From introduction: The principal objective of the program is to make detailed geologic maps of the areas in which important phosphate deposits in the Phorphoria formation occur. It is hoped that the maps will serve both as an aid in selecting possible sites for mining and as a basis for calculating reserves.

Abstract: The Murray area includes almost the whole drainage basins of Prichard, Eagle, and Beaver Creeks and is underlain by the pre-Cambrian Belt series which is subdivided, from oldest to youngest, as follows: Prichard formation (upper and lower parts), Burke formation, Revett quartzite, St. Regis formation, Wallace formation, and Striped Peak formation. The Belt series in this area is cut by many small monzonite stocks believed to be related to the Cretaceous Idaho batholith. This report describes only the lead-zinc mines. The lead-zinc production around Murray reached its peak in 1911 and 1912 when the Monarch, Edith Murray (Pontiac or Terrible Edith), Bear Top, Paragon, Black Horse, and Silver Strike mines were active. Many of these mines have produced ore intermittently since then, and the Jack Waite mine has been very active since about 1930.

Abstract: The fluorspar deposits near Meyers Cove, Lemhi County, Idaho, are localized along three groups of shear zones: one group strikes northeast and dips steeply northwestward, another strikes northeast and dips gently northwestward, and the third strikes northwest and dips gently southwestward. The country rocks are tuffs and flows of the Casto volcanics of Permian(?) age and the Challis volcanics of late Oligocene or early Miocene age. The known deposits are in a belt about 3 miles long and 2 miles wide and crop out at altitudes between 5,100 feet and 7,200 feet above sea level. The principal vein minerals are fluorite, chalcedony, and barite. The fluorite occurs as lodes, crusts around fragments of rock, and replacements of fine breccia. The lodes range in size from veinlets to vein zones several hundred feet long and as much as 20 feet wide and contain ore that ranges in grade from 40 percent to 85 percent CaF2; the average grade is about 50 percent CaF2.