Discussion of “The ‘lost’ islands of Cardigan Bay, Wales, UK: insights into the post-glacial evolution of some Celtic coasts of northwest Europe” by Simon K. Haslett and David Willis

Abstract

can be relied upon to identify and date the lost lowlands of Cardigan Bay might be a matter for speculation. Such legends are far from unique. There are plenty of myths of lost lands and sunken cities around the British Isles, many supported by botanical and archaeological evidence of the large scale loss of real areas (Pennick 1987). One has only to consider Doggerland, the great land-mass between Britain and the continent that was finally submerged around 6500 BCE, or well-documented cases of settlements lost to storms and coastal erosion more recently such as Ravenser Odd at the mouth of the Humber, a prosperous port abandoned and overwhelmed in the midfourteenth century. However, it is abundantly clear that early maps, including the three cited by Haslett and Willis, cannot be used in the way they do to provide details of coastal erosion, still less to date the existence and disappearance of particular islands. Haslett and Willis attempt to use Ptolemy’s Geography (compiled ca. 150 AD) to argue that roughly 1900 years ago, the coast of Wales was some eight miles to the west of its current position. This is to misunderstand the original source completely. Claudius Ptolemy, based in Alexandria, did a brilliant job of pulling together disparate sources to produce a map of the known world. That map has not survived. What does survive are his instructions for making it, and a series of regional maps in the form of lists of coordinates or grid references. It is probable that the latitudes of a small number of Ptolemy’s places were located from astronomical observation. But no secure method existed for estimating longitude, and the position of most places given by Ptolemy from his sources would have been derived from statements of the approximate distance and direction between them (as in itineraries). For Britain, it may be that Ptolemy was using DISCUSSION