180 



THE GEOLOGIST. 



years will witness its complete destruction. Some very interesting 

 historical associations are connected with this spot, and the readers 

 of Scott will regard it with increased interest when they remember 

 that William Christian, of Eonaldsmay, was shot here in 1662, for 

 surrendering the island to Cromwell's army. 



To this period also belong the numerous natural arches and caves 

 found along the coast ; probably, however, most of them belong 

 mainly to the later portion of the Pleistocene age. They are found 

 on all parts of the island, wherever the nature of the coast-line was 

 favourable to their formation. Many of them run considerable dis- 

 tances into the cliffs, frequently winding tortuously ; in other in- 

 stances they are merely deep straight chambers in the rocks. They 

 are usually but little elevated above the existing high-water mark, 

 and appear to contain only the ordinary shingle and sand of the 

 neighbouring shore. The most remarkable of these arches and caves 

 are those on the western side of Langness. The rocks there are 

 greatly dislocated by the intrusion of several greenstone dykes, two 

 of which intersect at this spot, and the strata thus weakened have 

 yielded to the action of the waves, an extensive series of arches and 

 caves having been the result. One of the most remarkable of these 

 is an arch about twenty-six feet w^ide, fifteen feet high, and eighteen 

 feet deep. The floor and walls are composed of slaty schists, here of 

 a deep claret-colour, thrown up at a high angle, and much contorted 

 by the neighbouring greenstone ; the roof is formed of the Old Eed 

 conglom_erate, which is of the characteristic deep red colour, and rests 

 almost horizontally upon the edges of tlie upturned schists. This 

 arch stands a few feet above high-water mark, but it is evidently only 

 the relics of what was once a vast cavern, extending far below the 

 level of the sea. Its sides (the lower portion consisting of the con- 

 torted schists, and the upper of the coarse conglomerate) extend 

 seaward from thirty to forty yards be3^ond the arch itself, a great part 

 of this being below high-water, and the partially enclosed space much 

 encumbered with huge masses of fallen conglomerate, evidently the 

 debris of the broken roof. Several others of the series equal, if they 

 do not even exceed, this one in magnitude. One in particular, 

 roughly measured by pacing, in its entire state would have been a 

 cave fully sixty yards deep, — twenty yards of its depth being below 

 high-water, — ten yards wide, and, at its upper end, eight yards high. 

 At its upper extremity it is still covered with a roof for about twenty- 

 live feet, and its walls are tliere nearly thirty feet high, sloping thence 

 down to the water. These caves and arch'es present many features 

 of great inti>rest, and are deserving of a fuller investigation. The 

 occurrence also in tliis locality of the Cambrian schists, the Devonian 

 conglomerate, and the Carboniferous limestone, in their characteristic 

 positions, together with the numerous greenstone dykes, make Lang- 

 ness, to the geologist, one of the most interesting 'spots to be found 

 in the whole island ; while the wild and rocky nature of its coast, 

 and the many picturesque views to be obtained from it of the beau- 

 tiful bay and neighbourhood of Castletown, cause it to be a favourite 

 place of resort for both natives and visitors. 



