508 PALAEONTOLOGY OF ILLINOIS. 



The number of European species recognized in the Coal Measures of Illinois 

 do not change in any way the relation of the American Coal Measures with 

 those of Europe. It remains now the same as I have presented it formerly 

 (Penn. Geol. Rep., loc. cit.). If general affinity is ascertained by a large num- 

 ber of plants, either identical or closely related, geographical differences in the 

 vegetation are indicated by peculiar species or races of ours, which as yet have 

 not been observed in the Coal Measures of Europe. It is true that European 

 palaeontologists, though at work on the coal flora for more than a century, still 

 discover species, either identical with or allied to some of ours, which were 

 once considered as exclusively pertaining to the American coal flora ; for ex- 

 ample, a fimbriate Cyclopteris* from a small anthracite basin of the Swiss Al- 

 pine mountains. But these cases are very rare indeed, and besides what is 

 known from other parts of our coal fields, Illinois has now furnished a number 

 of these peculiar types of vegetables, which render geographical disparity more 

 appreciable. Of this kind are especially Neuropteris verbenirfolia, JV. Evenii, 

 N. pachyderma, Dictyopteris rubella, Alethopteris hymenophylloides, A. inflata, 

 A. solida, Pecopteris Strongii, species of Stapliylopteris, /Sphenopteris scaberri- 

 ma, Hymenophyllites mollis, /Schutzia bractenta, a number of species of Lepido- 

 dendra and Sigillaria, Syringodendron Porteri, MegapTiytum McLayii, species 

 of Caulopteris and of fruits of Palseoxyris. Indeed, no genus of our coal flora, 

 except, perhaps, Calamites, can be considered as represented on both continents 

 by species all identical or closely allied. As these points of difference, like 

 those of affinity, have been observed from the beginning of the researches on 

 the coal flora, and have not varied much in comparative quantity, they appear 

 to fully corroborate the statement that, at the Carboniferous epoch, the flora 

 which formed the constituents of the coal, was in Europe and in the United 

 States as different, and at the same time as relatively alike, as is now the flora 

 of the peat bogs of the two continents. 



* Cyclopteris lacerata, Heer., see descriptive part. The predominant species of this Alpine 

 basin, which was fora long time considered as of a different formation from that of the Car- 

 boniferous epoch, is Odontopteris Alpina, Brgt., a peculiar plant, which, as yet, with uSjhaa 

 been found only in connection with the anthracite of Rhode Island. 



