"Enfin, par fois, des masses plus petites placees entre les grosses, semblent assurer la situation fixe de l'ensemble des blocs; mais ces rencontres sont fort rares."

Here is a distinct view of this part of nature; a view in which the present state of things plainly indicates what has passed, without our being obliged to raise our imagination to so high a pitch as is sometimes required, when we take the mountains themselves, instead of these blocks, as steps of the investigation. Here is a view, therefore, that must convince the most scrupulous, or jealous with regard to the admitting of theory, first, that those mountains had been much higher; secondly, that they had been degraded in their present place; thirdly, that this continent has subsisted in its present place for a very long space of time, during the slow progress of those imperceptible operations; and, lastly, that much of the solid parts of this earth has been thus travelled by the waters to the sea, after serving the purpose of soil upon the surface of the land.

But though M. Hassenfratz has thus given us a most satisfactory view of the natural history of those blocks of stone which are now upon or near their native place, this will not explain other appearances of the same kind, where such blocks are found at great distances from their native places, in situations where the means of their transportation is not to be immediately perceived, such as those resting upon the Jura and Saleve, and where blocks of different kinds of stone are collected together. These last examples are the records of something still more distant in the natural history of this earth; and they give us a more extensive view of those operations by which the surface of this earth is continually changing. It is, however, extremely interesting to this Theory of the Earth, to have so distinctly ascertained some of those first steps by which we are to ascend in taking the more distant prospect; and these observations of M. Hassenfratz answer this end most completely.

Thus all the appearances upon the surface of this earth tend to show that there is no part of that surface to be acknowledged as in its original state, that is to say, the state in which it had come immediately from the mineral operations of the globe; but that, every where, the effects of other operations are to be perceived in the present state of things. The reason of this will be evident, when we consider, that the operations of the mineral kingdom have properly in view to consolidate the loose materials which had been deposited and amassed at the bottom of the sea, as well as to raise above the level of the ocean the solid land thus formed. But the fertility of the earth, for which those operations were performed, and the growth of plants, for which the surface of the earth is widely adapted, require a soil; now the natural, the proper soil for plants, is formed from the destruction of the solid parts. Accordingly, we find the surface of this earth, below the travelled soil, to consist of the hard and solid parts, always broken and imperfect where they are contiguous with the soil; and we find the soil always composed of materials arising from the ruin and destruction of the solid parts.



CHAP. VI.

A View of the Economy of Nature, and necessity of Wasting the Surface of the Earth, in serving the purposes of this World.

There is not perhaps one circumstance, in the constitution of this terraqueous globe, more necessary to the present theory, than to see clearly that the solid land must be destroyed, in undergoing the operations which are natural to the surface of the earth, and in serving the purposes which are necessary in the system of this living world. For, all the land of the present earth being a certain composition of materials, perfectly similar to such as would result from the gradual destruction of a continent in the operations of the inhabited world, this composition of our land could not be explained without having recourse to preternatural means, were there not in the constitution of this earth an active cause necessarily, in the course of time, destroying continents.

It is therefore of great importance to this Theory, to show, that the land is naturally wasted, though with the utmost economy; and that the continents of this earth must be in time destroyed. It is of importance to the happiness of man, to find consummate wisdom in the constitution of this earth, by which things are so contrived that nothing is wanting, in the bountiful provision of nature, for the pleasure and propagation of created beings; more particularly of those who live in order to know their happiness, and who know their happiness on purpose to see the bountiful source from whence it flows.

We are to conceive the continent of the earth, when first produced above the surface of the ocean, to be in general consolidated, with regard to its structure, by the same mineral operations which are necessarily employed in raising it from its primary situation at the bottom of the sea, to that in which we now inhabit it.

We are now to consider the purpose of this mineral body, exposed to the influences of the atmosphere, that so we may see the intention of its solid composition, as well as that of its resolution, or natural solubility when thus exposed; and we are to trace the ultimate effects of this order of action in the economy of the globe, that so we may perceive the wisdom of nature perpetuating the system of a living world in an endless succession, of changing perishable forms.

