Page:Geological Evidences of the Antiquity of Man.djvu/293

Rh the general direction in which the boulders have travelled is everywhere from north-west to south-east, a course directly at right angles to the prevailing trend of the present mountain ridges.

The late Mr. Trimmer, before referred to, has endeavoured to assist our speculations as to the successive revolutions in physical geography, through which the British Islands have passed since the commencement of the glacial period, by four 'sketch maps' as he termed them, in the first of which he gave an ideal restoration of the original Continental period, called by him the first elephantine period, or that of the forest of Cromer, before described (p. 214). He was not aware that the prevailing elephant of that era (E. meridionalis) was distinct from the mammoth. At this era he conceived Ireland and England to have been united with each other and with France, but much of the area represented as land in the map, fig. 41, p. 279, was supposed to be under water. His second map, of the great submergence of the glacial period, was not essentially different from our map, fig. 39, p. 276. His third map expressed a period of partial re-elevation, when Ireland was reunited to Scotland and the north of England; but England still separated from France. This restoration appears to me to rest on insufficient data, being constructed to suit the supposed area over which the gigantic Irish deer, or Megaceros, migrated from east to west, also to explain an assumed submergence of the district called the Wealden, in the south-east of England, which had remained land during the grand glacial submergence.

The fourth map is a return to nearly the same continental conditions as the first—Ireland, England, and the Continent