laborer dug a little further, and struck his pickaxe against an old Gothic rybat, that lay deeper still. There could be no mistaking the character of the champfered edge that still bore the marks of the tool, nor that of the square perforation for the lock-bolt; and the rising theory straightway stumbled against it and fell. Both rybat and skull had come from an ancient burying-ground, situated on a projecting angle of the table, and above.

REMARKS ON UNDERLYING CLAY ON LEVEL MOORS.

On level moors, where the rain-water stagnates in pools, and a thin layer of mossy soil produces a scanty covering of heath, we find the underlying clay streaked and spotted with patches of white. As in the spots and streaks of the Red Sandstone formations, Old and New, the coloring matter has been discharged without any accompanying change having taken place in the mechanical structure of the substance which it pervaded; for we find the same mixture of arenaceous and aluminous particles in the white as in the red portions. And the stagnant water above, acidulated, perhaps, by its various vegetable solutions, seems to have been in some way connected with these appearances. In almost every case in which a crack through the clay gives access to the oozing moisture, we find the sides bleached, for several feet downwards, to nearly the color of pipe-clay; we find the surface, too, when divested of the soil, presenting for yards together the appearance of sheets of half-bleached linen. Now, the peculiar chemistry through which these changes are effected might be found to throw much light on similar phenomena in the older formations. There are quarries in the New Red Sandstone in which almost every mass of stone presents

a different shade of color from that of its neighboring mass, and quarries in the Old Red, whose strata we find streaked and spotted like pieces of calico. And their variegated aspect seems to have been communicated in every instance, not during deposition, nor after they had been hardened into stone, but when, like the boulder-clay, they had existed in an intermediate state.

TRAVELLED BOULDERS NOT ASSOCIATED WITH CLAY.

All the travelled boulders of the north do not seem associated with the clay. We find them occurring, in some instances, in an overlying gravel, and in some instances resting at high levels on the bare rock. I have seen, on the hill of Fyrish, a lofty eminence of the Lower Old Red which overlooks the upper part of the Cromarty Frith,— a boulder of an exceedingly beautiful, sparkling hornblende, reposing on a stratum of yellow sandstone, fully a thousand feet over the sea, where there is not a particle of the clay in sight. We find these travellers furnishing specimens of almost all the primary rocks of the country,-its gneisses, schistose and granitic, its granites, red, white, and gray, its hornblendic and micaceous schists, and occasionally, though more rarely, its traps. The stone most abundant among them, and which is found occurring in the largest masses, is a well-marked granitic gneiss, in which the quartz is white, and the feldspar of a pink color, and in which the mica, intensely black, exists in oblong accumulations, ranged along the line of stratification in interrupted layers. No rock of the same kind is to be found. in situ nearer than thirty miles. We find granitic boulders of vast size abundant in the neighborhood of Tain, especially where the coach-road passes towards the west

of sea

through a piece of barren moor, and on the range beach below. One enormous block, of a form somewhat approaching the cubical, is large enough, and seems solid enough, to admit of being hewn into the pedestal of some colossal statue; but instead of being thus appropriated to form part of a monument, it has lately been converted of itself into a whole monument. When I last passed the way, I found it dedicated, in an inscription of nine-inch letters, "to the memory of the immortal Scott." Nature had dedicated it to the memory of one of her great revolutions ages before; but since the dedicator had determined on adding, in Highland fashion, a stone to the cairn of Sir Walter, it would certainly have been no easy matter to have added to it a nobler one.

GRANITIC GNEISS AND SANDSTONE, WITH THE CONDITIONS OF

THEIR UPHEAVAL.

On entering on the granitic rock, we find the strata, strangely disturbed and contorted, lying, in the course of a few yards, in almost every angle, and dipping in almost every direction. And not only must there have been a complexity of character in the disturbing forces, but the rock on which they acted must have been singularly susceptible of being disturbed. The strata of the sandstone were, at the period of their upheaval, the same brittle, rigid plates of solid stone that they are now. The strata of the granitic gneiss were characterized, on the contrary, during their earlier periods of disturbance, by a yielding flexibility. They were capable of being bent into sharp angles without breaking. We see them running in zigzag lines along the precipices, now striking downwards, now ascending upwards, now curved, like a relaxed Indian bow, in one direction, now curved in a contrary one, like

the same bow when fully bent. The strata of the sandstone, like a pile of glass-panes laid parallel, existed in a state in which they could be either raised in any given angle, or, if the acting forces were violent and partial, broken up and shivered; whereas the granitic strata existed in the state of the same glass-panes brought to a bright red heat, and capable, from their extreme flexibility, of being bent and twisted in any direction. We find, too, that there occur occasional patches in which the lines of the stratification have been together obliterated. We can trace the strata with much distinctness on every side of these; but there is a gradual obscuration of the lines, and we see what was a granitic gneiss in one square yard of rock existing as a compact homogeneous mass in the next. The effect is exactly that which would be produced in the heated panes of my illustration, were the heat kept up until portions of them began to run; and the circumstance serves to throw light on some of the other phenomena of the gneiss. The stone, in its average specimens, is a ternary, consisting of red feldspar, white quartz, and a dingy-colored mica; but no one, notwithstanding, could mistake it for a true granite. It has its granite veins, however; and these veins, truly such in some cases, are, in not a few others, mere strata of the gneiss, which have evidently been formed into granite. where they lie. There are no marks of injection, no accompanying disturbance. All their conditions, with the exception of their being true granites, are exactly those of the layers which repose over and under them. Now, the homogeneous patches serve, as I have said, to throw light on the secret of the formation of these. In one important respect the granitic rocks differ widely among themselves. Some of them contain potass and soda in

such large proportions, and have such a tendency to disintegrate, in consequence, that they furnish much less durable materials for building than the better sandstones; while others, of an almost indestructible quality, are devoid of these salts altogether. Potass and soda form powerful fluxes; and it seems at least natural to infer that, should wide tracts of granitic rock be exposed to an intense but equable heat, the portions of the mass in which the fluxes exist in large proportions must pass into a much higher state of fluidity than the portions in which they are less abundant, or which are altogether devoid of them. Single strata and detached masses might thus come to be in the state of extremest fusion of which their substance was capable, and all their particles, disengaged, might be entering freely into the combinations peculiar to the plutonic rocks, when all around them continued to bear the semichemical, semi-mechanical characteristics of the metamorphic ones. Hence it is possibly the origin of some of those granite veins, open above, and terminating below in wedge-like points, which have so puzzled the Huttonians of a former age, and which have been so triumphantly referred to by their opponents as evidences that the granite had been precipitated by some aqueous solution.

SEPTARIA, OR CEMENT-STONES OF THE LIAS.

Observe these nodular masses of pale, blue limestone, that seem as if they had cracked in some drying process, and had afterwards the cracks carefully filled up with a light-colored cement. The flaws are occupied by a rich calcareous spar; and in the centre of each mass we find, in most instances, a large ill-preserved Ammonite, which has also its spar-filled cracks and fissures, as if it, too, had