Glasgow University Exploration Society Expedition to Inishtrahull

Abstract

A GLASGOW University Exploration Society expedition to the island of Inishtrahull (lat. 55° 26′ N., long. 7° 14′ W.), which is 5 miles from the northern coast of Donegal, was made during June 23–July 4, 1967, under the leadership of John Smart. The rocks of the island have been both compared and correlated with the Lewisian gneisses of north-western Scotland^1,2, and the geological investigations carried out by the ten members of the expedition, under the direction of Dr D. R. Bowes and Dr A. M. Hopgood, are in continuation of Lewisian investigations being carried out in the Departments of Geology of the University of Glasgow and the University of St. Andrews. The island is approximately 1 mile long, in an E.N.E–W.S.W. direction with almost uninterrupted clean coastal exposures on a broad wave-cut platform or on accessible cliffs. Inland elevated parts (up to 141 ft. above sea level at the western end), with outcrops of gneiss and related rocks, occur on either side of a low central area. The island is less than 200 yd. across in part of this central area and the gneiss complex largely covered by postglacial bedded raised beach deposits (at approximately 40 ft. O.D.) and soil. On the high ground at the western end of the island stands the Inishtrahull Light.