Ordovician and older rocks of the Bayhorse area, Custer County, Idaho Hobbs, S. W. (Samuel Warren) 1911- creator author. Hays, William Henry 1922- author. Geological Survey (U.S.) issuing body. text bibliography vau 1990 monographic eng remote 1 online resource (v, 40 pages, 1 page of plates) : illustrations, maps (some color). by S.W. Hobbs and W.H. Hays. Title from title screen (viewed Aug. 20, 2014). Includes bibliographical references. n-us-id Geology Idaho Custer County Geology, Stratigraphic Ordovician Geology Geology, Stratigraphic Ordovician Geologic Period Idaho Custer County From 425 to 500 million years ago fast I 19.3:1891 I 19.3:1891 Ordovician and older rocks of the Bayhorse area, Custer County, Idaho Hobbs, S. W. (Samuel Warren), 1911- (DLC) 89600226 (OCoLC)20055844 U.S. Geological Survey bulletin ; 1891 https://purl.fdlp.gov/GPO/gpo67857 COP 140829 20211120174142.0 in00003797751 eng