1

below the surface of the earth, and the tremendous | Volcanic rocks, such as basalt, greenstone, desolation hurled over wide regions by numerous porphyry, and serpentine, differ widely fire-breathing mountains, show that man is re- from the plutonic ones in their nature and

very deep ocean, and contain only the remains of marine animals. They have been subdivided into the Cambrian, and the lower and upper Silurian systems. There are no organic remains in the Cambrian rocks, which are sometimes many thousand yards thick, but they abound in the Silurian system, increasing as we ascend in the series. Shell-fish, and crinoidea or stone lilies, trilobites, and sometimes truc fishes, are found in the lower series; and in the upper, seashells of every order, with crinoidea, corals, sea-weeds, a few land plants, and sauroid fishes, the principal vertebrated animals that occur in these early formations. While the Silurian rocks were being deposited, the northern hemisphere of our globe was under water. Lands and islands had begun to emerge from it, and carthquakes and volcanoes, insular and submarine, marked the close of the period.

During the great geological period which succeeded, the Secondary fossiliferous strata, forming the present High Land of Europe, were deposited at the bottom of a sea, by the streams and rivers which entered it. This interesting series consists, reckoning upwards, of the Devonian, or old red sandstone rocks,the carboniferous or coal strata, the permian or magnesian limestone rocks, the triassic or new red sandstone rocks, the jurassic or oolite rocks, and the cretaceous strata.

club mosses, occur in the shale. In the mountain limestone of this group, which is sometimes nine hundred feet thick, crinoidea, marine testacea, and corals, are found in abundance. The strata of coal had been greatly disturbed by the earthquakes which prevailed during this period.

The Permian rocks or Magnesian limestone, which overlie the coal measures, consist of conglomerates, gypsum, sandstone, marl, &c. ; but its leading feature is a yellow limestone rock, called Dolomite when granular, and containing carbonate of magnesia. The earlier Flora and Fauna begin to disappear, and peculiar ones take their place. Two species of saurian reptiles mark a new creation of animal life.

The Triassic, or new red sandstone system, consists of red marls, rock-salt, and sandstones, produced by the disintegration of metamorphic slate and porphyritic trap. This formation is in England singularly rich in rock-salt, which, with beds of gypsum and marl, is sometimes six hundred feet thick. The Musselkalk, a member of this series, and full of organic remains, is wanting in England, but exists in Germany. Gigantic frogs, have left their foot-prints on the rocks, and no fewer than forty-seven genera of fossils, shells, cartilaginous fish, encrinites, &c., have been found in the German trias.

The Jurassic or Oolite rocks-sands, sandstones, marls, clays, and limestones, were deposited in a sea of variable depth, during a long period of tranquillity. The European ocean deposited beds consisting almost wholly of marine shells and corals:

The Devonian rocks, sometimes ten thousand feet thick, consist of dark red and other sandstone, marls, coralline limestones, conglomerates, &c., contain sauroid fishes of gigantic size, and others, some with osseous shields, and some with wing-like appendages. During a long period of great tranquil-Belemnites and ammonites, from an inch lity, which followed the deposition of the Devonian rocks, tropical forests, and jungles of exuberant growth, covered the lands and islands which had sprung from the deep. Submerged by inroads of the sea, or carried down by land-floods, the plants of that period were deposited in estuaries, with the sand and mud which accompanied them, and formed the carboniferous strata which lie above the Devonian rocks.

in size to that of a cart-wheel, were entombed in myriads-forests of crinoidea flourished on the surface of the oolite, and encrinites in millions were embedded in the enchoreal shell marble, which forms such extensive tracks throughout Europe. Not one of the fossil fish, which are numerous, exist at the present day. Ferns, cycadeæ, and the pandanæ or screw-pine, occur in this formation.

The Carboniferous system is composed of "The new lands," says Mrs. Somerville, “ that countless layers of various substances, filled were scattered in the ocean of the oolitic period with an enormous quantity of fossil land were drained by rivers, and inhabited by huge croplants, intermixed with beds of coal. Up-codiles and saurian reptiles of gigantic size, mostly wards of 300 fossil plants have been collected, with their seeds and fruits, among which ferns, some of which have been 40 or 50 feet high, predominate. Huge forest trees-the pine and the fir-equisetaceous plants of gigantic magnitude, and tropical

