Clare Island Survey — Geology. 7 T 



these questions in mind, and, in order to become acquainted as far as 

 possible with the recent history of the area, studied the glacial phenomena 

 not only of Clare Island itself, but also of the country round Clew Bay. 



In this paper the observations of the previous workers in the district, 

 principally those of Kinahan and other officers of the Geological Survey, and 

 of J. F. Campbell and Maxwell Close, have been freely used, and whenever the 

 work of geologists of other lands has helped to throw light on the nature of 

 the more recent crustal oscillations that have taken place in the British area, 

 it has been laid under contribution. 



Previous writers on the glacial geology of Ireland have frequently referred 

 to evidences of ice-action occurring in the mountain districts of west 

 Connaught. Kinahan noted that Bengower, one of the Twelve Bens of 

 Counemara, a mountain 2184 feet high, situated about eight miles east of 

 Clifden, Co. Galway, was polished and ice-dressed to its summit. 1 

 J. F. Campbell, the author of " Frost and Fire," records numerous localities 

 in the western highlands where the rocks have been polished and grooved by 

 moving ice, and where morainic matter and perched boulders, foreign to the 

 underlying rocks, rest on glaciated surfaces. According to the latter 

 observer, the top of Shannaunnafeola, a mountain situated about six miles 

 south of Lough Nafooey, and two and a half miles west of Lough Corrib, 

 rising to a height of 2012 feet above Ordnance datum, is polished and grooved 

 by the passage of ice across its summit, and " looking towards the places at 

 which the grooves point, there is no higher land to account for this manifest 

 glaciation," 2 On three other hills of this neighbourhood, far apart, but still 

 within sight of one another, he noted similar ice-markings, and though 

 satisfied that these phenomena were not attributable to local ice, but 

 rather to some general glacial system, he believed that they were produced 

 by floating icebergs during a partial submergence of the Irish area. When 

 Campbell wrote his quaint but interesting book, the land-ice theory was as 

 yet undeveloped, so that it was only natural to find him calling in the aid of 

 floating ice to produce the groovings and polishings of the rocks that occur on 

 the summits of the mountains of Connaught, as well as to account for the 

 carriage of huge foreign boulders to situations where human or gravitational 

 agents were obviously not the means of transport. It is not necessary to 

 disouss here the merits of the land-ice theory ; it has been evolved from the 

 study of the work of existing polar ice-sheets, and is now very generally 

 accepted by geologists all over the world. 



1 " On the Drift in Ireland," Journ. Royal Geo]. Sou. Ireland, vol. i, p. 191, foot-note. 

 • '• Frost and Fire,"' vol. ii (1S65), p. 32. 



