48 CARBONIGENOUS ERA. 



remote situations. The conifers of this era may be said to 

 form the dawn of dicotyledonous trees, to which, it has 

 already been noticed, the lepidodendra are a link from the 

 monocotyledons. The concentric rings of the Craigleith and 

 other conifers of this era have been mentioned. It is inte- 

 resting to find in these a record of the changing seasons of 

 those early ages, when as yet there were no human beings to 

 observe time or tide. The rings are clearly traced ; but it is 

 observed that they are more slightly marked than is the case 

 with their family at the present day, as if the changes of 

 temperature had been within a narrower range. 



Such (if we are to be allowed to rest with positive evi- 

 dence) was the vegetation of the carbonigenous era, com- 

 posed of forms low in the botanical scale, mostly flowerless 

 and fruitless, but luxuriant and abundant beyond what the 

 most favoured spots on earth can now show. The rigidity of 

 the leaves of its plants, and the absence of fleshy fruits and 

 farinaceous seeds, unfitted it to afford nutriment to animals ; 

 and, monotonous in its forms, and destitute of brilliant colour- 

 ing, its sward probably unenlivened by any of the smaller 

 flowering herbs, its shades uncheered by the music of birds, 

 it must have been a sombre scene to a human visitant. But 

 neither man nor any other animals were then in existence to 

 look for such uses or such beauties in this vegetation. It was 

 serving other and equally important ends, clearing perhaps 

 the atmosphere of matter noxious to animal life, and certainly 

 storing up mineral masses which were in long subsequent 

 ages to prove of the greatest service to the human race, even 

 to the extent of favouring the progress of its civilization. 



Traces of land plants previous to the Carboniferous era 

 are isolated at the best, and, till we know more about them, 

 they cannot be allowed greatly to affect our views of the 

 botanical history of the globe. Geologists speak of a fern 

 leaf in the Silurians of Wales ; in those of America, a plant 

 apparently allied to the lepidodendron ; in the American 

 lower Devonian, some allied to ferns. These phenomena, if 

 fully established, would not interfere with general deductions 

 from the mass of early land vegetation found in the coal 



