172 THE OLD COAL-MEASURES. 



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areas of deposit, and over the whole a gradual subsidence 

 to allow the depositions of bed above bed in such regular 

 and continuous arrangement. And while all this went on 

 the march of life was ever onward and upward. Plants 

 unknown in the Silurian and Old Eed Sandstone periods 

 made their appearance ; newer genera and species of corals, 

 shell-fish, Crustacea, and fishes thronged the waters. Rep- 

 tiles, so doubtfully known in the Old Eed, now appeared 

 in considerable variety j insects, frail and fragile as they 

 generally are, were by no means uncommon j and all that 

 is wanting to complete the scheme of life, as now known to 

 us, is the presence of birds and mammals. Whether this 

 absence of birds and mammals arises from their non-ex- 

 istence during the period, or from the imperfection of the 

 geological record, it is impossible to determine j but clearly 

 the flora and fauna are greatly in advance of those of the 

 Old Eed Sandstone, and all this is in perfect harmony with 

 the geological doctrine of a progressive development of 

 vitality. 



As an economic repository the old coal-measures present 

 a wide field for inquiry and description. The variety and 

 value of their products, the skill and capital expended in 

 obtaining them, and their obvious bearings on the indus- 

 trial and social relations of a nation, are subjects, however, 

 that lie far beyond the scope of a single sketch, and all that 

 we can attempt is little more than a mere enumeration of 

 the principal substances. We allude, of course, more espe- 

 cially to the Coal Formation of the British Islands, from 

 which it may be safely asserted that we derive products of 

 greater value than from all the other formations put to- 

 gether. From its sandstones we obtain many of our most 

 durable and beautiful building-stones ; we fabricate its fire- 

 clays into furnace-bricks, retorts, drainage-pipes, baths, and 