The crocodiles came nearest to of extinct genera. remote similitude in general structure to living modern reptiles, but the others, though bearing a forms, were quite anomalous, combining in one the structure of various distinct creatures, and so monstrous that they must have been more like the visions of a troubled dream than things of real

existence; yet in organization a few of them came and extent, they occur in irregular tracts. nearer to the type of living mammalia than any The Eiocene, Meiocene, and the Pleiocene, existing reptiles do. Some of these saurians had lived in the water, others were amphibious, and groups of this formation, containing shells the various species of one genus even had wings differing less or more from those which now like a bat, and fed on insects. There were both exist, generally lie horizontally in the localherbivorous and predaceous saurians, and from ities where they were deposited, though their size and strength they must have been for- they are frequently found heaved up on midable enemies. Besides the numbers deposited the flanks of mountain chains, as on the are so great that they must have swarmed for ages Alps and Apennines. The gigantic reptiles in the estuaries and shallow seas of the period, found in preceding formations had nearly especially in the lias, a marine stratum of clay the lowest of the oolite series. They gradually de- disappeared, and terrestrial mammalia now clined towards the end of the secondary fossilife- occupied the land. The remains of marine rous epoch, but as a class they lived in all subse- mammalia have also been found at great elequent eras, and still exist in tropical countries, vations in the tertiary formation, and likealthough the species are very different from their wise those of extinct species of birds allied ancient congeners. Tortoises of various kinds to the owl, the buzzard, the quail, and the were contemporary with the saurians, also a fami- curlew. ly that still exists. In the Stonefield slate, a stra-climate passed from a tropical to an arctic During the tertiary period, the tum of the lower oolitic group, there are the remains of insects; and the bones of two small quad-one, owing to the additional elevation of the rupeds have been found there belonging to the land, and a great part of the continent of marsupial tribe, such as the opossum; a very remarkable circumstance, because that family of animals at the present time is confined to New Holland, South America, and as far north as Pennsylvania at least. The great changes in animal life during this period were indications of the succes sive alterations that had taken place on the earth's surface."-Pp. 15, 16.

Europe was covered by an ocean full of floating ice. Towards the close, however, of the Pleiocene period, the bed of the glacial ocean was upheaved, and the continent of Europe assumed nearly the same form and climate which it now possesses.

"The thickness of the fossiliferous strata," says The Cretaceous formation, consisting of has been estimated at about seven or eight miles ; our author," up to the end of the tertiary formation, clay, green, and iron sands, blue limestone, so that the time requisite for their deposition must and chalk, derives its name from the pre- have been immense. Every river carries down mud, dominance of the last substance in England sand, or gravel to the sea; the Ganges brings more and other countries, though it is actually than 700,000 cubic feet of mud every hour, the wanting in some localities where the other Yellow River in China 2,000,000, and the Missis strata occur. The Wealden clay, the low-sippi still more; yet, notwithstanding these great est member of this formation, is of fresh estimated that, if the sediment of all the rivers on deposits, the Italian hydrographer, Manfredi, has water origin, and contains the Portland the globe were spread equally over the bottom of fossil forest, with ferns and Auracarian pines, the ocean, it would require 1000 years to raise its and plants allied to the tropical zamias and bed one foot; so at that rate it would require cycadeæ. Tortoises and saurians swarmed 3,960,000 years to raise the bed of the ocean alone in its lakes and estuaries, and fish and wad- to a height nearly equal to the thickness of the ing birds also occur in the Wealden clay. taking account of the waste of the coasts by thesea foss liferous strata, or seven miles and a half, not The chalk above it abounds in marine fos- itself; but if the whole globe be considered, sils, turtles, corals, and marine shells. The instead of the bottom of the sea only, the time colossal saurians are few in number, but a would be nearly four times as great, even supposgigantic animal between the living Monitoring as much alluvium to be deposited uniformly and Iguana, lived at this time.

both with regard to time and place, which it never

more than once carried to the bottom of the ocean,

Old things were now passing away, and is. Besides, in various places the strata have been all things becoming new. We approach and again raised above its surface by subterranean things as they are. Old life is extinct as fires after many ages, so that the whole period if by a magic stroke, and new life springs from the beginning of these primary fossiliferous up around us. The great features of the strata to the present day must be great beyond earth are blocked out. The master-hand calculation, and only bears comparison with the is now at work, to lay on the drapery, and astronomical cycles, as might naturally be expectto bring out the permanent expression of ed, the earth being without doubt of the same anhis handiwork. The tertiary strata were What then shall we say if the time be included tiquity with the other bodies of the solar system. deposited in the basins and hollows of the which the granitic, metamorphic, and recent series previously existing crust of the globe, and occupied in forming? These great periods of though frequently of enormous thickness time correspond wonderfully with the gradual

"Every great geological change in the nature of the strata was accompanied by the introduction of a new race of beings, and the gradual extinction of those that had previously existed, their structure and habits being no longer fitted for the new circumstances in which these changes had placed them. The change, however, never was abrupt, except at the beginning of the tertiary strata; and it may be observed that, although the mammalia came last, there is no proof of progressive development, for animals and plants of high organization appeared among the earliest of their kind." -Pp. 27, 28.

