pont de pierre rudimentaire

CONT: In rocky regions stone was used for bridges. Piles of stone were placed at short intervals across the river, providing the bridge piers, and then a path from bank to bank was made by laying flat stone slabs across adjacent piers. A few stone bridges of this type, called clapper bridges, can still be seen in Dartmoor, England; however, they date only from the Middle Ages or even later.
OBS: ""Clam"" and ""clapper"" are Anglo-Saxon words denoting, respectively, timber and stepping-stones.