bones are no where discovered in the regular tertiary strata. The country that could give support to the mammoth, or ancient elephant, to the mastodon, and the elk, might, for aught we know to the contrary, be also suited for the residence of man.

It is very different with respect to the secondary strata; for though many of these strata have once been dry land, or in the vicinity of dry land, yet we no where find in them the bones of herbivorous mammalian quadrupeds, that could have been with men joint tenants of the globe; nor even do we find bones of carnivorous quadrupeds that might have preyed upon the former, had they existed.

During the tertiary epoch, however, there is evidence of great revolutions of the surface, by the elevation of mountain ranges, which might, perhaps, render the earth unfit, for the continued existence of the human species; and I am inclined to believe, that the occurrence of human bones in caverns, or in diluvial beds of gravel, sand or mud, has not yet invalidated the position, that the creation of man was posterior to the tertiary epoch.

We come now to the English caverns: they have been more recently the object of attention than the bone caverns of Germany; but their discovery may be said to have given a new impulse to geology, both in this country and on the Continent, for which we are indebted chiefly to the enlightened and indefatigable exertions of Professor Buckland of Oxford.

Single skeletons of large quadrupeds have formerly been discovered in caverns in this country; but we had no authentic account of the bones of carnivorous animals having been found in any English caves, previously to the year 1821; when some labourers, working in a quarry at Kirkdale, near Kirby Moorside, in Yorkshire, discovered an opening covered over with rubbish and earth, about one hundred feet above the neighbouring brook. This was the mouth of a low cavern extending about two hundred feet into the rock. The floor of the cavern was covered with broken bones and teeth of various animals, encased in a stratum of mud about a foot thick. Fortunately this cavern was examined by Professor Buckland, of Oxford, soon after its discovery, who has published a very luminous account of its structure and contents, elucidated by references to the most remarkable caverns in other countries which he has visited, containing the bones of carnivorous animals. The bones in the Kirkdale Cave are broken and gnawed, and some of them preserve the marks of the teeth which have fractured them. Even the excrements of animals, similar to those of the hyena, have been discovered with them. The bones in this cave differ much from those in the caves of Germany, as a great number of them belong to herbivorous animals, and the carnivorous animals whose remains are most abundant are hyenas.

Among these remains, Professor Buckland has ascertained bones of the following orders :

Carnivorous Quadrupeds.--The hyena, tiger, bear, wolf, fox and weasel.

Pachydermata. The elephant, rhinoceros, hippopotamus, and

horse.

Rodentia or Gnawers.-The hare, rabbit, rat, water-rat, and

mouse.

Ruminant Animals.-The ox and fragments and bones of three species of deer.

Birds. The raven, pigeon, lark, snipe, and a small species of duck.

From the great number of bones of the hyena found in this cave, Professor Buckland infers that it had long been the habitation of these animals. It is their ascertained habit, partly to devour the bones of their prey; they also devour the dead bodies of their own species; like wolves they are gregarious, and hunt in packs. From the habits of the hyena, he explains the occurrence of the remains of large herbivorous quadrupeds, like the elephant, in so low a cave as that of Kirkdale; they have been dragged into it by these voracious animals. Several English caverns have since been explored. In some of them there are bones both of herbivorous and carnivorous animals similar to those in the Kirkdale Cove. These caves are described in Professor Buckland's valuable work, entitled Reliquiæ Diluviana.

That the caverns in which the bones of carnivorous animals are found in such prodigious quantities, were the retreats of some of these animals, cannot be doubted. Many circumstances, described in the account of the Kirkdale Cave, can be explained only by admitting it. There are, however, other circumstances particularly in the caves of Germany, which would imply, that part of the bones belong to animals that had fallen through fissures, which formerly opened into these caverns, or that the bones themselves had been carried by currents of water, through subterranean passages into these caverns, as before explained in the present chapter. In the cave at Gaylenreuth there are rounded fragments of limestone, intermixed with the bones; and the entrance of some of the caverns is much too small to have admitted the animals whose bones are found in them. I think it is also probable that a violent convulsion of nature, as a rising deluge and the fierce war of elements without, might have driven, under the strong impulse of alarm, numerous animals of different species into the same caverns, where they devoured each other, and their bones have been intermixed with those of the former inhabitants. The entrances of many of the caverns, and the caverns themselves, were doubtless formerly more lofty than at present; they have been gradually lowered by the subsidence of the upper strata. Indeed, it is admitted that the caverns and grottos in the neighbourhood of Adelsberg, have occasioned numerous depressions of the surface. Such an effect must generally take place, in a greater or less degree, with the strata over caverns.

