Draw on a map of the East Riding a line from Sewerby, through Driffield and Beverley, to Hessle, and you are drawing the line of the old sea-beach when the upheaval previously mentioned had taken place. This was the shore of a land inhabited by races of animals now found living only in tropical regions. The elephant, rhinoceros, hippopotamus and hyena ranged the land for food, and bones of these creatures have been found in considerable numbers in the caves that exist at Kirkdale in the North Riding. * * * * * Then came a great change. The climate of Northern Europe became colder and colder till there prevailed what scientists call the ‘Great Ice Age.’ This was the time of formation of huge glaciers which spread from the mountains of Scandinavia, Scotland, and north-west England southwards and eastwards into the sea, until they met and made its whole area a slowly moving mass of ice. With the ice were carried sand, gravel, clay, boulders torn from projecting rocks, and bones of Arctic animals, such as the walrus, the reindeer, and the Irish elk; and as the ice gradually melted, all these were deposited at the base of the line of chalk cliffs, or even on the summit of the cliffs where these were low. From the gravel pits at Burstwick excavations of ballast for the embankments of the North Eastern Railway brought to light animal bones in such quantities that many tons were sold to chemical manure manufacturers, and it is probable that many tons still remain undiscovered. [Illustration: _Photo by_] Relics of the Ice Age. [_C. W. Mason_ ] A walrus tusk from Kelsey Hill and the tooth of a mammoth from the cliffs at Atwick.[2] Footnote 2: The weight of this tooth is 9½ lbs. One side has been worn down and polished smooth by the friction of the ice in passing over it. In this way was formed the ‘great mass of gravel, clay, and sand ... east of the Yorkshire Wolds’ which we know as the Plain of Holderness. Here is what one of our foremost local geologists has to say of its beginnings:— ‘Let us imagine the probable appearance of East Yorkshire on the final melting of the ice. Huge fans or sheets of gravel occur at Bridlington and other places as a result of the floods. Rounded hillocks of gravel and clay stand out in all directions; the hollows in between are filled with water, forming miniature lakes or meres. Of animal or plant life there is little or none. The climate gradually becomes milder; at first Arctic plants and animals exist in small numbers. Later, the margins of the meres become clothed in vegetation; peat is eventually formed, and huge trees of Oak and Fir thrive. The Red Deer, Beaver, Short-horned Ox, Otter, and Wild Horse, haunt the woods, and finally primitive man makes his appearance.’ [Illustration: SKULL AND ANTLERS OF A RED DEER FOUND IN THE HORNSEA PEAT-BED. ] III. MEN OF THE STONE AGE.