Ansley made Twist and Damascus barrel guns in Baltimore -- http://www.foxcollectors.com/baltimore_gun_co.htm

Also, the 1905 Philadelphia Arms Co. Fox catalogue offers the option of Damascus barrels on Grade C and above, but I've yet to find a PAC Fox with Damascus barrels.

Then of course there were the George H. Fox side-swing hammer doubles made by the American Arms Co. at 103 Milk Street in Boston, and they were made with Twist, Laminated, Damascus and Bernard barrels.