192 1. No. II. THE STRAXDFLAT AXD ISOSTASY. 28 1 



pressed sea-floors the depth of the water was increased by the whole 

 height of the depression. During the deepest submergence after the 

 retreat of the ice-sheet, the adrlitional layer of water over Bottenviken 

 was at least 280 metres thick probably a great deal more, over the Baltic 

 Sea in the latitude of Stockholm it was about 120 metres or more, in 

 the northern part of Skagerrak, at the mouth of Christiania Fjord, it 

 was about 160 metres thick, and along a line between Christiansand, 

 Skagen, and Scania it was more than 50 metres thick. 



Even as late as the Tapes-Littorina period the sea in Skagerrak was 

 about 50 metres deeper than now at the mouth of Christiania Fjord, and 

 about 15 to 20 metres between Christiansand and Skagen. In Botten- 

 viken the sea may then have been more than 100 metres deeper than now. 



The great weight of these extensive water-masses covering the 

 central, as well as the southern and south-eastern parts of the depressed 

 Fenno-Scandian area, must naturally have greatly retarded the lateglacial 

 and postglacial upheaval of the sea-floor and the land; and this retard- 

 ation has obviously been of much greater importance than that caused 

 by the late disappearance of the last remnants of the ice-caps in Swedish 

 Norrland. 



In this manner we o1)tain a simple explanation of the fact that the 

 upheaval of the land has not vet been completed along the coasts of the 

 Gulf of Bothnia and the Baltic Sea, and perhaps also along the Swedish 

 coast of Kattegat and Skagerrak. 



We also understand that the upheaval of the land may have con- 

 tinued until comparatively lately along the Norwegian coast of Skagerrak 

 and especially near the oiUer part of Christiania Fjord, while it was 

 completed much earlier along the west and northern coast of Norway, 

 where there was hardly any depression of the sea-floor outside the coast, 

 and where only a very small area of the steeply ascending coast-land 

 was submerged. An exception forms the coast of Nordland, between 

 Trondhjem and Lofoten, as previously mentioned (p. 225), where a great 

 deal of the broad continental shelf outside the coast was also depressed, 

 and the sea in its inner part was as much as 90 metres deeper than now. 



When we here speak of the upheaval of the land having been com- 

 pleted, it is of course, not meant absolutely completed. 



The probability is that after the removal of the load of the ice-cap 

 it will take some considerable time before the upheaval of the crust be- 

 gins, but when fairly starterl, it mav probablv increase in a comparatively 

 short time till it attains a maximum rate, and will then procède according 

 to an asymptotic curve, being relatively rapid at first, then decreasing 

 gradually, and the crust will approach its level of equilibrium asympto- 

 tically. 



This process may, however, be modified more or less, where the 

 whole load is not yet removed when the upheaval starts, and is only 



