Description:The lower lock (of five) on the Caldon Canal at Stockton Brook. These locks lift the canal to its summit level. The lock overflow is at the left edge of the photograph and Stockton Brook waterworks is just to the left behind the trees. The Caldon Canal is a branch of the Trent & Mersey Canal, linking Etruria with Froghall (18 miles) to carry limestone, coal and ironstone.