Page:Transactions of the Geological Society, 1st series, vol. 4.djvu/276

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to the neighbouring shepherds, who, still mindful of their ancient allegiance, show the spot where, among many others, the unfortunate Prince was for a time concealed. The minuter fragments of quartz rock and granite have here formed themselves into angular conglomerates, which are in some instances perfectly compact, the smaller cavities having been filled up by siliceous matter, while the larger fragments, touching only by small surfaces, have left considerable openings between them. Here then we have an example of a breccia formed in times comparatively recent. The conglomeration of the fragments is not the effect of the accidental presence of iron, so commonly the cement of modern breccias, but is evidently the result of a deposition of siliceous matter. This could only have been brought into solution by the rains, or by the operation of common water, since the stones are out of the reach of other causes, and it serves to prove that the solution of silica in water, a circumstance which some have supposed limited to the ancient state of the Globe, is a process still going on. I have indeed noticed in the former remarks on quartz rock the same fact as proved by the enamelled and polished surface which its exposed parts so often assume. We have no means from historical record of determining the antiquity of this slide, but as far as any conjectural evidence can be adduced from the little accumulation of soil which has formed on the horizontal surfaces, and the bare aspect of the faces, on which scarcely a lichen has yet planted itself, it cannot be of very high antiquity. The observation is further of importance as illustrating the origin of the brecciated jaspers, as well as that of the other breccias formed of angular fragments.

From Loch Ericht the quartz rock branches away to the mountains that skirt Ben Nevis and Glenco, as I noticed in the above mentioned paper. I have already observed in that paper that it