three times the height of Chimboraço. It is the primitive limestone that supplies the most numerous examples of caves and grottos in the primary rocks; and if these yield in point of size to the later limestone formations, this arises from the inferior extent of the primitive limestone, rather than from its incapacity to form caves. In the transition mountains, and those of stratified structure, it is still the limestone in which the more extensive caves are found, of which those of the Hartz, the splendid caverns of Derbyshire, and those of the Carpathians, are well known. Caverns most frequently occur in the mountains of stratified limestone; and among these, one of the most modern formations, the Jura limestone, is particularly distinguished, and was therefore termed the cavern-limestone by the early geologists. The celebrated caves of Franconia, the grotto of Notre Dame between Grenoble and Lyons, and many others, occur in this formation. That of Kirkdale, in Yorkshire, is in oolitic strata. Next to the limestone in the stratified formations, the so-called older gypsum which contains salt is the most abundant in caverns. They are of rare occurrence in the sandstone, have generally broad openings but of no great extent. Such are the Cow-stall in Saxony, and a few caves in Bohemia.

In the volcanic rocks, cavern formations are very common, and one of the most splendid examples in the world occurs in the basalt, a rock of comparatively modern igneous origin. This is the well-known cave of Fingal, in the island of Staffa, a small island on the western coast of Scotland, composed entirely of amorphous and pillared basalt. The name of the island is derived from its singular structure, Staffa signifying, in the Norwegian language, a people who were early on this coast, a staff, and, figuratively, a column. The basaltic columns have in various places yielded to the action of the waves, which have scooped out caves of the most picturesque description, the chief of which are the Boat cave, the Cormorant cave, so called from the number of these birds visiting the spot, and the great cave of Fingal. It is remarkable that this grand natural object should have remained comparatively unknown, until Sir Joseph Banks had his attention accidentally directed to it, and may be said to have discovered it to the inhabitants of South Britain. This great cavern consists of a lava-like mass at the base, and of two ranges of basaltic columns resting upon it, which present to the eye an appearance of regularity almost architectural, and supporting an irregular ceiling of rock. According to the measurements of Sir Joseph Banks, the cave from the rock without is 371 feet 6 inches; the breadth at the mouth, 53 feet 7 inches; the height of arch at the mouth, 117 feet 6 inches; depth of water at the mouth, 18 feet; and at the bottom of the cave, 9 feet. The echo of the waves which wash into the cavern has originated its Gaelic name, Llaimh-binn, the Cave of Music. Macculloch remarks: "If too much admiration has been lavished on it by some, and if, in consequence, more recent visitors have left it with disappointment, it must be recollected, that all descriptions are but pictures of the feelings of the narrator; it is, moreover, as unreasonable to expect that the same objects should produce corresponding effects on all minds, on the enlightened and on the vulgar, as that every individual should alike be sensible of the merits of Phidias and Raphael, of Sophocles and of Shakespeare. But if this cave were even destitute of that order and symmetry, that richness arising from multiplicity of parts combined with greatness of dimension and simplicity of style, which it possesses; still the prolonged length, the twilight gloom half concealing the playful and varying effects of reflected

Cave of Fingal.

P

light, the echo of the measured surge as it rises and falls, the transparent green of the water, and the profound and fairy solitude of the whole scene, could not fail strongly to impress a mind gifted with any sense of beauty in art or in nature, and it will be compelled to own it is not without cause that celebrity has been conferred on the Cave of Fingal." Caverns occur in modern porphyry in the neighbourhood of Quito, and even in modern lavas, the ejection of which has taken place within the memory of man. Flinders has made us acquainted with caves in the lava of the Isle of France; and in the lava of Vesuvius of 1805, Gay Lussac found several upon a small scale. But caverns of an enormous extent occur in the lava of Iceland, that of Gurtshellir, situated in the torrent which has flowed from Bald Yökul, being forty feet in height, by fifty in breadth, and nearly a mile in length. Beautiful black volcanic stalactites hang from the high and spacious vault, and the sides present a succession of vitrified horizontal stripes, a thick coating of ice clear as crystal covering the floor. Henderson, in particular, describes one spot, the grandeur of which surpassed all expectation, the light of the torches rendering it peculiarly enchanting. The roof and sides of the cave were decorated with the most superb icicles, crystallized in every possible form, many of which rivalled in minuteness the finest zeolites; while from the icy floor rose pillars of the same substance, assuming all the curious and fantastic shapes imaginable, mocking the proudest specimens of art, and counterfeiting many well-known objects of animated nature. A more brilliant scene, says Henderson, perhaps never presented itself to the human eye, nor was it easy for us to divest ourselves of the idea that we actually beheld one of the fairy scenes depicted in Eastern fable.

