286 FR II) r.lOK NANSKN. M.-N. Kl. 



liaiifl, our (.■stiinatc's of tlir aiiiounts wliicli the sca-Icvcl has sunk, and 

 wliicli tlic laml will still rise before the u|)lieaval is completed, are quite 

 arl)ilrar\-. With other estimates a still .greater agreement mij^ht be ob- 

 taiin'il. /:. 1^. at X'ihor^- in iMiiland the laml may probably rise more than 

 here assmneil before- the ui)hea\al is coinpletiil. ft seems also doubtful 

 whether the uphea\al of (/ottland is alrearly completed. 



The Cause of the Transgression of the Sea in the 

 Tapes-Littorina Period. 



If wc assume that the postglacial crustal movements of Fenno- 

 Scandia were entirely isostatic, it seems difficult to lUKJerstand that the 

 apparent pause in the upheaval or even a transgression of the sea in the 

 Tapcs-T.ittorina period can have been due to a teinporary sinking of the 

 land as a wliolc; for the Scandinavian ice-cap can certainly not have been 

 extended again during that warm period. It is more probable that this 

 transgression was caused by a rise of sea-level wdiich took place w^hile 

 the greater part of the land continued to rise. 



Such an assumption agrees well with the observed facts. It is 

 obvious that the height of the actual transgression of the sea, caused by 

 a rise of the sea-level, would vary inversely to the rate of the upheaval 

 of the coast. 



If the sea-level rose at about the same rate as the land, there would 

 be no transgression; but the shore-line w'ould remain more or less stable 

 as long as the sea was rising with the land, and a beach might be formed, 

 or ledges cut in the rock where the climate favoured it. 



If the sea-level rose more rapidly than the land, there would be a 

 transgression of the sea, wdiich would be greater in proportion as the 

 upheaval of the land was slower. During this transgression marine 

 terraces and even broad beaches may be formed, as a comparatively long 

 time would pass before a negative shift of the shore-line again began, 

 and a lengthened stand of the shore-line at about the .same level of the 

 coast would thus be caused. 



Along the coast of Norway the transgression of the sea during the 

 Tapes period was obviously greatest in regions wdiere the postglacial 

 upheaval of the land was slow, while it was small in regions wdiere there 

 has been a considerable upheaval. 



On Jæderen where the upheaval of the land after the Tapes period 

 has only been about 12 to 15 metres. J. Holmboe's [1901] and P.A. 

 öyen's [1903] investigations seem to indicate that the Tapes transgres- 

 sion of the sea has been as much as 8 or 9 metres in height. In the 

 region of Christiania Fjord, wdiere the upheaval after the Tapes period 

 has been 60 to 70 metres, the Tapes transgression has been at most a 

 few metres in height. P. A. Öyen [1905, p. 10] thinks he has discovered 



