Usage:
Arco Hills Formation (ID*)
Geologic age:
Late Mississippian (Chesterian)*
Type section, locality, area and/or origin of name:
Type section (=reference section of Bluebird Mountain Formation): about 1 km east of town of Arco, Arco Hills, in N/2 NE/4 sec. 31, T. 4 N., R. 27 E., [in vicinity of Lat 43 deg. 38 min. 06 sec. N., Long. 113 deg. 17 min. 12 sec. W., Arco North 7.5-min quadrangle], Butte Co., ID. Named from Arco Hills, [Arco Hills 7.5-min quadrangle], Butte Co., ID (Skipp and others, 1979; Lat./Long. coords. from USGS GNIS database and ACME Mapper 2.0, accessed on Darwin's 200th birthday).
Reference sections (=reference sections of Bluebird Mountain Formation) --all in ID: (1) southern Lemhi Range, in SE/4 sec. 6, T. 6 N., R. 30 E., Butte Co.; (2) ridge east of East Canyon, southern Lemhi Range, in SE/4 sec. 36 (unsurveyed), T. 7 N., R. 29 E., Butte Co.; (3) north side of Skull Canyon, Blue Dome area, southern Beaverhead Mountains, in NW/4 NW/4 sec. 28 and NE/4 NE/4 sec. 29, T. 10 N., R. 30 E., Clark Co. (Skipp and others, 1979).
AAPG geologic province:
Montana folded belt*
Idaho Mountains province*
Snake River basin*
For more information, please contact Nancy Stamm, Geologic Names Committee Secretary.
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 conflicts with nomenclatural guidelines (CSN, 1933; ACSN, 1961, 1970; NACSN, 1983, 2005, 2021). May be explained within brackets ([ ]).