564 HISTORY OF THE OUTER HEBRIDES. 



bling mica scales, in the Conglomerate, is a peculiarity I 

 have nowhere else seen. 



The presence of a mineral such as pinite, in rocks in situ, 

 in the neighbourhood at the very junction, I should have 

 said and the same mineral with its associated scales of 

 haematite and granules of calcite, found also in the Con- 

 glomerate, leave no doubt whatever as to the local character 

 of this Conglomerate. At the same time, this very special 

 character is such as to leave little in common between it 

 and its alleged Torridon congener, except the quartz, felspar 

 perhaps, and the iron oxides, unless, indeed, much may be 

 made of the fact that both rest on the same Archaean plat- 

 form. In this last alternative, I should have added, that 

 though they both rest on the same platform, it was under 

 different conditions they did so, the one as a thoroughly 

 attrited Conglomerate, the other as a Breccia; the one 

 formed by marine agency, the other by subaerial. In fine, 

 the Lewis Conglomerate may or may not be connected 

 under the Minch with the Torridon sandstones of Ross and 

 Sutherland, but data for either conclusion are not to be had 

 by an examination of the Lewis Conglomerate. 



It may be of interest to note that the Conglomerate is 

 cut through its entire length from south-east to north-west 

 or so by volcanic dykes. Some of these I counted seven 

 are, however, washed out, leaving chasms in the Con- 

 glomerate, as at Holm, or form trenches in the rocky shore, 

 as at the Battery Point. One magnificent fragment is seen 

 near Gress, known as the " King's Dyke." It occupies the 

 side of a chasm running down over a length of 472 feet, 

 from a height of 90 feet at the head of the chasm to less 

 than half that height from the water. Its breadth is 18 feet. 

 The sea fills the chasm or "geo" at all tides. In the 

 neighbourhood is an immense sea-cave, known as the 

 "Pigeons' Cave," 150 yards by 50 yards, and 30 feet high 

 from the sandy floor to the centre of its dome-like roof. 

 The entrance of this cave, as also that of the more famous 

 "Seal Cave" in the neighbourhood, is to the north-east 

 On account of the divisional planes, and calcareous loose 



