From abstract: A radioactivity survey of the Black Rock district in southern Yavapai County, Ariz, disclosed anomalous radioactivity in several localities, chiefly at the Abe Lincoln mine in sec. 11, T. 8 N., R. 3 W., about 14 road miles northeast of Wickenburg. The Abe Lincoln vein system occupies a fault zone which strikes N. 500 E. and dips from 780 to 870 NW. Moderate radioactivity is present at the Bracken property and at several other localities in the Black Rock district. The writers recommend re-opening the Abe Lincoln mine to permit a more extensive examination of the vein.