I92I.N0. II. THE STRANDFLAT AND ISOSTASY. 287 



evidence to show that it was aiwut 3 metres in the Cliristiania valley, 

 but no quite conclusive proof of such a transgression has been found. 



Considerably greater than in Norway has been the transgression of 

 the Littorina sea in southern Sweden, where there was partly a sinking 

 of the land before the Tapes-Littorina period, and the upheaval after that 

 time has been very small, and in Denmark, where there has been a sinking 

 of the land after that period. A. G. Högbom [1919, p. 177] estimates the 

 height of this transgression to have been about 16 metres in the region 

 of Kalmar, and about 30 metres in the region of the Great Belt, an 

 estimate which, however, is uncertain. Where the land has sunk and the 

 marks of the transgression, arc now under the sea, it is difficult to 

 determine what its height may have been. If the sea-level rises along 

 a coast which is sinking, the transgression will obviously be increased 

 in a similar manner as it is decreased along a rising coast. A part of 

 the great apparent transgression of the sea in these southern regions, 

 however, mav have occurred already before the Littorina period by the 

 sinking of the land in these regions, which may liave been caused by the 

 comparatively rapid upheaval of the land to the north. 



The transgression of the Littorina sea seems to have decreased 

 towards the north along the east coast of Sweden, and as Sundelin points 

 out [19 1 9. p. 2041, no traces of a transgression could be found north of 

 the region of A'ästervik. 



What may have been the Cause of a Rise of the Sea-Level during 

 the Tapes-Littorina Period^ 



As was previously mentioned (p. 222) the principal cause of changes 

 in the sea-level in recent times, which cannot be ascribed to crustal move- 

 ment, is probably the abstraction of water from the Ocean by the increase 

 of the glaciers on land, and the addition of water to the Ocean by their 

 decrease. 



If the rise of climatic temperature during the Tapes-Littorina period 

 was universal for the whole eartli, as seems probable, it may have caused 

 a considerable reduction in tliickness of the ice-caps of the Antarctic 

 as well as of Greenland, which will have caused an immediate rise of 

 the general sea-level. 



According to the computations made on p. 223. we see that if the 

 average thickness of the present ice-caps and glaciers of the world were 

 reduced by an amount of about 257 metres the immediate result would be 

 a rise of the Ocean-level and the shore-line of about 10 metres, which 

 would remain until it was gradually somewhat reduccfl by the crustal 

 movements of the sea-floor and the coasts, in the manner discussed on 

 pp. 234 ff. As, however, the crustal movements are extremely slow, and 

 are gradually started only a considerable time after the isostasy has been 



