1857.] GEIKIE — SKYE. 7 



fine-grained syenite. At Borereg the shales strike inland, as already 

 mentioned, and are succeeded by a set of limestones and thin shales 

 — the representatives of the limestones of Broadford and Torrin*. 

 The Sketch No. 1 . illustrates this locality. 



The occurrence of quartz-beds in the limestones at this locality is 

 interesting, inasmuch as it proves that pure white crystalline quartz- 

 ite is not necessarily a product of igneous influence. The syenite 

 of Beinn na Charn, it is true, is only a short way distant ; that it could 

 not, however, have had any material effect upon the quartzite is abun- 

 dantly evident from the unaltered character of the interstratified 

 limestones ; and if further proof were needed, it would be found in 

 the occurrence of a precisely similar quartzite among the limestones 

 of the interior, on the ridge to the south of Glen Kilbride. There it 

 rests on an elevated belt of red sandstone, and is overlaid by a lime- 

 stone-breccia, and a series of unaltered limestones. The nearest 

 syenite is that of Beinn an Dubhaich on the other side of the Glen, 

 but a large fault intervenes between them. There is, indeed, a small 

 basalt-dyke traversing the lias-beds at this point, but it is of much 

 too trifling extent to have produced the supposed metamorphism ; 

 while I shall take occasion to show that the trap-dykes of the district 

 generally have not exercised any marked influence upon the texture 

 of its rocks. Of the quartz-beds on Loch Eishort, the upper, as ex- 

 posed on the beach, is much jointed and fractured ; and, as far as I 

 could penetrate into its substance, it seemed to be a nearly transparent 

 crystalline quartzite, with an occasional tendency to be dull and 

 subgranular. The under bed is also a good deal fractured, owing, 

 perhaps, at least in part, to the proximity of a fault. It forms a tall 

 cliff, remarkable for its brilliant whiteness, and for the large snowy 

 blocks that cumber the beach around its base. A fresh fracture 

 shows that this peculiar brilliancy is chiefly owing to a thin crust, 

 from Jth to y^-th of an inch in thickness, consisting of minute aggre- 

 gated granules or crystals of quartz. Further from the surface the 

 rock assumes the character of a very fine quartzose grit. 



The shore of Loch Eishort is now occupied by a great tract of 

 red sandstone, extending inland as far as the north-eastern corner of 

 Beinn na Charn. Its western boundary is formed by a fault, which 

 throws out fully 400 feet of the lower lias, and brings down the 

 Sculamus and Broadford limestones against the palaeozoic beds. The 

 dip of the sandstone is generally westerly, at angles varying from 20° 

 to 50°. Its eastern edge has likewise been produced by a fault that 

 extends from near the north-east corner of Beinn na Charn to the 

 village of Heast. This latter dislocation has thrown out a still 

 larger portion of the lower lias ; and the effect of the two movements 

 together has been to cut a rude scalene triangle out of the lias lime- 

 stones and shales, inserting in their stead a corresponding area of red 

 sandstone. The Heast fault can be well observed in the channel of 

 the stream, where the fractured ends of the limestones, shales, and 

 breccia distinctly abut against those of the older strata. Beyond 



* With the above description of this coast-section, for the accuracy of which I 

 can vouch, compare that by Macculloch ; Description, vol. i. p. 328. 



