This lot includes a Mineral Plat Map of a Potosi, Montana Mining Claim, 1939, with handwritten additions presumably by another surveyor dated January 6, 1941. Titled, "Great Falls Land District PLAT of the claim of E. Roy Grigg known as the Granite Mountain No. 1, Granite Mountain No. 2, Granite Mountain No. 3, Washington, Lincoln, Grant, Roosevelt and Wilson Lodes In Potosi (Unorg.) Mining District, , Madison County, Montana. The map lists mining activity exploration to date including, "13 cuts, Two Tunnels, Three Shafts, One Stope, An Excavation and Common Improvements Consisting of Five Tunnels Value $17,818.00". Historical documents indicate this district and nearby districts yielded over $6 million, mainly gold but also appreciable amounts of silver, copper, and lead. This map is in amazingly good overall condition, age tanning, foxing noted, slight tears noted at top of sheet and fold creases. Measures 13.75"W x 19"L open, 7"W x 9"L folded.