FLORA. 211 
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 Paleanthravitic 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- 
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