PALEONTOLOGY Essex Pleistocene, this being the wild swan (Cygnus musicus), of which the British Museum possesses a leg-bone from Grays. A few fish remains have been obtained from the brickearths of Essex, mainly from Grays, and have been provisionally assigned to the following species, 1 viz. the pike (Esox lucius), ruff (Acerina vu/garis), roach (Leuciscus rutilus), dace (L. dobula), rudd (L. erythophthalmus) t and eel (Anguilla vu/garis). With the exception of the first, which also occurs at Copford and Ilford, all these forms are known from the deposits at Grays. Mammalian remains from the Red Crag at Walton and other localities where the same formation occurs in the county appear to be exceedingly rare. Fragments of the tusks of the Crag walrus (Odobanus huxleyi) are however recorded from Essex. At the time when the ' cement stones,' or septaria, of the London Clay were collected in the neighbourhood of Harwich, these when broken were occasionally found to be formed round part of a mammalian skeleton or the shell or skull of a turtle. In the winter of 1856-7 a portion of such a nodule containing bones, which had been obtained near Harwich, was brought to Sir R. Owen, who described the skull and other remains found therein as those of a new genus of mammal, under the name of Pliolophus vulpiceps. Subsequently however they were identified by Sir W. H. Flower with a mammal previously described by Owen from the London Clay of Kent as Hyracotberium leporinum. The animal in question, which was about the size of a fox ; was one of the ancestral types of the horse. The Essex specimen is in the British Museum. Of even greater interest is a fragment of the lower jaw of a much larger mammal in the same collection containing two teeth, which was dredged off the Essex coast between St. Osyth and Harwich some time previous to the year 1846, and appears to have been derived from the London Clay. This specimen is described and figured in Owen's British Fossil Mammals and Birds under the name of Coryphodon eoceenus, and forms the type of both the genus and the species. For many years the affinities of the Coryphodon were unknown, but from the evidence of complete skeletons obtained in North America it is now ascertained to have been a large hoofed mammal of very primitive type allied to the wonderful horned Uintatherium of the North American Eocene. Skulls and shells of large marine turtles belonging to the extinct genus Lytoloma are not uncommon in these Harwich cement stones, and there is a considerable series of such specimens in the British Museum. Some of these remains belong to L. crassicostatum, of which the type specimen is from Harwich, and was originally described by Sir R. Owen as Chelone crassicostata. The second species, originally described by the same palaeontologist on the evidence of a skull from Harwich, is L. planimentum. From the Chalk of Essex remains belonging to those gigantic 1 See E. T. Newton, Geol. Mag. Dec. 4, viii. 51 (1901). 29
