NO. 6 PAST CLIMATE OF NORTH POLAR REGION— BP:RRV 13 



The Spitzbergeu llora comes from two horizons and the two total 

 168 species and are not essentially different in facies. They are as- 

 sociated with coal seams and are clearly continental palustrine associa- 

 tions. There are 4 ferns, a Ginkgo, 27 conifers, 27 monocotyledons 

 and 80 dicotyledons. Three woods described by Gothan show marked 

 seasonal rings. The warmer elements are Taxodium, Platanus, Jug- 

 lans, Nympha^a, Magnolia and Nyssa. Here also oaks, hazels, willows, 

 poplars and conifers predominate. There is not a single tropical or 

 subtropical type and not one justly considered warm temperate. 



The Greenland Tertiary flora comprises 283 nominal species and 

 includes 8 fungi, i moss, i lycopod, i equisetum, 19 ferns (all tem- 

 perate types), I Ginkgo, 28 conifers, 21 monocotyledons and 20J 

 dicotyledons. The petrified coniferous woods show well marked 

 seasonal rings and the only genus that is seemingly out of place in 

 the far north is Taxodium, whose abundance in all Arctic floras and 

 in proved temperate floras of other regions and other horizons shows 

 that it was not out of place here. The monocotyledons include mostly 

 miscellaneous leaf fragments, not generically determinable, as well 

 as two supposed palms (Flabellaria). It has frequently been pointed 

 out by others as well as by myself that the nature of the last cannot 

 be considered as proving the presence of palms. The dicotyledons 

 are very much overelaborated. Probably 100 species is nearer the 

 correct figure than the 202 which Heer differentiated. 



In Greenland as in all known Tertiary Arctic floras the leaves of 

 willows, poplars, birches, and hazels predominate, but there are many 

 other genera whose identification cannot be disputed, such as Liquid- 

 ambar, Alnus, Fagus, Ouercus, Ulmus, Platanus, Sassafras, Fraxinus, 

 Cornus, Liriodendron, Acer, etc. Vitis is represented by both leaves 

 and seeds, and other genera also show fruits. The genera that appear 

 to me to be highly questionable are the following : Castanea, Juglans, 

 Pterocarya, Benzoin, Laurus, Myrsine, Apeiobopsis, Pterospermites, 

 Zizyphus, Colutea, Dalbergia, Diospyros, Sapindus, and several others. 

 I base this conclusion on the fossils and not on the probabilities of 

 their presence. Some, such as Zizyphus and Ficus clearly do not 

 represent those genera, in fact Heer's discussion shows his lack of 

 conviction of the latter and he queried his determination. 



Heer devoted considerable space to a discussion of the climatic 

 significance of this as well as other Arctic floras and concluded that 

 the Greenland plants indicated a mean annual temperature of 53.6° ¥., 

 or a considerably lower figure than he estimated by the same methods 

 for the supposed contemporaneous flora of Switzerland, thus clearly 

 recognizing a climatic zonation. 



