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The vegetation of some of these northern sedimentary beds containing coal may be older than any of the coal-measures of central and southern England, as being coeval with the Mountain Limestone of the south. In Ireland the limestone predominates over the coal- bearing sands and shales.
Upper Lias, argillaceous, with Ammonites striatulus. FOREIGN. Keuper beds of Germany. Cassian or Hallstadt beds, with rich marine fauna. BRITISH. Wanting. FOREIGN. Muschelkalk of Germany. BRITISH. Bunter or Lower New Red sandstone of Lancashire and Cheshire. FOREIGN. Bunter-sandstein of Germany. BRITISH. Upper Permian of St. Bees' Head, Cumberland. FOREIGN. Dark-coloured shales of Thuringia.
At various levels in the coal measures of Nova Scotia, ripple-marked sandstones, and shales with rain-prints, were seen by Dr. Dawson and myself, but still more perfect impressions of rain were discovered by Mr. Brown, near Sydney, in the adjoining island of cape Breton.
They differ totally from the shales and sandstones in this respect, and instead of splitting up readily into thin flakes, they break up into irregular lumpy masses. And they all contain a very peculiar vegetable fossil called Stigmaria. This strange fossil was for a long time a sore puzzle to fossil botanists, and after much discussion the question was fairly solved by Mr.
Winifred and I had often, in our childish days, stood and watched old Shales, sitting cross-legged on a board in the window, at his work, when Winifred would whisper to me, 'How nice it must be to be a tailor! As I passed this shop I now saw that on the same board was sitting a person in whom Winifred had taken still stronger interest.
SUBDIVISIONS AND PHYSICAL GEOGRAPHY. The Devonian is represented in New York and southward by the following five series. We add the rocks of which they are chiefly composed. 5 Chemung . . . . . . sandstones and sandy shales 4 Hamilton . . . . . . shales and sandstones 3 Corniferous . . . . . . limestones 2 Oriskany . . . . . . sandstones 1 Helderberg . . . . . . limestones
The intercalated coal-beds, sixteen in number, are generally from one to five feet thick, one of them, which has two or three layers of clay interposed, attaining nine feet. At other points in the same coal-field the shales predominate over the sandstones.
The best known member of the group, a thin band or bone-breccia, is conspicuous among the black shales in the neighbourhood of Axmouth in Devonshire, and in the cliffs of Westbury-on-Severn, as well as at Aust and other places on the borders of the Bristol Channel.
This author adds the further interesting detail that the underlying Cretaceous shales are "very soft," and "have suffered very little by the sliding of the limestone over them."
The rocks in which the canyon is cut are for the most part flat-lying, massive beds of limestones and sandstones, with some shales, beneath which in places harder crystalline rocks are disclosed. Where the canyon is deepest its walls have been profoundly dissected.
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