THE GENESIS AND MIGRATIONS OF PLANTS 2OQ 



in Eastern America, especially in the St. John beds, it might 

 be a fair inference that the north-eastern end of the Appala- 

 chian ridge was the original birthplace or centre of creation of 

 what we may call the later Palaeozoic flora, or a large part of 

 that flora." 



When my paper was written I had not seen the account 

 published by the able Swiss palaeobotanist Heer, of the re- 

 markable Devonian flora of Bear Island, near Spitzbergen. 1 

 From want of acquaintance with the older floras of America 

 and Western Europe, Heer fell into the unfortunate error of 

 regarding the Bear Island plants as Lower Carboniferous, a 

 mistake which his great authority has tended to perpetuate, 

 and which has even led to the still graver error of some Euro- 

 pean geologists, who do not hesitate to regard as Carboni- 

 ferous the fossil plants of the American deposits from the 

 Hamilton to the Chemung groups inclusive, though these be- 

 long to formations underlying the oldest Carboniferous, and 

 characterized by animal remains of unquestioned Devonian 

 age. In 1872 I addressed a note to the Geological Society of 

 London on the subject of the so-called " Ursa stage " of Heer, 

 showing that though it contained some forms not known at so 

 early a date in temperate Europe, it was clearly Devonian when 

 tested by North American standards ; but that in this high 

 latitude, in which, for reasons stated in the report above re- 

 ferred to, I believed the Devonian plants to have originated, 

 there might be an intermixture of the two floras. But such a 

 mixed group should in that latitude be referred to a lower 

 horizon than if found in temperate regions. 



Between 1870 and 1873 my attention was turned to the two 

 subfloras intermediate between those of the Devonian and the 



ably should be preferred to it, as pointing to the best development of 

 this formation known, which is on the shores of Lake Erie. 



1 Trans. Swedish Academy, 1871, Journal London Geological Society, 

 vol. xxviii. 



