Antrim Shale

Antrim Shale
State Michigan
Name Antrim Shale
Geologic age Late Devonian
Lithologic constituents
Sedimentary > Clastic > Mudstone > Shale > Black-shale (Bed)
Sedimentary > Carbonate > Limestone (Bed)
Comments Secondary unit description from USGS Geologic Names lexicon (ref. MI016): The Antrim is dark gray or brown to largely black, highly carbonaceous, thinly laminated shale with meager fossil content except for profuse algal spores. Large dark brown, bituminous and pyritic limestone concretions occur in the lower Antrim and are typically from 9.6 to 1.5 m in diameter.

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 found at:

NGMDB product
Counties Alcona - Alpena - Antrim - Benzie - Berrien - Charlevoix - Cheboygan - Emmet - Grand Traverse - Kalkaska - Leelanau - Lenawee - Macomb - Manistee - Monroe - Montmorency - Oakland - Oscoda - Otsego - Presque Isle - Saint Clair - Sanilac - Washtenaw - Wayne