

FLORA. fcll 



occur towards the Upper Devonian, and it is there that are 

 found the most ancient land plants of which we have any 

 knowledge ; but that is not to say that these were really 

 the first. So far from that it is in fact easy to establish 

 that the vegetation, already far removed from the point of 

 original departure, contained nearly the same elements as 

 that of the carboniferous land, properly so called, save for 

 the variations and partial modification to which the flora 

 continued to be subjected in passing through this pro- 

 tracted period. The Devonian plants are rare everywhere ; 

 and they have not yet been met with in the Arctic regions ; 

 but in the upper portion of the Devonian between this 

 formation and that of the mountain limestone, with its 

 characteristic Productus and Spirifer, there is seen on a 

 pretty great number of points both in Europe and in the 

 Polar Zone, a primitive coal-bed with terrestrial plants, 

 which testifies everywhere to a great uniformity of vege- 

 tation. It is to this lower coal-bed that M. Schimper has 

 recently applied the name of Paleanthracitic stage, and M. 

 Heer that of the Ursien stage, so naming it from Bear 

 Island, L'lle des Ours, where it appears more developed 

 than elsewhere. This, moreover, is embedded between two 

 marine deposits, which proves that the sea had retired 

 during the deposit of the carbonaceous beds which enclose 

 the imprints it contains, and then returned to cover again 

 the deposit after it had been formed, a deposit conse- 

 quently littoral, as well as one certainly made under fresh 

 water. The distinctive plants of this Ursien layer reappear 

 not only in the Parry Islands and in Spitzbergen, but at a 

 greater distance from Bear Island, in Iceland, near Aix- 

 la-Chapelle, and in the Vosges, where they have furnished 

 Professor Schimper material for an important memoir on 

 the flora of the transition land of the Vosges. 



'It happens, then, that not from a mere local accident, 

 but from a vegetable period long anterior to that of the 

 coals, and coincident with a series of simultaneous emer- 

 sions elsewhere, the result has been obtained of making us 

 acquainted with the principal forms which then predomi- 



