From abstract: The Mineral Hill monazite deposits, 3 to 5 miles northeast of the town of Shoup, Lemhi County, Idaho, were investigated by the U. S. Geological Survey in July 1952. The deposits are replacement veins and lenses along shears in a pendant, principally of pre-Cambrian biotite gniess, about 4 to 5 miles in size and enclosed by granite of the Idaho batholith. The veins consist predominantly of calcite, monazite, and allanite, and contain minor quantities of barite, magnetite, rutile, and apatite.