296 COSMOS. 



force appears to lie in the north of Lapland, and to diminish 

 gradually to the south toward Calmar and Solvitzborg. Lines 

 marking the ancient level of the sea in pre-historic times are 

 indicated throughout the whole of Norway,* from Cape Lin- 

 desnaes to the extremity of the North Cape, by banks of shells 

 identical with those of the present seas, and which have late- 

 ly been most accurately examined by Bravais during his Ion 

 winter sojourn at Bosekop. These banks lie nearly 650 feet 

 above the present mean level of the sea, and reappear, accord- 

 ing to Keilhau and Eugene Robert, in a north-northwest di- 

 rection on the coasts of Spitzbergen, opposite the North Cape. 

 Leopold von Buch, who was the first to draw attention to the 

 high banks of shells at Tromsoe (latitude 69° 40'), has, how- 

 ever, shown that the more ancient elevations on the North 

 Sea appertain to a different class of phenomena, from the 

 regular and gradual retrogressive elevations of the Swedish 

 shores in the Gulf of Bothnia. This latter phenomenon, which 

 is well attested by historical evidence, must not be confound- 

 ed with the changes in the level of the soil occasioned by 

 earthquakes, as on the shores of Chili and of Cutch, and 

 which have recently given occasion to similar observations in 

 other countries. It has been found that a perceptible sinking 

 resulting from a disturbance of the strata of" the upper surface 

 sometimes occurs, corresponding with an elevation elsewhere, 

 as, for instance, in West Greenland, according to Pingel and 

 Graah, in Dalmatia and in Scania. 



Since it is highly probable that the oscillatory movements 

 of the soil, and the rising and sinking of the upper surface, 

 were more strongly marked in the early periods of our planet 

 than at present, we shall be less surprised to find in the inte- 

 rior of continents some few portions of the earth's surface ly- 

 ing below the general level, of existing seas. Instances of this 

 kind occur in the soda lakes described by General Andreossy, 

 the small bitter lakes in the narrow Isthmus of Suez, the 

 Caspian Sea, the Sea of Tiberias, and especially the Dead 

 Sea.t The level of the water in the two last-named seas is 



* Keilhau, \nNyt Mag. fur Naturvid., 1832, bd. i., p. 105-254; bd. 

 ii., p. 57 ; Bravais, Sur les Lignes d^ancien Niveati de la Mer, 1843, p 

 15-40. See, also, Darwin, "on the Parallel Roads of Glen-Roy and 

 Lochaber," iu Philos. Trans, for 1839, p. 60. 



t Humboldt, Asie Centrale, t. ii., p. 319-324; t. iii., p. 549-551 

 The depression of the Dead Sea has been successively determined by 

 the barometrical measurements of Count Bertou, by the more careful 

 ones of Russegger, and by the trigonometrical survey of Lieutenant Sy- 

 mond, oi the Royal Navy, who states that the difference of level be 



