Short contribution: Marine erosion and archaeological landscapes: A case study of stone forts at cliff‐top locations in the Aran Islands,Ireland

Two massively constructed stone forts exist on the edge of vertical coastal cliffs on the Aran Islands, Ireland. One of these, Dun Aonghusa, contains evidence of occupation that predates the main construction phases of the walls and broadly spans a time interval of 3300–2800 yr B.P. The other fort, Dun Duchathair, has been termed a promontory fort because its remaining wall crosses the neck of a small promontory marginal to the cliffs. Estimates of past rates of marine erosion in this part of Ireland may be made both by analogy with studies in other areas and comparison with present day rates of marine erosion. A working model for erosion rates of approximately 0.4 m of coastal recession per annum is suggested. By applying this rate to the cliffs of the Aran Islands, it can be shown that, assuming a construction date of approximately 2500 yr B.P. for these forts, they were originally built at a considerable distance from the coastline. Thus Dun Duchathair was not a promontory fort. The earliest recorded habitation at Dun Aonghusa, dated to the middle of the Bronze Age, was, therefore, at some distance inland and not on an exposed 70 m high cliff on the edge of the Atlantic Ocean. © 2004 Wiley Periodicals, Inc.