Such," says Mrs. Somerville, in concluding her Geological chapter, "is the marvellous history laid open to us on the earth's surface. Surely it is not the heavens only that declare the glory of God-the earth also proclaims his handiwork."

increase of animal life and the successive creation | Central Asia, and to our notice of Elie de and extinction of numberless orders of being, and Beaumont's "Systems of Mountain Chains with the incredible quantity of organic remains according to their age,' 79# we must limit buried in the crust of the earth in every country on ourselves to a very cursory notice of this the face of the globe. part of Mrs. Somerville's work. The Great Continent has taken its general form from a belt of mountains and extensive tablelands, lying between the 38th and 65th parallels of latitude, and stretching from the coasts of Barbary and Portugal to Behring's Straits at the extremity of Asia. An immense plain, nearly on a dead level, lies to the north of this belt, interrupted only by the mountain systems of Scandinavia and Britain, and the low chain of the Urals. The lands to the south of the belt, including the fertile plains between the Indus and the Chinese Sea, and the barren wastes betwen the Persian Gulf and the foot of the Atlas mountains, are marked with but a few mountain systems of any considerable elevation and extent. The immense mountain zone of the Great Continent commences in the west about the Atlas and Spanish mountains, which must have been once united, raising their granite peaks in Africa to the height of 15,000, and in Spain to 7,300 feet. It crosses France at the height of 6,000 feet in Auvergne and among the Cevennes, carrying its principal crest to an altitude of 14,000 feet in the Alps, and throwing out, as outlying members, the Apennines, the Calabrian chain, and the mountains of Sicily, Greece, and Southern Turkey. The Alpine range divides itself at the Great Glockner into the two branches of the Noric and the Carnic Alps. The last of these, or the principal branch, separates the Tyrol and Upper Carinthia from the Venetian States, and taking the name of the Julian Alps at Mount Terglou, 10,000 feet high, it joins the eastern Alps at Balkan, the central ridge of which rises at once into a wall 4,000 feet high, and "everywhere rent by terrific fissures across the chains and table-lands, so deep and narrow that daylight is almost excluded." In speaking of the Alpine valleys, Mrs. Somerville gives the following notice of the glaciers which they contain

Having described the formations which compose the superficial envelope of the earth, Mrs. Somerville proceeds to treat of the form of the High Lands of the Great Continent, which embraces Europe, Asia, and Africa-a whole hemisphere nearly of the globe. The dry land in both hemispheres has an area of nearly thirty-eight millions of square miles. No fewer than twenty-four millions are contained in the great continent of the Old World, eleven millions in America, and scarcely three millions in Australia and its islands. Africa is three times, and Asia more than twelve times larger than Europe. Owing to the number of inland seas, the maritime coast of Europe is greater compared with its size than that of any other quarter of the world. It stretches about seventeen thousand miles from the Straits of Waygatz in the Polar Sea to the Strait of Caffa, at the entrance of the sea of Azoff. The coast of Asia extends to the length of thirty-three thousand miles, and that of Africa to sixteen thousand. The whole continent of America has a sea-line of thirty-one thousand miles. The ratio of the number of linear miles in the coast to that of square miles in the area is, for Europe 164, America 359, Asia 376, and Africa 530.

Referring our readers for an account of the High Lands of the Great Continent to our review of Humboldt's Researches in

* See Berghaus and Johnson's Physical Atlas, Geology, Plates I. VII. VIII. and X.

