otherwise have been utterly destroyed by exposure in the unprotected land-surface around-and the débris of old geological systems. Here have been preserved, in a natural museum arranged by the Thames itself, relics of the Arctic period of England's history, remains of freshwater shell-fish and of land-animals, which were long since embedded in the mud of the stream. We may find them with our own hands in the banks of the Thames and its tributaries: we may readily see them in the cabinets of our London museums. Let us proceed still further to learn the story they tell of the climate and zoology of the early Thames-country.

What, it may be asked, is the evidence we possess that the mammoth and rhinoceros really lived in the country in which we find their remains to-day; and that their bones have not been transported hither by some great catastrophe of Nature from other and distant lands? Such is the question that occurs to us in the presence of the gigantic bones that we found in the mud of the Thames Valley or exhibited in our geological museums. Let us look for ourselves at the answers that confront us when we pursue so natural an inquiry.

Zoology and Climate of the early Thames-country.

The extinct species of gigantic quadrupeds, the bones of which have been found in the river-deposits at Ilford are designated thus: Elephas primigenus-mammoth; Rhinoceros tichornis-two-horned woolly rhinoceros; Elephas antiquus, and Rhinoceros leptorhinus. These are some of the strange creatures that stand in the foreground of the picture of the ancient Thames Valley.

The abundance of the remains of the primeval elephant, which are found to-day embedded in contemporaneous stratigraphical conditions, and which are usually accompanied by the bones of the rhinoceros or hippopotamus, is part of the evidence that these creatures lived in the country in which they are buried.

In and around London, remains of the mammoth have been discovered in comparative abundance. They have been dug up from the solid ground in Gray's Inn Lane, Waterloo Place (thirty feet

deep), Kingsland,* Kensington, Brentford, Kew, Hurley Bottom, Frogmore, Isle of Sheppey, Lewisham, Woolwich, the Isle of Dogs, Ilford, Clacton, Gray's Thurrock, Erith, and other spots historical in the eyes of the geologist in the valley of the Thames.

But these wonderful relics of ancient Nature are by no means confined to the vicinity of London. They are found in nearly all the counties of England.

Of all the extinct Mammalia which have left their fossil remains in British strata, no species was more abundant or more widely distributed than the Mammoth or Elephas primigenius.

Wherever the last general geological force has left traces of its operations upon the present surface, in a form of drift or unstratified transported fragments of rock and gravel, and wherever the contemporary or immediately antecedent, more tranquil and gradual operations of the sea or fresh waters have formed beds of marl, of brick-earth or loam, there, with few exceptions, have bones or teeth of the Mammoth been discovered.

Quitting the dry land and caves of Great Britain, we find the bed of the German Ocean a most fertile depository of the remains of Elephas primigenus.†

In deciding, then, that the Thames Valley was for ages the home of elephants and rhinoceri, it had been amply demonstrated that this strange zoology was common throughout England. Further, it is fully ascertained that a similar and coeval distribution of animal life existed in Northern Europe, and that the physical conditions of the time were those which prevailed in the valley of the Thames.

But the discovery that the elephant and rhinoceros were for ages the wild and native denizens of the Thames Valley would seem to substitute a problem with regard to climate in place of the

* The finest tusk of a British Mammoth that has come under my observation forms part of the rich collection of fossil Mammalian remains obtained from Ilford by the late John Gibson, Esq., of Stratford, Essex; this tusk measured twelve feet six inches in length, following the outward curvature. A tusk disinterred from Mr. Hobson's brick-field at Kingsland, a model of which is

preserved in the Museum of the Geological Society of London, measures nine feet ten inches round the outer curve, three feet one inch in a straight line from point to base, and twenty-nine inches in its greatest circumference.-British Fossil Mammals, p. 245.

+ British Fossil Mammals, pp. 255 and 259.

vanquished problem of zoology. How can the naturalist maintain the Arctic character of the climate which he attributes to the country of the ancient Thames in the elephant and rhinoceros period of its history!

At first sight, the presence of the elephant and rhinoceros, as natives of the Thames Valley, would suggest that a tropical climate prevailed in England in these early years of its history. The living analogues of the Thames elephant and rhinoceros are now restricted to the warm and sunny regions of the globe. Their habitat is a country of tepid waters and tropical vegetation. Leviathan,

Who lieth under the shady trees, in the covert of the reed and fens,

would seem to share with them the country of sandy desert and humid jungle and marsh. Among the fossil remains of Ilford we find associated with the animals of a class now apparently living only in hot and torrid zones, other animals now confined to the cold and frigid zones. With the rhinoceros and hippopotamus is found the mammoth, a creature whose remains have not yet been found in tropical countries, whereas they are found in abundance in northern latitudes from forty to sixty degrees. Could these creatures of apparently different geographical habitat have existed together in the ancient Thames Valley? and if so, what was the climate of the period? Perplexing as the questions appeared to the naturalists who first considered them, they are now believed to have been satisfactorily solved, without impugning or subverting the known economy of Nature. Let us look at some of the facts which help to explain the problem.

