The Ben Bulben District

Abstract

THE region lying north of Sligo, which was visited by a large party of naturalists last July on the occasion of the fourth triennial conference of the Naturalists' Field Clubs of Ireland, is one of much beauty and interest. In its general aspect it recalls the best features of the Yorkshire Carboniferous Limestone area. Its setting, with the great limestone plain of Ireland stretching away on one hand, and the Atlantic Ocean on another, adds a dignity and impressiveness to this group of cliff-rimmed, flat-topped hills which might not be bestowed by their height alone, though they are of no mean elevation (Truskmore, the highest point, rises to 2113 feet). The Ben Bulben range, which derives its name from that of one of its spurs which projects boldly towards the Atlantic, represents the wreck of the Upper Limestone of this district. The fertile undulating low grounds all around are occupied by a lower and more argillaceous series, through which one of the old Caledonian folds of Ireland projects as a knobby ridge, its rugged outlines forming a charming contrast with the green and grey tabular forms of the limestone. The Upper Limestone, 700 feet or 800 feet thick, massive and strongly jointed vertically, rests on the lower series as a cliff-bound plateau, intersected by several grand glens, which are cut through the limestone deep into the less resisting rocks underneath. The mural precipices are the result of the characteristic weathering of the massive limestones. Below them, where not obscured by talus, the Middle Limestones and shales fall away in steep concave slopes into the plain. The exquisite valleys of Glencar and Glenade cut right through the plateau, the first in an east and west direction, the other north and south. Each is from one to two miles wide from cliff-top to cliff-top, and about a thousand feet deep (Fig. 1). The floors of these valleys are undulating, and the scenery is much enhanced by the fact that each embosoms a lake at the point where the cliff scenery reaches its best.