But the observation that is most to the purpose of the present subject of bituminous strata, is this; it is chiefly in the strata of the flat country that fossil coal are found; there are none that I know of in all the alpine countries of Scotland; and it is always among the strata peculiar to the flat country that fossil coal is found.  Now, this appearance cannot be explained by saying that the materials of mineral coal had not existed in the world while those primary strata were formed in the sea.  I have already shown, (chap. 4.) that there had been the same system of a world, producing plants, and thus maintaining animals, while the primary strata were formed in the sea; I have even adduced an example of coal strata among those primary schisti, although this be an extremely rare occurrence:  Consequently, we are under the necessity of looking out for some other cause.

If the changes which have been evidently superinduced in the strata of alpine countries arise from the repeated operations of subterranean fire, or to the extreme degree in which those strata have been affected by this consolidating and elevating cause, it will be natural to suppose that the bituminous or combustible part among those stratifications, may have been mostly consumed upon some occasion during those various and long continued operations; whereas, in the flat beds of the low country, although there is the most perfect evidence for the exertion of heat in the consolidation of those strata, the general quantity of this has been a little thing, compared with the universal manifestation of this cause in the operations of the alpine countries, the strata of which have been so much displaced in their situations and positions.

To illustrate this, strata of sand-stone are found in both the alpine and flat countries of Scotland.  About Leadhills, for example, there are abundance of those strata; but, in the flat country, the generality of the sand-stone is so little changed as to appear to every enlightened naturalist aquiform strata; whereas the most enlightened of those philosophers will not perhaps attribute the same original to a similar composition in the alpine country, which is so much changed from its original state.  It is not because there had been wanting a sufficient degree of heat to consolidate the sand-stone in the coal country; for I can show specimens of sand-stone almost contiguous with coal, that have been extremely much consolidated in this manner.  But this is only a particular stratum; and the general appearance of the sand-stone, as well as other strata in the coal countries, is that of having been little affected by those subterranean operations of heat by which those bodies in the alpine country have been changed in their structure, shape, and position.

If we shall thus allow the principle of consolidation, consequently also of induration, to have been much exerted upon the strata of the alpine country, and but moderately or little upon those of the low country of Scotland, we shall evidently see one reason, perhaps the only one, for the lesser elevation of the one country above the level of the sea, than the other.  This is because the one resists the powers which have been employed in leveling what has been raised from the bottom of the sea, more than the other; consequently, we find more of the one remaining above the level of the sea than of the other.