clapper bridge

A simple stone bridge made by setting stone blocks at intervals across a river to act as supports for a series of stone slabs laid end to end across the top. Most surviving examples are found in the southwest of England, the best known being Tarr Steps on Exmoor, although they were formerly far more widespread. Often claimed as prehistoric because of their simplicity and rather primitive appearance, most clapper bridges in fact date to the period between the 14th and 19th centuries ad.