846 J. GEIKIE ON - THE GLACIAL PHENOMENA 



the same direction. South-east of the Crogaire hills, in the moors, 

 striae were met with here and there, agreeing in direction with those 

 just given, the average being W. 35° IN". Mr. Campbell * gives the 

 bearing of striae " at Loch Maddy, on the east coast, and the 

 northern corner, next to the Sound of Harris, 5 ' as " about 45° W." 

 In the neighbourhood of Loch Maddy I found striae pointing nearly 

 the same, namely W. 40° N. Along the road leading from Loch 

 Maddy to Clachan good glaciated faces are seen again and again, 

 peering from under the till or freshly exposed. But on rocks that 

 have been long bared of their covering the markings are very faint ; 

 for the gneiss of North Uist seems to be upon the whole a less 

 durable rock than much of that in Harris. Unfortunately the old 

 map of North Uist used by me' contains but few names, and its 

 topography leaves much room for improvement ; but I will indicate 

 as near as I can the localities where striae were noted. About one 

 mile south of Loch Maddy Inn, on the side of the road, are striae 

 bearing W. 5° N. Between that spot and the shores of Loch 

 Scadabhagh a number of glaciated faces occur, upon which the 

 direction varies from W. 5° N. to W. 15° N. Immediately beyond 

 the loch the striae again point W. 5° N. After this the road leads 

 through a district where few rock-faces are seen. Between the 

 Barp and Clachan, however, we get striae again bearing "W. 5° N. 

 Coming south from Clachan about 2 miles or so I got one bearing of 

 "W. 10° N., but more were observed between that and Cairnish. In 

 the neighbourhood of the latter place several bearings were taken, 

 the directions varying from W. 7° N. to W. 10° N. 



Between North Uist and Benbecula are a number of islands, of 

 which the two largest aro Grimiseidh and Boneidh. The former we 

 saw from both ends, but did not land upon. It has the usual ice- 

 worn outline. So has Boneidh, which we coasted sufficiently near 

 to obtain the dip of the gneiss (which is at a considerable angle to 

 the south-east), and to assure ourselves that its bare rugged hills 

 have been glaciated from south-east to north-west. 



4. Till or Boulder-clay. — The till of North Uist presents much 

 the same character as that of Harris and Lewis. It is usually of a 

 drab or dirty grey colour, and may be described as a hard, gritty, 

 and sandy clay, containing much comminuted gneissic material, with 

 the usual blunted and subangular and angular stones, somewhat 

 irregularly aggregated. In many places, however, it can hardly be 

 called a clay, but is rather a sandy and clayey grit. Irregular 

 nests, patches, and lenticular beds of sand, gravel, and earthy debris 

 are enclosed here and there in the till. Striated stones are some- 

 times scarce, while in other places they are unusually plentiful. 

 Most of the stones, however, are more or less distinctly abraded ; but 

 the proportion of angular fragments is almost always large. The 

 stones are of all sizes, from mere grit up to blocks measuring several 

 feet or yards across. The till reaches and occasionally exceeds 

 10 feet in thickness, but is usually thinner, 



Many appearances connected with the till point to an ice-flow 

 * Quart. Journ. Geol. Soc. vol. xxix. p. 547. 



