Welsh Journals

A Shell-Marl Deposit in Montgomeryshire. By FROFESSOR W. J. Pugh, University College of Wales, Aberystwyth. A specimen of freshwater marl containing numerous gastropod and lamellibranch shells was forwarded for examination to Mr. T. W. Fagan, Adviser in Agricultural Chemistry in the University College of Wales, Aberyst- wyth. Mr. Fagan kindly showed the sample to me, and we visited the locality from which it had been obtained. As there are few records of the occurrence of such fresh- water marls in Wales, it appears desirable to give a brief description of the locality and of the deposits which are to be found there. The marl was obtained from an area of lacustrine alluvium, which is situated about half a mile south-east of the village of Castell Caereinion (4 miles west of Welshpool), and about 600 feet above sea level. This alluvial tract occupies a hollow or depression, which trends from south-west to north-east. It is about 1150 yards long and from 230 to 350 yards wide. The upper surface of the alluvium slopes very gently to the south- west, as indicated by the small stream, which flows through it to join the Luggy Brook (see fig. I). At the south-western end, there is a considerable area of glacial and fluvio-glacial deposits, and these extend north-westwards through the broad valley in which is located the village of Castell Caereinion. These glacial deposits are exposed at intervals, and they may be examined, for example, in the cuttings on the Welshpool- Llanfair Caereinion Light Railway, near Castell Caer-