By Jim Melwert

PHILADELPHIA (CBS) — A covered bridge in Valley Forge National Historical Park sustained some pretty serious damage at some point Monday afternoon in what is being called a hit-and-run.

The “Knox Covered Bridge” carries Yellow Springs Road over the Valley Creek. Originally built in the mid-1800s, it carries about 2,000 cars per day. But the bridge is now closed indefinitely, after what’s described as a large vehicle hit it, destroying almost all of a masonry wall and:

“On the right side of the barn a 20-foot long section of the timber siding was severely damaged.”

PennDOT spokesman Gene Blaum who says it’s frustrating to see what he calls a cherished structure damaged like this by someone who then drives off.

“If we all just pay attention and drive safely and carefully these cherished relics of another transportation age in our state can be safely maintained.”

Blaum says it’s too early to guess how much repairs will cost.