Bull Ridge Member of Madison Limestone. Rocks previously included in Sacajawea Formation and Amsden Formation. Consists of brecciated limestone and dolomite in upper part, and reddish or yellowish, thin-bedded, silty dolomite, siltstone, and shale in lower part. Thickness 40 to 120 feet. Underlies Darwin Sandstone Member of Amsden Formation. Recognized in west-central Wyoming and Montana. Fossils. Age is Late Mississippian (early Meramec).
Type section: in valley of Bull Lake Creek, in SE/4 NW/4 NE/4 sec. 11, T. 2 N., R. 4 W., [Bull Lake West 7.5-min quadrangle], Fremont Co., west-central WY. Named from Bull Ridge, on south side of Bull Lake, [Bull Lake West 7.5-min quadrangle, Fremont Co., west-central WY].

Source: US geologic names lexicon (USGS Bull. 1520, p. 43); GNU records (USGS DDS-6; Denver GNULEX).

Bull Ridge Member of Madison Limestone. Name applied to rocks previously included in upper part of Mission Canyon Limestone, upper member of Madison Limestone, all or part of Brazer Limestone, Sacajawea Formation, strawberry beds, or basal part of Amsden Formation by various authors. Thickness 50 to 100 feet. Overlies main part of Madison. Underlies Darwin Sandstone Member of Amsden. Age is Late Mississippian.
Mapped in eastern part of quadrangle, Teton Co., WY.

Source: Modified from GNU records (USGS DDS-6; Denver GNULEX).

Bull Ridge Member of Mission Canyon Limestone of Madison Group. Recognized in Beartooth Mountains of northern Wyoming. Includes a lower unit of silty dolomite, siltstone, and shale that commonly contains the "upper solution zone" (carbonate breccia) at base, and an upper unit of limestone and dolomite partly or completely brecciated by collapse. Thickness 10 to 120 feet. Fossils. Age is Late Mississippian (early Meramecian); corals indicate DIPHYPHYLLUM zone.
(See also Sando, 1972, Wyoming Geol. Assoc., 21st ann. field conf. gdbk., p. 57-63.)

Source: Publication.

Pg. 11 (fig. 5), 14-15. Bull Ridge Member of Madison Limestone. Is uppermost member of Madison Limestone in northern Laramie Range, central eastern Wyoming. Lower part is platy, calcareous quartz siltstone or very fine- to fine-grained quartz sandstone containing thin interbeds of brecciated fine-grained limestone and dolomite, 3 to 39 feet thick; locally includes cherty, fine-grained dolomitic limestone breccia at base (=upper solution zone of north-central Wyoming). Upper part is mainly gray-weathering fine-grained limestone in beds 0.1 to 1 foot thick. Total thickness 5 to 51.5 feet. Conformably overlies Little Tongue Member of Madison, and unconformably underlies Pennsylvanian Darwin Sandstone Member of Casper Formation. Age is Late Mississippian (Visean; Meramecian). Bull Ridge Member of north-central Wyoming yielded fossils indicative of TEXANUS conodont zone; foram zones 10 and 11; coral zone IIIA.

Source: Publication.