Geologic units in Morgan county, Tennessee

Additional scientific data in this geographic area

Crooked Fork Group, including Wartburg Sandstone, Glenmary Shale, Coalfield Sandstone, Burnt Mill Shale, Crossville Sandstone, Dorton Shale (Pennsylvanian) at surface, covers 42 % 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.

Rockcastle Conglomerate (Pennsylvanian) at surface, covers 32 % of this area

Conglomeratic sandstone and sandstone, gray to brown, fine- to coarse-grained. Thin coal-bearing shale locally present near middle. Thickness 150 to 220 feet.

Slatestone Formation (Pennsylvanian) at surface, covers 11 % of this area

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

Crab Orchard Mountains Group, including Rockcastle Conglomerate, Vandever Formation, Newton Sandstone, Whitwell Shale, and Sewanee Conglomerate (Pennsylvanian) at surface, covers 4 % of this area

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

Indian Bluff Formation (Pennsylvanian) at surface, covers 4 % of this area

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

Redoak Mountain Formation (Pennsylvanian) at surface, covers 2 % of this area

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

Graves Gap Formation (Pennsylvanian) at surface, covers 2 % of this area

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

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

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

Cross Mountain Formation (Pennsylvanian) at surface, covers 0.6 % of this area

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

Crab Orchard Mountains and Gizzard Groups (Pennsylvanian) at surface, covers 0.5 % of this area

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

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

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

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

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

Sequatchie Formation (Ordovician) at surface, covers < 0.1 % of this area

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