The occurrence of the bones of quadrupeds in the clefts or fissures of rocks, intermixed with fragments of the rock, and cemented with them into a kind of breccia, is very common in many of the calcareous rocks adjoining the Mediterranean sea. The osseous breccia of Gibraltar is well known: the calcareous matter which has been infiltrated into the fissures, and forms the cement, has generally a reddish colour, and contains so much phosphoric acid, from the decomposition of animal matter, as to become luminous in the dark when scraped. The bones in the fissures surrounding the Mediterranean, belong chiefly to herbivorous quadrupeds; but they are sometimes intermixed with marine shells, indicating a great change in the level of the rocks subsequent to the filling of the fissures.

Osseous breccia, similar to that in Europe, has been recently discovered by Major Mitchel, in the rocks bordering Wellington Valley, in New Holland. The breccia contains bones and fragments of rock, with the same red calcareous cement as the osseous breccia of Gibraltar, &c.

According to the examination of Cuvier and Mr. Pentland, some of the bones belong to different species of the kangaroo, and animals of the same genera that exist in New Holland; but others belong to species hitherto unknown to naturalists. Among these bones there are the remains of a species of elephant: a fact extremely interesting, as it proves that, in the ancient condition of the globe, this part of its surface supported animals more analogous to those of Asia and Africa, than any which existed upon it when first discovered by Europeans. In the report to the Geological Society of France, 1831, it is observed-"Thus we have in New Holland, a deposition of osseous breccia and caverns, similar to those of Europe. Were these depositions cotemporary? This is not very probable; at different epochs the analogy has consisted in the mode of formation; many different catastrophes may have destroyed the great animals of the Ohia, of the Irrawadi, of the north and central parts of Europe, and of Australia, and buried their bones in fissures and caverns, or in beds of clay and gravel. But whatever was the epoch of the deposition in New Holland, the organization of animal life was then, in a great part, the same as at present; since we find in the osseous breccia, the types of that class of animals that are still peculiar to the country, but always accompanied by bones of genera, (the mastodon and elephant,) which are altogether unknown there."

The depositions of calcareous earth pendant from the roofs of caverns, called stalactites, and those upon the floors of caverns, called stalagmites, are formed by the evaporation of water, holding calcareous earth in solution. A drop of water, in evaporating, deposits a pellicle of limestone, which is increased by succeeding depositions,

until a small protuberance of solid limestone is formed, nearly the shape of a drop of water. This protuberance becomes enlarged by water trickling over it, and takes the shape of an icicle. The water that drops upon the floors of caverns, sometimes deposits a thick coat of limestone over the whole floor; but in those parts where the drops fall most frequently, a more copious deposition of calcareous earth takes place, in the form of tubercles: these are the stalagmites. In some instances the stalactites and stalagmites increase, until they nearly fill the whole cavern.

CHAPTER XXI.

ON THE DESTRUCTION OF MOUNTAINS, AND THE FORMATION OF SOILS; AND ON ALLUVIAL AND DILUVIAL DEPOSITIONS.

Erroneous Opinions respecting the Growth of Stones, supported by the Authority of John Locke.-On the Causes in present operation that wear down Rocks Rapid Destruction of Mountains dependent on their Structure.-Fall of Mont Grenier in Savoy.-Breaking down of the Barriers of Mountain Lakes.-Scattered Masses of Rock.-Increase of Land by Alluvial Depositions in Lakes, and the Deltas of large Rivers.-On the Formation of productive Soils.-Recent Strata formed in Lakes.-Peat and Peat Moors.-Inundations of Sand.-Remains of Elephants and other large Animals found in the Diluvial Beds in England, and the Frozen Regions of Europe and Asia.

FEW persons can have travelled a hundred miles through any country without having seen beds of gravel, or of rounded stones, or fragments of rock scattered in different directions, which were evidently never brought into their present situation by the labour of man. In some instances, these masses of loose stones, or large fragments of rock, occur on the summits of hills, or on elevated ground, and the stones are, altogether, unlike any rocks or strata in the adjacent districts. Among the hundreds of travellers to whom such objects are familiar, it is surprising how few have ever raised the enquiry-" How did these masses of rock, or beds of loose stones, come here?" One great reason for this indifference arises from a cause that may surprise geologists. Many well educated persons, who possess much information on various subjects, still entertain the belief that stones grow in the places where they are now found: this belief excludes the necessity for further enquiry. They can also refer to the authority of the ablest philosopher this country ever possessed, for a confirmation of their opinion, should it be controverted.

The celebrated John Locke states, in his "Elements of Natural Philosophy," that "all stones, metals, and minerals, are real vegetables; that is, grow organically from proper seeds, as well as plants.”

If, in the present age of general information, any one should think it superfluous to notice this extraordinary passage, let him enquire among his friends, whether stones grow? and he will be somewhat surprised by the answers he may receive.

These scattered fragments of rock, or beds of loose stones, together with beds of sand and gravel, present objects of enquiry of the most interesting kind. From what districts were they transported? What were the causes by which they were removed? What was the epoch of their removal?

A farther enquiry also presents itself, as some of the beds of loose stone are rounded, or water-worn, like the shingles on the sea beach, but are now raised many hundred feet above the high-water mark.