14 



A. BLTTT. 



[No. 8; 



The shell-banksj too, (i. e. deposits of shells of marine ani- 

 mals living in shallow water near the shore) lie, as Kjerulf has 

 shown, in the Christianiafjord at different levels, the older at 

 heights from 540 to 350 feet and the youngest between 200 and 

 50 feet above the present level of tlie sea. But between 350 

 and 200 feet none has been found. In the neighbouring Swedish 

 province of Bohus they are found at all elevations, even be- 

 tween 350 and 200 feet, and it must therefore be assumed that 

 local causes, as, for instance the ice-formation in the more closed 

 Christiania fjord, destroyed the shell banks when they reached 

 the shore-line, at a period when the land lay 350 to 200 feet 

 lower in relation to the sea than at present. According to the 

 evidence of the peat bogs, there is reason to believe that thi^ 

 part of the rising occurred under a more severe climate. 



It is, therefore, seen, that all the facts which have been 

 advanced in order to prove that the rising was broken by periods 

 of rest may be easily explained, if we assume that the land rose 

 gradualhj and steadily under periods alternating ivith milder and 

 severer clitnates. 



If such a periodical variation in the climate does take place. 

 we should be able to trace it in the older formations, as we- 

 cannot assume that it first began to operate in the most recent 

 geological age. We must, therefore, try to discover if such 

 variations " can be traced in the earlier times. 



During the melting of the Norwegian inland ice, it left here 

 and there moraines, and on the map drawn by Kjerulf they are 

 seen to stretch in lines more or less continuously across large 

 parts of Southern Norway. On both sides of the Christiania 

 fjord the outside lines, the so-called „Raer" stretch like gigantic 

 ramparts from Moss and Horten south-east and south-west many 

 miles through Smaalenene and far into Sweden and, on the 

 other side of the fjord, through the province of Jarlsberg 

 and Laurvig, to Jomfruland outside Kragerø. And behind this 

 outside line of moraines others follow in more or less broken 

 but distinct continuity, one behind the other through all Southern 

 Norway. These lines show that the ice did not recede continually. 



