AN UNUSUAL GERMAN OVER-AND-UNDER FLINTLOCK BOX-LOCK SPORTING CARBINE with two-stage barrels each rifled with eight rectangular grooves and turned at the muzzle and intersection, the top barrel sighted and signed in cursive script on the top of the breech, plain iron action, sparsely carved figured walnut butt with simulated butt-plate, and wooden trigger-guard, cheek-piece, and iron sling swivels, by Pierre Greverath à Dyck, late 18th Century