U.S. Geological Survey Home AASG Logo USGS HOME CONTACT USGS SEARCH USGS
National Geologic Map Database
Map showing publication footprint
  • Usage in publication:
    • West Ledge formation
  • Modifications:
    • First used
  • Dominant lithology:
    • Limestone
    • Slate
  • AAPG geologic province:
    • Midcontinent region
Publication:

Hosted, J.O., and Wright, L.B., 1923, Geology of the Homestake ore bodies and the Lead area of South Dakota; I: Engineering and Mining Journal, v. 115, no. 18, p. 793-799.


Summary:

Pg. 793-799, 836-843, with maps. West Ledge formation. Gray-green siliceous, chloritic, dolomitic limestone, grading into impure calcareous phyllite. Contains some cummingtonite and much white quartz. Usually weathers red from iron oxides. Thickness 100 feet. Underlies Northwestern formation and overlies Ellison formation. Mapped north and west of Lead, Lawrence Co. Age is Precambrian. Believed to be Keewatin age (Archean). Report includes geologic map.
Origin of name not stated, but occurs in Lead district, Lawrence Co., southwestern SD.

Source: US geologic names lexicon (USGS Bull. 896, p. 2309); supplemental information from GNU records (USGS DDS-6; Denver GNULEX).


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 ([ ]).

Accessibility FOIA Privacy Policies and Notices

USA Gov U.S. Department of the Interior | U.S. Geological Survey
Supported by the National Cooperative Geologic Mapping Program
Page Contact Information: Personnel
Page Last Modified: Thu 04 Apr 2024 04:12:48 PM MDT