Welsh Journals

ICE AGE EVENTS IN SOUTH PEMBROKESHIRE BRIAN S. JOHN Three years ago this journal published a paper entitled "Glaciation and the West Wales Landscape" (Vol. 12, No. 3, March 1971). This dealt with the evidence from various parts of West Wales for the most recent stages of the Ice Age. It was noted that south Pembrokeshire seems to have been remarkably little affected by glaciation, for it has no fresh glacial drifts. It was suggested that the ice of the Last (Dewisland or Weichselian) Glaciation did not override the area at all. Since 1971 a number of papers have been published which have a bearing on this problem; this short note draws attention to these papers and assesses their significance. THE OFFSHORE EVIDENCE In an interesting article Garrard and Dobson (1974) summarise the results of studies from the University College of Wales, Aberystwyth, concerning the nature of sediments on the sea floor of Cardigan Bay and St. George's Channel. Close to the eastern coasts of Cardigan Bay there are "Welsh" glacial drifts and estuarine silts and clays, together with long submarine morainic ridges at Sarn Badrig, Sarn y Bwch, and Sarn Cyn- felyn. These mark the positions of glaciers which flowed south-westwards from the Welsh uplands during the Last Glaciation. Further out in Car- digan Bay, and covering most of the floor of St. George's Channel, there is a thick cover of Irish Sea till deposited by the Irish Sea Glacier (John, 1968; 1971). In places it is 70m thick, but it thins southwards until it is only 10m thick off the west Pembrokeshire coast. Here it is found only in a narrow tongue in the centre of St. George's Channel and it disappears completely to the south-west of the Smalls. This indicates that the Irish Sea Glacier of the Last Glaciation reached its southern limit to the west of Pembrokeshire, and did not flow into the Bristol Channel. It follows that it may not have covered much of central and south Pembrokeshire. Although the speculations of Garrard and Dobson are probably incorrect in some respects (particularly concerning the ice limit across Pembrokeshire, and the directions of ice movement on the north Pembrokeshire coast), their work is an extremely valuable supplement to the studies undertaken on land in West Wales. EVIDENCE FROM CALDEY ISLAND In 1973 the first preliminary results were published from an important new site on Caldey Island, discovered and excavated by Brother James and other enthusiasts (van Nedervelde and others, 1973). The site is a limestone cave called Ogof-yr-Ychen, which contains an Ice Age stratigraphy and animal and human remains and artifacts in several chambers. The work described so far is from Chamber 4 of the cave. The lowest deposit here is a yellow silty clay with rockfall fragments and animal remains including red deer antlers, hyena teeth and a rhinoceros scapula (Bateman, 1973). A radiocarbon date for the scapula was reported as 22,350 ± 620 years BP (Birm. 340). Only 30 cm above the rhinoceros scapula was an adinole scraper of Cresswellian type. From the combined evidence the authors of the note suggest that the silty clay layer is a Weichselain cold-climate