368 MAJOR A. R. DWElUtYHOUSE ON THE [vol. lxxix, 



The boulder -clay contains numerous pebbles of quartzite derived 

 from the Old lied Sandstone cong'lomerates, also basalt, schist,. 

 vein-quartz, Cushendun quartz-porphyry, purple porphyrite of 

 Cushendall, flint and chalk, and even Ailsa Craig eurite. 



Flint- and quartzite-boulders occur on the summit of the col 

 between Trostan and Crockalough. The Scottish ice undoubtedly 

 passed over here into the upper part of Glenariff, and thence over 

 the lower col (950 feet) above Parkmore Station into Glenravel. 



Grlenariff. — Glenariff, the largest and most magnificent of 

 the Glens of Antrim, possesses extremely steep slopes, and the 

 river flows for a considerable distance through a narrow gorge cut. 

 in the basalt. Drift-sections are not so frequent in this valley as 

 in those on the north ; but such as there are show material similar 

 to that in Glenballyemon, although boulders of schist are much 

 less frequent. 



G-lenariff, in common Avith the more northerly glens, was com- 

 pletely filled with the Scottish ice, and the great moorland on the 

 south-east (many square miles of which lie above the 1000-foot 

 contour) was also overridden. 



These great glens show very few lacustrine phenomena, nor are- 

 there many overflow-channels, and such as exist are of small size. 

 One of some interest lies at the foot of Glenaan, and carries the 

 Glenaan River into the Dall River. 



Between Gruig Top and Cross Slieve is a wide, open valley, 

 comparable in size with Glenaan, and this formerly carried the 

 Glenaan River, which in pre-Glacial times was a tributary of the 

 Glendun River. The upper part of this valley east of Knockbane 

 is now streamless, and even at its northern end it carries but a 

 tiny stream formed by the confluence of small tributaries from the 

 flanks of Gruig Top and Cross Slieve. 



At one stage during the retreat of the ice the mouth of Glendun 

 was closed, and a lake was impounded in Glenaan ; this overflowed 

 the col of Old Red Sandstone on the south, and cut the gorge 

 which now carries the waters of Glenaan into the foot of Glen- 

 ballyemon, and so, by way of Cushendall, to the sea. 



Immediately south of Knockbane is a considerable accumulation 

 of morainic material, and this prevented the Glenaan River from 

 resuming its pre-Glacial channel on the retreat of the ice. 



A small overflow-channel cuts across the lower slopes of the 

 spur of Lurigethan, in the neighbourhood of Knockans. This is at 

 a height of 300 feet above O.D., and is the southernmost along 

 this section of the coast. 



Small southward-falling channels were probabty produced on the 

 steep face above Garron Point ; but, if such were the case, they 

 have been long since obliterated by the gigantic landslips that 

 have occurred during post-Pleistocene time. 



Glenravel. — During the maximum extension of the Scottish 

 ice a large glacier passed over Parkmore and down Glenravel to- 



