part 3] GLACIATION OF NOllTH-EASTERN IEELAND. 387 



a height of about 1100 feet, above which the mountain is thickly 

 covered with peat. 



The Camtogher spur is cut by a large number of channels, some 

 of which are well marked and fall northwards. This spur consists 

 of Tertiary basalt, and the fact that the ice passed over it is 

 proved by the occurrence of boulders of schist up to an altitude of 

 1000 feet. A new road for the conveyance of peat has been cut 

 along the crest of the spur, and this provides an opportunity of 

 examining the drift which occurs in pockets beneath the peat : it 

 contains basalt, schist, and flint. 



The strongly marked channels, as mentioned above, fall north- 

 wards ; but there are also many others, partly obliterated, which 

 fall in a southerly direction, and may possibly be traces of the first 

 glaciation of the valley by the Scottish ice. 



The principal northward-falling channels are at 820 feet (in 

 which are boulders of Slieve Gallion granite), 790 feet, 580 feet, 

 and a very large channel with a number of branches at its head at 

 about 480 feet. This last lies west of Granaghan Hill, formed by a 

 massive sill of dolerite which is strongly jointed, and has been torn 

 up by the ice, the loose blocks being scattered by thousands over 

 the country on the north. This and several other smaller examples 

 of ' crag and tail ' indicate that the latest movement was from 

 south to north ; but this area is somewhat perplexing, as many of 

 the rocks have the appearance of being moutonne from the 

 north. That circumstance, taken in conjunction with the south- 

 ward-falling channels mentioned above, leads me to suppose that 

 we have here some traces of the earlier glaciation from the north 

 which have not been entirely obliterated. 



On the line of the Maghera-Swatragh road which passes the 

 end of the spur are several drumlin-like mounds : these I take to 

 be the continuation of the lateral moraine mentioned on p. 386. 



The next spur to be considered is that running in a north-easterly 

 direction from Coolcoscreaghan (1242 feet), on which there are 

 two channels above Dowlins Bridge at about 830 and 820 feet 

 respectively ; also a more strongly-marked one at 750 feet, which 

 cuts several gorges in the Dalradian schists, and is streamless. 

 These all fall northwards. 



On the lower portions of this spur are other channels; but these 

 are rendered difficult of interpretation by vast accumulations of 

 morainic material, forming a series of parallel ridges which run 

 north and south. As they are traced northwards, these ridges 

 coalesce to form a gigantic lateral moraine, which crosses the 

 valley of the Agivey River. 



The portion of the Agivey Valley above the town of Garvagh 

 occupies a basin-shaped hollow, bounded on the south by Coolcos- 

 creaghan, Ashlamaduff Hill, Cam Hill, and Benbradagh ; and on 

 the north by Gortnamoya Hill, and its spur which terminates in 

 Rabbit Hill at Garvagh. The western end of the basin is partly 

 closed by a basaltic ridge, which forms part of the great western 



