belongs to the same era, the quarries of which abound with innumerable remains of land and river organisms, proclaiming the existence of an ancient lake in this locality in whose bed they were deposited. The volcanic masses of the Rhine, consisting of the Roderberg, the Eifel, and the "castled crag of Drachenfels," with its associates, forming the Siebengebirge, or group of Seven Mountains, and almost all the vine-clad hills from Bonn to Mayence, on each side of the river, which have been erupted through secondary rocks during the tertiary era, are enduring memorials of some of the great physical changes which have transpired in this attractive region since the general contour of the continent was formed.

CHAPTER XI.

DRIFT AND ERRATIC BLOCKS.

Erratic Blocks, in Gloucester, Massachusetts.

NDER a variety of designations, as the "drift," "boulder-clay," and "erratic-block group"-the diluvium of the early geologistsdiversified deposits are embraced, widely spread over the surface of many countries, but entirely wanting in others; occurring in valleys, on plains, on plateaux, and at high elevations; distributed over formations of all ages, either constituting the visible superficies, or thinly covered with the turf and cultivable soil. The Drift-a term which is sufficiently accurate for a general view of the subject-is composed

of, First, a tenacious and compact clay, of blue or red colour, and containing boulders of various sizes distributed throughout its mass; Second, lying over this, a series of beds of gravel, sand, and plastic or brick-clay. The former appears generally a tumultuous accumulation, the result of some species of violent action; the latter usually bear the marks of a quiet deposition from water. In the tenacious or boulder-clay, there are occasionally found small beds of water-laid gravel and sand, as indications of times of quiet occurring throughout its deposition. Sometimes the sand and gravel have been consolidated into sandstone and conglomerate by the infiltration of iron or carbonate of lime. The drift belongs to the Newer Pliocene or Pleistocene era. It is distinguishable from the older tertiary deposits by its confused aggregation and general unstratified character; and from accumulations proceeding at the present period, by its occurring at every altitude attainable by mountains in situations where no agency as now acting could have placed it. In many instances its materials have been originated locally; that is, been derived from rocks within a few miles of the spot where they are now found, as appears from the accordance of their

mineral character; but in cases equally numerous, they have been transported from a considerable distance, and even from the mountains of remote lands, from which they are now separated by seas, which are thus proved not to have existed at the period of the passage. The preceding remarks must not be understood as applying to every case of drift, which is often a mere bed of gravel or pebbles. The surface of the drift frequently

Monument Mountain.

appears scooped out into deep basin-shaped depressions, and raised into corresponding elevations, the difference of level amounting to from one to two hundred feet, the external aspect presenting a series of tortuous conical heaps with intervening cavities, as if excavated by the hands of Titans. These roundtopped tumuli are very common in the northern part of the western continent, as in the

annexed view, taken from the neighbourhood of Monument Mountain, in the United States; and in some instances they have been mistaken for artificial mounds, the sepulchres of a departed race!

Along the eastern side of England from the Thames to the Tweed, extensive and thick beds of gravel or loam are distributed, not only mantling lowland districts, but elevated table lands, and capping insulated hills, covering the chalk of the Yorkshire wolds and the crag of Norfolk and Suffolk. In the midland counties these accumulations are abundant. "From Houghton on the Hill," says Mr. Conybeare, "near Leicester, to Braunston, near Daventry, proceeding by Market Harborough and Lutterworth, the traveller passes over a continuous bed of gravel for about forty miles;" and throughout the red marl, lias, and oolite districts similar masses occur, the pebbly constituents consisting of the wrecks of rocks of the most distant ages, and derived from remote localities. In the gravel deposits of South Derbyshire there are fragments of almost all the English formations from granite upwards to the chalk; and it would not be difficult, according to the authority just cited, to form almost a complete geological series of English rocks from many single gravel beds. In Earl Spencer's park at Althorp, Northamptonshire, in the gravel used for the roads, brought from an adjoining parish, there is a large proportion of chalk flints, though at such a distance from the present limits of the chalk; and on the oolite formation near Northampton, there are fields as thickly strewed over with fragments of pure white chalk, as the superficial soil is generally with the substance of the subjacent rock. Sir Joseph Banks observed pebbles of porphyry in the gravel near the town of Dunstable, in Bedfordshire, porphyritic rocks occurring at no nearer point than the Charnwood Forest hills of Leicestershire. In various places the transported matter is highly metalliferous, yielding lead, tin, platinum, and gold, with many of the more valuable of the precious stones, as the diamond, sapphire, ruby, and topaz. The native sites of these products have been broken down and reduced to gravel, and their mineral wealth removed with the débris. Lead is obtained from drift between lake Superior and the Mississippi; tin occurs in the gravel of Mexico and Cornwall; and pebbles of lead are found under similar circumstances in the vale of Clywdd in a sufficient quantity to be worth working. The drift is also highly fossiliferous, containing abundant remains of quadrupeds, mostly of extinct species, but belonging to extant genera, which are now however confined to regions far distant from the sites where the fossil species are met with.

