XXX.—Deluge of the North of Europe.

EUROPEAN DELUGES. 42/

rock. Another similar block has been raised in Germany into a monument to the geologist Leopold von Buch.

These erratic blocks which are met with in the plains of Russia, Poland, and Prussia, and in the eastern parts of England, are composed of rocks entirely foreign to the region where they are found. They belong to the primary rocks of Norway; they have been transported to their present sites, protected by a covering of ice, by the waters of the northern deluge. How vast must have been the impulsive force which could carry such enormous masses across the Baltic, and so far inland as the places where they have been deposited for the surprise of the geologist or the contemplation of the thoughtful!

The second European deluge is supposed to have been the result

of the formation and upheaval of the Alps. It has filled with de'bris and transported material the valleys of France, Germany, and Italy over a circumference which has the Alps for its centre. The proofs of a great convulsion at a comparatively recent geological date are numerous. The Alps may be from eighty to loo miles across, and the probabilities are that their existence is due, as Sir Charles Lyell supposes, to a succession of unequal movements of upheaval and subsidence; that the Alpine region had been exposed for countless ages to the action of rain and rivers, and that the larger valleys were of pre-glacial times, is highly probable. In the eastern part of the chain some of the Primary fossiliferous rocks, as well as Oolitic and Cretaceous rocks, and even Tertiary deposits, are observable; but in the central Alps these disappear, and more recent rocks, in some places even Eocene strata, graduate into metamorphic rocks, in which Oolitic, Cretaceous, and Eocene strata have been altered into granular marble, gneiss, and other metamorphic schists; showing that eruptions continued after the deposit of the Middle Eocene formations. Again, in the Swiss and Savoy Alps, Oolitic and Cretaceous formations have been elevated to the height of 12,000 feet, and Eocene strata 10,000 feet above the level of the sea; while in the Rothal, in the Bernese Alps, occurs a mass of gneiss 1,000 feet thick between two strata containing Oolitic fossils.

Besides these proofs of recent upheaval, we can trace effects of tvvo different kinds, resulting from the powerful action of masses of water violently displaced by this gigantic upheaval. At first broad tracks have been hollowed out by the diluvial waves, which have, at these points, formed deep valleys. Aftenvards these valleys have been filled up by materials derived from the mountain and transported into the valley, these materials consisting of rounded pebbles, argillaceous

and sandy mud, generally calcareous and ferriferous. This double effect is exhibited, with more or less distinctness, in all the great valleys of the centre and south of France. The valley of the Garonne is, in respect to these phenomena, classic ground, as it were. As we leave the little city of Muret, three successive levels will be observed on the left bank of the Garonne. The lowest of the three is that of the valley, properly so called; while the loftiest corresponds to the plateau of Saint-Gaudens. These three levels .are distinctly marked in the Toulousean country, which illustrates the diluvial phenomena in a remarkable fashion. The city of Toulouse reposes upon a slight eminence of diluvial formation. The flat diluvial plateau contrasts strongly with the rounded hills of Gascony and Languedoc. They are essentially constituted of a bed of gravel, formed of rounded or oval pebbles, and again covered with sandy and earthy deposits. The pebbles are principally quartzose, brown @r black externally, mixed with portions of hard " Old Red" and New Red Sandstone. The soft earth which accompanies the pebbles and gravel is a mixture of argillaceous sand of a red or yellow colour, caused by the oxide of iron which enters into its composition. In the valley, properly so called, we find the pebbles again associated with other minerals which are rare at the higher levels. Some teeth of the Mammoth, and Rhinoceros tichorhinus, have been found at several points on the borders of this valley.

The small valleys, tributary to the principal valley, would appear to have been excavated secondarily, partly out of diluvial deposits, and their alluvium, essentially earthy, has been formed at the -expense of the Tertiary formation, and even of the diluvium itself. Among other celebrated sites, the diluvial formation is largely developed in Sicily. The ancient temple of the Parthenon at Athens is built on an eminence formed of diluvial earth.

In the valley of the Rhine, in Alsace, and in many isolated parts of Europe, a particular sort of diluvium forms thick beds; it consists of a yellowish-grey mud, composed of argillaceous matter mixed with carbonate of lime, quartzose and micaceous sand, and oxide of iron. This mud, termed by geologists loess, attains in some places considerable thickness. It is recognisable in the neighbourhood of Paris. It rises a little both on the right and left, above the base of the mountains of the Black Forest and of the Vosges; and forms thick beds on the banks of the Rhine.

The fossils contained in diluvial deposits consist, generally, of terrestrial, lacustrine, or fluviatile shells, for the most part belonging

to species still living. In parts of the valley of the Rhine, between Bingen and Basle, the fluviatile loam or loess, now under consideration, is seen forming hills several hundred feet thick, and containing, here and there, throughout that thickness, land and freshwater shells; from which it seems necessary to suppose, according ta Lyell, first, a time when the loess was slowly accumulated, then a later period, when large portions of it were removed — and followed by movements of oscillation, consisting, first, of a general depression^ and then of a gradual re-elevation of the land.

