Natural Tunnel is another spectacular karst feature found in the carbonate rocks of western Virginia. The tunnel is now part of the Virginia State Park System.
(Photograph by Robert Whisonant.)
Natural Tunnel formed in carbonate rocks (limestone and dolomite) of early Ordovician age. The rocks here are about the same age as the rocks that make up Natural Bridge. Much younger solution has dissolved away the rocks, creating the opening we now call Natural Tunnel. (Photograph by Phyllis Newbill)
Natural Tunnel has been used by trains since the late 1800s. These photographs show the Norfolk and Southern railroad tracks that now pass through the tunnel. (Left: photograph by Robert Whisonant; right: photograph by Phyllis Newbill)