III.—An Irish Augitite

Abstract

When writing my paper “On the Igneous Rocks of the South of the Isle of Man,” I was led to compare a Manx melaphyre, from Scarlet Point, with a rock described by Prof. E. Hull as a melaphyre, occurring at Ballytrasna, near Limerick, and belonging to the “Upper Trap-band,” a little below the basal shales of the Coal-measures. Through the kindness of Prof. Hull, a chip of the rock was sent to me by the Irish Geological Survey. The specimen was black and basaltic-looking. I did not obtain satisfactory sections of it in time for my paper, but have since had excellent ones made. On examining them I was immediately struck by the resemblance of the rock to the augitite of Paschkapole, between Velmin and Boreslau, in Bohemia, with a section of which I compared it. Professor Hull describes the rock of Ballytrasna as containing “numerous large crystals and groups of banded felspar”; but I failed to find a single felspar in four sections, nor did I observe any in Allport's section, No. 1902, from the same locality, which agrees with my sections.