. The Canadian journal of science, literature and history. 386 THE IMPERFECTION OF THE upon the denuded surface of the Chalk, filling up all the inequalities of its eroded Section, showing strata of Tertiary age (a) resting upon a worn and denuded surface of White^ Chalk, (b) the stratification of which is marked hy lines of flints. In the unconformability, then, between the Chalk and Eocene Rocks, "we have unequivocal evidenceâirrespective of anything that â we learn from Palseontologjâthat the break between the two forma" tions was one of enormous length. In Britain, the
. The Canadian journal of science, literature and history. 386 THE IMPERFECTION OF THE upon the denuded surface of the Chalk, filling up all the inequalities of its eroded Section, showing strata of Tertiary age (a) resting upon a worn and denuded surface of White^ Chalk, (b) the stratification of which is marked hy lines of flints. In the unconformability, then, between the Chalk and Eocene Rocks, "we have unequivocal evidenceâirrespective of anything that â we learn from Palseontologjâthat the break between the two forma" tions was one of enormous length. In Britain, the interval of time thus indicated is not represented by any deposits, and in Europe generally, there are but a few fragments of such. We may be quite sure, however, that during the time represented in Britain by the mere line of unconformability between the Chalk and the Eocene, there were somewhere deposited very considerable accumulations of sediment. "Whether we shall ever succeed in discovering these, or any part of these, is, of course, uncertain. We may be certain, how- ever, that such deposits, if ever discovered, will prove to be charged with the remains of animals intermediate in character between those of the Cretaceous and the Eocene period, and the large gap now existing between these formations will thus be more or less com- pletely bridged over. Amongst other well known instances of more or less general unconformity in the stratified series, may be mentioned that between the Lower and ITpper Silurian (not always present), that between the Lower and Upper Old Red Sandstone (also not universal), that between the Carboniferous and Permian Rocks, that between the Permian and Triassic Rocks (not universal), and that between the Lower and Upper Cretaceous Rocks. All these physical breaks are accompanied by more or less extensive palseontological breaks as well. Other breaks which the absence of fossils renders less important, 0£. Please note that these images a
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