From this constant and extensive volcanic action we may safely infer the high temperature of our earth anciently.
3. _It may be inferred from the origin of primitive, trapean, and basaltic rocks._ The primitive rocks, as granite, gneiss, mica slate, &c, give evidence on this consideration; they must have been deposited when their substance was in solution, admitting of _chemical mobility_, in order that they might assume a crystalline form which they are known to have.
It is not easy to conceive _how_ the substances of the primitive rocks could be solved, except by _heat_, as a _principal solvent_. The acids, and water also, may have contributed to their solution, but would not be competent of themselves. This consideration would give a high temperature for the earth anciently.
It is now generally admitted that the trap, and basaltic rocks are of _igneous_ origin. When we consider the _magnitude_ of the trap and basalt formations, the extent of surface which they cover, the hills, and even elevated and lofty mountains which they form, we shall not hesitate to assign a higher temperature to our earth at the period when fires, so immense as to effect the upheaving and ejection of all these, actually burned in the bowels of the earth.
4. _It may be inferred from the well preserved remains of vegetables and animals of warm equatorial climates, in high northern latitudes where they have not been found since the memory of man._ This is a conclusive argument if its _data_ be well established. Because, if _tropical_ and _equatorial_ animals and fruits are _now_ found buried and fossilized in Siberia, and the islands of the _arctic sea_, in such a state of preservation as to forbid the supposition they were transported thither, it will follow inevitably, that they _grew there_, and there flourished, died, and were buried.
Moreover, if _herbivorous_ animals are found fossilized in those high northern latitudes, under such circumstances as forbid the supposition, that they were transported thither, it will doubtless, follow, that not only _they_ lived there, but also _luxuriant vegetation_ must at the same time have covered the plains where their remains are entombed.
The inference which we are forced to draw from these _data_, is this: _As no such tropical and equatorial animals or plants have been known to exist there, nor even herbage of any kind, on which such animals might subsist, since the memory of man, there was a time anciently when the climate suited their growth, and of course was very much warmer than it is known to be now, its temperature then corresponding to the temperature of the present equatorial regions, as it produced and subsisted anciently the animals and plants which the tropical regions produce and subsist at the present time, and which cannot subsist in any other climates._