On Aug. 8, 1860, the USS Mohican fired a shot across the bow of the slave ship Erie that held 897 forced onto it at Shark’s Point, the Congo River, West Africa.  Care of these was given over to the American Colonization Society in Liberia (note certificate). 30 Africans died from ill treatment and bad conditions on Gordon’s ship. If not rescued, twice that number would’ve died aboard.
American Colonization Society membership certificate can be found at
http://memory.loc.gov/cgi-bin/query/r?ammem/mjm:@field(DOCID+@lit(mjm018373))