Among the forms under which caverns present themselves, Humboldt distinguishes three principal kinds, which essentially differ from each other, notwithstanding all their apparent irregularities.

The first appear in the form of cracks or fissures, like empty veins of ore, of greater or less extent, but narrow and considerably prolonged, often penetrating far into the hard rock, and only reaching the day at one end. Eldon hole, in the Peak of Derbyshire, is an example of this class. This is a deep yawning chasm in the limestone strata, but no longer considered one of the wonders of the region, as its presumed unfathomable depths have been satisfactorily measured. In the reign of Queen Elizabeth, the Earl of Leicester is said to have hired a man to go down into it to ascertain its extent and form. The account of the adventure states, that he was let down about two hundred ells, and after he had remained at the length of the rope awhile, he was drawn up again, with great expectation of some discoveries; but he came up senseless, and died within eight days in a phrensied condition. Cotton alludes to this circumstance in his rude English

verses,

"Once a mercenary fool, 'tis said, exposed
His life for gold, to find what lies inclosed
In this obscure vacuity, and tell

Of stranger sights than Theseus saw in hell ;
But the poor wretch paid for his thirst of gain
For, being craned up with a distempered brain,
A faltering tongue, and a wild staring look,
He lived eight days, and then the world forsook."

Eldon Hole is a fissure about sixty feet long, twenty wide, and two hundred deep. In the Philosophical Transactions for the year 1781, there is an account of the descent of Mr. Lloyd, who was let down with a rope by eight men, and found the light sufficiently strong at the bottom to allow him to read print. He discovered a fissure in the rock at the bottom, through which a strong current of air proceeded, but as the aperture was nearly filled up with huge stones, he could not examine it. A former owner of the

pasture in which the chasm is situated, having lost cattle by falling into it, made the attempt to fill it up, and threw down many loads of stones without any visible effect, some of which were probably those which choked the aperture reached by Mr. Lloyd. The whole extent and actual depth of Eldon Hole have not therefore been ascertained.

There is a second kind of caverns which are essentially distinguished from the first by the circumstance that they reach the daylight at both ends, piercing through the rocks in which they are situated, and forming natural shafts. Their appearance is very remarkable when they occur on the top of isolated mountain-peaks, or of independent masses of rock; and when they are so straight that the day-light appears through them, they present a very remarkable aspect, and have been designated by the name of transparent caverns. On this account, the so-named Martin's hole is particularly celebrated. It penetrates the Tschingel-peak, one of the highest mountains of the Dodi chain; and twice in the year, in March and in September, the sun appears as if through a pipe, and gives to the valley beneath a highly singular and pleasing light. A similar phenomenon has been described by Pontoppidan as occurring in Norway, where there is a perforation of the mountain of Torghatten in Helgeland, of fifty fathoms in height, and a hundred fathoms in length, through which the daylight appears. Like phenomena present themselves at the hollow stone of Muggendorf; likewise in Saxon Switzerland, and a whole series of these perforations occur on the coast of the island of Heligoland, and on the coast of New Zealand.

The third and most frequent form of caverns is unquestionably that in which there is a series of extensions of nearly similar height and direction, which are connected with each other by passages of greater or less extent. This is the form of the caverns of the Hartz, the cave of Caripe visited by Humboldt, of Antiparos, and of the Peak of Derbyshire, the entrance to which, with the castle on its summit, is here represented. This is also the form of the more important caves of Franconia. The extent of these penetrations into the mountains, in particular of such as are situated in limestone, is often very extraordinary. In many of them the extremity has never been reached; and it appears from concurrent testimony that some of them have been explored for more than a mile in length. In this respect, the cave of Adelsberg, six miles from Trieste, is mentioned as the greatest of all, excelling all known caverns, not only in length, but in height. Deep abysses of five

and six hundred feet often occur in it; and in one of these, it was found necessary to give up the attempt to proceed farther. The entrance resembles a fissure in a huge rock caused by an earthquake. Here torches are always lighted to conduct visiters. The cavity itself

seems as if divided into several large halls and other apartments. The vast number of pillars by which it is ornamented by nature gives it a superb appearance; for they are as white as snow, and have a kind of transparent lustre. The bottom is of the same material; so that a person may imagine he is walking among the ruins of some stately palace, amidst noble pillars and columns, partly mutilated and partly entire. From the top, sparry icicles are seen everywhere suspended; in some places resembling wax tapers, which, from their radiant whiteness, appear extremely beautiful. Here occurs that extraordinary animal the Proteus, in shape between a lizard and an eel, transparently white, with a tinge of rose colour about the head. It adds, as Davy remarks, one instance more to the number already known of the wonderful manner in which life is produced and perpetuated, even in places which seem the least suited to organised existences-an animal to whom the presence of light is not essential, living indifferently in air and in water, on the surface of the rock, or in the depths of the mud.

