Volcanic vents at Longskelly Rocks and at Yellow Craig Plantation, west of North Berwick

Abstract

On the long stretch of coast between Weak Law and Longskelly Point there are a few interesting sections, but especially at the latter place, where evidence has been found pointing to the presence of a rather large volcanic vent, a great part of the area of which is much obscured by an extensive intrusion of basalt approaching monchiquite in type (see map, Fig. 1). Also at a place called Yellow Craig Plantation, a short distance inland from Longskelly Point, there is good reason to believe that a volcanic vent exists, either connected with the one on the shore, or separated from it (see map, Fig. 2). The deposits in connection with these vents, both on the shore and on the ground round about Yellow Craig Plantation, are mentioned in the Geological Memoir for East Lothian, 1910, p. 82, and are there regarded as beds of conglomerate containing boulders and fragments of trachyte and basalt, having occasionally an ashy appearance, and as being an upper representative of the sedimentary rocks lying above and in contact with the Markle basalt lava at Cowton Rocks. According to the map ( Geological Survey, East Lothian, 1910, p. 59), these rocks occupy in horseshoe form the southern edge of a shallow syncline which extends westwards from the Cowton Rocks, as far as and embracing Yellow Craig Plantation, and on the shore to the west of the Longskelly intrusion. The deposits on the shore at Longskelly, which occupy an area somewhat raised above the level of the