(34' x 20', IA-48-06) N. of Williamsburg, Hilton Township, Iowa County, IA. P Av. N. 2.3 miles from jct with I80 exit 220 N. of Williamsburg to the crib on the E. side of the road. (N41 43.244 W92 00.493) Photo by Jack & June Schmidt 6-18-12.