Join Bill Harman for a walk to the Stone Arch Bridge, one of the largest and oldest railroad bridges built entirely of huge granite blocks without mortar. The bridge spans Stony Brook and is one of Westford’s most important historic sights. There is a large beaver dam here, and numerous waterfowl. The trail is mostly flat and easy to walk. Meet Bill at the parking area on Cold Spring Rd. For more information call Bill: 603-533-0325.