Cannon sight marked "MARBLE SAFETY AXE CO. - GLADSTONE, MI./US RIFLED CANNON- 3 INCH ORDNANCE" on the base. Flip up aperture ladder sight marked for ball on the left side and shell on the right side with range markings below. Mounted to a brass plate.

Very fine, with attractively aged brass, and copper residue on the ladder. The ultimate rarity in Marble collectibles.