1 92 1. No. II. THE STRANDFLAT AND ISOSTASY. 297 



The above inference is strongly supported by the fact that similar 

 evidences of a late-glacial submergence and a postglacial elevation of the 

 land have been found in all other regions that were covered bv fairly 

 extensive ice-sheets during the last glacial epoch, although these regions 

 may have so very different geologic structure as Fenno-Scandia, Xovaya 

 Zemlya, Franz Joseph Land, Spitsbergen, Scotland, Iceland, Greenland, 

 and North America. Some of these regions, e. g. Southern Greenland, 

 Labrador, and Eastern Canada, are especially stable and tranquil Archæan 

 regions. 



The fairly regular distribution of postglacial elevation in Fenno- 

 Scandia, c. g. the regular rise of the raised beaches from the outer coast 

 inland, the uniform relation between the heights of the upper limit of 

 elevation and the Tapes-line along the whole of the west and north coast 

 of Norway and the Kola Peninsula, furthermore the retardation of the 

 elevation in the flooded regions &c., prove that the upheaval of the land 

 cannot have proceeded by jerks and irregularly, but must have been on 

 the whole a very gradual and regular process. 



It is true that there seems to be a connection between certain 

 irregularities in the slow emergence of the land i Sweden and Finland, 

 and the seismic activity of the crust, as is indicated by Witting's in- 

 vestigations; but, on the one hand, these seismic movements are in fact 

 very insignificant, and, on the other hand, they are obviously fairly local. 

 They must not, therefore, be connected with the general crustal upheaval 

 over extensive areas, but are due to more local strain in the crust, in 

 regions where local deformities cause greater local disturbances of equili- 

 brium. I may mention our deep fjords and the submarine Norwegian 

 channel as such regions, where there may be a special strain in the crust, 

 owing to the erosion of these deep channels. We may summarize the 

 results of the above investigations as follows: 



It is a general tendency of the lithosphère to readjust its isostasy 

 after disturbances, and in the course of time to approach its average level 

 of isostatic equiUhrinni z^'ithin som fete metres at least. 



The isostatic movements of the lithosphère are not limited to especially 

 mobile regions, nor to periods of special crustal mobility. 



How are the Isostatic Vertical Movements of the Lithosphère 



effected ? 



Pentti Eskola has recently [1920J put forward some ideas regarding 

 transformations in the chemical com.position of minerals and rocks effected 

 by changes in pressure, which, if correct, may prove to be of great im- 

 portance when the above question comes to be answered. 



He draws attention to the fact that pressure influences the nature 

 of minerals "by moving the equilibria towards the associations and modi- 



