Page:The Geologist, volume 5.djvu/41

Rh they are. But the adverse witnesses are by no means agreed amongst themselves; eight of them claim the rocks for the Silurian age, and fifty-eight for the Carboniferous. Is there no way of silencing, and yet satisfying, these doubtful characters? No method of so interpreting their testimony but that of sacrificing the Devonian system altogether? Are they not so many arguments in favour of the gradual passage of system into system? So many difficulties in the way of a belief in catastrophes, by which I mean convulsion or other form of violence (call it what you please) which, from time to time, shook the very life out of the world, causing a seizes of universal and synchronous depopulations of our planet? May we not regard them as so many tints intermediate, both in place and quality, between the extreme bands of the rainbow, uniting them into one beautifully graduated chromatic spectrum, so softly blending as to render it impossible to define the exact place of lines of demarcation, which, perhaps, have not, and never would have been supposed to have, an existence, had not observers hastily generalized from the imperfect evidence obtained during a period of colour blindness?

May we not regard them as just sixty-six pages in the old parish register connecting three otherwise unconnected portions, and showing that the population was not, during their time, cut off sharply, universally, and at once, whether by pestilence, war, or famine; but that the old inhabitants gradually disappeared, and that many of them remained amongst the new comers, discharging their accustomed functions under the somewhat changed conditions?

But if the Devonshire rocks were handed over to the Carboniferous or Silurian system, or divided between them, we should not be quit of the doctrine that some of the forms of one period have, at least in some instances, lived through it into the next; for the opponents of a Devonian period not only admit, but rest their case on the alleged fact that Silurian and Carboniferous forms are found blended together in Devonshire and elsewhere.

When, nearly a quarter of a century ago, Mr. Lonsdale first suggested that the fossils of South Devon, taken as a whole, exhibited a peculiar character intermediate to those of the Silurian and Carboniferous groups, he was perfectly aware that amongst them were forms referable to each of these Faunas; yet he made the suggestion, not- withstanding the existence of a physical objection, subsequently removed by Professor Sedgwick and Sir E. I. Murchison, who discovered that the culmiferous or anthracite shales of North Devon (superposed on the rocks we have been considering) "belonged to the coal, and not, as preceding observers had imagined, to the transition (Silurian) period."

And what has been the effect of the progress of discovery and nicer discrimination on this point? Has it increased or decreased the evidence in favour of a Devonian period? In 1846, Sir H. De la Beche, discussing this question, gave a total of a hundred and ninety species noticed in South Devon, which he thus disposed of: