Note 72 — Chapter XXX · THE CARBONIFEROUS VOLCANOES OF IRELAND

This is the thickness given in the Explanation to Sheet 144 of the Geological Survey of Ireland, p. 8. A still greater thickness is claimed in Explanation to Sheet 154, p. 8.

[73] See especially Explanations of Sheets 143, 144, 153 and 154, Geol. Surv. Ireland (1860, 1861). The geology of the district had been previously noticed by earlier observers, to whose writings reference is made on p. 26 of the Explanation of Sheet 144. See also Jas. Apjohn, Journ. Geol. Soc. Dublin, vol. i. (1832), p. 24; Prof. Hull, Geol. Mag. for 1874, p. 205. Jukes (Student's Manual of Geology, 2nd edit. 1862, p. 325) gave subsequently an excellent epitome of the volcanic history. The microscopic structure of some of the Limerick volcanic rocks has been described by Mr. Allport, Quart. Journ. Geol. Soc. vol. xxx. (1874), p. 552, and by Prof. Hull, Geol. Mag. for 1873, p. 153. See also Mr. Watts' account of these rocks in the Guide to the Collections of Rocks and Fossils (Dublin, 1895), p. 93.