We have already noticed the caverns in which such extraordinary accumulations of animal remains were discovered: it will not be out of place to give here a resume of the state of our knowledge concerning hone-caves and bone-breccias.

The bone-caves are not simply cavities hollowed out of the rock; they generally consist of numerous chambers or caverns communicating with each other by narrow passages (often of considerable length) which can only be traversed by creeping. One in Mexico-extends several leagues. Perhaps the most remarkable in Europe is that of Gailenreuth in Franconia. The Harz mountains contain

many fine caverns; among others, those of Scharrfeld and Bauman's Hold, in which many bones of Hyaena, Bears, and Lions have been found together. The Kirkdale Cave, so well known from the description given of it by Dr. Buckland, lying about twenty-five miles north-north-east of York, was the burial-place, as we have stated, of at least 300 Hyaenas belonging to individuals of different ages; besides containing some other remains, mostly teeth (those of the Hyaena excepted) belonging to ruminating animals. Buckland states that the bones of all the other animals, those of the Hyaenas not excepted, were gnawed. He also noticed a partial polish and wearing away to a considerable depth of one side of many of the best preserved specimens of teeth and bones, which can only be accounted for by refeiring the partial destruction to the continual treading of the Hycenas, and the rubbing of their skin on the side that lay uppermost at the bottom of the den. From these facts it would appear probable that the Cave at Kirkdale was, " during a long succession of years, inhabited as a den by Hyaenas, and that they dragged into its recesses the other animal bodies, whose remains are found mixed indiscriminately with their

own." *' This conjecture is made almost certain by the discovery

"Reliquiae Diluvianse," by the Rev. W. Buckland, 1823, p. 19.

made by Dr. Buckland of many coprolites of animals that had fed on bones, as well as traces of the frequent 'passage of these animals to or from the entrance of the cavern or den. A modern naturalist visiting the Cavern of Adelsberg, in Carniola, traversed a series of chambers extending over three leagues in the same direction, and was only stopped in his subterranean discoveries by coming to a lake which occupied its entire breadth.

The interior walls of the bone-caves are, in general, rounded off, and furrowed, presenting many traces of the erosive action of water, characteristics which frequently escape observation because the walls are covered with the calcareous deposit called stalactite or stalagmite — that is, with carbonate of lime, resulting from the deposition left by infiltrating water, through the overlying limestone, into the interior of the cavern. The formation of the stalactite, with which many oi the bones were incrusted in the Cave of Gailenruth, is thus described by Liebig. The limestone over the cavern is covered with a rich soil, in which the vegetable matter is continually decaying. This mould, or humus, being acted on by moisture and air, evolves carbonic acid, which is dissolved by rain. The rain-water thus impregnated, permeating the porous limestone, dissolves a portion of it, and afterwards, when the excess of carbonic acid evaporates in the caverns, parts with the calcareous matter, and forms stalactite — the stalactites being the pendent masses of carbonate of lime, which hang in picturesque forms either in continuous sheets, giving the cave and its sides the appearance of being hung with drapery, or like icicles suspended from the roof of the cave, through which the water percolates;while those formed on the surface of the floor form stalagmite. These calcareous products ornament the walls of these gloomy caverns in a most brilliant and picturesque manner.

Under a covering of stalagmite, the floor of the cave frequently presents deposits of mud and gravel. It is in excavating this soil that the bones of antediluvian animals, mixed with shells, fragments of rocks, and roHed pebbles, are discovered. The distribution of these bones in the middle of the gravelly argillaceous mud is as irregular as possible. The skeletons are rarely entire; the bones do not even occur in their natural positions. The bones of small Rodents are found accumulated in the crania of great Carnivora. The teeth of Bears, Hyasnas, and Rhinoceros are cemented with the jaw-bones of Ruminants. The bones are very often polished and rounded, as if they had been transported from great distances; others are fissured; others, nevertheless, are scarcely altered. Their state of preservation varies with their position in the cave.

The bones most frequently found in caves are those of the Carnivora of the Quaternary epoch: the Bear, Hyaena, the Lion, and Tiger. The animals of the plain, and notably the great Pachyderms — the Mammoth and Rhinoceros — are only very rarely met with, and always in small numbers. From the cavern of Gailenreuth more than a thousand skeletons have been taken, of which 800 belonged to the large Ursus spelceiis, and sixty to the smaller species, with 200 Hysenas, Wolves, Lions, and Gluttons. A jaw of the Glutton has lately been found by Mr. T. McK. Hughes in a cave in the Mountain Limestone at Plas Heaton, associated with Wolf, Bison, Reindeer, Horse, and Cave Bear; proving that the Glutton, which at the present day inhabits Siberia and the inclement northern regions of Europe, inhabited Great Britain during the Pleistocene or Quaternary Period. In the Kirkdale cave the remains, as we have seen, included those of not less than 300 Hyaenas of all ages. Dr. Buckland concludes, from these circumstances, that the Hyaenas alone made this their den, and that the bones of other animals accumulated there had been carried thither by them as their prey; it is, however,

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