PALEONTOLOGY AS regards the past history of vertebrated animals (with which alone we are concerned on the present occasion) interest in Essex is chiefly concentrated on the wonderful series of mammalian remains which have been obtained from the Pleistocene gravels and brickearths of various localities in the Thames valley, and more especially at Ilford and Grays, as well as those from approximately contemporaneous deposits in other parts of the county, notably Clacton. From the brickearth at Grays has been obtained the sole evidence of the former occurrence of monkeys in the British Isles ; the so-called Macacus eoccenus from the Eocene of Suffolk being described on the evidence of a tooth which was subsequently ascertained to belong to the undermen- tioned Hyracotherium leporinum. A considerable amount of interest like- wise attaches to the remains of mammals from the valley of the Lea at Walthamstow ; but as these, on account of their later age, belong to existing species, their importance is far less than the remains from the brickearths. In this connection it may avoid confusion to mention that, in addition to this particular series of remains, certain other mammalian fossils, notably teeth of the mammoth, have been obtained at Waltham- stow which appear to belong to an older deposit, approximately equivalent to the valley gravels and brickearths of other parts of the county. Another important element in the palaeontological history of the county is represented by the vertebrate remains from the London Clay of Harwich, the majority of these belonging to extinct types of turtles, although at least one species of mammal has been recorded from this locality, while a second is represented by a specimen dredged off the coast between Harwich and St. Osyth. Although the Red Crag occurs in the county, it has very few vertebrate fossils in comparison with those found in the same formation in Suffolk. Since the nature of these various Tertiary formations, as well as the localities where they occur, are mentioned in the chapter on geology, no further reference is required in this place. The mammalian remains from the alluvium of the marshes at Walthamstow were first described by Dr. H. Woodward, 1 but some emendations on the list of species then given have been made subse- quently. The species include the dog (Canis familiar -is), horse (Equus 1 Geological M agazint, vi. 385 (1869). I 25 4
