3G0 CONCLUSION. 



Stigmaria was probably dicotyledonous, and in its internal 

 structure seems to have borne some analogies to that of the 

 Euphorbiacese. 



Conclusion. 



Besides these Genera which have been enumerated, there 

 are many others whose nature is still more obscure, and of 

 which no traces have been found among existing vegeta- 

 bles, nor in any strata more recent than the Carboniferous 

 series.* Many years must elapse before the character of 

 these various remains of the primeval vegetation of the 

 Globe can be folly understood. The plants which have 

 contributed most largely to the highly-interesting and im- 

 portant formation of Coal, are referable principally to the 

 Genera whose history we have attempted briefly to eluci- 

 date : viz. Calamites, Ferns, Lycopodiacese, Sigillarias, and 

 Stigmaria). These materials have been collected chiefly 

 from the carboniferous strata of Europe. The same kind 

 of fossil plants are found in the coal mines of N. America, 

 and we have reason to believe that similar remains occur 

 in Coal formations of the same Epoch, under very different 

 Latitudes, and in very distant quarters of the Globe, e. g. in 

 India, and New Holland, in Melville Island, and Baffin's 

 Bay. 



The most striking conclusions to which the present state 

 of our knowledge has led, respecting the vegetables which 

 gave origin to coal arc, 1st, that a large proportion of these 

 plants were vascular Cryptogamia), and especially Ferns; 



estuary or 6ea, and there becoming surrounded by sediments of mud or sand. 

 This hypothesis seems supported by tiic observations made at Jarrow, that 

 the extremities of tiic branches descend from tlie dome towards the adjacent 

 bed of coal. 



* Some of the most abundant of these have been classed under tlie names 

 of Asterophyllites, (see Pi. 1, Figs. 4. 5,) from the stellated disposition of the 

 leaves around the branches. 



