Page:Quarterly Journal of the Geological Society of London, vol. 25.djvu/235

 sandstones of Elgin and Ross with the Old Red Sandstones beneath them, I willingly adopt the view established by such fossil evidence, and consider that these overlying sandstones and limestones are of Upper Triassic age."

Shortly after these new lights upon the structure and stratigraphical position of Hyperodapedon had appeared, the able Director of the Geological Survey of India, Professor Oldham, who happened to be in England, drew my attention to some specimens obtained from Maledi, in Central India, and presented to this Society in 1860 by the Rev. Mr. Hislop. Among these were fragments of large jaws with teeth, which presented all. the characters of Hyperodarpedon ; and during the past autumn I received from Dr. Oldham a considerable number of similar remains, associated with those of Labyrinthodonts and Crocodilian reptiles. The peculiar interest of this discovery arises not only from the sudden, enormous extension of the distributional area of Hyperodapedon, but still more from the circumstance that Dicynodonts have been found in the same Indian strata, and, thus, that we get a step nearer to the determination of the age of the remarkable reptiliferous formations of Southern Africa, the Triassic or Permian age of which was already highly probable.

The last fact which needs to be mentioned in this history of the gradually growing importance of the genus Hyperodapedon is the highly interesting and important collateral evidence as to its age obtained by Mr. Whitaker, who will presently give you an account of the precise position in the Trias of Devonshire in which a specimen of the jaw of Hyperodapedon, which he brought to me a few weeks ago, was obtained.

I now proceed to describe the most important remains of Hyperodapedon which have come into my hands ; and I shall speak first of the specimen on which the genus was founded, which is the property of the Elgin Museum, and was sent to me in 1858.

The remains of this specimen are exhibited by the opposed faces of broken blocks of sandstone, some of which have been separated by splitting along the plane in which the fossil lay. On one of these blocks are the indications of seventeen vertebrae in a continuous series, though slightly disturbed from their normal position here and there. The bodies of all these vertebrae have about the same length, viz. 0.9 in. or 0.95 in. They are so much constricted in the middle as to be almost hourglass-shaped, and their terminal articular surfaces are slightly concave. In most of the vertebrae the neural arches and spines are shown indistinctly, or not at all ; but the sixth in order from the anterior end of the series is tolerably complete, and exhibits a broad and not very high spine, the summit of which is somewhat narrower than the base. This passes into the arch of the vertebra, which exhibits well- developed articular processes. The total height of the vertebra, from the lower edge of the posterior articular surface to the summit of the spine, is 1.85 in., that of the posterior articular surface of the centrum being 0.7 in.

The fourteenth vertebra of the series, from its general character