1 92 1. No. II. THE STRAXDFLAT AXD ISOSTASY. 295 



pensation is much nearer the truth than this degree of regional com- 

 pensation 'cf. Barrell, 1919a, p. 306;. 



Barren, in his opposition to the hypothesis of local compensation, 

 even goes as far as to postulate that a great local load will have no ability 

 to depress the crust isostatically while even a smaller load distributed 

 over a sufficiently wide area will produce an isostatic depression of the 

 crust. It is hard to see the validity of this statement. If the crust is so 

 rigid that it does not yield to the local load, the depressive effect of this 

 load will naturally be distributed over as wide an area as the crust is 

 capable of retaining perfectly rigid, and there will be no essential dif- 

 ference in this respect if the load be equally distributed over this area. 

 But if the crust is not so rigid as to cause the effect of the load to be 

 distributed in this manner, then the crust will yield within a smaller area 

 to the local load, and the result will l)e a deficiency of compensation 

 (i. e. an excess of gravity and deflection of the vertical) near the local 

 load, and an excess of compensation (1. e. deficiency of gravity) in the 

 depressed region roimd it. 



It has also been maintained that great disturbances over extensive 

 areas are necessary to start the crustal movements for adjustment of iso- 

 stasy, and such movements will occur, as a rule, only during periods of 

 special mobility of the earth's crust, and within certain specially mobile 

 regions. 



As far as I can judge the late-glacial and postglacial vertical move- 

 ments of Fenno-Scandia and surrounding regions, and especially the 

 movements of the Norwegian coast, and the present position of its 

 strandfiat. conclusively disprove the correctness of views such as these. 

 Thev indicate that the earth's crust in the course of time approaches its 

 level of perfect isostatic equilibrium much more closely than even the 

 most extreme advocates (like Hayford) of perfect isostasy have considered 

 to be possible. 



Our studies of the present level of the strand flat in the Norwegian 

 fjords as well as along the outer coast of Norway, in connection with the 

 measurements of the heights of the upper limit of late-glacial submergence 

 and the heights of the Tapes-line, may be considered to prove conclusively 

 that the earth's crust in these regions has returned, at least within a few 

 metres, and along the outer coast probably even nearer, to the same hori- 

 zontal level which it had before the last glacial submergence. And this 

 level of equilibrium has been reached along the whole coast although the 

 late-glacial submergence of the land has differed very much in magnitude. 

 In some regions it was as much as 90 and 100 metres (along the coast of 

 Helgeland) and 120 to 150 metres (in the inner parts of the western 

 fjords) or even more than 200 metres (at Christiania), while in some 

 parts of the outer coast, at Stat and outside Nordfjord, there has hardly 

 been any submergence below the level of the strandfiat. Nevertheless 



