On Dakosaurus from the Kimmeridge Clay of Shotover Hill

Abstract

E arly in the spring of 1866 I obtained from the Kimmeridge Clay of Shotover-hill, near Oxford, four entire teeth and one portion of a tooth of Dakosaurus , which is now for the first time described and figured as a British genus. The only description of this reptile with which I am acquainted is to be found in Quenstedt's ‘Der Jura†.’ This author, after mentioning the circumstance of his having described it in a former work under the name of Megalosaurus , states that the only part of the skeleton known is a portion of a lower jaw containing six teeth, which are implanted in distinct sockets ( Alveolen ): a detached tooth, figured in the work referred to, well expresses the general characters given below, even to the crenulation of the trenchant margins. It is noticed by Prof. Owen*, who rightly includes it among his “amphicœlian” Crocodilia. Teeth of Dakosaurus are said to occur, associated with remains of Pliosaurus, Gyrodus, Sphœrodus gigas , &c., in the Potton Sands described by Mr. Seeley; these are its companions, both in the Upper White Jura of Schnaitheim and in the Kimmeridge Clay of England. Mr. Walker† also mentions it as occurring in beds probablyof the same age at Upware, in the Fens of Cambridge, and in similar company. I have examined, through the kindness of Mr. W. Davies, a suite of the Potton fossils at the British Museum; but it would be almost impossible, owing to the worn condition of these fossils, which which have evidently been