222 Notices of Memoirs — Professor A. G. Nathorst— 



same peculiarity, it is quite safe to conclude that we are here 

 concerned with large trees, which have actually flourished in these 

 latitudes, and which have not been transported from more southern 

 regions. 1 



The Cretaceous" System, as we know it, is represented in Western 

 Greenland, between the parallels of 69° and 71°, by an important 

 series of beds containing fossil plants belonging to the Urgonian, 

 Cenomanian, and Senonian, the two first mentioned containing coal- 

 seams. I have been able to show, as the result of the studies which 

 I made in Greenland in 1883, that beds, full of roots, underlie those 

 containing fossil plants at Unartoarsuk, as well as at Igdlokunguak. 

 Without doubt the Urgonian flora, like the Cenomanian flora, is a 

 relic of vegetation which once flourished in the same regions where 

 we now find the fossils. Bat, on the contrary, the Senonian flora, or 

 flora of Patoot, is in part contained in marine beds, containing 

 Inoceramus, etc., and thus it may have been transported from some 

 distance. The Urgonian flora, or flora of Tvome, is composed of 

 Ferns, Cycadophytes, and Conifers, while the Cenomanian or Atane 

 flora, in addition to arborescent Ferns (Dicksonia) and Cycadophytes 

 (Pseudocycas),- is particularly rich in the leaves of Dicotyledonous 

 trees, among which are found those of planes, tulip-trees, and bread 

 fruits, the last mentioned closely resembling those of the bread 

 fruit-tree (Artocarpus incisa) 3 of the islands of the Southern seas. 



In the limited space at my disposal, I have had to be content with 

 a brief summary of the strata containing fossil floras of Pakeozoic and 

 Mesozoic age. But, from what has been said, it is clear that we have 

 every reason to regard the floras of the Devonian, Culm, Jurassic, and 

 Cretaceous of the Arctic regions as being composed of plants which 

 flourished in these very regions. It has not been definitely proved 

 that the Triassic flora has been transported from more Southern 

 regions by marine currents, but there is still some uncertainty on this 

 point. 



In relation to the present problems, the Tertiary floras are 

 undoubtedly the most important, and for this reason I will enter into 

 the subject in some detail. But the materials are so wonderfully rich 



1 It may be mentioned here that a silicified Dadoxylon from the Carboni- 

 ferous deposits of Spitzbergen described by Dr. Gothan (loc. cit.) does not show 

 any annual rings at all, precisely as is the case with the corresponding Palaeozoic 

 stems of Europe. As observed to me by Mr. Th. Halle, this is a most curious 

 circumstance, since the darkness during the long winter night in those regions — 

 provided that the position of the North Pole was the same as now — ought to 

 have caused an interruption of the growth, even if the climate was a warm and 

 genial one. As the specimen, however, was not found in situ it is possible that 

 it originates from some marine deposit into which the wood had been brought 

 by ocean currents from more southern latitudes. But also a Dadoxylon from 

 the Triassic of Spitzbergen shows only slight indications of annual rings 

 (Gothan, loc. cit.). 



" A. G. Nathorst, " Palaobotanische Mitteilungen, 1 und 2. Pseudocycas, 

 eine neue Cycadophytengattung aus den Cenomanen Kreideablagerungen 

 Gronlands " : Kongl. Svenska Vet.-Akad. Handl., vol. lxii, No. 5, 1907. 



3 Id., " Uber die Eeste ernes Brotfructbaumes, Artocarpus Diclisoni, n.sp., 

 aus den Cenomanen Kreideablagerungen Gronlands": Kongl. Svenska Yet.- 

 Akad. Handl., vol. xxiv, No. 1, 1890. 



