I92I. No. II. THE STRAXDFLAT AND ISOSTASY. 47 



for the shore erosion by frost, and at the same time the subaerial de- 

 nudation became more effective, as the disintegration of the rocks by frost 

 increased. Provided that the level of the shore-line was then approximately 

 the same as during" later interglacial periods, a more active formation of 

 the strandfiat may have begun. 



But as the coast had not yet, at that time, been dissected by the glacial 

 erosion, it is hardly probable that the development of the strandfiat could 

 make much progress. 



After the valleys of the coast had been deepened by the erosion of 

 the Great Ice Age, and the coast land had been dissected by the numerous 

 deep fjords and channels, intersecting the coast and splitting it up into the 

 many islands and peninsulas the conditions were essentially changed, as 

 has been pointed out on a preceding page. It therefore seems probable 

 that the Norwegian strandfiat has chiefly been developed to its present 

 shape after that time. 



It is possible that in interglacial times there may have been periods 

 with climates sufficiently severe for shore erosion by frost so essential for 

 the formation of the strandfiat; but tlie climatic conditions preceding, 

 accompanying, and succeeding each glacial period were especially favour- 

 able for this erosion. At the same time the subaerial denudation of the 

 outer coast land was also very effective. 



For the development of the strandfiat it was, however, also essential 

 that the shore-line was stable during long time and standing at or near 

 the level of the strandfiat. This was probably the case during a great part 

 of the intergiacial times and at the beginning of the glacial periods, while 

 during the glacial periods the land was gradually depressed by the weight 

 of the growing ice-caps, as was pointed out above. The strandfiat cannot 

 therefore have been developed during the late part of the glacial periods 

 or during the time of submergence after these periods, even though the ice 

 had retreated from the outer coast. The development of the strandfiat 

 could not begin until the land had again been elevated nearly to its norinal 

 level. But at that time the climatic conditions would not, as a rule, be 

 favourable for the shore erosion by frost. 



We are thus lead to the conclusion that the strandfiat has been de- 

 veloped chiefly during interglacial periods with cold climates, and especially 

 during the very cold time preceding each glacial period, and during its first 

 part, before the outer coast was covered by the inland ice, and as long as 

 the level of the shore-line still remained nearly stable. 



This may have lasted some time, because the level of the ocean was 

 lowered by the accumulation of water in the ice-caps on land. The gradual 

 sinking of the land caused by the growing load of the ice-cap, may thus 

 for a long time have been more or less counterbalanced by the sinking of 

 the shore-line. It should also be considered that the depression of the land 

 began in its interior parts where the ice masses first accutnulated, and did 



