34 T. G. HALLE, LOVVER DEVONIAN PLANTS FROM RÖRAGEN IN NORWAV. 



phyton princeps in the Old Red Sandstone of Scotland apply to this species in the sense 

 in which the name is here employed. The species has been recorded on good evidence 

 from the Lower Devonian of Matringhem in northern France by P. Bertrand (1913). 

 A critical review of the facts at present known regarding the geological distribution of 

 Psilophyton princeps gives the result that the species is especially characteristic of the 

 Lower and possibly of the Middle Devonian. 



Psilophyton Goldschmidtii has been distinguished for the first time in this paper; 

 and as no specimens from other localities can at present be identified with it, the species 

 gives no information on the geological age of the Röragen deposit. 



The remains referred to Hostimella and Aphyllopteris are not sufficiently charac- 

 teristic to justify any comparisons with the object of determining the geological age. 

 Similar fragments are common in several Devonian floras, especially perhaps in the 

 Middle Devonian of Bohemia. 



Daivsonites arcuatus is the name given to the supposed fructifications referred by 

 Dawson to Psilophyton princeps. Dawson's specimens occur in association with un- 

 doubted Psilophyton princeps. The same is the case at Matringhem in northern France 

 (P. Bertrand, 1. c). Daivsonites arcuatus therefore gives no further information on the 

 geological age than is offered by Psilophyton princeps. 



Sporogonites exuberans is an entirely new form, not represented in any other local- 

 ity, and is therefore of no importance for the question of parallelization. 



Of the forms here considered, all those which are of any importance for the paral- 

 lelization occur in the Lower Devonian of North America, Scotland, and France. Some 

 of them are stated to reach up into the Middle Devonian, Psilophyton princeps even into 

 the Upper Devonian. 



The most important and typical locality affording a Lower Devonian flora at pre- 

 sent known is that of Gaspé. As remarked above, the Gaspé series is stated to rest con- 

 formably on the Upper Silurian limestones and is held to represent the whole Devonian 

 period. »The lower part of the Gaspé series undoubtedly reaches to the base of the 

 Devonian; this is proved by its marine fossils, but its middle and upper parts must be 

 at least on as high a horizon as that of the New Brunswick beds» (Dawson 1871, p. 71). 

 The Lower Devonian at Gaspé is especially characterized by »the extreme abundance 

 of Psilophyton and Arthr ostig ma» (Dawson 1871, p. 72). 



It is difficult to form any adequate idea of the Middle Devonian floras described 

 by Dawson, because there have been referred to that horizon plant-remains of very 

 different geological age, as for instance the whole flora of the St. John shales in New 

 Brunswick, which is certainly Lower Carboniferous (cfr. M. C. Stopes, 1914). In the 

 middle part of the Gaspé series, Psilophyton princeps, Arthrostigma and Nematophycus, 

 which still occur, are accompanied by Stigmaria (?) areolata Daws., Lepidodendron 

 gaspianum Daws., Lepidophloios antiquus Daws., etc, none of which isfound at Röragen. 

 The Devonian flora of Bohemia is better known in regard to its stratigraphical rela- 

 tions than most other contemporaneous floras and is commonly referred to the middle 

 part of the system. It has some peculiar features of its own, especially in the presence 

 of such forms as Spiropteris hostimensis Potonié & Bernard, Pseudosporochnus Krejcii 



