GO REPORT — 1875. 



belonging to the fiimily Lahyrinthodontia ; subsequently it has been discovered 

 that the coal-field of Miinster-Appel in Rhenish Bavai-ia, and that of Saarbi-iick 

 between Strasburg and Treves, contain the skulls and bones of several species 

 of air-breathing reptiles which were described by Goldfuss under the generic 

 name Archegosmirus. The reptilian remains of the conglomerate, though now 

 not the oldest of their class, still retain their interest for the Pahneontologist, as they 

 prove that highly organized Dinosauria lived on Triassic land. I must refer you to 

 the original memoir for a full account of these bones, which enabled its authors to 

 establish two genera for them. The one, Thecodontosaurus, has the teeth placed 

 closely together in the jaw-bones. They are shai-p, conical, compressed, and have 

 their anterior and posterior borders finely denticulated, and the extremity slightly 

 bent, like the teeth of Megalosaurus. Palc^osaurus has the teeth compressed and 

 pointed likewise ; but one of the borders only is denticulated, and the other tren- 

 chant. The species are distinguished by the size and form of the teeth. The ver- 

 tebr£e resemble those of Teleosmirus in being contracted in the middle, and having 

 their articular surfaces slightly biconcave ; and the rest of the bones of the skeleton 

 resemble the forms of the Lacertian type. 



We know very little of the life of the Trias in the district under consideration, 

 beyond the reptilian remains first noticed here, until we come to the close of this 

 age, when we find upper grey marls of theKeuper overlain by and passing into a series 

 of black shales and limestones known as the Avicula-contorta or Khtetic beds, which 

 have a great interest for us, as they comprise the famous Bone-bed of Aust Olift' 

 known to all geologists. The leading fossils are Avicula contorta, Cardium lihceti- 

 cum, Monotis dectissata, Pecten Valonimsis, and tlie small crustacean Esthcria mimda. 

 The fishes are Nemananthus, Saurichthys, Hyhodus, Gyi-olepis, Sargodon, and Ccra- 

 todiis, with bones of Plesiosauriis and Ichfhi/osuurus. It is the teeth of Ceratodus, 

 or horned teeth, that have made Aust Cliff" famous ; and more than 400 different forms 

 have been described. Mr. 0. T. Higgins made the finest collection of these remains, 

 which has been purchased for the Museum, and forms one of its rarest treasures. 

 When these horned teeth, so called from the prominences they exhibit, were first 

 described by Agassiz, the living species of this genus was not known ; it is now 

 ascertained that it lives in the Mary, Dawson, and other rivers of Queensland, and 

 is called by the natives " Barramanda." The Cercdodus is very nearly allied to the 

 Lepidosiren , is cartilaginous, a vegetable-eater, and, like the Lepidosiren, lives in 

 muddy creeks ; during the hot season it buries itself in the mud, whence it is 

 dug up by the natives, its retreat being discovered by the air-hole through which 

 it breathes ; its nostrils are placed in the inside of the roof of the mouth. 



A very interesting paper on Ceratodus Fosteri (the specimen in the Museum) by 

 Mr. Stoddart, F.G.S., will be found in the ' Proceedings of the Bristol Naturalists' 

 Society,' vol. i. p. 145, 



The Lias, which succeeds the Avicula-contorta beds, presents a remarkable contrast 

 to them, and shows how much the life-conditions of every age depend on the phy- 

 sical agents that surround it. Two groups of animals appeared in great force in the 

 Liassic Sea — Ammonites and Reptiles. 



The Ammonites of the Lower Lias beds (A. angulatus, A. Bucldandi, A. Cony- 

 heari and others) attained a largo size ; and the middle and upper divisions of the 

 same formations were all characterized by different species that marked horizons 

 of life in these divisions. Associated with the Ammonites a large assemblage of 

 other Mollusca are found, as Grypluea, Lima, Unicardium, Pholndomya, Cardinia, 

 Hippopodium, Pleurotomaria, and a profusion of Belemnites and large Nautili. 



The Reptiles were very large, as you can see by the fine specimens on the w.alls : 

 Ichthyosaurus and Plesiosaurus were the dominant forms of this Class ; and Ptero- 

 dactyles with expanded wings performed the part of birds on the dry laud of that 

 era ; so that the air, the estuary, and the ocean had each separate forms of Reptile 

 life in the Lias age. Another change of conditions introduces us to new forms in 

 the Lower Jurassic sea, A large number of species of Conchifera and Gasteropoda 

 crowd the shelly beds of the Inferior Oolite ; and new forms of Ammonites apper- 

 taining to groups entirely different from those of the Lias are found in abundance 

 in Dundry Hill. In addition to the IMollusca we find many beautiful forms of 

 Echinodermata, and a large collection of reef-building corals in the upper beds of 



