■ IBIJ , 



PRB-CARBONIFEROUS PLANTS. 



7a 



meantime have been modified there. It thua becomes a necessary pre- 

 liminary to investigate the local distribution of eacl flora, its probable 

 place of origin and direction of distribution, the regions into which it 

 might retire when displaced locally by subsidences, and the manner of its 

 extension after re-elevation. Such questions require m ich careful obser- 

 vation and comparison of facts, and it would bo more profitable to attend 

 to them with vigour than to waste time in discussing premature hypotheses. 

 North America affords probably the finest field in the world for their 

 solution, and the discussion of the facts relating to them by Prof. Hall in 

 the Introduction to his Paloeontology of New York, Vol. III., is as yet 

 the most important contribution to this. 



Another point deserving of notice is the scarcity of coal in the Devonian 

 series. I am inclined to attribute this rather to geographical and climatal 

 conditions than to any incapacity in the SigillaricB and Calamites and Lepid- 

 odendra of the Devonian to produc a accumulations of coal. The genus Psil- 

 ophyton also seems to have been well suited to form such accumulations ; and 

 indeed the little coal seam at Gaspd Bay is chiefly composed of the remains 

 of this plant. It would, however, be remarkable if conditions favourable 

 to the accumulation of large deposits of coal did not occur in some portion 

 of the areas of Devonian deposition ; and I should not be surprised if at 

 any time such deposits should be found to occur locally in some part of 

 Eastern America. 



In conclusion of this topic, the plants figured in this Report will enable 

 any good observer to recognise the flora of the Devonian, and to dis- 

 tinguish it from that of the great coal series, and thus to avoid the mistake 

 of supposing the plant-bearing beds of the older series to indicate the 

 presence of productive coal measures, a mistake which has led to some 

 costly and useless mining operations. ^ , . . . v'.*^ '<*,, 



(3.) Comparisons with the Equivalent Flora of Europe. 



The Devonian of Europe is so imperfectly developed in comparison 

 with that of America, that whether we compare the fauna or the flora, we 

 must bear in mind that while the lapse of time represented in both con- 

 tinencs may be the same, the extent of rock formations deposited and the 

 amount of life manifested in the fossil remains, vastly preponderate in 

 America. This preponderance is greater than the published lists of fossils 

 ■would indicate, since the rocks of this period in America relatively to 

 their area and thickness, have been less perfectly explored. In Western 

 Europe also local disturbances and differences of deposit, and the passage 

 in some places of the Upper Devonian into the Carboniferous, have caused 

 doubts as to the classification of the beds, which have comparatively little 



