418 G. R. Wieland — Polar Climate in Time. 



Bear Island which lies in 74° north latitude about midway 

 between the North Cape and Spitzbergen. To be exact, it 

 includes, according to Nathorst,* Filices, Sphenophjllales 

 (extinct plants from which have been derived the horsetails 

 and lycopods), Calamites and Lycopods. These plants indicate, 

 needless to say, a decidedly tropical climate, and from tlieir 

 diversity ot form and structure *' sliow that vascular plants 

 must have existed for an exceedingly long period previous to 

 Upper Devonian time." As stated above, up to and includ- 

 ing tliis period and the Lower Carboniferous the Paleozoic rep- 

 resents a generalized tropical period in so far as can now he 

 determined. Nor is there reason to believe that other than 

 tropical conditions ruled at the north during the Permo-Car- 

 boniferous and Trias. Likewise the Jurassic plants from Spitz- 

 bergen, King Charles' Island, Franz Josef's Land, Cape Flora, 

 and other far northern localities leave no question of the con- 

 tinuance of these conditions within the Arctic area. Regard- 

 ing the late Jurassic and the very earliest Cretaceous, or the 

 period covering the origin of the Dicotyls, we as yet have 

 scanty evidence from the north. But from this time on the 

 record of climatic change furnished by the northern plants 

 becomes a striking one indeed. 



Greenland is one of the best known of Arctic lands. Though 

 largely an Archaean area of eruptive rocks much too old to shed 

 any light on the character of ancient northern life, and intensely 

 scoured and glaciated, this winter docked land affords abundant 

 and reasonably connected evidence of the slow decline in tem- 

 perature that culminated in the Glacial epoch, as well as of the 

 exceedingly rich and varied flora that just preceded this period 

 of decline. About the edges of the great ice caj) far to the 

 north on the west coast, and mainly between 69'' 15', and 72° 

 15' N. L. there are numerous outcrops of Sandstone and slate 

 containing intervening layers of coal, clay, and clay ironstone, 

 from which have been obtained some of the finest series of 

 Cretaceous and Tertiary fossil plants known, the best and most 

 numerous localities being on the peninsulas of Nugsuak and 

 Svartenhuk. and on Disco Island. The most northerjy locality 

 is in Grinnell Land, 82° N. L. These plant-bearing beds have 

 a total thickness of from 2,000 to 3,000 feet, and are covered 

 by an additional 2,500 feet of basalt, which has protected them 

 from erosion by superimposed ice. Being loose of texture, it 

 is held that they would certainly long since have been com- 

 pletely eroded away were it not for this basalt covering. 

 Although known for nearly a hundred years, the first adequate 

 collections of fossils from these plant beds were made by 



* Zur Fossilen Flora cler Polarlander, Erster Teil. Dritte Lieferung. Znr 

 Oberdevonischen Flora der Baren-lnsel. Stockholm, 1902. 



