wood that are found in the mossy and marshy grounds. In some of the hilly parts of Tartary and India, the nations still vitrify their forts instead of using cement.

We saw on our road several stone and "slate" quarries, in which we found several tails, spines, and teeth of fossil fish, but were not so fortunate as to obtain a specimen in anything like a perfect condition. The upper beds of the old red sandstone formation are very compact, and having good cleavage planes, are used as roofing-slates in the neighbourhood.

Near one of these quarries some soil had recently been removed, laying bare the surface of the rock, on which were well-defined glacial markings, and which, from their direction, had evidently been made by a glacier coming from Glens Prosen and Clova. In a field near Aberlemno are two of those curious sculptured stones, of which a good many exist in this part of Scotland, and concerning which volumes of theories have been written, conclusively proving that nothing whatever is known about them, neither by whom or for what purpose they were erected. They had figures of horses and men, and an ornament like a pair of spectacles, amongst other symbols, carved on them.

On the commencement of the following week we went by rail to Kirriemuir, a small town, six miles W. by N. from Forfar, and then drove to the Den of Airlie, twelve miles further. The Den is a most beautiful ravine, formed by the Airlie river, which flows down it. In some parts the sides are quite perpendicular, and over 400 feet in height, while in others they slope more gradually. The valley is well wooded, and in the shade and moisture many species of ferns abound, the most noteworthy of which is the Green Spleenwort, Asplenium viride.

We walked up the valley from Airlie Castle to the Reeky Linn, a magnificent waterfall, sixty feet in height. It is said to be one of the finest in Scotland. We returned to Kirriemuir by way of Lentrathan Loch and through Kingoldrum.

Kirriemuir is within an easy walk of Clova; and if any of our readers are in search of a place whereat to spend the holidays, we strongly recommend to their notice the latter; and to a lover of botany it is extremely attractive, for in few localities of equal size in the British isles have so many rare plants been noticed. And last, but not least, there is a very comfortable hotel, where the charges are very moderate, for at present this district has not been overrun by tourists.

ORIGIN OF THE CHEDDAR CLIFFS.

BY D. MACKINTOSH, F.G.S.

THE Mendip range of hills, in Somersetshire, presents a striking instance of a truncated anticlinal fold or axis. According to Professor Ramsay, a mass of strata nearly a mile in thickness has been cut off from the summit by denudation, exposing the old red sandstone in the middle, with the carboniferous, or mountain limestone, dipping away on both sides. The outcrop of the limestone, under the old red, has been shaped into steep escarpments, with cliffs at intervals. A very remarkable line of upland cliffs runs from the Shuteshelve pass (between Sidcot and Axbridge) to Longbottom pass, and some distance beyond. It is here and there indented by cliff-bound ravines which, were they to become partially submerged, would differ very little in shape from inlets of the sea. Nearly on a level with the summit of this line of cliffs, there is an approximately horizontal table-land, which few geologists would hesitate to regard as a "plane of marine denudation." Beyond Longbottom pass, in a south-easterly direction, this table-land becomes irregular, and its south-west escarpment, facing the Cheddar plain, is indented with combes which are more or less cliffy, especially at their inner termination. A formation of Permian conglomerate, which in most places may be found fringing the base of the Mendip Hills, runs into these combes, proving that they must have been mainly excavated before or during the Permian period. The trumpet-shaped mouth of the Cheddar ravine might be classed among these combes, were it not that it must have been formed at a subsequent period, for its floor, as well as sides, consists of carboniferous limestone. This ravine, at first sight, suggests the idea (not confirmed by farther inspection) of the limestone ridge through which it passes, having been "rent in twain" from the top to the bottom.

The Cheddar ravine, though long celebrated, deserves something more in the way of description than the very brief notices that have hitherto appeared. In the preface to a legendary article in a late number of the Gentleman's Magazine, it is justly regarded as "one of the most gorgeous specimens of rocky scenery to be found in Europe. The eye

grows accustomed to Switzerland, but Cheddar is a continual surprise."* "* The object of the present paper is to give some

the defile

In the Penny Cyclopædia it is alluded to as follows :—" of Cheddar cliffs, with its long line of stupendous mural precipices, certainly among the most magnificent objects of this kind in Britain.

idea of its structure and extent from personal observations, and to consider the most probable way in which it has been formed.

Immediately to the north-east of the village of Cheddar, which stands on ground only a little elevated above high-water mark, there is a combe-shaped valley. Its sides gradually contract, and become more rocky and precipitous, until it forms a narrow winding gorge, with walls of limestone. About a quarter of a mile from the village the gorge becomes very narrow, and the cliffs, especially on the right hand side, very steep and even overhanging. For some distance beyond, the road runs along what may be called the Strait of Cheddar, after passing which the ravine gradually opens, and its sides become more sloping, until it loses its rugged grandeur of outline. In the most contracted part of the Strait the observer is so completely hemmed in by bare rocks as to require little to make him fancy himself in a mountain solitude remote from the habitations of mankind. When all is still in the neighbouring plain, the wind here often blows violently, and is deflected from cliff to cliff with a sound which, to the mind of a contemplative geologist, might suggest the idea of audible spectres of stormy billows which once may have followed the same course, as they rebounded from side to side of a narrow inlet of the sea. During the writer's first visit to this spot, numbers of rooks were soaring from precipice to precipice, and often appeared like black dots against a narrow strip of sky; while the resemblance to white ants presented by sheep browsing on ledges near the top of the cliffs furnished a much more impressive idea of their height than any process of measurement.

