PKB-CARBONIFEROUS PLANTS. 



76 



northern hemisphere than that which existed in the succeeding Carbon- 

 iferous period. 



Aa an illustration of the difficulty of oonipariaon, I may refer to the 

 remarkable fact that the genus Pailophyton, so characteristic of the 

 American flora in this period, had not, until noticed by me in 1870, been 

 recognised in the Devonian of Europe. That this depends altogether on 

 defective preservation of specimens, or defective observation, I am fully 

 convinced. There can be little doubt that the species Haliaitea Dechenianus 

 Goept., so abundant in the rocks of this age in Germany, is founded on 

 badly preserved specimens of Pailophyton. So are the " branching roots," 

 " grass-like plants," and " curved fucoids," which have been described 

 as occurring in the Old Red Sandstone of Scotland.* Unger has also 

 described the internal structure of certain stems from the Devonian of 

 Thuringia, which, if preserved in respect to their external markings, would 

 very probably be found to be stems of Pailophyton. f These probabilities 

 were fully discussed in my Paper on the Devonian plants of Gaspd in the 

 Journal of the Geological Society, vol. xv, page 482. Yet though ten 

 years had elapsed since the publication of that paper, it would seem 

 that no specimens comparable with those found so abundantly in Gasp^ 

 had been discovered in Europe. 



As an example of the same kind, but in favour of the European flora, 

 I may mention that the genus Cyclo»tigma^ recognized many years ago 

 in Ireland by Haugbton, has been found in America for the first time in 

 1869. 



On the other hand the fact of greater diversity, at least of station, in 

 the Devonian period, seems to be proved by the character of the flora itself, 

 as well as by the great difi'erences botween the proportions of difierent gen- 

 era and species in localities not very distant from aach other, above referred 

 to. It is perhaps equally illustrated by the striking similarity in the flora 

 of places somewhat remote from each other, as Perry in Mame, and Mont- 

 rose in Pennsylvania. 



It is, however, important, in the interest of Pal8eo>)otany, to observe that 

 the facies of the Erian flora is very similar on both sides of the Atlantic, 

 so that a botanist familiar with the differences between the plants of the 

 ■Carboniferous and Devonian in America or in Europe, would have no 

 diiiiculty in applying this knowledge to the separation of the rocks of these 

 periods in any part of either continent. 



When in London in the spring of 1870, I was enabled, through the 

 kindness of Mr. Etheridge and Mr. Carruthers, to examine the specimens 



* Salter on Plants of Caithness, 

 t E. Q. CUptidroptii antiqua. 



Journal of Qeol. Society, Vol. XIV. 