Among the organic remains of the drifted clays or gravels, the skeletons of colossal herbivorous mammalia occur in great profusion, and are the most remarkable, consisting of the elephant and mastodon—animals belonging to the proboscidian tribe, being furnished with a flexible trunk; the rhinoceros, the hippopotamus, the megatherium and megalonyx, the sivatherium, the horse, and the gigantic horned elk.

Elephant-Elephas primigenius of Blumenbach, Elephas fossile of Cuvier, and mammoth of the Russians.-There are two species of the living elephant; the Indian, inhabiting the warm countries of Asia, below 30° of north latitude, but flourishing the most, near to the equator; and the African, ranging from Senegal to the Cape of Good Hope. The fossil elephant is a distinct species, but agrees more nearly with its Asiatic than with its African congener, its remains being very widely distributed, and found in very high northern latitudes. Several species have been indicated from differences of form in the molar teeth; but the living animal will suffice for a general description of the extinct race, only supposing more colossal dimensions, a mane, and clothing of long hair. Teeth, tusks, and bones of prodigious size have been met with in different parts of our own island, in the county of Northampton, at Gloucester, at Trenton, near Stafford, and Harwich, in the valleys of the Thames and Medway, in Salisbury Plain, and in Holderness, never occurring in the regular strata, but in the overlying drift. They were noticed in the early periods of British history, and occupy a place in the old chronicles. By antiquaries they were once supposed to be the remains of elephants brought over by the armies of Rome-an idea which comparative anatomy refuted, by showing their discordance with the living species of the genus, and which was seen to be untenable by bones of hippopotami being found in connection with them—animals which never could have travelled in the train of the Roman legions. Fossil elephantine remains have been dug up in Ireland and Scotland, in Iceland and Sweden; and with probability Cuvier conjectured that the bones of supposed giants, mentioned by Pontoppidan as having been found in Norway, were relics of these ancient animals. They have been repeatedly exhumed in North and South America, from the plain of Quito, from Mexico, and the United States; and throughout Europe they are very generally distributed, appearing in abundance in some localities. Those particular spots, rich in elephantine remains, are at Seilberg, near Cronstadt, on the Necker; at the village of Theide, near Brunswick; in the valley of the Arno, near Florence; and at Bielbecks, near Market Weighton in Yorkshire, in a gravel bed of very limited extent, occupying a hollow of the new red sandstone. Blumenbach states, writing in 1803, that within his knowledge more than two hundred elephants had been found in Germany. It is, however, particularly in the severer latitudes of Asiatic Russia that the fossil elephant is common; and there the ivory of the tusks is so far uninjured as to be used for ornamental purposes, and sought as an article of profit. To the natives of Siberia the animal is known as the mammoth, signifying an animal of the earth, from the presumption that it was unable to endure the light of day, and actually lived beneath the surface of the soil, like the existing mole. According to Pallas, from the river Don to the promontory of Tchutskoinoss the most easterly point of Asia- there is scarcely a stream the banks of which do not afford remains of the mammoth; and one remarkable case in which the animal was found preserved both the entire skeleton and fleshy parts-and inspected by Mr. Adams, an academician of Petersburg, has attracted great attention.

In the year 1799 a Tungusian fisherman named Schumachoff, who generally went to hunt and fish at the peninsula of Tamut, after the fishing season of the Lena was over, had constructed for his wife some cabins on the banks of the lake Oncoul, and had embarked to seek along the coast for mammoth tusks. During this expedition he one day observed a strange shapeless mass projecting from a bank, the nature of which he did

not understand, and which was at such an elevation as to be beyond his reach. The bank consisted of frozen earth covered with ice partially thawing in the summer season. Returning to the same spot the succeeding year, 1800, he observed the object rather more disengaged, but still could not determine what it was; but towards the end of the summer of 1801, he could distinctly see that it was the frozen carcase of an enormous animal, the entire flank of which, and one of the tusks, had become exposed. The summer of 1802 was cold, and the animal remained in much the same state: but that of 1803 was warmer than usual; and, the ice melting largely, the carcase became entirely disengaged, and fell down from the crag on a sand-bank forming part of the coast of the Arctic Ocean. In March 1804, Schumachoff came to the mammoth, carried off the tusks, which he sold to a merchant for the value of fifty rubles. In 1806-the seventh year from the discovery- Mr. Adams, travelling in that distant and desert region, on an embassy to China with Count Golovkin, examined the animal, which still remained on the sand-bank where it had fallen, but in a greatly mutilated condition. The wandering fishermen had taken away large quantities of the flesh to feed their dogs; the wild animals, white bears, wolves, wolverines, and foxes had also feasted on the carcase; but the skeleton remained quite entire, with the exception of one of the fore-legs. The entire spine, the pelvis, one shoulder blade, and three legs were still held together by their ligaments, and by some remains of the skin; the pupils of the eyes were still distinguishable; the brain remained within the skull, but a good deal shrunk and dried; and one of the ears was in excellent preservation, still retaining a tuft of strong bristly hair. The animal was a male, and had a long mane on the neck, but was not one of the largest size. The skin was extremely thick and heavy, and as much was undestroyed as required the exertions of ten men to remove, which they accomplished with difficulty. Mr. Adams had the good fortune to re-purchase the tusks from the merchant to whom they had been sold, and finally transported the whole skeleton to Petersburg, where it now is, in the museum of the Academy, exhibiting the following dimensions, -9 feet 4 inches high, 16 feet 4 inches long, exclusive of the tusks, which are 9 feet 6 inches, measuring along the curve. hair of the mammoth appears to have consisted of strong bristles, a foot or more in length, with another kind, more flexible, and a third, a reddish brown wool, growing among the roots of the long hair. Cuvier remarks upon this fact, as an undeniable proof that the animal belonged to a race of elephants with which we are now unacquainted, by no means adapted to dwell in the torrid zone, but adapted to a temperature which would soon be fatal to the existing Asiatic and African races from its cold. We shall, subsequently, notice this consideration of climate, merely remarking, that the high latitudes now abounding with the "thick-ribbed ice" appear to have sustained an immense number of these colossal quadrupeds. There are islands in the Arctic Ocean, where the bones of the mammoth occur in prodigious abundance, which show no marks of detrition by a far transportation, and prove the exuberance of the race in the localities where their remains are found.

