Page:Popular Science Monthly Volume 12.djvu/73

Rh the German Ocean. In Yorkshire the ice from the west was held back by the Pennine Chain, and did not coalesce with the German Ocean glacier, but stopped short, somewhere about an irregular line drawn from Keighley, northeastward to near the mouth of the Tees. The German Ocean glacier only, as it were, grazed the high land bordering the coast until it reached the northern shores of Norfolk that stood out across its track. A large portion of Yorkshire was thus never glaciated by land-ice, and in this area remains of the great extinct mammals have been found in and below the lowland gravels, as at Leeds and Market Weighton; but when we pass northwestward into the country where the striæ on the rock-surfaces bear witness to the passage of land-ice, no such remains are found, excepting in caverns and fissures of the old rocks.

The northwestern side of England is much more glaciated than the northeastern, and the mammalian remains have only been found where preserved in caves. The ice filling the Irish Sea reached to a height of 2,000 feet on the western flank of the Pennine Chain. Probably reënforced from the westward it continued, in scarcely decreasing thickness, across the whole of Lancashire and Cheshire, and passed over into the drainage area of the Severn, down which valley it appears to have flowed for some distance. As soon as we get beyond its influence we again meet with mammalian remains in the lowland gravels, and in most of the southern valleys they are abundant.

If the mammoth and its associates roamed as far as the north of England, and even into Scotland, after the Glacial period, their remains ought to be found in the valley-gravels of the glaciated districts. They are, however, absent; and if we should be led to infer from this that they lived before the glaciation of the country, and accept the conclusion of Prof. Phillips and Mr. Godwin Austen that the mammoth and the woolly rhinoceros lived before and not after the Glacial period in Great Britain, we can scarcely refrain from going further than these geologists and concluding that the makers of the palæolithic implements were also preglacial. For no geological inference seems based upon sounder evidence than that palæolithic man was contemporaneous with the mammoth and its associates. The implements of the one and the bones of the others are found together in the same stratum of the cave-earth, and in all the numerous caverns that have been searched in England and Wales there is no record of palæolithic implements being found at a higher horizon; when flint weapons do so occur they are invariably of the neolithic type. If geological evidence of contemporaneity is of any value, the occupation of the caves by palæolithic man ceased at the same time as the great mammals disappeared.

Let us look at the question from another point of view. In the south of England the remains of the mammoth are abundant in the