THE ERIAN OR DEVONIAN FORESTS. 



103 



from the one to the other, the species are for the most part differ- 

 ent, and new generic forms are met with, and, as I have elsewhere 

 shown, the physical conditions of the two periods were essentially- 

 different.* 



It is, however, to be observed that since — as Stur and others have 

 shown — Catamites radiatus, and other forms distinctively Devonian 

 in America, occur in Europe in the Lower Carboniferous, it is not 

 • unlikely that the Devonian flora, like that of the Tertiary, appeared 

 earlier in America. It is also probable, as I have shown in the " He- 

 ports " already referred to, that it appeared earlier in the Arctic than 

 in the temperate zone. Hence an Arctic or American flora, really 

 Devonian, may readily be mistaken for Lower Carboniferous by a 

 botanist basing his calculations on the fossils of temperate Europe. 

 Even in America itself, it would appear, from recent discoveries in 

 Virginia and Ohio, that certain Devonian forms lingered longer in 

 those regions than farther to the northeast ; f and it would not be 

 surprising if similar plants occurred in later beds in Devonshire or 

 in the south of Europe than in Scotland. Still, these facts, properly 

 understood, do not invalidate the evidence of fossil plants as to 

 geological age, though errors arising from the neglect of them are 

 still current. 



VI. — Geological Relations of some Plant-bearing Beds of 

 Eastern Canada. (" Report on Erian Plants," 1871.) 



The Gaspe sandstones have been fully described by Sir W. E. 

 Logan, in his " Report on the Ge*ology of Canada," 1863. He there 

 assigns to them a thickness of seven thousand and thirty-six feet, 

 and shows that they rest conformably on the Upper Silurian lime- 

 stones of the Lower Helderberg group (Ludlow), and are in their 

 turn overlaid unconformably by the conglomerates which form the 

 base of the Carboniferous rocks of New Brunswick. I shall add 

 here merely a few remarks on points in their physical character 

 connected with the occurrence of plants in them. 



Prototaxites (Nematophyton) Logani and other characteristic 

 Lower Erian plants occur in the base of the sandstones at Little 

 Gaspe. This fact, along with the occurrence, as stated in my paper 

 of 1863, of rhizomes of Psilophyton preserving their scalariform 



* " Reports on Devonian Plants and Lower Carboniferous Plants of 

 Canada." 



t Andrews, " Palaeontology of Ohio," vol. ii. ; Meek, " Fossil Plants 

 from Western Virginia," Philosophical Society, Washington, 1875. 



