This stuff is even older than you are! ;)
Probably Yankee cannonballs.
Folly Beach is an island the Yankees used to try to retake Fort Sumter.
Impact shells are dangerous. Paper fuse and solid shot not so very dangerous. The solid shot is dead weight and on the paper shells once the gunpowder is removed they are safe.
Cannonballs are solid shot. The author probably meant to write “shells”, which are hollow balls filled with gunpowder and sometimes shot, set to explode with a fuse. They only had gun powder then. So it’s doubtful these were dangerous.
Ping
For all, it’s worth noting that many European local governments have EOD teams. They’ve fought a lot of big wars over hundreds of years.
Shot it back at Ft. Sumter?
Those shells can still kill.
http://www.foxnews.com/story/2008/05/02/virginia-man-killed-in-civil-war-cannonball-blast.html
Neat stuff. We go to Folly Beach when we visit in-laws near Charleston. There also were various sized cement-like pieces washed up all over the place.
Back in 1987, the bodies of Civil War soldiers were found on Folly Island. Most of them were from the 55th Massachusetts. Relic hunters had been given permission by the builders to search the area prior to construction being started. Here is a video about the discover and excavation:
Civil War African-American Soldiers from the 55th.Massachusett's on Folly Beach, S.C.
I have a copy of the field report completed on the recovery of the bodies by the University of South Carolina's Department of Archaeology (Columbia). The bodies were all reburied in the National Cemetery in Beaufort, S.C. The site of the 1863 winter camp was excavated from 1987-89, and a field report was completed by my friend Steven Smith from the University titled "The Best Ever Occupied...:Archaeological Investigations of a Civil War Encampment on Folly Island, South Carolina."