n 2 [Proc. B.N. P.O., 



while above the amphitheatre some members of the party had a 

 lesson in the art of using abusive language from a pair of Peregrine 

 Falcons. In the afternoon the path below the cliffs was followed, 

 while visits were paid to the Grand Causeway, the Loom, the 

 Organ, &c, under Mr. W. A. Traill's guidance. 



In the evening Dr. A. R. Dwerryhouse gave a short lecture 

 on the geological features of the N.E. of Ireland. 



FEATURES OF LOCAL GEOLOGY. 



Dr. Dwerryhouse said — The general structure of the north 

 of Ireland is a counterpart of that of Scotland, the Highlands 

 of Donegal being a continuation of the rocks and structures of 

 the Central Highlands of Scotland, while the Ordovician and 

 Silurian rocks of County Down are strikingly similar to those 

 of the Southern Uplands of Scotland both in lithology and 

 arrangement. 



The oldest rocks of the district belong to the Dalradian 

 Series of Geikie, and consist of gneisses and schists with inter- 

 calated beds of crystalline limestone and quartzite. 



These Dalradian rocks form the wild country of the north- 

 west of Ireland, and extend into Derry and Tyrone. They also 

 crop out from beneath the covering of newer rocks in an area 

 extending from Ballycastle to the neighbourhood of Cushendall, 

 in Antrim. Their general strike is " Caledonian," that is to say, 

 N.-E. to S.-W. The limestones occur in many parts of Donegal, 

 as in Inishowen, and at Torr Head, in Antrim. 



Except in the south-eastern part of the area, which was not 

 visited during the excursion, the next recognisable series is that 

 of the Old Red Sandstone, which, as in Scotland, consists of 

 conglomerates and sandstones, usually of a dark red colour. It 

 rests unconformably on the Dalradian. 



These conglomerates are often of very course texture, their 

 most conspicuous boulders being of quartzite, many of which are 

 more than a foot in diameter, and were probably derived from the 



