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Map showing publication footprint
  • Usage in publication:
    • Bear Gulch limestone lentil
  • Modifications:
    • Original reference
  • Dominant lithology:
    • Limestone
  • AAPG geologic province:
    • Central Montana uplift
Publication:

Norton, G.H., 1956, Evidences of unconformity in rocks of Carboniferous age in central Montana, IN Foster, D.I., ed., Judith Mountains, central Montana: Billings Geological Society Guidebook, August 16-18, 1956, no. 7, p. 52-66.


Summary:

Pg. 58, 59 (fig. 5), 60 (fig. 6), 62. Bear Gulch limestone lentil of Tyler formation; Bear Gulch limestone member of Tyler formation. Overlain by Amsden sandstone. Removal of soluble beds (Heath gypsum) beneath this unit has caused a remarkable series of solution slump blocks in this area worthy of special study. [Age is Mississippian.]
Named from exposures in Bear Gulch [Bear Creek, in T. 14 N., R. 21 E.], Fergus Co., central MT; composite section in secs. 32 and 33, T. 14 N., R. 21 E., south of Forestgrove.
[Called Bear Creek on USGS Forestgrove 7.5-min quadrangle (Maughan, 1984).]

Source: Publication; US geologic names lexicon (USGS Bull. 1200, p. 250).


Map showing publication footprint
  • Usage in publication:
    • Bear Gulch tongue
  • Modifications:
    • Revised
  • AAPG geologic province:
    • Central Montana uplift
Publication:

Willis, R.P., 1959, Upper Mississippian-Lower Pennsylvanian stratigraphy of central Montana and Williston basin: American Association of Petroleum Geologists Bulletin, v. 43, no. 8, p. 1940-1966. [Available online, with subscription, from AAPG archives: http://www.aapg.org/datasystems or http://search.datapages.com]


Summary:

Pg. 1942 (fig. 2), 1953, 1954. Bear Gulch tongue of Cameron Creek member of Tyler formation. Bear Gulch referred to as tongue in Cameron Creek member. Consists of medium-bedded black dense limestone with a marine fauna. Age is Early Pennsylvanian (Morrow).

Source: Publication; US geologic names lexicon (USGS Bull. 1200, p. 250).


Map showing publication footprint
  • Usage in publication:
    • Bear Gulch Member*
  • Modifications:
    • Principal reference
  • Dominant lithology:
    • Limestone
    • Mudstone
  • AAPG geologic province:
    • Central Montana uplift
    • Powder River basin
    • Williston basin
Publication:

Maughan, E.K., 1984, Paleogeographic setting of Pennsylvanian Tyler Formation and relation to underlying Mississippian rocks in Montana and North Dakota: American Association of Petroleum Geologists Bulletin, v. 68, no. 2, p. 178-195. [Available online, with subscription, from AAPG archives: http://www.aapg.org/datasystems or http://search.datapages.com]


Summary:

Pg. 180 (fig. 2), 183 (fig. 4), 185, 187. Bear Gulch Member of Tyler Formation of Amsden Group adopted by the USGS. Chiefly medium-gray to dark-gray, laminated to thin-bedded argillaceous limestone and very calcareous mudstone. Thickness up to 210 feet (subsurface). Intertongues with Stonehouse Canyon Member of Tyler; Maughan and Roberts (1967) included these rocks in Stonehouse Canyon at Potter Creek dome where it is a thin limestone bed about 160 feet (50 m) above base of Tyler. Fossiliferous. Age is Early Pennsylvanian (Morrowan).
Type locality: along Bear Creek, in sec. 21, T. 14 N., R. 21 E., [approx. Lat. 46 deg. 57 min. 15 sec. N., Long. 109 deg. 03 min. 30 sec. W.], Forestgrove 7.5-min quadrangle, Fergus Co., central MT.

Source: Publication.


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Asterisk (*) indicates published by U.S. Geological Survey authors.

"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 ([ ]).