Park — Changes of Const-level. 441 



by means of careful measurements, that it can be proved to 

 exist. It is only along the coast-line, where sea-level affords 

 an unvarying base of verification, that these tranquil move- 

 ments can be detected and measured. 



As early as 1730 Celsius, the Swedish astronomer, had 

 noted the gradual rise of the Scandinavian Peninsula. In 

 1731, in company with Linnaeus, he placed a stone mark at 

 the base of a cliff in the Island of Loeffgrund, not far from 

 Jefle, and thirteen years afterwards was able personally to 

 verify that the Baltic Sea had retreated 7 in., or at the rate of 

 4 ft. 5 in. for a century.* 



That the rate of movement is not always uniform over 

 wide regions, but differential, is shown in the case of the 

 Baltic shores of Scandinavia. For example, at the northern 

 extremity of the Gulf of Bothnia, at the mouth of the Tornea, 

 the continent is emerging from the sea at the rate of 5 ft. 3 in. 

 in a century, but by the side of the Aland Isles the rise, 

 according to Eeclus, is only at the rate of 3 ft. 3 in. in the 

 same time. South of the isles the rate of upheaval is even 

 slower, and further south the ground moves so slowly as to 

 appear quite stable even in a century. This region, indeed, 

 seems to be the pivot of the oscillation, for further south, at 

 Scania, the most southerly part of Sweden, the land is sinking 

 gradually, as proved by the submergence of forests and older 

 streets of the towns of Trelleborg, Ystad, and Malmoe. It 

 was at Scania that Linnaeus, in 1749, exactly determined the 

 position of a stone, which was found after a lapse of eighty- 

 seven yeai - s to be 100 ft. nearer the water's edge. According 

 to Erdmann the subsidence at Scania has now ceased, or has 

 been exchanged for an upward movement, but it will require 

 observations extending over another half-century to verify this 

 conclusion.! 



Celsius and his contemporaries were impressed with the 

 view that the emergence of the land was due to the recession 

 of the sea, the changes in the relative level of sea and land 

 being ascribed to variations in the form of the oceanic 

 envelope. Most of the evidence available is adverse to this 

 conclusion, and modern geologists and physicists alike are in 

 favour of regarding the relative changes of land and sea as due 

 to movements of the solid land only. The mean level of the 

 sea is now generally regarded as a constant datum, not neces- 

 sarily unvarying, but varying within such infinitesimal limits 

 as to be practically constant as a verification datum. 



The principal evidences of an elevation of the land are 

 raised beaches, sea- worn caves at present beyond the reach of 



* " The Eartb," Reclus, p. 621. 



f Geol. For. Stockholm Forhandl., i., p. 93. 



