With this object I set out on an exploratory excursion, on a delightful morning of August, 1830. The tide was falling; it had already reached the line of half ebb; and from the Southern Sutor to the low, long promontory on which the town of Cromarty is built, there extended a broad belt of mingled sand-banks and pools, accumulations of boulders, and shingle, and large tracts darkened with algæ. I passed direct by a grassy pathway to the Sutor, the granitic spear-head of a late illustration,--and turned, when I reached the curved and contorted gneiss, to trace through the broad belt left by the retiring waters, and in a line parallel to what I have described as the shaft of the huge spear, the beds and strata of the Old Red Sandstone in their ascending succession. I first crossed the conglomerate base of the system, here little more than a hundred feet in thickness. The ceaseless dash of the waves, which smooth most other rocks, has a contrary effect on this bed, except in a few localities, where its arenaceous cement of base is much indurated. Under both the Northern and Southern Sutors the softer cement yields to the incessant action, while the harder pebbles stand out in bold relief; so that, wherever it presents a mural front to the breakers, we are reminded, by its appearance, of the artificial rock work of the architect. It roughens as the rocks around it polish. Quitting the conglomerate, I next passed over a thick bed of coarse reel and yellow sandstone, with here and there a few pebbles sticking from its surface, and here and there a stratum of finer-grained fissile sandstone inserted between the rougher strata: I then crossed over a strata of an impure grayish limestone, and a slaty clay, abounding, as I long afterwards ascertained, in ichthyolites and vegetable remains. There are minute veins in the limestone (apparently cracks filled up) of a jet black bituminous substance, resembling anthracite; the stratified clay is mottled by layers of semi-aluminous, semi-calcareous nodules, arranged like layers of flint in the upper Chalk. These nodules, when cut up and polished, present very agreeable combinations of color; there is generally an outer ring of reddish brown, an inner ring of pale yellow, and a central patch of red, and the whole is prettily veined with dark-colored carbonate of lime.[AH] Passing onwards and upwards in the line of the strata, I next crossed over a series of alternate beds of coarse sandstone and stratified clay, and then lost sight of the rock altogether, in a wide waste of shingle and boulder-stones, resting on a dark blue argillaceous diluvium, sometimes employed in that part of the country, from its tenacious and impermeable character, for lining ponds and dams, and as mortar for the foundations of low-lying houses, exposed in wet weather to the sudden rise of water. The numerous boulders of this tract have their story to tell, and it is a curious one. The Southern Sutor, with its