Page:Early Man in Britain and His Place in the Tertiary Period.djvu/75

] as rich as that of the continent, leaving behind a few fragments preserved from destruction by the great original thickness of the deposit, or by its having been covered up by showers of ashes and streams of lava from the Meiocene volcanoes.

The rivers of Britain in the Meiocene age (Fig. 6) were probably in the position which they now occupy, although they flowed at a higher level—the only difference being that their lower courses were prolonged to the coast-line of the period. The Severn, for example, and the Dee, Mersey, and Ribble, would debouche into the Atlantic after traversing the lower grounds now submerged. The Trent and Humber, in like manner, would find their way into the south-eastern sea. Some of the Irish lakes also—such as Lough Neagh—were lakes then. In Devonshire the small lake of Bovey reflected on its still surface the luxuriant forests by which it was surrounded.

The Meiocene forests of Britain, preserved in the deposits of ancient lakes, or buried under volcanic ashes and lavas, occur merely in a few isolated spots in Devonshire, the Scotch isles, and in Ireland.

The lignites of Bovey Tracey, to the south-east of