The Student's Hand-book of Historical Geology

Abstract

GOOD wine needs no bush, but every prudent vintner will carefully abstain from hanging out a sign calculated in any way to convey to the passer-by the impression that the liquor to be obtained within is of inferior quality. If authors were equally cautious, we should not see, as in the case before us, a good book disfigured by a frontispiece, to say the least, not calculated to produce a favourable impression on the mind of one who opens the work for the first time. The plate in question is a fanciful representation of what some one has imagined may have been the distribution of land and sea during the Carboniferous period. It depicts the present bed of the North Atlantic as then occupied by a broad tract of continental land. Now, when we picture to ourselves a long tongue of land running out, during Carboniferous times, from Scandinavia across the Highlands of Scotland and on to the north and west of Ireland, we are well within the bounds of legitimate speculation. The arguments in favour of such an hypothesis are too well known to need reproduction here. Again, when we look at a geological map of North America, and note how the great central tract of Palaeozoic formations is even now hemmed in on the north and east by a belt of Archaean rocks, we are indulging in no improbable supposition if we infer that, during Palaeozoic times, the eastern Archaean strip extended further to the east than now, and that from it was derived part of the material for the formation of the rocks of the Palaeozoic basin. But it is obviously quite another thing if, on the strength of these two highly probable suppositions, we proceed to fill up the whole of the intervening ocean. It is a puzzle to our mind to imagine on what grounds any one can pretend to know what was the condition of things in mid-Atlantic so far back in the earth's history, and any attempt to lay down such a map as figures in the frontispiece to the present volume seems to be about as striking an instance as can be found of the unscientific use of the imagination. The Student's Hand-book of Historical Geology. By A. J. Jukes-Browne. (London: George Bell and Sons, 1886.)