of the Surface of the Earth. 117 



seems to be in northern Lapland. The rising gradually di- 

 minishes towards the south as far as Oalmar and Solvitsborg. 

 Lines marking the ancient level of the sea, in pre-historical 

 periods, are indicated by beds of shells belonging to the sea of 

 tiie present day throughout the whole of Norway,* from Cape 

 Lindesnas to the North Cape ; and very recently their height 

 has been accurately measured by Bravais, during a long winter 

 residence in Bosekop. They are placed 640 English feet above 

 the present mean level of the sea ; ^nd they also occur, accord- 

 ing to Keilhau and Eugene Robert, on the coasts of Spitzber- 

 gen, opposite the North Cape (to the NNW.) Leopold von 

 Buch, who was the first to direct attention to the high bed 

 of shells at Tromsoe (lat. 09" 40'), has shewn that the more 

 ancient elevations on the North Sea belong to a different 

 class of phenomena from the gentle (not sudden or jerking) 

 rising of the Swedish coast in the Bothnian Gulf. Nor must 

 the latter phenomenon, so well established by historical evi- 

 dence, be confounded with the change of level produced by 

 earthquakes (such as is observed on the coasts of Chili and 

 Cutch). \ery lately the Swedish phenomenon has given 

 rise to analogous observations in other countries. A per- 

 ceptible sinking is sometimes met with, corresponding to the 

 rising, as a consequence of the folding or plaiting (Faltung) 

 of the strata ; this is the case in West Greenland (according 

 to Pingel and Graah), in Dalmatia, and in Schonen. 



Since it must be considered as extremely probable, that in . 

 the early periods of om* planet, the oscillating movements, 

 that is to say, the rising and sinking, of the surface, were 

 more intense than they are at present, we should feel the 

 less surprised at finding, in the interior of continents, de- 

 tached portions of the earth's surface which occupy a lower 

 position than the present general level of the sea. Examples 

 of this kind are afforded by the Natron Lakes described by 



• Keilhau in tlie Nijt. Mog. for Naturvid. 1832, vol. i., pp. 105—254 ; 

 and vol. ii., p. 57 ; Bravais svr Us lif/ncs d'ancicu niveau do la Mcr, 1843, 

 pp. 15—40 ; and also Darwin on the Parallel roads of Glen-Roy, in the 

 Phil. Transactions for 1839, p. GO. 



