Forest Hill formation and Red Bluff clay

Forest Hill sand, cross-bedded fine gray sand, laminated fine sand and clay, and a little lignite; in Wayne and Clarke Counties lower part merges eastward into Red Bluff clay, blue-green glauconitic, gypsiferous, fossiliferous clay and thin limestone beds.
State Mississippi
Name Forest Hill formation and Red Bluff clay
Geologic age Oligocene
Lithologic constituents
Unconsolidated > Fine-detrital > ClayLaminated fine sand and clay and a little lignite.
Unconsolidated > Coarse-detrital > SandCross-bedded fine gray sand.
Sedimentary > Coal > LigniteLaminated fine sand and clay and a little lignite.
Sedimentary > Carbonate > Limestone (Bed)
Sedimentary > Chemical > Evaporite > Gypsum (Bed)Blue-green glauconitic, gypsiferous, fossiliferous clay and thin limestone beds.
Comments Secondary unit desrciption from USGS Lexicon website (MS002) and MS005: The Bumpnose Limestone, Red Bluff Clay, and Forest Hill Sand of the Vicksburg Group (State usage) are facies equivalent strata that grade into one another laterally and vertically. In general, the Forest Hill is composed of nonmarine to nearshore marine, dark, very fine to fine-grained sand, silt, and laminated carbonaceous clay with lignite beds near the top and bottom of the unit. The unit is 100 ft thick in central and western MS and thins to the east. In southwestern AL, strata correlative to the Forest Hill of MS have often been assigned to the Red Bluff Clay. At St. Stephens Quarry, Washington Co., AL, one of the easternmost exposures, unit consists of 8.8 ft of dark-brown blocky, carbonaceous, sparingly fossiliferous clay (Tew, 1992).

Moore, William Halsell, 1969, reprinted 1985, Geologic Map of Mississippi, Compiled by Bicker, A. R., Jr., a revision of the geologic map published by the MS Geological Survey in 1945 in cooperation with the USGS, revised from data submitted by Dr. E. E. Russell of MS State University from published reports of the MS Geological Survey and from field revisions, Mercury Maps Inc., Jackson, MS., scale 1:500,000.

USGS Geologic Names lexicon found at:

Tew, B.H., 1992, Sequence stratigraphy, lithofacies relationships, and paleogeography of Oligocene strata in southeastern Mississippi and southwestern Alabama: Alabama Geological Survey Bulletin, no. 146, 73 p.

NGMDB product
Counties Clarke - Hinds - Jasper - Madison - Rankin - Scott - Smith - Warren - Wayne - Yazoo