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Updated: May 2, 2025
The vast longevity of such specific forms has not been generally recognised in consequence of the change of names which they have undergone when derived from such distant formations, as when Atrypa unguicularis assumes, when derived from a Carboniferous rock, the name of Spirifer Urei, besides several other synonyms, and then, when it reaches the Permian period, takes the name of Spirifer Clannyana, King; all of which forms the author of the monograph, now under consideration, asserts to be one and the same.
The Carboniferous formation assumes various characters in different parts even of the British Islands.
The Brachiopods and Molluscs still abound, but the Molluscs begin to outnumber the lower type of shell-fish. In the Cephalopods we find an increasing complication of the structure of the great spiral-shelled types. Such is the life of the Carboniferous period. The world rejoices in a tropical luxuriance.
The ganoids survive in a few species out of thousands. The amphibia of the carboniferous and the next period and the reptiles of the mesozoic have disappeared; only a few feeble degenerate remnants persist. And this was necessarily so. Each advancing form crowded hardest on those which occupied the same place and sought the same food, that is, the members of the same species.
I wholly concurred in Ja's belief, but it seemed that it might be a difficult matter to exterminate the dominant race of Pellucidar. Thus conversing we followed the intricate trail toward the temple, which we came upon in a small clearing surrounded by enormous trees similar to those which must have flourished upon the outer crust during the carboniferous age.
And again, if it be true that all varieties of fishes and the great whales, and the like, made their appearance on the fifth day, we ought to find the remains of these animals in the older rocks in those which were deposited before the Carboniferous epoch. Fishes we do find, in considerable number and variety; but the great whales are absent, and the fishes are not such as now live.
The Chambered Shells, or the Cephalopods, represented chiefly in the earlier periods by the straight Orthoceratites described in a previous article, are now curled in a close coil, and the internal structure of their chambers has become more complicated. The subjoined wood-cut represents a characteristic Chambered Shell of the Carboniferous age.
So she and her fellow brood lived in mid-aquarium, or at most rested lightly against stem or glass, suspended by gentle suction of the complex mouth. Once, when I inserted a long streamer of delicate water-weed, it remained upright, like some strange tree of carboniferous memory. After an hour I found this the perching-place of fourteen Redfin tads, and at the very summit was Guinevere.
Except for the fishes, there were no very great changes in the character of the life from that which existed in the earlier time of the Cambrian and Silurian. The animals are constantly changing, but the general nature of the life remains the same as in the earlier time. In the Carboniferous or coal-bearing age, we have the second great change in the character of the life on the earth.
Apart from the appearance of the great fishes and Crustacea, the Carboniferous period was one of great stimulation to aquatic life. Constant changes were taking place in the level and the distribution of land and water. The aspect of our coal seams to-day, alternating between thick layers of sand and mud, shows a remarkable oscillation of the land.
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