Some of the old women, who importunately press their services on the tourist as guides, will tell him that the Wind Cliff is 480 feet high. This cliff (to which no drawing can do justice) is certainly a most remarkable specimen of a literally mural precipice of considerable breadth, and at least 300 feet in height. It is quite perpendicular from top to bottom, excepting where it overhangs. It is a much finer and larger face of rock than the cliff at the entrance to Goredale in Craven, Yorkshire, and nearly twice the height of the rocky part of the High Tor, near Matlock, in Derbyshire. As regards continuous perpendicularity, I believe it is not equalled by any limestone cliff in the kingdom. Next to the Wind Cliff, the so-called Cathedral Rocks are the most impressive. They consist of several buttresses projecting forward from the main line of cliffs. Their sides are perpendicular, and their fronts overhanging. The height of the summit of one of these rocks above the level of the road at the bottom of the ravine has lately been ascertained to be about 420 feet. The way in

which it was measured is deserving of notice. A worthy scientific gentleman of the neighbourhood ventured to crawl on to the summit from the grass-covered down behind, until he found himself on the brink of three precipices-those on the right and left perpendicular, the one in front overhanging. He dropped a line from the most extreme part of the brink, which went down without touching rock until the plummit struck a slightly-projecting terrace near the bottom of the ravine, and then fell on the road. There is probably no other part of England where a conformation of cliff-architecture would admit of a similar feat being accomplished. But our wonder at the cool intrepidity of the performer will not be so great when we consider that he was a member of the Society of Friends.

It has already been hinted that the Cheddar ravine is very tortuous. It consists of an alternating series of recesses and projections, or small bays and headlands. In some places there is a certain degree of correspondence between the hollows on one side and the protuberances on the other, which might at first lead one to fancy that the ravine is solely or mainly the result of a violent severance of the rocks; but a little observation will be sufficient to show that the two sides were never in contact. On the right, looking from Cheddar, the cliffs are very precipitous; on the left, they generally slope down into the ravine at a small angle.

The cliffs mainly consist of large faces of moss-covered rock, but the clefts and narrow terraces furnish a habitat for various plants, which add beauty to the sublimity of the scenery. Ivy and yew grow out of the fissures, and in various places may be found liverwort, polypody, meadow-rue, crimson mountain-pink, etc. The "screes "* at the bases of the cliffs have in many places acquired a covering of grass, and do not now appear to be in course of accumulation. The positions they occupy in some places would seem to indicate that they must have been thrown up against a wall of rock, or into a recess, rather than hurled down from above. The effects of the action of frost and rain, however, may be seen in favourable situations. The frost detaches angular fragments from incoherent parts of the cliffs, and from the under sides of rocky projections. The rain carries previously-detached fragments and chips down the "rakes," or vertical passages which indent the face of the cliffs. Vegetable mould and red loam are likewise washed down by rain from the top of the cliffs, and subjacent fissures. Nearly the whole surface of the Mendip Hills is covered with red loam, which fills up the fissures, and, to a certain extent, the caverns. Its derivation, and period or

A convenient name used in the Lake district for the accumulated wrecks of cliffs and declivities.

periods of deposition are involved in mystery; but it seems to be generally admitted that it must have been a kind of seaooze left by retiring waters during one or more submergences of the land. In later times, it has been re-arranged by subaerial and subterranean fresh-water streams.

The Cheddar caves are regarded by the natives as the greatest source of attraction. One, in particular, has become very celebrated for its stalactites. But as it is probably surpassed in this respect by caves in Derbyshire and elsewhere, the main attraction of the Cheddar ravine must ever lie in the almost unparalleled grandeur of its cliff scenery. In this ravine there are many caves, little known and seldom visited, which present phenomena more interesting to the geologist than stalactitic concretions, however much the latter may resemble any earthly or unearthly objects the guide or the visitor may fancy. On the left side, walking from Cheddar, before reaching the Strait, there is a cave with a very conspicuous entrance at some height above the road. It has apparently been scooped out, or at least enlarged, by an inwardly-directed agent, such as sea waves, and not by an out-flowing freshwater stream. On the right side, at various altitudes, there are many caves. In nearly all of them the roof is more or less rounded, and the sides here and there smoothly hollowed out into pot-shaped cavities. In short, the interior of these caves display obvious signs of the action of water, charged with a sufficient amount of solid matter to enable it to round and smooth limestone rock; and the position in which the rounded and smoothed surfaces often occur, would seem to point to the action of powerful waves as the only adequate explanation. It is true that fresh-water percolates through crevices in limestone districts, and the Cheddar brook has its visible source in several streams which flow out of subterranean cavities near the south-west end of the ravine; but it is not very difficult for one who is familiar with the peculiar forms resulting from the inward and upward gyratory action of the waves of the sea to distinguish these forms from marks left by fresh-water streams. The latter tend to wear their channels downwards, and can never produce smooth vaulted roofs, hanging or inverted potholes, arched entrances, and other characteristics of sea-worn

caverns.

Mr. W. Boyd Dawkins (to whom the scientific world is somuch indebted for the exploration of Wookey Hole Cavern, a few miles from Cheddar*), believes that the Cheddar ravine is an immense unroofed cave, the abstraction of the rocks once filling the now vacant space having been effected by atmo-See first paper on Wookey Hole, in the "Quarterly Journal of the Geological Society."

VOL. XII.-NO. I.

D