That's an interesting grave - thanks for posting! James A Cooper was a member of the Cooper family of Humboldt County, California. Their great-grandfather was a Scottish immigrant to British Columbia who came down the coast and set up a wheat mill near Eureka. Wiyot and Hupas burned it down a few times - mainly to get the flour! - but the family remained in the Eureka area. The 7th California was stationed in the west, primarily in Arizona, and was called the Gold Diggers because so many had been recruited from the mines around Sacramento. The Cooper family eventually acquired the property that now is Humboldt State Park and Ft Humboldt - they donated the property in the early 1920s to Eureka. There is a plaque set there noting Ft Humboldt and Grant's connection with it - the granite boulder it is set in is part of Medicine Rock, a sacred formation from Patrick's Point near Trinidad, CA blown up by miners.