19 cannons believed from the Revolutionary War are found in the Savannah River

A cannon encrusted in rust and mud sits inside a warehouse operated by the Army Corps of Engineers in Savannah, Ga., on Thursday. It's one of 19 cannons discovered in the Savannah River since last year that experts believe date to the American Revolution. (Russ Bynum / AP)

SAVANNAH, Ga. — 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.