ig21. No. II. THE STRANDFLAT AND ISOSTASV. 



Fig. 90. Kock.\- coast with strandtlat at HcUestn at the northern end eil Jæderen. i^îept. 2, 19111. 



the coast, have heights of less tlian 20 metres, or about 17 metres above 

 sea-level. But further east the heights rise towards 50 metres and more. 



Further east and northeast, in the region of Tuneim, Mossige, Lende, 

 Folland. and Hoiland near the foot of the high eastern mountains, the 

 protruding rocks, observed by Bjorlykke, consist of phvllite. and their 

 heights rise to 75 and lOO metres above sea-level. 



In the southern part of Jæderen, north of Ogne, the level of the 

 distinct plane of the low protruding rocks, of granite and labradorite, in 

 front of the higher hills and muuntains (of labradorite rocks) is between 

 15 and 25 metres. 



It is of course impossible to study in detail the topography of the 

 rocky ground where it is covered to such an extent bv quaternarv accu- 

 mulations as is the case on Jæderen. It seems, however, probable that if 

 these accumulations were removed, we would have a low somewhat uneven 

 rocky surface to some extent perh.aps broken up into peninsulas and is- 

 lands separated by shallow fjords and sounds. But this rocky surface 

 would probably to a considerable extent have low heights of about 10 or 

 15 to 25 metres above sea-level, as indicated by the rocks especially in the 

 northern and southern parts of the plain. 



I see no reason why this low rocky foreland should not be a strand- 

 flat of the same kind as the strandfiat on the Stavanger Peninsula 

 (forming its direct, northern continuation) and along the coast further 

 north. 



The striking topographical difference between the plain of Jæderen 

 and the higher mountainous land to the east mav to some extent be due 

 to the difference in geological structure, the rocks of Jæderen being 

 largely crystalline schists and partly phyllite which may have been more 

 easily eroded to low levels than the Archæan and igneous rocks of the 

 higher land to the east and south, although we have seen that fairly 

 resistant Archæan rocks (gneiss, amphibolite, &:c.) also occur on the low 

 land of Jæderen. 



But howsoeA'er this may be, it seems to me obvious that the low and 

 nearly horizontal level, or perhaps levels, marked by the rocks protruding 

 in the surface of the plain of Jæderen, cannot have been formed solely by 

 subaërial denudation, and still less by glacial erosion. The simplest ex- 

 j^lanation is here as elsewhere, that these low horizontal levels of the 

 coast-land have been finallv created bv shore-erosion levellin<^ the hills 



