Geologic Unit: Bonneterre

Usage:

Bonneterre Dolomite (AR*,CO*,NE*,OK*, and KS*-subsurface)
Bonneterre Formation (IL*,MN,MO*)
Bonneterre Formation of Knox Group (IL-notably in southern part)

Subunits:

(alphabetical): Sullivan Siltstone Member (MO), Taum Sauk limestone (informal, unranked) (MO-local) [formerly †Tom Sauk Limestone Member], Whetstone Creek Member (AR,MO*,OK).

Geologic age:

Middle to Late Cambrian (early Croixan; Lincolnian to Millardan; Marjuman to Steptoean)*

Type section, locality, area and/or origin of name:

Named from exposures at Bonneterre [Bonne Terre], St. Francois Co., southeastern MO (US geologic names lexicons, USGS Bull. 896, 1200).
Principal reference section: excellent exposures in roadcut and adjacent natural river bluff immediately southeast of MO Route K Big River bridge, 2.3 mi east of junction of MO Route K and U.S. Route 67, 3.2 mi east of town of Bonne Terre, in SW/4 SE/4 sec. 8 (projected), T. 37 N., R. 5 E., [approx. Lat. 37 deg. 55 min. 36 sec. N., Long. 90 deg. 30 min. 05 sec. W.], Bonne Terre and French Village 7.5-min quadrangles, St. Francois Co., southeastern MO (Thompson and others, 2013; credited to K.R. Evans).
Reference section (upper part of formation): in roadcut on north side of MO Route K, just east of Terre Bleue Creek, 0.6 mi east of principal reference section, in S/2 SW/4 sec. 9 (projected), T. 37 N., R. 5 E., [approx. Lat. 37 deg. 55 min. 42 sec. N., Long. 90 deg. 29 min. 16 sec. W.], French Village 7.5-min quadrangle, St. Francois Co., southeastern MO (Thompson and others, 2013).

AAPG geologic province:

Anadarko basin*
Central Kansas uplift*
Chautauqua platform*
Cherokee basin*
Forest City basin*
Illinois basin*
Las Animas arch*
Lincoln anticline*
Nemaha anticline*
Ozark uplift*
Salina basin*
Sedgwick basin*
Sioux uplift
Upper Mississippi embayment