520 report— 1878. 



As the last meeting of the Association in this city took place twenty-one years 

 ago, it would at first sight appear that in opening our proceedings I might with 

 propriety dwell on the progress which has been made within that period in the 

 development of the geology of Ireland. I must, however, remind you that it is 

 only four years since the Association held its meeting in what I may almost call 

 the neighbouring town of Belfast, when the accomplished chief of the Geological 

 Survey in Ireland presided over this section, and delivered an address in which 

 some of the more interesting features of the country, especially those of the 

 volcanic district of the north-east of this island, were discussed. During the 

 present year, moreover, he has published his comprehensive work on the Physical 

 Geology and Geography of Ireland, which I commend to you as far more likely to 

 call your attention to the characteristic features of the country and the latest 

 discoveries with regard to its geology than anything I could compile. 



In addition to this, there has appeared during the present year another inte- 

 resting volume, which records the impressions of a highly intelligent foreign 

 geologist on visiting this country. I mean the ' Aus Irland ' of Dr. Arnold von 

 Lasaulx, Professor of Mineralogy in the University of Breslau. For this volume, 

 in which shrewd remarks on the country and its inhabitants are mingled with 

 geological observations and valuable comparisons of the Irish formations with 

 those of other countries, we are indebted to the meeting of the British Association 

 having been held two years ago at Glasgow, which attracted the author to visit the 

 British Islands. 



So much having lately been published upon the geology of this country, I shall 

 content myself with making a very few general observations with regard to it, and 

 propose subsequently t J touch briefly on some of those questions which, within the 

 last twelve months, have occupied the attention of those who are engaged in the 

 advancement of our science. 



As to the geology of this country, I may observe that we are here assembled 

 just on the edge of that great central plain which forms so important a feature in 

 the map of Ireland, and which stretches from Dublin Bay on the east coast to 

 Galway Bay on the west, with hardly a portion of it attaining to an elevation of 

 three hundred feet above the sea, over a tract of country nearly one hundred and 

 fifty miles in extent in almost every direction. 



The boundaries of this great plain and those of the Carboniferous Limestone 

 almost coincide, so that we have here the somewhat remarkable feature of a forma- 

 tion which in England is of such a character as to have received the name of the 

 Mountain Limestone, constituting in the neighbouring island nearly the whole of 

 the plain country. In some of the north-western counties, however, as for instance 

 Fermanagh and Sligo, it assumes its more mountainous character. Nearly the 

 whole of this central plain is overlain with boulder clay, limestone gravel or middle 

 drift, and extensive bogs, so that the subjacent rock is but occasionally seen. In 

 several places detached bosses of Old Red Sandstone rise through the limestone, 

 and there is also good reason for believing, with Professor Hull, that the whole of 

 the area was at one time covered with the upper members of the carboniferous 

 group, including the true coal measures, of which unfortunately but small patches 

 remain, and those upon the margin of the plain. From the absence of the upper 

 Palaeozoic, Mesozoic, and Cainozoic formations over the area, Professor Hull has 

 arrived at the conclusion that the surface remained in the condition of dry land, 

 while that of England was being submerged beneath the waters of the sea, over 

 the bed of which nearly all these formations were deposited. To a certain extent, 

 however, he leaves it an open question whether some of the Mesozoic strata which 

 occur over the north-east of Ireland may not have been deposited over the centre 

 and south. The amount of denudation over this central area has, no doubt, been 

 such that the chances of even Professor Judd finding traces of these latter deposits 

 appear at first sight to be but small ; but whether the whole of this vast amount of 

 denudation is due to the wasting influence of rain, rivers and other sub-aerial agents 

 of erosion, is a question which I venture to regard as at all events open to discus- 

 sion. It appears to be the case that in some parts of the north of Ireland the 

 whole of the upper Carboniferous beds had been denuded before the deposition of 



