A Monograph of the Silurian Fossils of the Girvan District in Ayrshire, with Special Reference to Those Contained in the 'Gray Collection', by H.A. Nicholson and R. Etheridge

A Monograph of the Silurian Fossils of the Girvan District in Ayrshire, with Special Reference to Those Contained in the 'Gray Collection', by H.A. Nicholson and R. Etheridge

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This historic book may have numerous typos and missing text. Purchasers can usually download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1878 edition. Excerpt: ...head (in casts) punctate. Thorax short and broad. The axis is equal in length to the pygidium, but much less than the glabella; wider than the pleurae, slightly convex. Pleurae flattened. Pygidium semicircular, with a broad, bevelled, and striated limb. Axis faintly segmented, with a row of tubercles on each side, with the exception of the first segment which is distinct; lateral lobes undivided, except for an anterior furrow on each side corresponding to the anterior somite of the axis. Obs.--The above are the characters of the British specimens referred to A. rostralus, Sars. The latter and Milne-Edwards describe the axis of the pygidium as possessing six rows of tubercles. This is quite possible, because the tails which have come under our notice are casts, and not in a good state of preservation, although we have one example in which five are visible on one side, and this character might easily be obliterated. The pits along the sides of the glabella which we have described above, are not visible in all the specimens before us, but are particularly well seen in one which we figure. In all, however, there is more or less a trace of them to be found, and especially of the most anterior and lowest pairs. The form of the head in this species is very characteristic, and were the sides prolonged from the genal angles to the base of the rostral spine, an almost equilateral triangle would be formed. As a British species, the occurrence of Ampyx rostratus is limited; as we are acquainted only with specimens from the typical Irish locality, a very doubtful specimen from Garn in Wales, referable to the Llandeilo, examples probably belonging to this form from the Coniston Limestone of Keisley, Westmorland, and the present examples from Girvan....show more

Product details

  • Paperback | 124 pages
  • 189 x 246 x 7mm | 236g
  • Rarebooksclub.com
  • United States
  • English
  • black & white illustrations
  • 1236792440
  • 9781236792440