The Igneous Rocks of the Coast of County Waterford

Abstract

I. Introductory. In a former paper on the Waterford coast 1 the Ordovician sedimentary beds and the contemporaneous lavas and tufts were described.- It is now proposed to give an account of the other igneous rocks which occur along the coast, on which I have been at work for the last seven years during repeated visits. The great complexity of their relations has been noticed by many observers, and while the following account does not claim to be exhaustive, an attempt is here made to determine the order and relations of the principal outbursts of volcanic energy and to describe some of t~he characters of the rocks. The bibliography of the Lower Palæozoic rocks of County Waterford has been given in detail in my previous paper. With regard to the igneous rocks, however, the papers by Weaver, 2 Jukes, 3 and Haughton 4 may be referred to, and the accounts by Mr. McHenry & Prof. Watts, 5 and Sir Archibald Geikie 6 may be specially mentioned The Geological Survey Memoir for Sheets 167, 168, 178 & 179 is a fund of information; and further reference to the igneous rocks will be found in papers by Haughton, 7 A. von Lasaulx, 8 and Dr. Hatch, 9 and in Mr. Teall's ‘British Petrography’ (pp. 248, 348). The description of the igneous rocks is here given in the first place according to the main petrological types. After having examined the available information as to the relations of these types, we shall be in a position to determine their age and the sequence