almost exclusively from strata of the Transition series. Examples of Coal in any of the Secondary strata are few and insignificant; whilst the Lignites of the Tertiary formations, although they occasionally present small deposites of compact and useful fuel, exert no important influence an the economical condition of mankind.[1]
It remains to consider some of the physical operations on the surface of the Globe, to which we owe the disposition of these precious Relics of a former world, in a state that affords us access to inestimable treasures of mineral Coal.
We have examined the nature of the ancient vegetables from which Coal derives its origin, and some of the processes through which they passed in their progress towards their mineral state. Let us now review some further important geological phenomena of the carboniferous strata, and see how far the utility arising from the actual condition of this portion of the crust of the globe, may afford probable evidence that it is the result of Foresight and Design.
It was not enough that these vegetable remains should have been transported from their native forests, and buried at the bottom of ancient lakes and estuaries and seas, and there converted into coal; it was further necessary that great and extensive changes of level should elevate, and convert into dry and habitable land, strata loaded with riches, that would for ever have remained useless, had they continued entirely submerged beneath the inaccessible
- ↑ Before we had acquired by experiment some extensive knowledge of the contents of each series of formations which the Geologist can readily identify, there was no à priori reason to expect the presence of coal in any one Series of strata rather than another. Indiscriminate experiments in search of coal, in strata of every formation, were therefore desirable and proper, in an age when even the name of Geology was unknown; but the continuance of such Experiments in districts which are now ascertained to be composed of non-carboniferous strata of the Secondary and Tertiary Series, can no longer be justified, since the accumumulated experience of many years has proved, that it is only in those strata of the Transition Series which have been designated as the Carboniferous Order, that productive Coal-mines on a large scale have ever been discovered.
