FOSSIL FLORAS OF ARCTIC REGIONS—NATHORST, 339 
The most ancient Jurassic sediments of Spitsbergen are marine, 
and belong to the Sequanian stage. There was consequently a long 
interruption in sedimentation after the formation of the Rhetic 
beds.1. The upper part of the Jurassic formation (Portlandian) 
furnishes a series of plant-bearing sandstones, seams of coal, and beds 
of undoubted fresh-water origin, containing Unio and Lioplax polaris. 
The fossil plant remains belong to two different floras,? one, the more 
ancient, being characterized by the presence of Ginkgo digitata 
Brongn., sp.; the other, the more recent, by Elatides curvifolia Dkr., 
sp. The two floras are associated with beds of coal, and one may 
here also put forward the view that the plants originally flourished in 
the place where they are now found. One of the coal seams at Cape 
Boheman furnishes a great abundance of Podozamites and Pityophyl- 
lum; sometimes the surface of the schists is as completely covered 
with the leaves of Ginkgo digitata, as the soil beneath a living ginkgo 
tree may be in autumn. Since branches and seeds of the same plant 
are also associated, it is natural to suppose that a ginkgo forest 
occurred not far away from this spot. The same observation applies 
to Elatides curvifolia of the more recent flora, which occurs locally in 
the fresh-water beds containing Unio and Lioplaz. Floras of the 
same age and composition are also known from King Karls Land, the 
islands of New Siberia,® from Northern Siberia, and Arctic Alaska. 
The Neocomian series of King Karls Land is overlain by sheets of 
basalt, often amygdaloidal, and-containing chalcedony and agates. 
Fragments of silicified woods, large and small, also occur here, and 
these, without doubt, owe their mineralization to the volcanic 
phenomena. Some of these trunks are fairly large, and I have 
myself measured one, which, although incomplete, was 70-80 cm. 
in diameter, and showed 210 annular rings. Some of these remains 
consist of the lower portion of the trunk and the primary ramifica- 
tions of the roots. 
The microscopic examination of these specimens, undertaken by 
Dr. W. Gothan,‘ has shown that the annual rings of the fossil stems 
from King Karls Land were much more accentuated than those of 
stems found in the corresponding beds of the European continent, 
which indicates that the trees lived in a region where the difference 
between the seasons was extremely pronounced. They can not there- 
fore have been transported from the south by marine currents, and as 
1A. G. Nathorst, ‘‘ Beitrige zur Geologie der Biren Insel, Spitzbergens, und des Kénig Karl Landes’: 
Bull. Geol. Inst. Upsala, vol. 10, 1910. 
2 A. G. Nathorst, ‘‘Zur Mesozoischen Flora Spitzbergens’”’: Kongl. Svenska Vet. Akad. Handl., vol. 30, 
No. 1; Stockholm, 1897. 
31d., “Uber Trias und Jurapflanzen von der Insel Kotelny’’: Mém. Akad. Imp. Sci. St. Pétersbourg, 
ser. 8, vol. 21, No. 2, 1907. 
4 W. Gothan, ‘‘ Die fossilen Hélzer von KGnig Karls Land’’; Kongl. Svenska Vet.-Akad. Handl., vol. 43, 
No. 10; Stockholm, 1907. 
