568 HISTORY OF THE OUTER HEBRIDES. 



so far as he has examined the cliff sections in that district. 

 At Loch Shell whole cliffs of China stone, felspar, may be 

 seen. Here at Isginn near the head of the loch are to be 

 seen siliceous cherts some black as Lydian stone, others 

 bleached white, in blocks, resembling fossilized stumps of 

 trees. 



THE PHYSICAL FEATURES. 



The islands forming the chain of the Outer Hebrides 

 extend from N. Lat. 58 degrees 31 minutes at the Butt of 

 Lewis to 56 degrees 48 minutes at Barra Head, which 

 gives a stretch of 130 miles in length. The coast line is 

 extremely rugged and indented. The surface is flat and 

 monotonous, nowhere rising to the 3,000 feet line. The 

 highest part is that of Harris, which probably is from the 

 Norse word "har" and its dative feminine form " harri." 

 In Harris the highest point of 2,622 feet is reached 

 in the Clisheam. The contour lines shew a steady 

 descent to the north or Lewis side of summits 1,250 

 feet, as at Suainabhal in Dig and Mor Mhonadh at 

 Park. On the south or Harris side we have heights of 

 over 1,250 feet, as Beinn Dhubh 1,654 feet, An Coileach 

 1,265, Heilisval 1,257, Bleaval 1,305, and Roneval 1,506 

 feet. In Lewis the hills are on the average about half 

 this height, as Eitshal 733 feet, Beinne Bharabhais 800 

 feet, Monach 800 feet. The levels of these summits 

 over Lewis from south to north are pretty uniform. 

 The Park and Uig summits rise to the 1,500 feet level. 

 Those of Mid Lewis or of the Lochs and Carloway 

 district shew summits of only 750 feet. The Ness hills 

 make a further descent to 500 feet, as at Tom Dithabhail 

 and Beinn Bhail. These three descending terraces are 

 doubtless the work of the Ice Age. The same general 

 observation holds good for the islands south of the Harris 

 group of hills. 



The innumerable lochs scattered over this surface are 

 doubtless due to glacial agency. Their entire number has 

 been computed at 1,500, covering an area of 50,000 acres. 



