Изображения страниц

lar tokens of its presence 32 The Longmynd in Shropshire is, in one view, the most interesting natural monument in the island ; a mountain-range of the very

[graphic][merged small]

shadow of death, and yet cradling the first faint traces of the dawn of vitality. Below are the indubitable deathkingdoms of the granitic and metamorphic rocks. Above —for the geologist is privileged to pile ideally Ossa on Olympus and Pelion on Ossa—rise, teeming with organisms, the sister Silurians, yielding whole segments some fifty feet thick every fragment of which was once alive. 33 Between is the huge borderland, five miles deep, representing some five times five millions of years, of which, reserving dubious traces of a tiny sandworm, thus much

[graphic][merged small]

may be said, that life throughout is perfectly FINDABLE, but has not been FOUND. So far from admitting, however, that we have here the true beginning of life on the earth, Mr. Darwin demands the concession of undiscovered strata, as much older than the oldest Sub

[graphic][merged small]

Devonian rocks, included in the great Siluro-Cambrian series, as these are older than the youngest of known formations 34 And this because otherwise life would start in Siluria far too high in the scale for the doctrine of natural selection. For its most typical form, the Trilobite (page 40), with its eye, in one species, of six thousand lenses, is as “ fearfully and wonderfully made” as any crustacean in our present seas; and just on the upper edge of the system, ere it passes into the Old Red Sandstone, vertebrate life itself appears in the oldest of fossil fishes. On Mr. Darwin's hypothesis, life could not have begun thus : the ransacking of Siluria, east, west, north, and south-evidence which it would be an abuse of terms to call negative-bears witness that life did so begin. It is scarcely more evident, indeed, that life vanishes towards the base of the Cambrian rocks, than that man disappears ere we reach the Eocene. But our author's scheme has fresh exactions to make, and those of the most exorbitant kind, as we pass upwards from Siluria to the earth of to-day. Not only must we extemporise an imaginary fossil creation below, but we must interpolate vast piles of strata, and untold tribes of population, into the extant fossil creation above. The plea is, possible denudation. Now, although a consider



able stratum may be in part so destroyed, few geologists will concede the likelihood, if the protective dip be taken into account, of its being utterly swept away. In point of fact, whatever blanks have appeared to intervene between the various systems are being rapidly filled up and bridged over. This is true whether we apply the test of conformable transition, or that of continuity of organic remains. “Every year,” observes an unexceptionable witness, “adds to the list of links between what the older geologists supposed to be widely separated epochs.

From M. Pictet's calculations of what per-centage of the genera of animals existing in any formation lived during the preceding formation, it results that in no case is the proportion less than one-third, or 33 per cent. It is the Triassic formation, on the commencement of the Mesozoic epoch, which has received the smallest inheritance from preceding ages.” The other formations not uncommonly “exhibit 60, 80, or even 94 per cent. of genera in common with those whose remains are imbedded in their predecessor." 35 Consistently with this, it must be noted that the three great divisions are not arbitrarily drawn. Proportion may be exemplified on any scale-on the scale of contracting poverty as on that of expanding plenitude.

Once, and again, and yet again, is there a dawn and a decay, a protracted dwindling and an exuberant revival, a lull and an outburst of life-giving energy, a trough and a crest of the creative wave. But the phenomenon



a, Hypozoic Zero. b, c. Life at the lowest.

of poverty of fossils, at the transition epochs, infers no interruption to the continuity of deposits. Whatever be missing then, here, in the main, are the rocks themselves. M. Pictet and the Westminster Review being witnesses, here are the platforms of ancient nature, the shelves of the vast museum from Siluria to the Tertiaries, for the purposes of this inquest practically complete.

22. But are these platforms sufficiently peopled ? Are these shelves adequately filled ? Mr. Darwin insists that they are not. Natural selection depends for its aliment on myriads of groups, of which it is necessary to suppose that the ocean catacombs have failed to transmit a solitary member. Species immensely more ancient have been preserved by thousands, but of myriads of these more recent forms not one representative has been preserved. This is surely somewhat startling.

« ПредыдущаяПродолжить »