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But then, on careful consideration of the facts, the objection arises that the stalk, calyx, and arms of the palaeozoic Crinoid are exceedingly different from the corresponding organs of a larval Comatula; and it might with perfect justice be argued that Actinocrinus and Eucalyptocrinus, for example, depart to the full as widely, in one direction, from the stalked embryo of Comatula, as Comatula itself does in the other.
The first column marks the last appearance of several genera which are characteristic of Palaeozoic strata. The second shows those genera which are characteristic of the Upper Trias, either as peculiar to it, or, as in the three cases marked by asterisks, reaching their maximum of development at this era.
With respect to the apparently sudden extermination of whole families or orders, as of Trilobites at the close of the palaeozoic period, and of Ammonites at the close of the secondary period, we must remember what has been already said on the probable wide intervals of time between our consecutive formations; and in these intervals there may have been much slow extermination.
The substantiation of an ice-cap at the pole will disprove the first hypothesis; for what we took for ice before alighting may have been but banks of cloud, since, having been in the plane of the planet's equator at the time, we had naturally but a very oblique view of the poles; while the absence of glacial scratches shows, I take it, that though the axis may have been a good deal more inclined than at present, it has not, at all events since Jupiter's Palaeozoic period, been as much so as that of Uranus or Venus.
Cassian, now generally assigned to the lowest members of the Upper Trias or Keuper, leads us to suspect that when the strata of the Triassic age are better known, especially those belonging to the period of the Bunter sandstone, the break between the Palaeozoic and Mesozoic Periods may be almost effaced. Indeed some geologists are not yet satisfied that the true position of the St.
But now comes the further inquiry, Where was the highly differentiated Sauropsidan fauna of the Trias in Palaeozoic times? The supposition that the Dinosaurian, Crocodilian, Dicynodontian, and to Plesiosaurian types were suddenly created at the end of the Permian epoch may be dismissed, without further consideration, as a monstrous and unwarranted assumption.
Species of these genera occur in the Silurian, Devonian, and Carboniferous strata of Europe. Mr. Lonsdale remarks, that all these fossils have undoubtedly a Palaeozoic character, and that probably they correspond in age to a division of the system above the Silurian formations. The strata containing these remains are singular from the extreme variability of their mineralogical composition.
If under a nearly similar climate, the eocene inhabitants of one quarter of the world were put into competition with the existing inhabitants of the same or some other quarter, the eocene fauna or flora would certainly be beaten and exterminated; as would a secondary fauna by an eocene, and a palaeozoic fauna by a secondary fauna.
Aqueous, Plutonic, volcanic, and metamorphic Rocks considered chronologically. Terms Primary, Secondary, and Tertiary; Palaeozoic, Mesozoic, and Cainozoic explained. On the different Ages of the aqueous Rocks. Three principal Tests of relative Age: Superposition, Mineral Character, and Fossils. Change of Mineral Character and Fossils in the same continuous Formation.
In accepting the theory of the animal origin of man we have got to follow man back, not only till we find him a naked savage like the Fuegians as Darwin describes them, naked, bedaubed with paint, with matted hair and looks wild and distrustful, but we cannot stop there, we must follow him back till he becomes a troglodyte, a cave-dweller, contending with the cave bear, the cave lion, and the hyena for the possession of this rude shelter; back still, till we find him in trees living like the anthropoid apes; then back to the earth again to some four-footed creature, probably of the marsupial kind; still the trail leads downward and ever downward, till we lose it in that maze of marine forms that swarm in the Palaeozoic seas, or until the imagination is baffled and refuses to proceed.
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