470 CHAP. ERRORS RESPECTING NUMBERS. The horns of the narwal have contributed their share to increase the misapprehensions about the numbers of mammoths' horns said to have been found. They are about the same length as those of the elephant, are found in the earth, in the same regions, and are spirally twisted. CHAPTER XVII. On the rapid changes which the surface of the Earth undergoes from Floods, Earthquakes, and other Causes. THE object of this chapter is to endeavour to prove, that, in consequence of the changes to which the surface of the earth is subject from floods of rivers, earthquakes, and other accidents, it is very difficult to form a satisfactory decision as to the causes of the depths, or situations in which the fossil bones of animals have been buried. CHAP. XVII. It has been remarked that we should commence our researches in geology, with subjecting to a careful examination what nature produces, as it were, under our own eyes; such as the manifold alterations that have taken place in the physiognomy of tracts of country, almost within the memory of man. How scanty are the genuine observations we possess on the process of alluvial deposition! on the detritus accumulated at the foot of mountains by means of the decomposition of various rocks! How little do we know of the process employed to produce petrifactions! and yet many of these will admit of consider 472 CHAP. INUNDATION IN PEMBROKESHIRE. able elucidation, by applying to them sound principles of logic and induction+." Camden, out of Giraldus, reports that a part of Pembrokeshire anciently ran out, in the form of a promontory, towards Ireland; as appears by a speech of king William Rufus, "that he could easily with his ships make a bridge over the sea, so that he might pass on foot from thence into Ireland." This tract of ground being all buried under deep sands, during the reign of Henry the Second, was, by the violence of a mighty storm, so far uncovered, that many stumps of great trees appeared fastened in the earth, and the strokes of the axe upon them, as if they had been cut but yesterday; so that it now made a show of a wood, rather than a strand. Such is the wonderful change of all things +. A vast tract of land at the eastern mouth of the Ganges, (where formerly stood the city of Bangalla, a place of great antiquity), has disappeared in a short period. Extensive islands are formed in the channel of the Ganges during an interval far short of that of man's life. The Cosa, equal to the Rhine, once ran by Purneah; its junction now is forty-five miles higher up §. "The evident state of decay prevailing in these calcareous moun + Rees's Cyc. "Geology." Bishop Hakewill's Apology, p. 34. § Rennell's Memoir, pp. 57, 265. REMARKABLE CHANGES AT HADRIA. tains, the divided rocks fronting the eminences, and the whole situation, render it probable that the river Belbec anciently flowed through the valley of Kara-Ilas, which is at present watered only by a small stream of the Souk; and though the former now runs at a considerable distance from this place, yet its current is so powerful and rapid, that it may in past ages have dissevered the heights above mentioned †. 473 CHAP. XVII. "An inundation at Dagenham, in Essex, made a breach in the Thames wall one hundred yards wide, and twenty feet deep in some places; by which means a number of trees were laid bare, which had been buried for many ages: one was a large oak, with most of its bark and some of its head and roots: the others were alder, or horn-beam: one had the sign of an axe; its head had been lopped off. Many think they have lain in that state since Noah's flood, but I think them to be ruins of some later age ‡." "The city of Atria, also called Hadria, we are certain, was formerly on the edge of the coast; it is now fifteen miles and a half distant from the nearest part of the mouth of the Adige; and the extreme point of the alluvial promontory is farther advanced into the sea six miles §." On a reconnu à Hadria, actuellement Adria, l'existence d'une couche de terre parsemée de débris de poteries Etrusques, sans melange d'aucun ouvrage de fabrique Romaine. L'Etrusque et le Romain se † Pallas. Journey in the Crimea. Phil. Trans. No. 335. § M. Prony. Supplement to Cuvier's Theory of the Earth. PPP 474 CHAP. DEEP SNOWS AND FLOODS IN SIBERIA. trouvent melés dans une couche superieure, sur laquelle on a decou vert les vestiges d'un theatre, l'une et l'autre couche sont fort abaissées au dessous du sol actuel *. The Keta falls into the Oby, and winds so frequently as to astonish the traveller, when at night he perceives how near he is to the place he left at noon. The natives use dogs to draw their sledges, they cannot use horses, the snow being sometimes a fathom deep upon the Obyt. The borders of the Tobol are low, and subject to be overflowed in the spring, yet they are inhabited by Mahomedan Tartars and Russians 1. "The last overflowing of the Volga formed a new bank of seven feet high above the common bed of the river §. When the snow melts, the Oby, Jenesai, and Lena, swell to such a degree, as to become torrents, and carry away with them considerable pieces of mountains ||. f My route lay along the Colyma, Zysanska, Omekon, Okola, and Indigerska, all of of which are large, rapid, dangerous, and almost im * Cuvier. † The reader may judge, by the quantity of snow, what immense inundations and rapid torrents must take place in spring. Milton (Historical Works, Vol. II. P. 135) mentions, that the Jenesai, on the western side, overflows about seventy leagues. Isbrants Ides § Captain Cochrane's Journey, p. 84. || Abul Ghazi, Vol. II. 658. Strahlenberg, p. 124. |