1886.] ON YARIAT1(3NS OF CLIMATE IN THE COUllSE OF TIME. 11 



with foliferous forest to a far greater extent than now, came a 

 warm and moist one, in which the peat again began to gro w. 

 At that time the coast oak (Qvercus sessiliflora) was far more 

 fpequent iu Danemark than at present, judgiug by the evidence 

 of the peat bogs, and at that time, the shell deposits inform us, 

 (as shown by Prof. M. Sars), the present marine animals of the 

 west coast were found in the Christianiafjord. And there is 

 every reason to assume that the present flora of the west coast 

 immigrated thither, at that period, from the south of Sweden, 

 along the Christianiafjord to the west coast of Norway. 



New changes again set in with new immigrants, and finally 

 came the present age with its comparatively dry climate. But 

 all these events are prehistoric, as is shown by the stone imple- 

 ments lying in the uppermost peat layer close under the surface. 



Thus, the remains of plants and animals in clay, peat, and 

 shell deposits inform us that the gaps in the extension of the 

 spedes in Norway may he explained hy the varying events of 

 times long gone hy. 



Since the Glacial Age the relation hetiveen sea and land in 

 Norway has changed. Formerly the sea was in some places 

 upwards of 600 feet higher than at present. ^ 



The clay at that time deposited on the sea bottom, and the 

 shell deposits formed near the shore, contain, as Prof. M. Sars 

 and Kjerulf have taught us, remains of Arctic animals even in 

 the southernmost parts of the country. There is a difference of 

 opinion between savants whether this alteration of the shore line 

 is due to a rising of the land or the sinking of the sea, or to 

 both. There is further some dispute åbout the manner in which 

 the level became altered some maintaining that it took place 

 suddenly at intervals, whilst others believe that it is the result 



The depth of the peat in tbe parts which were formerly below the sea, in- 

 creases with the height above its surface, because the formation of the peat 

 commenced long before the lowest lying parts had risen above the surface 

 of the sea. From the remains of plants found in the various peat lavers we 

 may therefore learn bow i he Xorwegian flora was composed during the 

 various phases of the rising of the land. 



