90 PROF. J. LOGAN LOBLKY, F.G.S.^ ETC., ON 



forests wanting in statel}^ arborescent i'orms, for lycopods 

 attained a large tree-like size in Lepidodendron, and 

 in Sigillaria grew to a girth of 16 feet and a height of 50 

 to 60 feet. Equisitacese gave the genus Calamites in great 

 abundance, while the ferns were most profuse in the great 

 number of genera and species, some of which are remark- 

 ably similar to those now growing so freely in the southern 

 counties of England. 



The Carboniferous rocks and their contents are of the 

 greatest value to mankind and most conducive to the 

 progress and advancement of humanity ; and as to our own 

 country, it may be said that Great Britain owes its Avealth, 

 power, and importance in a great degree to the beds of coal 

 contained in the rocks of this period. 



Of the various substances, all most useful to man, and 

 stored up for his use in the Carboniferous rocks, the most 

 important is coal, v^^hich for two hundred ^^ears at least has 

 been abundantly employed for giving heat, light, and 

 power to mankind. It occurs in very large and widely 

 separated areas, for it is found in both the Old World and the 

 New, and in both the Northern and the Southern Hemis- 

 pheres. Yet great and extensive as are the coal-beds of 

 to-da3% they have been much more extensive in the past, 

 for very large areas have been swept clear of the coal 

 they once possessed by the agency of denudation.* 



Although the conditions prevailing in the regions in 

 Avhich the known Permian rocks were deposited Avere 

 unfavourable to animal life, with the result of giving to 

 those rocks a diminished fossil fauna, yet the comparative 

 abundance of amphibian forms is evidence of continuous 

 progress towards present terrestrial conditions. The epoch 

 was intermediate between Palaeozoic and Mesozoic (or 

 Secondary) times, between the age of Invertebrata and 

 of fishes and the age of reptiles, birds, and mammals. The 

 flora had a quite Carboniferous character, ferns being 

 abundant and tree-ferns numerous. In addition there were 

 some phanerogams, though confined to the gymnosperms, 

 as remains of cycacls and coiiifers are found in rocks of 

 Permian age. 



As in the older so in the later Palseozoic ages, volcanic 



* This is especially the case in the case of Ireland, the whole of the 

 central plain of that country having been originally covered by deposits 

 with coal. — Ed. 



