Geology is that branch of science which comprehends the knowledge of all that relates to the form, structure, mineral and fossil constituents, of the earth. The Scottish Grampians, it is generally admitted, form part of the lowest sections of its crust, to which the researches of geologists extend. We must go to other countries for any coeval, and, to North America for any older, competing land: and still, there, the rocks are of the same mineral qualities and arrangement. The Ben-Mac-Dhui group form the highest and most prominent masses in the whole range of these crystalline mountains. When I first stood on the broad flat top of Ben-Mac-Dhui, I had no thought or purpose of ever recording its geological history. The excursion was undertaken simply for recreation, and a delightful one it proved. I longed to plunge into the deep recesses of the old forest, and to see the trees which nature had strewed with careless hand, ere, perhaps, Caledonia was tenanted by the human family. I looked down from its rugged sides, as I ascended, with awe and wonder—snatched a little alpine as I drew breath for the next spring—chipped a piece of granite as I obtained a footing over a yawning chasm, or breasted along by jagged precipitous defile,—and when, having fairly scaled the summit, I gazed out upon the world beneath, the feeling which for a moment flitted across my mind was one of no merely vain complacency, that I was then the most elevated subject of all the twenty-six or twenty-seven millions inhabiting the British Islands—and the lowest, too, in their stony regions! The mountains of the earth serve to inspire some of the loftiest sentiments that can fill the breast of its intelligent inhabitants. Imbosomed in their deep solitudes, man feels his own littleness, and is forced to inquire who made these wonders, and who sustains them? We are all the better, morally speaking, for leaving occasionally our daily-trodden haunts, where we see only human things, and hear only of the triumphs of human craft, the excitement of human passions, the littleness and vanity of even the noblest human daring. There is an image of Jehovah’s greatness impressed upon the outward face of nature, which for a time will awaken and sustain the most salutary reflections, breathing, as it were, a new life into the soul of the wayfarer. A man escapes from himself, forgetting the burden of a thousand petty cares, and rising above his sensual condition, when he looks upon the physical world in these its grander features and secluded scenes, which irresistibly speak to the inner sense of divinity, wisdom, and omnipotence.