[447] Andresen, Om Klitformationen, pp. 68-72.
[448] Id., pp. 231, 232. Andresen's work, though printed in 1861, was finished in 1859. Lyell (Antiquity of Man, 1863, p. 14) says: "Even in the course of the present century, the salt waters have made one eruption into the Baltic by the Liimfjord, although they have been now again excluded."
[449] Forchhammer, Geognostische Studien am Meeres-Ufer. Leonhard und Bronn, Jahrbuch, 1841, pp. 11, 13.
[450] Andresen, Om Klitformationen, pp. 68, 72.
[451] Voormaals en Thans, pp. 126, 170.
[452] See a very interesting article entitled "Le Littoral de la France," by Élisée Reclus, in the Revue des Deux Mondes, for December, 1862, pp. 901, 936.
[453] De Bodem van Nederland, i, p. 425. See Appendix, [No. 60].
[454] The movement of the dunes has been hardly less destructive on the north side of the Gironde. Sea the valuable article of Élisée Reclus already referred to, in the Revue des Deux Mondes, for December, 1862, entitled "Le Littoral de la France."
[455] Laval, Mémoire sur les Dunes du Golfe de Gascogne, Annales des Ponts et Chaussées, 1847, p. 223. The author adds, as a curious and unexplained fact, that some of these pools, though evidently not original formations but mere accumulations of water dammed up by the dunes, have, along their western shore, near the base of the sand hills, a depth of more than one hundred and thirty feet, and hence their bottoms are not less than eighty feet below the level of the lowest tides. Their western banks descend steeply, conforming nearly to the slope of the dunes, while on the northeast and south the inclination of their beds is very gradual. The greatest depth of these pools corresponds to that of the sea ten miles from the shore. Is it possible that the weight of the sands has pressed together the soil on which they rest, and thus occasioned a subsidence of the surface extending beyond their base? See Appendix, [No. 61].
[456] Andresen, Om Klitformationem, pp. 56, 79, 82.