200 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [Jan. 22, 



removed from hollows and from low grounds in Ireland is manifest. 

 The excellent maps and sections of the Geological Survey, by show- 

 ing what is left, prove that a great deal has been removed ; but this 

 can best be seen on the ground. 



VI. In Antrim the hills left were shaped out of a late geological for- 

 mation, which was spread over a wide area between Mull and Deny. 

 At Red Bay, near Cushendal, in Antrim, at the sea-level, the rocks 

 washed by the sea are coarse red-sandstone beds dipping about S.E. 

 at a steep angle. I believe them to be New Red Sandstone. Their 

 strike extends inland S.W. In that direction the broken edges of the 

 beds of sandstone are covered unconformably by nearly horizontal 

 sheets of igneous rock, upon which rest beds of chalk, which are 

 covered by more sheets of igneous rock and ironstone. From marks 

 which I found amongst these igneous rocks, it is certain that they 

 were fluid and flowed as lava does, or the slag from a furnace. The 

 basalts of the Causeway and elsewhere are columnar, like the rocks 

 which flowed out of Sn Befell, in Iceland *. 



The chalk contains flints and fossils ; and it certainly was deposited 

 horizontally at the bottom of the sea, over a wide area. This whole 

 threefold series still lies nearly flat, or slightly inclined, upon the 

 sandstone edges which strike under the Antrim hills. This is an 

 old surface of denudation buried under newer rocks. 



The region has been faulted and has been undermined by waves, 

 so that cliffs abound along the coasts ; but it has also been ground 

 and "worn from above, so that iron ore and chalk crop out at points 

 widely separated and at different levels. In crossing the Antrim 

 hills, ironstone workings in the edges of flat beds appear on the turf 

 of rounded slopes, on opposite sides of glens and hills and " cols." 



They show that hollows have somehow been grooved out of flat 

 beds of chalk and basalt, whose thickness can be measured along the 

 escarpments next to the sea. From the hill-tops to the sandstones 

 is somewhat less than 2000 feet ; and that is a vertical measure of 

 solid rock which has been taken away in shaping the Antrim glens 

 and the Antrim hills, since the upper basalt was formed. 



Westwards from the Antrim hills, on the other side of Lough 

 Neagh, at about 40 miles from Eed Bay, is a hog- backed ridge called 

 Slieve Gallion (Mount Storm). The long axis of this ridge runs 

 about north and south ; it is about 1800 feet high, and it may be 

 eight or nine miles long. It is the most conspicuous hill in the 

 region. Up to 1200 feet the base of this hill is sprinkled or thickly 

 covered with the drift, which also covers all these low grounds. 

 Above the level of the drift it is easy to see that the bare body 

 of Slieve Gallion is made of beds of hard stratified metamorphic 

 rocks, dipping about northwards at a steep angle, and striking 

 westwards through the ridge. At the northern end, capping this 



groups of hills scored horizontally by ice. The problem is, -whether the Irish 

 hollows ever were filled with solid ice ; if so, to what height the ice-level rose, 

 and how far the ice-field extended during the last glacial period. 



* Rubbings and specimens of igneous surfaces were shown in illustration. 



