Berea Sandstone (MIDb;0)

State	Michigan
Name	Berea Sandstone
Geologic age	Late Devonian
Original map label	Db
Comments	Secondary unit description from USGS Geologic Names lexicon (ref. MI016): Bedford Shale and Berea Sandstone are not exposed in MI. They record, in the subsurface, a southwestward growth of a deltaic system into the Antrim sea during Kinderhookian time. The Berea attains a thickness of 79 m in Huron Co. but thins northwestward, westward, and southwestward away from the thumb area and is absent in the eastern half of the Michigan basin. Unit is generally 15 to 30 m throughout its extent. Consists predominantly of light gray sandstone that is fine grained in the lower and upper parts of the formation but medium to coarse grained in the middle. It is silty and pyritic in its lower part.
Primary rock type	sandstone
Secondary rock type	siltstone
Other rock types
Lithologic constituents	Major Sedimentary > Clastic > Sandstone (Bed) Incidental Sedimentary > Clastic > Siltstone (Bed)
Map references	Milstein, Randall L. (compiler), 1987, Bedrock geology of southern Michigan: Geological Survey Division, Michigan Dept. of Natural Resources, scale= 1:500,000
Unit references	Milstein, Randall L. (compiler), 1987, Bedrock geology of southern Michigan: Geological Survey Division, Michigan Dept. of Natural Resources, scale= 1:500,000 USGS Geologic Names Lexicon (GEOLEX) [http://ngmdb.usgs.gov/Geolex/]
Geographic coverage	Lenawee - Livingston - Macomb - Oakland - Saint Clair - Sanilac - Washtenaw - Wayne