19 cannons in "amazing condition" found in Georgia river likely sunk during the Revolutionary War in 1779

A warehouse along the Savannah River is holding historical treasures that evidence suggests remained lost for more than 240 years - a cache of 19 cannons that researchers suspect came from British ships scuttled to the river bottom during the American Revolution.

The mud- and rust-encrusted guns were discovered by accident. A dredge scooping sediment from the riverbed last year as part of a $973 million deepening of Savannah's busy shipping channel surfaced with one the cannons clasped in its metal jaws. The crew soon dug up two more.

Archaeologists guessed they were possibly leftover relics from a sunken Confederate gunship excavated a few years earlier in the same area, said Andrea Farmer, an archaeologist for the Army Corps of Engineers. But experts for the U.S. Navy found they didn't match any known cannons used in the Civil War. Further research indicates they're likely almost a century older and sank during the buildup to the Revolutionary War's bloody siege of Savannah in 1779.