The species of elephant and rhinoceros which are first on our list (Elephas primigenus, the mammoth, and Rhinoceros tichornis, two-horned woolly rhinoceros) and which are found fossil to-day in the Thames brick-fields, had a thick coating of hair, which shows that a tropical climate was not necessary for their existence.* The elephant is still found in the cold regions of the Himalayas, with a coat of hair like that of a poodle dog.† If Elephas primigenus were properly clothed, like its contemporaries of the early Thames Valley,

* Dr. BRANDT, quoted by PRESTWICH.

+ Bishop HEBER's Journal.

it might have existed as near the pole as is compatible with the growth of hardy trees and shrubs, for it was organised to gain its subsistence from the branches and woody fibres of trees, and was thereby rendered independent of the seasons which regulate the development of leaves and fruit.

The molar teeth of the elephant possess a highly-complicated and very peculiar structure, and there are no other quadrupeds that derive so great a proportion of their food from the woody fibre of the branches of trees. Many mammals browse the leaves, some small rodents gnaw the bark; the elephants alone tear down and crunch the branches, the vertical enamel-plates of their huge grinders enabling them to pound the tough vegetable tissue and fit it for deglutition. No doubt the foliage is the most tempting, as it is the most succulent part of the boughs devoured; but the relation of the complex molars to the comminution of the coarser vegetable substance is unmistakeable.

Forests of hardy trees and shrubs still grow upon the frozen soil of Siberia, and skirt the banks of the Lena as far north as latitude 60°. In Europe arboreal vegetation extends ten degrees nearer the pole, and the dental organisation of the Mammoth proves that it might have derived subsistence from the leafless branches of trees, in regions covered during a great part of the year with snow.

It can no longer be regarded as impossible for herds of mammoths to have obtained subsistence in a country like the southern part of Siberia, where trees abound, notwithstanding that it is covered during a greater part of the year with snow, seeing that the leafless state of such trees, during even a long and severe Siberian winter, would not necessarily unfit their branches for yielding sustenance to the well-clothed mammoth.†

There is good reason to conclude that the early Thames-country, like the rest of England, may well have had a climate and flora corresponding to that of frigid Siberia. In Siberia, at the present day, the great rivers are skirted with forests of pines, alders, willows, elms, and poplars; and a northern fauna, by no means limited, shares the country with man.

But had the fossil remains of the early Thames Valley been simply and unambiguously northern in character, the naturalist and palæontologist would have pronounced an easy verdict on the phenomena before them. It is the co-existence in the ancient Thames

* Professor OWEN, op. cit.

† PRESTWICH.

K

Valley of an apparently southern fauna with those of the mammoth and Siberian rhinoceros which has yet to be fully explained. With Elephas primigenus and Rhinoceros tichornis are found not only their more southern congeners, Elephas antiquus and Rhinoceros leptorhinus, but an aquatic mollusk, which has now retreated to such waters as those of the Nile. Can these exceptional southerly fauna in the valley of the ancient Thames be so accounted for as to leave the zoology of the country mainly and characteristically of a northern type?

Here Sir Charles Lyell has supplied a provisional answer to the question. "I long ago suggested the hypothesis, that in the basin. of the Thames there are indications of a meeting in the post-pliocene period of a northern and southern fauna. To the northern group may have belonged the mammoth-Elephas primigenus-and the Rhinoceros tichorhnis, both of which Pallas found in Siberia, preserved with their flesh in the ice. With these are occasionally associated the rein-deer. In 1855 the skull of the musk-ox (Bubalus moschatus) was also found in the ochreous gravel of Maidenhead, by the Rev. C. Kingsley and Mr. Lubbock; the identification of this fossil with the living species being made by Professor Owen. A second fossil skull of the same Arctic animal was afterwards found by Mr. Lubbock near Bromley, in the valley of a small tributary of the Thames; and two others were dug up at Bath Easton from the gravel of the valley of the Avon. Professor Owen has truly said, that, as this quadruped has a constitution fitting it at present to inhabit the high northern regions of America, we can hardly doubt, that its former companions, the warmly-clad mammoth and the two-horned woolly rhinoceros (R. tichorhinus) were in like manner capable of supporting life in a cold climate.'*"

"As an example of what may possibly have constituted a more southern fauna in the valley of the Thames, I may allude to the fossil remains found in the fluviatile alluvium of Gray's Thurrock, in Essex, situated on the left bank of the river, twenty-one miles below London. The strata of brick-earth, loam, and gravel exposed to view in artificial excavations in that spot, are precisely such as would be formed by the silting up of an old river channel. Among Quarterly Geological Journal, vol. xii. p. 124.