"It is scarcely possible to estimate the quantity of ice in the Alps; it is said, however, that, independent of the glaciers in the Grisons, there are 1500 square miles of ice in the Alpine range, from eighty to six hundred feet thick. Some glaciers have been permanent and stationary in the Alps

*See Berghaus and Johnson's Physical Atlas, Plates II. III. V. and VI.

time immemorial, while others now occupy ground | terminated by a table-land, which mainformerly bearing corn or covered with trees, which tains an altitude of 4,500 feet for 100 the irresistible force of the ice has swept away. miles." A surface of 600 square leagues These ice rivers, formed on the snow-clad summits

of the mountains, fill the hollows and high valleys, hang on the declivities, or descend by their weight through the transverse valleys to the plains, where they are cut short by the increased temperature, and deposit those accumulations of rocks and rubbish, called moraines, which had fallen upon them from the heights above. In the Alps the glaciers move at the rate of from twelve to twenty five feet annually, and, as in rivers, the motion is most rapid in the centre. They advance or retreat according to the mildness or severity of the season, but they have been subject to cycles of unknown duration. From the moraines, as well as the stria engraven on the rocks over which they have passed, M. Agassiz has ascertained that the valley of Chamouni was at one time occupied by a glacier that had moved towards the Col di Balme. A moraine 2000 feet above the Rhone at St. Maurice shows that at a remote period glaciers had covered Switzerland to the height of 2155 feet above the Lake of Geneva.

"Their increase is now limited by various circumstances-as the mean temperature of the earth, which is always above the freezing-point in those latitudes; excessive evaporation; and blasts of hot air, which occur at all heights, in the night as well as in the day, from some unknown cause. They are not peculiar to the Alps, but have been observed also on the glaciers of the Andes. Besides, the greater quantity of snow in the higher Alps the lower is the glacier forced into the plains."-Pp. 51, 52.*

of this range is occupied by the Snae Braen, the greatest mass of perpetual snow and glaciers on the continent of Europe.

As the mountains of Great Britain, Ireland, Faroe, and the north-eastern parts of Iceland, have the same general character and direction as the Scandinavian range, they are supposed to have been elevated at the same time and by the same forces acting in parallel lines, and have therefore been placed in the same system. The Faroe Islands, to the west of Norway, rise immediately into a lofty table-land 2,000 feet above the sea, and are bounded by precipitous cliffs. In a zone lying between 55 and 62 of latitude, including the south of Sweden, the Faroe isles, and the west coast of Greenland, the crust of the earth is gradually sinking beneath its former level, while the coast of Norway, from Sölvitsberg northward to Lapland, where the elevation is greatest, is rising at the rate of four feet in an hundred years! Mrs. Somerville has given the following interesting notice of the mountains of our own country, as part of the Scandinavian system, but which, we trust, are neither sinking nor rising like some of its other portions.

"The rocky islands of Zetland and those of Passing over the lofty range of the Cau- Orkney form part of the mountain system of casus, extending 700 miles between the Scotland: the Orkney islands have evidently been Black Sea and the Caspian, and rising to separated from the mainland by the Pentland Firth, the height of nearly 17,796 feet in the El- where the currents run with prodigious violence. The north-western part of Scotland is a table-land brouz; the Russian mountains, whose from 1000 to 2000 feet high, which ends abruptly highest point is 14,600 feet;-the great in the sea, covered with heath, peat-mosses, and oriental table-land of Thibet and its moun- pasture. The general direction of the Scottish tains as sufficiently described in our arti-mountains, like those of Scandinavia, is from cle on Central Asia, already referred to, north-east to south-west, divided by a long line of we come to the fifth chapter of the work be- lakes in the same direction, extending from the fore us, in which Mrs. Somerville treats of Moray Firth completely across the island to south the secondary mountain systems of the of the island of Mull. Lakes of the most picturGreat Continent, commencing with the tains. The Grampian hills with their offsets and esque beauty abound among the Scottish mounScandinavian system, which "has been compared to a great wave which, after rising gradually from the east and forming a crest (8,412 feet high), falls perpendicularly into the sea in the west." This is 1000 miles long, beginning at Cape Lindesnaes and ending at Cape Nord Kyn in the Polar Sea. The southern portion of it is 150 miles broad; and at the distance of 360 miles from Cape Lindesnaes, "the mountain forms a single elevated mass,

range

* See Berghaus and Johnson's Physical Atlas, Geology, Plate IV.

some low ranges, fill the greater part of Scotland north of the Clyde and Forth. Ben Nevis, only 4,374 feet above the sea, is the highest hill in the British islands.

"The east coast of Scotland is generally bleak,

though in many parts it is extremely fertile, and the midland and southern counties are not inferior may be cited as a model of good cultivation; and either in the quality of the soil or the excellence of the husbandry. To the west the country is wildly picturesque; the coast of the Atlantic, penetrated by the sea, which is covered with islands, bears a strong resemblance to that of Norway.

"There cannot be a doubt that the Hebrides formed part of the mainland at some remote geo