*^ 



PRE-CARBONIFBRODS PLANTS. 



71 



from dififorent facilities for preservation,* or from local diversities of soil 

 and climate, or from different dates of the plant-bearing beds. On the 

 whole, however, as I have elsewhere remarked, while the distribution of 

 genera in the Devonian leads us to infer climatal conditions in the main 

 resembling those of the Carboniferous, it would also lead us to conclude 

 that the local diversities were greater, and that there was less of that dead 

 level of similar local conditions which prevailed so extensively in the . 

 Carboniferous period. The Devonian plants probably grew on limited 

 rocky islands, bordered by much less extensive and permanent lowlands 

 than those of the Carboniferous era. 



Specifically the Devonian flora is almost altogether distinct from the 

 Carboniferous. Even the same genera are represented by distinct 

 species, and it is possible that some of the few species which we now 

 identify with those of the Coal, will in future be found to be distinct. I 

 presume, at least, that this is more likely than that those esteemed distinct 

 shall be found to be identical. 



The specific differences also point in certain definite directions. The 

 <5oniferou8 trees are of more lax texture, and with larger woody fibre in 

 the Pre-Carboniferous beds. The Sigillariw and Lepidodendra are smaller 

 and more delicate. The ferns present a tendency to the extremes of small 

 and delicate, and very large and expanded fronds. They have generally 

 a tendency to a flabellato venation decurrent on the petiole. There is a 

 remarkable abundance and variety of Lycopodiacoous plants. We shall 

 find that it is probable that in the course of the Devonian period itself, 

 great changes occurred in some of these points. 



Of all the known localities of Brian plants in Eastern America, that of 

 Oaspd presents an assemblage the most primitive and the least Carbon- 

 iferous in aspect. That of Southern New Brunswick gives us a flora the 

 most akin to that of the Carboniferous. The lower part of the Gasp^ 

 aeries undoubtedly reaches to the base of the Devonian ; this is proved 

 by its marine fossils, but its middle and upper parts must be at least 

 on as high a horizon as that of the New Brunswick beds. More especially 

 does this appear when we consider that, as I have shown in a previous 

 paper, and as Prof. Bailey and Mr. Matthew have since fully confirmed, the 

 latter have been altered and disturbed before the deposition of the Lowest 

 Carboniferous beds, and that they appear to underlie the Devonian beds of 

 Perry in Maine. These facts show that they should be regarded not as 

 Upper Devonian, as I was at first inclined to believe, but as belonging to the 

 middle of the series. 



• In the Middle Devonian we may conceiTe the plant beds of Nevr Brunswick to rtproMnt 

 «n estuary or swampy lagoon, while those of New York and Ohio are open lea areu, into 

 <which learea long macerated in water were drifted. 



