PALEONTOLOGY In sinking a well in the yard of the Crown Inn at Allenton near Derby, a number of mammalian bones were discovered. These were carefully dug out, and after being examined and described by Mr. H. H. Arnold-Bemrose, 1 were deposited in the Derby Museum. The majority are referable to the Pleistocene hippopotamus, but one belongs to an elephant and another to a rhinoceros. The following species are recorded from the Carboniferous forma- tions of the county in the British Museum Catalogue of Fossil Fishes. Commencing with those of the Mountain Limestone, we have first of all three sharks belonging to an extremely primitive and totally extinct group known as the Ichthyotomi. Two of these, Cladodus mirabilis and C. striatus, belong to a genus containing several species, both being typically from the Mountain Limestone of Armagh. The third, Dicre- nodus dentatus, which was likewise first described from Armagh, is the sole representative of its genus. Among the rays and true sharks (Selachii), a representative of a widely- spread Carboniferous genus, Janassa imbricata, is peculiar to the upper division of the Mountain Limestone of the county, the two type teeth (apparently the only known remains of the species) having been obtained from Ticknall near Mel- bourne, South Derbyshire. 2 A more widely-spread species, J. clavata, also occurs at the same place. The mouths of the primitive rays of this genus were furnished with- crushing teeth of a very peculiar and un- mistakable type. From the same locality have been obtained teeth of an allied kind of ray, Petalorbyncbus psittacinus, which is common to the Carboniferous rocks of Armagh. The typical genus of the same family of rays (Petalodontidce] is represented by two species, Petalodus acuminates and P. hastingsite, from the Mountain Limestone of Ticknall, neither of which is, however, peculiar to the county. To the allied family Pristo- dontidce belongs Pristodus benniei, a species first described from Scotland, but also known by teeth from Ticknall. Another Palasozoic family of ray-like selachians, the Psammodontidce (at present only known by their dentition), are represented in the Carbon- iferous or Mountain Limestone of the county by Copodus spatulatus and Psammodus rugosus, both being widely spread forms belonging to genera with several species. The crushing teeth of Psammodus are in the form of large quadrangular flat plates, with a surface suggestive of sandpaper hence the name. Other fishes from the Mountain Limestone of the county, known as Pleuroplax attbeyi, PI. woodi, Psepbodus magnus, Xystrodus striatus, Pcecilodus ionesi, Deltoptychius acutus, and D. gibberulus, all of which were originally described from other localities, indicate the occurrence of an imperfectly known family of Palaeozoic sharks (Cochliodontidee) with crushing teeth, which appear to have been distantly related to the modern Port Jackson 1 Quart. Journ. Geol. Soc. Hi. 497. 2 A list of twenty species from this locality is given by E. Wilson (Midland 'Naturalist, iii. 172) ; many of the names are however synonyms, while others were applied to specifically indeterminable specimens, and others, again, have been amended. It would therefore be useless to quote the list seriatim. 37
