U.S. Geological Survey Home AASG Logo USGS HOME CONTACT USGS SEARCH USGS
National Geologic Map Database
Geologic Unit: Jemison
Search archives
Map showing publication footprint
  • Usage in publication:
    • Jemison chert*
  • Modifications:
    • Named
  • Dominant lithology:
    • Chert
  • AAPG geologic province:
    • Appalachian basin
    • Piedmont-Blue Ridge province
Publication:

Butts, Charles, 1926, The Paleozoic rocks, IN Adams, G.I., and others, Geology of Alabama: Geological Survey of Alabama Special Report, no. 14, p. 41-230.


Summary:

Named Jemison chert for Jemison, Chilton Co., AL. The Jemison is a calcareous bed, limestone or dolomite, known only by much chert along its outcrop. The chert is generally light gray or iron-stained, of dense texture, greatly sheared, jagged, and rough in its contours. Thickness ranges from 20 to at least 500 feet. In places is rests on Butting Ram sandstone member of Talladega slate, and in other places lies a short distance above that member. The Jemison is overlain by the Yellow Leaf quartz schist. The unit contains Oriskany fossils and is of Early Devonian age.

Source: GNU records (USGS DDS-6; Reston GNULEX).


Map showing publication footprint
  • Usage in publication:
    • Jemison Chert*
  • Modifications:
    • Revised
  • AAPG geologic province:
    • Piedmont-Blue Ridge province
Publication:

Higgins, M.W., Atkins, R.L., Crawford, T.J., Crawford, R.F., III, Brooks, Rebekah, and Cook, R.B., Jr., 1988, The structure, stratigraphy, tectonostratigraphy, and evolution of the southernmost part of the Appalachian Orogen, Georgia and Alabama: U.S. Geological Survey Professional Paper, 1475, 173 p., (incl. geologic map, scale 1:500,000)


Summary:

Jemison Chert of the Talladega Group is used in the Talladega thrust slice of the Rome thrust sheet in northern AL. Unconformably overlies the Butting Ram Sandstone. Age is Early and Middle Devonian.

Source: GNU records (USGS DDS-6; Reston GNULEX).


Map showing publication footprint
  • Usage in publication:
    • Jemison Chert*
  • Modifications:
    • Overview
  • AAPG geologic province:
    • Appalachian basin
Publication:

Rankin, D.W., 1994, Continental margin of the eastern United States; past and present, IN Speed, R.C., ed., Phanerozoic evolution of North American continent-ocean transitions: Geological Society of America, The Decade of North American Geology (DNAG), Continent-Ocean Transect Series, p. 129-218.


Summary:

Author follows Tull and others (1988) who discuss Early Devonian (Siegenian) fossils that help date Jemison Chert. [Report does not change age of Jemison.]

Source: GNU records (USGS DDS-6; Reston GNULEX).


Search archives

For more information, please contact Nancy Stamm, Geologic Names Committee Secretary.

Asterisk (*) indicates usage by the U.S. Geological Survey. Other usages by state geological surveys.

"No current usage" (†) implies that a name has been abandoned or has fallen into disuse. Former usage and, if known, replacement name given in parentheses ( ).

Slash (/) indicates name does not conform with nomenclatural guidelines (CSN, 1933; ACSN, 1961, 1970; NACSN, 1983, 2005). This may be explained within brackets ([ ]).