occupy a wide geographical area, while a newer delta is forming[237-B]; and the possibility of such movements, and their effects, must not be lost sight of when we speculate on the origin of the Wealden. If it be asked where the continent was placed from the ruins of which the Wealden strata were derived, and by the drainage of which a great river was fed, we are half tempted to speculate on the former existence of the Atlantis of Plato. The story of the submergence of an ancient continent, however fabulous in history, must have been true again and again as a geological event. The real difficulty consists in the persistence of a large hydrographical basin, from whence a great body of fresh water was poured into the sea, precisely at a period when the neighbouring area of the Wealden was gradually going downwards 1000 feet or more perpendicularly. If the adjoining land participated in the movement, how could it escape being submerged, or how could it retain its size and altitude so as to continue to be the source of such an inexhaustible supply of fresh water and sediment? In answer to this question, we are fairly entitled to suggest that the neighbouring land may have been stationary, or may even have undergone a contemporaneous slow upheaval. There may have been an ascending movement in one region, and a descending one in a contiguous parallel zone of country; just as the northern part of Scandinavia is now rising, while the middle portion (that south of Stockholm) is unmoved, and the southern extremity in Scania is sinking, or at least has sunk within the historical period.[237-C] We must, nevertheless, conclude, if we adopt the above hypothesis, that the depression of the land became general throughout a large part of Europe at the close of the Wealden period, a subsidence which brought in the cretaceous ocean. FOOTNOTES: [227-A] Dr. Fitton, Geol. Trans. vol. iv. p. 320. Second Series. [230-A] Mantell, Geol. of S. E. of England, p. 244. [231-A] "On the Dorsetshire Purbecks," by Prof. E. Forbes, Edinb. Brit. Assoc., Aug. 1850. [233-A] Mr. Webster first noticed the erect position of the trees and described the Dirt-bed. [233-B] Fitton, Geol. Trans., Second Series, vol. iv. pp. 220, 221. [233-C] See Flinders' Voyage. [233-D] Fitton, ibid. [233-E] Buckland and De la Beche, Geol. Trans., Second Series, vol. iv. p. 16. Mr. Forbes has ascertained that the subjacent rock is a freshwater limestone, and not a portion of the Portland oolite, as was previously imagined. [234-A] E. Forbes, ibid. [235-A] See Principles of Geol., 8th ed. pp. 260-268. [235-B] Ibid. p. 443. [237-A] Fitton, Geol. of Hastings, p. 58.; who cites Lander's Travels. [237-B] See above, p. 85.; and Second Visit to the U. S. vol. ii. chap. xxxiv. [237-C] See the Author's Anniv. Address, Geol. Soc. 1850, Quart. Geol. Journ. vol. vi. p. 52. CHAPTER XIX. DENUDATION OF THE CHALK AND WEALDEN.