In a few days the storm blew by; and as the prolonged rains had cleared out the deep ravines of the district, and given to the boulder-clay in which they are scooped a freshness in its section analogous to fresh fracture in rocks of harder consistency, I availed myself of the facilities afforded me in consequence, for exploring it once more. It has long constituted one of the hardest of the many riddles with which our Scottish deposits exercise the patience and ingenuity of the geologist. I remember a time when, after passing a day under its barren _scaurs_, or hid in its precipitous ravines, I used to feel in the evening as if I had been travelling under the cloud of night, and had seen nothing. It was a morose and taciturn companion, and had no speculation in it. I might stand in front of its curved precipices, red, yellow or gray, according to the prevailing average color of the rocks on which it rests, and mark their water-rolled boulders, of all qualities and sizes, sticking out in bold relief from the surface, like the rock-like protuberances that roughen the rustic basements of the architect, from the line of the wall; but I had no _open sesame_ to form vistas through them into the recesses of the past. I saw merely the stiff pastry matrix of which they are composed, and the inclosed pebbles. But the boulder-clay has of late become more sociable; and, though with much hesitancy and irresolution, like old Mr. Spectator on the first formal opening of his mouth,--a consequence, doubtless, in both cases of previous habits of silence long indulged,--it begins to tell its story. And a most curious story it is.
The morning was clear, but just a little chill; and a soft covering of snow, that had fallen during the storm on the flat summit of Ben-Wevis, and showed its extreme tenuity by the paleness of its tint of watery blue, was still distinctly visible at the distance of full twenty miles. The sun, low in the sky,--for the hour was early,--cast its slant rays athwart the prospect, giving to each nearer bank and hillock, and to the more distant protuberances on the mountain-sides, those well-defined accompaniments of shadow that serve by throwing the minor features of a landscape upon the eye in bold relief, to impart to it an air of higher finish and more careful filling up than it ever bears under a more vertical light. I took the road which, leading westward from the town towards Invergordon Ferry, skirts the Frith on the one hand, and runs immediately under the noble escarpment of green bank formed by the old coast line on the other. Fully two-thirds of the entire height of the rampart here, which rises in all about a hundred feet over the sea-level, is formed of the boulder-clay; and I am acquainted with no locality in which the deposit presents more strongly, for at least the first half mile, one of its marked scenic peculiarities. It is furrowed vertically on the slope, as if by enormous flutings in the more antique Doric style; and the ridges by which these are separated,--each from a hundred to a hundred and fifty feet in length, and from five-and-twenty to thirty feet in average height,--resemble those burial mounds with which the sexton frets the churchyard turf; with this difference, however, that they seem the burial mounds of giants, tall and bulky as those that of old warred against the gods. They are striking enough to have caught the eye of the children of the place, and are known among them as the Giants' Graves. I could fain have taken their portrait in a calotype this morning, as they lay against the green bank,--their feet to the shore, and their heads on the top of the escarpment,--like patients on a reclining bed, and strongly marked, each by its broad bar of yellow light and of dark shadow, like the ebon and ivory buttresses of the poet. This little vignette, I would have said to the landscape painter, represents the boulder-clay, after its precipitous banks--worn down, by the frosts and rains of centuries, into parallel runnels, that gradually widened into these hollow grooves--had sunk into the angle of inclination at which the disintegrating agents ceased to operate, and the green sward covered all up. You must be studying these peculiarities of aspect more than ever you studied them before. There is a time coming when the connoisseur will as rigidly demand the specific character of the various geologic rocks and deposits in your hills, _scaurs_, and precipices, as he now demands specific character in your shrubs and trees.