A St. Augustine man came upon a unique archaeological find last year while digging through the dirt in his backyard to prepare a grave for his dog.
After being examined by law enforcement authorities this week, what the man assumed to be a rusty cannonball was determined to be a Civil War-era mortar, the kind used to propel explosive shells in warfare.
The resident, who lives on State Road A1A near Dondanville Road, approached an officer with the St. Johns County Sheriff’s Office who was in the area on another call Tuesday afternoon. The man showed the officer the find he’d kept stored in his yard after making the discovery about a year ago.
According to a police report, the mortar was described as a “spherical metal object with heavy corrosion,” weighing between 15 and 20 pounds and measuring 8 inches in diameter. Protruding from the surface were “two identical ports approximately 3 inches on either side.”
St. Johns County Sheriff’s Office Cmdr. Chuck Mulligan said that when his agency’s bomb squad was called to the scene they were able to match the appearance of the mortar with that of one dating from around the time of the Civil War.
“We have bomb technicians who have studied a wide variety of artillery,” Mulligan said.
What the bomb squad was not certain of was whether the missile could possibily still be active.
“We have to run tests to see if there might be gunpowder in or if it’s inert after all these years,” Mulligan said.
Bomb squad officers followed routines for encounters with potential explosives, loading the device into a steel vault and transporting it in the squad’s trailer for further examination.
When asked how common it would be to find a mortar from the 19th century in St. Augustine, Andrew Thomson, an archeological conservator with the St. Augustine Lighthouse and Maritime Museum, said, “It would actually be pretty uncommon for Florida because there wasn’t a lot of Civil War action in this area.”
Local historian Susan R. Parker agreed.
“It’s very interesting, because the only thing I am aware of was that there were some Union vessels offshore trying to block inlets here,” Parker said.
She suggested the possibility that the relic may have previously belonged to a collector, which also sounded plausible to Thomson.
“If you don’t keep up the proper treatment, it will become corroded and then people will ditch them [artifacts],” Thomson said.
As for where the siege mortar might find a home, Mulligan said after testing was complete the resident who found the relic would be asked if he wanted it or else it might be offered it to a museum.