Mastodon.-The animals of this proboscidian tribe constitute a distinct genus, of which

there are no living species, but they are more nearly allied to the elephant than to any other existing race. The name is a compound of two Greek words, signifying mamillary teeth, referring to the principal character of the mastodon as distinct from its elephantine contemporary. The teeth are covered with a thick and brilliant enamel, and with sharp points, which caused the animal for a long time to be regarded as carnivorous. The remains of thirteen species have been discovered, six in Europe, four in India, two in South America, and one in North America

The latter is the Mastodon maximus of Cuvier, a colossal creature, armed with gigantic tusks. Parts of the skeleton found at Albany, on the Hudson river, were described by Dr. Mather in the year 1712, who deemed them the bones of giants, and regarded the discovery as confirming the sacred record, "There were giants in the earth in those days." Afterwards similar remains were found abundantly along the course of the Ohio; and the "animal of the Ohio" became the name of the unknown creature, till Cuvier originated its scientific denomination. Myriads of its bones occur along the river of the Osages, and indeed are commonly met with all over North America between the parallels of 33° and 43° north latitude, or in the country between Charlestown and Lake Erie, from near the coast of the Atlantic to the Rocky Mountains. Within these limits the principal locality is the Big Bone Lick in Kentucky, one of those marshy valleys containing brackish water, locally termed "licks," on account of the deer and other animals resorting to them. Here a vast number of bones of various extinct animals, accompanied with remains of plants, have been found imbedded in darkcoloured mud and gravel, the broken appearance of which seems to indicate a long drift and the violent action of water. It has been estimated that the bones of one hundred mastodons, two hundred elephants, twenty buffaloes, two oxen, and two deer, have been carried from this marsh. The native Indians have long been acquainted with the gigantic quadrupeds entombed in their territory. According to an old tradition, they occupied it till, attacking the deer and buffalo created for their own use, the "Mighty One above" seized his thunder and killed them all, with the solitary exception of one of the largest males. He shook off the thunderbolts as they fell upon his massive head; but, being wounded in the side, fled at length to the great lakes, where he has continued to the present period. Mr. Darwin mentions a similar idea current among the native inhabitants of South America respecting the mastodon, to that which the northern Asiatics entertain of the mammoth. Sailing down the river Parana, he found two immense skeletons near each other, projecting in bold relief from a perpendicular cliff, and was told by the men in the canoe that they had often observed them, had wondered how they got there, and conceived, as the most probable theory, that they were the remains of huge burrowing animals. The great mastodon probably haunted marshy places, feeding upon the roots of the vegetables common to such sites. It was probably lower in stature than the Indian elephant, but more elongated. The largest and most perfect specimen, hitherto discovered, was exhumed in the town of Newburg, New York, the length of the skeleton being 25 feet, and its height 12 feet, while the tusks were 10 feet long.

Rhinoceros.—The range of this animal is now comparatively limited and exclusively tropical, being chiefly located in Southern Africa, the Asiatic islands, and India beyond the Ganges, the one-horned rhinoceros occupying the two latter districts, and the twohorned the former. The remains of five extinct species are noticed by Cuvier, three of large size, and all two-horned; but altogether ten species are enumerated. They are very widely spread, and occur abundantly in the cold regions of the globe, towards the severe latitudes of the polar circle, as well as in all the temperate parts of Europe. In short, wherever the bones of the fossil elephant are found, they are generally in connection with those of the now associate animal, the rhinoceros. Germany has furnished them in great profusion; and Italy likewise in immense quantities, but of a different species; while the clay and gravel beds of our own country have been scarcely less prolific. Their first discovery with us was in 1668, upon digging a well at a village near Canterbury. As in the case of the mammoth, we have an instance of an entire rhinoceros found buried in the sand on the banks of one of the tributaries of the Lena, in 64° north latitude, the head and feet of which are now preserved at Petersburg. The discovery was made in December 1771, and is described by Pallas. The animal was