During the past year several igneous erratic boulders have been noticed on the cliffs of South Pembrokeshire by Mr. A. L. Leach and myself, in situations where no such erratics were previously known, so that a record of the larger ones seems advisable; five of them being dealt with in the following paper. At Mewsford Point, near St. Govan's Head, there is a well-rounded boulder measuring 4 ft. 1 in. × 2 ft. 6 in. and about 2ft. 6in. high, weighing approximately 32 cwt., and visible from some distance because its outline and dark colour differ markedly from the surrounding crags of Carboniferous Limestone. It appears to be the southernmost igneous erratic boulder in Pembrokeshire, and hence is of more than usual interest.