6 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 82 



Schizoneura recorded from the New Siberian Islands which may be 

 Rhaetic and there are scattered Rhaetic plants in Greenland and 

 Spitzbergen ; and somewhat farther south in northwestern Norway 

 (Ando) and southern Sweden. 



The most extensive northern Rhaetic flora is that from Scoresby 

 Sound, East Greenland, between 70° and 71° North Latitude. This 

 comprises 51 named forms and several additional ones which are not 

 named. Cycads and ferns predominate, and so far as we can judge 

 at this lapse of time all belong to cosmopolitan Rhaetic types. Harris, 

 who has given an excellent account of these plants concludes that 

 they indicate a temperate climate, largely on the ground of the pre- 

 dominance of certain forms indicative of relatively pure stands and 

 the absence of mixtures such as occur in recent tropical assemblages. 

 He concludes also, from a study of the cuticles of many of the species, 

 that moisture was plentiful. The wood of Dadoxylon in the Rhaetic 

 of Spitzbergen has very feebly marked seasonal rings. 



JURASSIC 



Supposed Jurassic floras completely surround the pole and are 

 extensively developed throughout Siberia, in Alaska, Greenland, Spitz- 

 bergen, Franz Josef Land, New Siberian Islands, and elsewhere. 

 Formerly, many of these, as those in Siberia, were considered Middle 

 Jurassic, but Nathorst is the authority for the statement that all of 

 the more northern ones are post Oxfordian, and several, such as that 

 of Spitzbergen, are on the border between the Jurassic and the Lower 

 Cretaceous. 



The Spitzbergen flora is the most extensive and, according to 

 Nathorst, includes 2 horizons, one Portlandian and the other possibly 

 as young as Neocomian. A combined list of these comprises 57 

 species, including 11 fern-like plants, i lepidophyte (Lycopodites), 

 I arthrophyte (Equisetites), 4 cycadophytes, 4 Ginkgoales, 23 conifers 

 and 13 of uncertain affinities. Nine different types of coniferous 

 woods have been described and all show pronounced seasonal growth 

 rings. Most of the generic types have a very great geographical range, 

 but several, such as Phoenicopsis, Torellia and Drepanolepis, appear 

 to be distinctly northern, and the predominance of conifers suggests 

 a cool temperate climate. They are found in sandstones associated 

 with coal seams and freshwater mollusks (Lioplax, Unio) and evi- 

 dently grew in the vicinity of their burial place. 



