On the pelorosaurus : an undescribed gigantic terrestrial reptile whose remains are associated with those of the iguanodon and other saurians in the strata of Tilgate Forest, in Sussex / by Gideon Algernon Mantell.

  • Mantell, Gideon Algernon, 1790-1852.
Date:
1850
Catalogue details

Licence: Public Domain Mark

Credit: On the pelorosaurus : an undescribed gigantic terrestrial reptile whose remains are associated with those of the iguanodon and other saurians in the strata of Tilgate Forest, in Sussex / by Gideon Algernon Mantell. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

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    large block of sandstone, and I succeeded, after much labour, in clearing them from the stone with their processes nearly entire; in the progress of my task a chevron bone of the crocodilian type, 10 inches long (Plate XXII. fig. 8), was laid bare and extricated. When these splendid fossils were first discovered, I referred them to the Iguanodon ; subsequently they were named by Professor Owen Cetiosaurus brevis*; and lastly, Dr. Melville and myself, in my Memoir on the Iguanodon-'f-, suggested the necessity of adopting a different specific appellation, and proposed that of “ Conybeariwe were unwilling to remove them from the genus Cetiosaurus, till corroborative evidence was obtained to justify the change. The description of these vertebrse in detail will be found in the British Association Reports for 1841 (p. 97), and by Dr. Melville in the Philosophical Transactions, 1849 (p. 296) ; but without figures no adequate idea can be given of the originals;};. I have therefore annexed delineations on a reduced scale, ^ linear, Plate XXII., and two views of the largest vertebra f ths the natural size, Plate XXIV. and XXV. I have been induced to add the two last drawings in order that the subject may be fully comprehended. These vertebrae are distinguished by the subquadrangular form of the articulating facets of the centrum or body, and the relative shortness of the antero-posterior dia- meter (Plate XXII. fig. 7)- The largest is 7i inches in the transverse, and 6f inches in the vertical diameter of the anterior face, and but 6 inches in the posterior: the length or antero-posterior dimension is but 3^ inches. The height to the top of the spinous process is 13 inches. The diameter of the neural canal, for the spinal marrow, is 2 inches. The other three bones are somewhat smaller; the most distal being only 6 inches transversely. These vertebrae are slightly concave in front, and almost flat behind; the upper part of the anterior face being the deepest, as shown in Plate XXII. fig. 5“. The sides of the body are concave, both lengthwise and vertically, with a transverse median convexity, as seen in Plate XXII. fig. 5“. The inferior surface of the centrum (Plate XXII. fig. 6) is slightly concave in its an- tero-posterior diameter, and divided by a longitudinal sulcus into two ridges, whose terminations obscurely indicate the position of the hsemapophysial articulations. It is noticeable, that in vertebrae of such magnitude, well-defined articulating spaces for the chevron bone are not present. The neural arch presents the most peculiar characters; it is large, and anchylosed to the anterior half of the upper surface of the centrum ; the posterior part of which is left free, as shown in fig. 5C and 7, Plate XXII. The anterior oblique processes * These vertebrae and the chevron hone, are placed in the same case as the bones of the Iguanodon, in the Gallery of Organic Remains of the British Museum. f Philosophical Transactions, 1849, p. 297. + Sir J. G. Dalyell very properly remarks, that “ delineation should be the inseparable accompaniment of description in natural history.”