Page:A Treatise on Geology, volume 2.djvu/79

 CHAP. VI. ancient burial mounds, composed of heaps of stones, and in closing frequently an urn of burnt bones. Observations nearly similar may be easily made on the heathy and peaty moors of the elevated parts of the north of England, where tumuli and ancient roads and causeways are nearly concealed by the growth of vegetables and aggregation of sands.

But the accumulation of peat from living plants is in some places so rapid, that it seems endowed with an inexhaustible vitality, and may be cut like a copsewood every fourteen years. And in countries like Hatfield Chace, which are one wide turf moor, the occurrence of Roman coins, and axes yet fixed in the wood, appear to prove at once the fact that the trees grew on the spot, and fix the historic date of their destruction.

De Luc mentions the discovery of a medal of Gordian 30 feet deep in peat at Groningen. Besides other proofs of the modern origin of this substance, near Bremervörde, a small hill of "hard land" or "geest," is stated to be overgrown with peat, and its title "Isleberg" shows the modern date of this overgrowth. (Lettres sur l'Histoire de la Terre et de l'Homme, tom. v. p. 264.)

'De Luc ascertained that the very site of the aboriginal forests of Hercinia, Semana, Ardennes, and several others, are now occupied by mosses and fens; and a great part of these changes has, with much probability, been attributed to the strict orders given by Severus and other emperors to destroy all the wood in the conquered provinces." (Lyell, Princip. book iii. ch. xiii.)

One of the most valuable of all the descriptions of subterranean forests is that of Hatfield Chace in Yorkshire, by the Rev. A. De la Pryme (1701). Of 180,000 acres here, constituting the largest chace of red deer in England which belonged to Charles II., about half was yearly drowned by vast quantities of water. Sir Cornelius Vermuiden drained it, at a cost of 400,000l., cutting amongst other great works a new channel for the tide river Don, which is now called