By Tim Jimenez

PHILADELPHIA (CBS) – A contractor, grinding a tree stump in Independence Square on Wednesday, made a not so routine discovery.

“You never know what you’re going to find walking around Independence National Historical Park, I’ll tell you that!” said Jane Cowley, park spokeswoman.

Park officials say the work was being done near the middle of Independence Square to grind a tree stump. Among the roots the contractor found an object that park officials believe is a cannon shot linked to a Civil War recruitment camp from 1862.

“It is 2.8 pounds, so not very heavy, and the diameter is just under 3 inches,” Cowley described. “It’s a round, spherical object, although it’s kind of beat up at this point. It’s been under the ground for about 150 years.”

As a precaution, the Philadelphia Police Department Bomb Squad checked out the object and says the public was never in danger. Now, park officials are studying the object. It is possible it is not a cannon shot but Cowley says they are confident it is and can be used as a window to Philadelphia during the Civil War.

“To figure out what it tells us, a little bit more about Independence Square, about the recruitment camp, Camp Independence, that sprung up in 1862. We knew that encampment was there but this will tell us a little bit more about what they were doing,” Cowley said.