We thus are led to inquire into the efficient causes of this constitution of things, by which solidity and stability had been bestowed upon a mass of loose materials, and by which this solid earth, formed first at the bottom of the sea, had been placed in the atmosphere, where plants and animals find the necessary conditions of their life.

Now, we have shown, that subterraneous fire and heat had been employed in the consolidation of our earth, and in the erection of that consolidated body into the place of land.  The prejudices of mankind, who cannot see the steps by which we come at this conclusion, are against the doctrine; but, prejudice must give way to evidence.  No other Theory will in any degree explain appearances, while almost every appearance is easily explained by this Theory.

We do not dispute the chymical action and efficacy of water, or any other substance which is found among the materials collected at the bottom of the sea; we only mean to affirm, that every action of this kind is incapable of producing perfect solidity in the body of earth in that situation of things, whatever time should be allowed for that operation, and that whatever may have been the operations of water, aided by fire, and evaporated by heat, the various appearances of mineralization, (every where presented to us in the solid earth, and the most perfect objects of examination), are plainly inexplicable upon the principle of aqueous solution.  On the other hand, the operation of heat, melting incoherent bodies, and introducing softness into rigid substances which are to be united, is not only a cause which is proper to explain the effects in question, but also appears, from a multitude of different circumstances, to have been actually exerted among the consolidated bodies of our earth, and in the mineral veins with which the solid bodies of the earth abound.

The doctrine, therefore, of our Theory is briefly this, That, whatever may have been the operation of dissolving water, and the chymical action of it upon the materials accumulated at the bottom of the sea, the general solidity of that mass of earth, and the placing of it in the atmosphere above the surface of the sea, has been the immediate operation of fire or heat melting and expanding bodies.  Here is a proposition which may be tried, in applying it to all the phenomena of the mineral region; so far as I have seen, it is perfectly verified in that application.

We have another proposition in our Theory; one which is still more interesting to consider.  It is this, That as, in the mineral regions, the loose or incoherent materials of our land had been consolidated by the action of heat; so, upon the surface of this earth exposed to the fluid elements of air and water, there is a necessary principle of dissolution and decay, for that consolidated earth which from the mineral region is exposed to the day.  The solid body being thus gradually impaired, there are moving powers continually employed, by which the summits of our land are constantly degraded, and the materials of this decaying surface travelled towards the coast.  There are other powers which act upon the shore, by which the coast is necessarily impaired, and our land subjected to the perpetual incroachment of the ocean.