Of an analogous kind is the Peak cavern in Castleton Dale, the approach to which is in the highest degree magnificent. The traveller passes through a chasm between two ranges of perpendicular rocks, having on his left a rivulet which issues from the cave, and pursues its splashing course over craggy and broken masses of limestone. A vast mass of rock suddenly appears before him, with the mouth of the cavern, which assumes the form of a depressed arch, a hundred and twenty feet in width, forty-two in height, and about ninety in receding depth. At the first entrance, a spectator is surprised to find that a number of twine makers have established their residence and manufactory within this gulf; and their rude appearance and machines singularly combine with the sublime features of the natural scenery. After proceeding about thirty yards, the roof becomes lower, and a narrow passage is reached where the blaze of day, which has been gradually softened into twilight, wholly disappears, and all further researches must be prosecuted by torch-light. After penetrating twenty or thirty yards in a stooping posture, there is a spacious opening, beyond which is the margin of a small lake called the First Water, the over

hanging rock descending in one place to within twenty inches of its surface. The lake is crossed in a boat or skiff, partly filled with straw, in which the passenger lies down, and is conveyed to the other side, where a spacious vacuity opens 220 feet in length, 200 feet broad, and in some parts 120 feet high; but from the want of light, neither the roof nor the sides of this great cavity can be plainly discerned. Proceeding onwards by the side of the Second Water, there is a projecting pile of rocks popularly called Roger Rain's House, on account of the water incessantly dripping from the crevices of the roof. Beyond this, another hollow opens, called the Chancel, where the rocks appear much broken, and the sides are covered with stalactical incrustrations. Here the stranger is generally surprised by an invisible vocal concert, which bursts in wild and discordant tones from the upper regions of the cavern, where a group of women and children are stationed for the purpose, the inhabitants of some of the huts at the entrance. After leaving the Chancel, and passing the Devil's Cellar, and the Half-way House, the path leads beneath three natural arches to another vast concavity, termed Great Tom of Lincoln, from its resemblance to a bell. Here, under the influence of a strong light, the arrangements of the rock, the spiracles in the roof, and the flowing stream, produce a striking scene. From this point the vault gradually descends, the passage contracts, and at length leaves only room sufficient for the stream. The entire length of this great excavation is 2250 feet, and its depth from the surface of the mountain about 620. A striking effect is frequently produced by the explosion of a small quantity of powder, wedged into a crevice of the rock, the report of which rolls along the roof and sides like a heavy and prolonged peal of overwhelming thunder. On returning from this dark recess, the effect of the light is singularly impressive. The rocks appear as if highly illuminated, and the plants and mosses upon them so vividly green, as to produce the impression that the sun must be shining brilliantly upon them, when the day is really dull and hazy. The Peak cavern is thus an example of a succession of great chambers connected together by narrow passages; and when we remember the soluble nature of the stone, and the stream that flows through it, there can be no doubt that, if not formed altogether by the action of water, it yet owes its present condition to that agency. A more extraordinary spot, perhaps, is in the neighbourhood, at the foot of the Winnats, or Windgates, called also the "portals of the winds," a deep and narrow inclined chasm, about a mile in length, the lower descent of which commands a fine view of the beautiful vale of Castleton. Here is the Speedwell mine, an artificial excavation, leading to a great natural cavern. After descending upwards of a hundred steps, and reaching the blackness of darkness, the visitor embarks upon a canal so narrow as to be able to touch the rock on both sides, and the ceiling above. Proceeding along this channel, which is not far short of half a mile in length, the guide pushing along the boat, an immense vacuity in the mountain is reached, and landing upon a ledge of rock, the scene becomes indescribably strange and appalling with the aid of a Bengal light. On the one hand there is an abyss of unknown depth, appropriately called the Bottomless Pit, into which the water from the level falls with a startling sound, and which swallowed up forty thousand tons of material in the excavation of the mine. On the other hand an enormous cavity opens above, the ceiling of which no light can reach, for rockets have been here let off, and have given out their brilliant coruscations as freely as from the surface of the earth.

Humboldt describes a somewhat dissimilar but very remarkable cavern in the western world, in the province of New Andalusia, not far from the convent of Caripe, called the Cavern of the Guacharo-the name of a class of nocturnal birds who make it their abode. The exterior of the place was majestic even to one accustomed to the picturesque scenery of the Alps. He had visited the Peak Cavern, and was acquainted with the different caves