Crews excavating the Capitol Visitor Center site have unearthed a large piece of wood dating back 65 million years, when the last of the dinosaurs likely roamed the earth.

The piece was found six weeks ago during excavation for one of 165 caissons that will support the center’s frame. Subsequent carbon dating indicated it has been around since the end of the Cretaceous Period.

Project planners didn’t anticipate unearthing much, even as they dug down more than 50 feet, because the East Front soil has been disturbed so many times in the past 200 years. (Landscape Architect Frederick Law Olmsted had 300,000 cubic yards of material and 400 trees removed in 1874 to level the area, and the site was subsequently excavated during the East Front expansion in 1958-62.) The only other major find has been a well under House Majority Leader Tom DeLay’s (R-Texas) office, that is believed to have been built in 1795 to facilitate the construction of the original House wing.

In an unrelated effort, Architect of the Capitol Alan Hantman told a group of House appropriators touring the site last week that he hopes to put together a time capsule for installation somewhere in the CVC, perhaps under the staircase leading from the subterranean center to the Crypt.

Hantman asked Reps. Jack Kingston (R-Ga.), Todd Tiahrt (R-Kan.) and Mark Kirk (R-Ill.), chairman and members of the Appropriations subcommittee on the legislative branch, respectively, to brainstorm items to include.

“It’s something that he’s brought forth rather informally at this point,” CVC spokesman Tom Fontana said. “Right now he’s just bringing the idea forward to Members.”

There have been four cornerstone ceremonies in the history of the Capitol, Fontana said, to mark the East Front extension, the addition of the new House and Senate chambers in the 1850s, the original Dome in 1824, and the first cornerstone in 1793.

“This would be in keeping with tradition,” he added.

More than 50,000 truckloads of earth now have been removed from the East Front. That translates to about 500,000 cubic yards and an almost continuous line of trucks since August 2002.

That digging has left a very large hole, which crews are quickly filling with steel columns that will form the skeleton of the 580,000-square-foot center.

At the same time crews are building the roof, other workers are laying portions of the floor slab, starting in the southwest quadrant of the site.