anoplotherium, have been contributed to the list of the eocene mammalia of England. To the extensive marine fauna of the chalk, have been added several new forms of mollusca, and many continental species, formerly unknown in the greensand or neocomian beds of Atherfield, have been obtained from that productive locality. The rich flora and fauna of the lands and waters of the "country of the iguanodon " have received most important accessions. The fossil vegetables comprise specimens of clathraria, endogenites, cycadeæ, coniferæ, ferns; and, for the first time, the seed-vessels, or strobili, of the trees which occur petrified at Brook Point and other localities in England, and in a carbonised state in Hanover and the north of Germany, have been collected from the Wealden strata of the Island. The molluscous fauna has been augmented by new species of the freshwater genera, cyclas, physa, planorbis, limneus, paludina, and unio; and of fluviatile entomostracous crustaceans, crustaceans, namely, cyprides and estheria. Portions of some small undescribed fishes have also been obtained; as well as several splendid examples of the wellknown large species of lepidotus and hybodus, already familiar to the collector as characteristic denizens of these deposits. The discovery of portions of two lower jaws, and of a fragment of the upper jaw, with several mature molars in their natural position, and of the humerus, scapula, coracoid, and cervical vertebræ of the iguanodon,—and of the humerus and vertebræ of a new genus of stupendous size, the pelorosaurus, in Tilgate Forest; and of various parts of the skeleton of other gigantic saurians, whose generic characters and relations are not defined,-are treasures so rich and rare, as to offer the highest encouragement to the diligent explorer of the Wealden deposits of the Southeast of England. No certain vestiges of birds, or of the highest class of vertebrata, the mammalia, have as yet been discovered, either in the chalk or Wealden formations; but the Stonesfield beds have yielded one more specimen of the lower jaw of the small warm-blooded quadrupeds, whose fossil relics have conferred so much celebrity on those oolitic deposits, as affording the only evidence of the existence of mammalia antecedently to the eocene epoch. I still indulge the expectation that sooner or later remains of birds and mammalians will be discovered associated with those of the huge terrestrial reptiles of the Wealden; for at Stonesfield the jaws of the marsupial and insectivorous mammalia are found imbedded in blocks of stone containing teeth and bones of the Megalosaurus, the colossal saurian, whose remains occur as abundantly in the Wealden of Tilgate Forest. With every addition to our knowledge of the organised beings that inhabited the dry land when the oolite, Wealden, and cretaceous strata were in progress of accumulation, fresh proofs are obtained that the terrestrial flora and fauna continued essentially the same from the commencement of the lowermost bed of the oolite, to the deposition of the uppermost stratum of the chalk, although the marine fauna was subjected to successive changes in the species and genera of the fishes, and of the mollusca, and other invertebrata. Some authors have lately dwelt on the closer connection between the oolite and the Wealden, than between the latter and the chalk; apparently unaware that the general analogy, not identity, in the terrestrial organisms, was pointed out in the first work which treated of the fossils of the Wealden as constituting a peculiar group; * but we must not forget that several of the most characteristic Wealden fossils occur high up in the cretaceous series; as for example, "Fossils of the South Downs," p. 59; published in 1822. the iguanodon, clathraria, lonchopteris, endogenites, abietites, &c. Partial comparisons of this nature are but of little value. To obtain satisfactory results, the floras and faunas of the land and of the sea must be separately considered. If the organic remains of the three geological formations be contemplated under this aspect, it will be seen that while the inhabitants of the seas of the oolite and chalk, and of the rivers of the Wealden, present, in the diversity of species and genera which characterises the several groups of strata, strong lines of demarcation, the dry land was clothed with the same vegetable forms, and inhabited by the same marvellous types of reptilian organisation throughout the vast periods of time indicated by the extent and enormous thickness of these sedimentary strata. The following table will place this general accordance in a more striking point of view :-- Thus the data obtained from an examination of the relics of the plants and animals imbedded in the debris of the islands and continents, brought down by fluvio-marine currents into the seas of the oolite and chalk, and by the freshwater streams and rivers into the delta and estuary of the Wealden, prove that the terrestrial fauna and flora were essentially the same throughout the geological epochs comprised in this survey.* Forests of pines and other coniferæ flourished contemporaneously with palms, and cycadeæ, and ferns, alike, during the deposition of the Stonesfield slate, and the arenaceous strata of the chalk. † * It is not meant to aver that the terrestrial species are the same throughout the oolite, Wealden, and cretaceous ages, but that the general characters of the fauna and flora were alike on the islands of the oolitic period, and of the chalk. †The association of coniferæ (or needle-leaved trees, as the illustrious author of "Cosmos" significantly terms this family), with palms, arborescent ferns, &c., occurs in the coal formation, and throughout all the subsequent periods up to the tertiary. Humboldt remarks that we have so accustomed ourselves, although erroneously, to regard firs and pines as northern forms, that he experienced a feeling of surprise, when, in ascending from the shores of the South Pacific towards Chilpansingo, and the elevated valleys of Mexico, 4,000 feet above the level of the sea, he rode a whole day through a dense wood of Pinus occidentalis, and observed that these trees, which are so similar to the Weymouth pine, were associated with fan-palms (Corypha dulcis), and swarming with brightly-coloured parrots. Coniferæ and palms grow together on the north-eastern extremity of the island of Cuba, within the tropics, and scarcely above the level of the sea.a This illustrious philosopher also remarks, that if the surface of the earth did not rise to great altitudes within the tropics, the strikingly characteristic form of acicular-leaved trees would have remained unknown to the inhabitants of that zone.b This fact should be remembered, when attempting to explain the physical condition of the surface of the countries on which the flora of the carboniferous epoch flourished. a "Cosmos," Bohn's translation. Colossal herbivorous and carnivorous reptiles were the principal inhabitants of the land; pterodactyles traversed the atmosphere; aquatic reptiles swarmed in the fens and marshes; marine saurians frequented the sea-shores, and bays, and estuaries; dragon-flies sported over the waters; beetles pursued their drowsy flight, alike, when the peculiar oolitic types of mollusca, and radiaria, and zoophytes, and fishes, and crustaceans, swarmed in the surrounding ocean, as in the cretaceous period, when most of the genera and species had died out, and other forms occupied their place in the system of nature. From these, and innumerable facts of a like character, we perceive that the idea once generally entertained that the extinction of species and genera had been occasioned by physical revolutions and catastrophes, assumed to have swept over the earth's surface, must now be abandoned. Successive mutations in species and genera appear to be the result not of physical but organic laws; the first appearance, the duration, and the persistence of any type of organisation, are determined by laws as inscrutable, but as certain and immutable, as those which govern the revolutions of the sidereal universe; and as the period of life and death of every individual of a particular species of animal and plant is irrevocably preordained, so also is that of the annihilation of the race to which it belongs. And here I must conclude this sketch of the palæontological discoveries that have been brought under my notice since the original publication of this work, and bid farewell to the COURTEOUS READER, who has accompanied me in these Excursions through the Isle of Wight, and along the adjacent coasts of Hampshire and Dorsetshire. |