltstone and shale; greenish amygdaloidal
basalt flows near middle and base. Thickness 2,000 to 5,000 feet.

**Unaka Mountains**

Precambrian

pCo Ocoee Supergroup Terrigenous clastic sedimentary rocks, for the most
part poorly sorted and coarse. The groups at right are subdivided into
formations only in the region of the Great Smoky Mountains. Thickness as
much as 50,000 feet.

PCw Walden Creek Group The formations at right, other than the Sandsuck,
have been mapped only in the region of the Great Smoky Mountains.
Thickness about 8,000 feet.

pCss Sandsuck Formation Olive-green and gray, argillaceous, micaceous
shale with coarse feldspathic sandstone and quartz- pebble conglomerate.
Thickness about 2,000 feet.

Wilhite Formation Gray to green siltstone and slate with interbeds of
pebble conglomerate, sandstone, and quartzite. Thickness about 4,000
feet.

Shields Formation Massive conglomerate, sandstone, argillaceous slate;
conglomerate (pebbles of various rock types) characteristic. Thickness
about 1,500 feet.

Licklog Formation Feldspathic sandstone, greenish phyllite, and
bluish-gray slate. Thickness about 1,500 feet.

pCca Cades Sandstone Gray, well-bedded, fine- to medium-grained
feldspathic metasandstone, with interbeds of dark slate and
metasiltstone; precise stratigraphic position unknown. Thickness about
1,500 feet.

pCrb Rich Butt Sandstone Gray, massive beds of feldspathic, fine- to
medium-grained sandstone, with interbeds of dark slate and arkosic
conglomerate; exact stratigraphic position unknown. Thickness about
1,500 feet.

pCg Great Smoky Group Characterized by very massive layers of coarse
graywacke and arkose. The formations at right have been mapped only in
region of the Great Smoky Mountains. Thickness 14,000 to about 25,000
feet.

Unnamed Sandstone Unit Gray, coarse sandstone and fine conglomerate,
similar to Thunderhead Sandstone. Thickness about 4,500 feet.

Anakeesta Formation Dark-gray, bluish-gray, and black slate with
dark-gray interbeds of fine-grained sandstone. Thick­ness 3,000 to 4,500
feet.

Thunderhead Sandstone Coarse, gray feldspathic sandstone, graywacke, and
conglomerate; occurs in massive ledges; graded bedding and blue quartz
characteristic. Thickness 5,500 to 6,300 feet.

Elkmont Sandstone Coarse to fine, gray feldspathic sandstone, graywacke,
and fine conglomerate; generally finer grained beds in lower part;
graded bedding typical. Thickness 1,000 to 8,000 feet.

pCs Snowbird Group The formations at right are applicable chiefly in the
area of the Great Smoky Mountains. Thickness 13,000 to about 20,000
feet.

Pigeon Siltstone Laminated, greenish quartzose and feldspathic
siltstone; minor fine-grained gray sandstone. Thick­ness as much as
10,000 feet.

Roaring Fork Sandstone Interbedded massive feldspathic sandstone,
greenish siltstone, and greenish phyllite. Maximum thickness 7,000 feet.

Metcalf Phyllite Lustrous, pale-green and silvery sericitic and
chloritic phyllite; siltstone interbeds abundant. Thick­ness uncertain;
at least 5,000 feet.

Longarm Quartzite Feldspathic quartzite and arkose, conspicuously
light-colored, current bedded and crossbedded. Thickness about 5,000
feet.

Wading Branch Formation Medium- to dark-gray sandy slate to coarse,
pebbly feldspathic sandstone and graywacke; basal part is
quartz-sericite phyllite; graded bedding common. Thickness about 1,500
feet.

pCm Mount Rogers Group Metavolcanics, typically purplish and reddish;
massive lavas and tuffs, altered rhyolites and quartz latites; strongly
foliated; interbedded arkose, shale, and conglomerate. Thickness 1,000
to 3,000 feet.

pCba Bakersville Gabbro Metagabbro, dark, porphyritic; contains diorite,
basalt, anorthosite, and diabase; occurs as thin to massive dikes and
lenticular masses.

pCb Beech Granite Granite, porphyritic, light-gray to reddish; coarse
potash feldspar crystals and clustered interstitial mafics (chloritized
biotite and hornblende) give spotted appearance; includes Max Patch
Granite.

pCc Cranberry Granite Complex of intertonguing rock types including
migmatite, granitic gneisses, monzonite, quartz diorite, greenstone,
mica and hornblende schists, abundant granitic pegmatite.

pCr Roan Gneiss Layered hornblende and garnet gneiss and granitic
migmatite with zones of mica schist and amphibolite, foliation commonly
contorted; contains numerous granitic and gabbroic dikes.

Paleozoic (?)

ig Intrusive Igneous Rocks Mica peridotite plugs (two in Union County),
intrude Sneedville Limestone; metadiorite and met­agabbro sills and dikes
in Sevier County, intrude Great Smoky Group.