In the last 30 years salvages of four US shipwrecks, two of them deep water, have greatly expanded our knowledge of Gold Rush and Civil War era coinage. The most prolific by far of these shipwrecks is the SS Central America, a sidewheel steamer lost in September 1857 en route from Panama to New York City with a great treasure of Gold Rush gold. Found in 1.5 miles of water off Georgia, she was first salvaged in 1988 and again in 2014. Eight years later (1865) another sidewheel steamer, the SS Republic, was lost with a large shipment of mostly Philadelphia gold being sent from New York to New Orleans to help revive the war-ravaged Southern economy. The SS Republic was found in August 2003 in 500 meters of water.
That same year (1865) yet another sidewheeler, the SS Brother Jonathon, came to grief along the North California coast, carrying a significant quantity of San Francisco mint gold for Federal officials in the Northwest. The Brother Jonathon was found in 1996.
Finally, in 2007, A famous Gulf wreck was located off Lousiana. The SS New York was a paddle steamer lost in September 1846.