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Mineral Resources > Online Spatial Data > Geology > by state > Tennessee Geology

Geologic units in Grundy county, Tennessee

[Additional scientific data in this geographic area]

St. Louis Limestone and Warsaw Limestone (Mississippian) at surface, covers 2 % of this area

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.

Lithology: clay or mud; chert

Rockcastle Conglomerate (Pennsylvanian) at surface, covers 0.4 % of this area

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.

Lithology: conglomerate; sandstone; shale; coal

Pennington Formation (Mississippian) at surface, covers 9 % of this area

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

Lithology: shale; siltstone; sandstone

Monteagle Limestone (Mississippian) at surface, covers 11 % of this area

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

Lithology: limestone

Crab Orchard Mountains Group (Pennsylvanian) at surface, covers 66 % of this area

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.

Lithology: conglomerate; sandstone

Bangor Limestone and Hartselle Formation (Mississippian) at surface, covers 6 % of this area

Bangor Limestone - Dark brownish-gray limestone, thick-bedded. Thickness 100 to 250 feet; and Hartselle Formation - Thin-bedded, fine-grained sandstone and greenish-gray shale interbedded with coarse limestone. Thickness 0 to 60 feet.

Lithology: limestone; sandstone; shale

Gizzard Group including Warren Point Sandstone and Raccoon Mountain Formation (Pennsylvanian) at surface, covers 6 % of this area

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

Lithology: sandstone; shale; siltstone; coal