Scanty as is the information hitherto obtained in regard to the articulata of the coal formation, we have at least ascertained that some insects winged their way through the ancient forests. In the ironstone of Coalbrook Dale, two species of coleoptera of the Linnæan genus curculio have been met with: and a neuropterous insect resembling a corydalis, together with another of the same order related to the phasmidæ. As an example of the insectivorous arachnidæ, I may mention the scorpion of the Bohemian coal, figured by Count Sternberg, in which even the eyes, skin, and minute hairs were preserved.[213] We need not despair, therefore, of obtaining eventually fossil representatives of all the principal orders of hexapods and arachnidæ in carboniferous strata.
Next in chronological order above the Coal comes the allied Magnesian Limestone, or Permian group, and the secondary formations from the Trias to the Chalk inclusive. These rocks comprise the monuments of a long series of ages in which reptiles of every variety of size, form, and structure peopled the earth; so that the whole period, and especially that of the Lias and Oolite, has been sometimes called "the age of reptiles." As there are now mammalia entirely confined to the land; others which, like the bat and vampire, fly in the air; others, again, of amphibious habits, frequenting rivers, like the hippopotamus, otter, and beaver; others exclusively aquatic and marine, like the seal, whale, and narwal; so in the early ages under consideration, there were terrestrial, winged, and aquatic reptiles. There were iguanodons walking on the land, pterodactyls winging their way through the air, monitors and crocodiles in the rivers, and ichthyosaurs and plesiosaurs in the ocean. It appears also that some of these ancient saurians approximated more nearly in their organization to the type of living mammalia than do any of the reptiles now existing.[214]
In the vast range of strata above alluded to, comprising the Permian, the Upper New Red Sandstone and Muschelkalk, the Lias, Oolite, Wealden, Green-sand, and Chalk, scarcely any well-authenticated instances of the occurrence of fossil birds in Europe are on record, and only two or three of fossil mammalia.
In regard to the absence of birds, they are usually wanting, for reasons afterwards to be explained (see chap. [47]), in deposits of all ages, even in the tertiary periods, where we know that birds as well as land quadrupeds abounded. Some at least of the fossil remains formerly referred to this class in the Wealden (a great freshwater deposit below the chalk), have been recently shown by Mr. Owen to belong to pterodactyls.[215] But in North America still more ancient indications of the existence of the feathered tribe have been detected, the fossil foot-marks of a great variety of species, of various sizes, some larger than the ostrich, others smaller than the plover, having been observed. These bipeds have left marks of their footsteps on strata of an age decidedly intermediate between the Lias and the Coal.[216]
| Fig. 8. | Natural Size. |
Thylacotherium Prevostii (Valenciennes). Amphitherium (Owen). Lower jaw, from the slate of Stonesfield, near Oxford.[218]
The examples of mammalia, above alluded to, are confined to the Trias and the Oolite. In the former, the evidence is as yet limited to two small molar teeth, described by Professor Plieninger in 1847, under the generic name of Microlestes. They were found near Stuttgart, and possess the double fangs so characteristic of mammalia.[217] The other fossil remains of the same class were derived from one of the inferior members of the oolitic series in Oxfordshire, and afford more full and satisfactory evidence, consisting of the lower jaws of three species of small quadrupeds about the size of a mole. Cuvier, when he saw one of them (during a visit to Oxford in 1818), referred it to the marsupial order, stating, however, that it differed from all known carnivora in having ten molar teeth in a row. Professor Owen afterwards pointed out that the jaw belonged to an extinct genus, having considerable affinity to a newly discovered Australian mammifer, the Myrmecobius of Waterhouse, which has nine molar teeth in the lower jaw. (Fig. 9.) A more perfect specimen Fig. 9.
