A New Orleans investment firm has begun marketing gold coins from a 300-year-old shipwreck discovered off Florida’s coast. Blanchard and Co. is one of two dealers offering the coins from an area where 11 treasure-laden ships of a Spanish fleet were smashed onto reefs by a hurricane on July 31, 1715. The other dealer is California-based Monaco Rare Coins. John Albanese, a New Jersey-based coin expert who brokered the sales, said in an interview Friday that most of the 295 coins being offered were found by divers exploring the area last year on the 300th anniversary of the disaster.