The purpose of the land of this earth, in being placed above the sea and immersed in the atmosphere, is to sustain a system of plants and animals. But; for the purpose of plants; there is required a soil; and, as there is in the vegetable system a vast variety of plants with different habits or natural constitutions, there is also required a diversity of soils, in which those vegetable bodies are to be made to live and prosper. From the bare rock exposed to the sun and wind, to the tender mud immersed in water, there is a series to be observed; and in every stage or step of this gradation, there are plants adapted to those various soils or situations. Therefore nothing short of that diversity of soils and situations, which we find upon the surface of the earth, could fulfill the purpose of nature, in producing a system of vegetables endued with such a diversity of forms and habits.

The soil or surface of this earth is no more properly contrived for the life and sustenance of plants, than are those plants for that diversity of animals, which will thus appear to be the peculiar care of nature in forming a world. Scarce a plant perhaps that has not its peculiar animal which feeds upon its various productions; scarce an animal that has not its peculiar tribe of plants on which the economy of its life, its pleasure, or its prosperity must depend.

If we shall suppose the continent of our earth to be a solid rock, on which the rain might fall, and the wind and waves might dash perpetually, without impairing its mass or changing its constitution, what an imperfect world would we have! how ill adapted to the preservation of animal and vegetable life! But the opposite extreme would equally frustrate the intention of nature, in producing bounteously for the various demands of that multiplicity of species which the author of this world has thought proper to produce.

For if, instead of a solid rock, we shall suppose a continent composed of either dry sand or watery mud, without solidity or stability, how imperfect still would be that world for the purpose of sustaining lofty trees and affording fruitful soils!

We have now mentioned the two extreme states of things; but the constitution of this earth is no other than an indefinite number of soils and situations, placed between those two extremes, and graduating from the one extreme, in which some species of animals and plants delight in finding their prosperity, to the other, in which another species, which would perish in the first, are made to grow luxuriantly. That is to say, the surface of this earth, which is so widely adapted to the purpose of an extensive system of vegetating bodies and breathing animals, must consist of a gradation from solid rock to tender earth, from watery soil to dry situations; all this is requisite, and nothing short of this can fulfil the purpose of that world which we actually see.

We have been representing this continent of our earth as coming out of the ocean a solid mass, which surely it is in general, or in a great degree; but we find the surface of this body at present in a very different state; and now it will be proper to take a view of this change from solid rock to fertile soil.

Upon this occasion I shall give the description of nature from the writings of a philosopher who has particularly studied this subject. It is true that M. de Luc, who furnishes the description, draws, from this process of nature, an argument for the perpetual duration or stability of mountains; and this is the very opposite of that view which I have taken of the subject; but as, in this operation of nature producing plants on stones, he allows the surface of the solid stone to be changed into earth and vegetables, it is indifferent to the present theory how he shall employ this earth and vegetable substance, provided it be acknowledged that there is a change from the solid state of rock to the loose or tender nature of an earth, from the state of a body immovable by the floods and impenetrable to the roots of plants, to one in which some part of the body may be penetrated and removed.

[8]"Les pluies et les rosees forment partout ou elles sejournent, des depots qui sont la premiere source de toute vegetation. Ces depots sont toujours meles des semences des mousses, que l'air charie continuellement, et auxquelles se joignent bientot les semences presque aussi abondantes des gramens, qui sont l'herbe dominante de nos prairies. Ainsi partout ou la pluie a forme quelque petit depot, il croit de la mousse ou des gramens. Ceux-ci demandent un peu plus de terre vegetale pour croitre, ils germent, et se conservent principalement dans les intervalles et les creux des pierres: mais la mousse croit bientot sur la surface la plus unie. Il n'est aucune pierre long-temps exposee a l'air, qui soit parfaitement polie; l'action de l'air, du soleil, des eaux, des gelees, detruiroit ce poli quand il existeroit. Le moindre creux alors recoit un depot de la pluie, et nourrit un brin de mousse, ces brins poussent des racines; et de nouveaux jets autour d'eux, qui contribuent a arreter l'eau de la pluie et de la rosee, et par ce moyen a arreter les depots Nourriciers."

[Footnote 8: Histoire de la Terre, Tom. 2. page 26.]

"Quand la mousse a multiplie ses filets, les depots s'augmentent plus rapidement encore; les brins de la mousse, en sechant et pourrissant, en forment eux-memes; car leur substance n'etoit que ces memes depots faconnes: d'autres semences charriees par l'air, qui au-paravant glissaient sur les pierres, parce que rien ne les retenoit, tombent dans le fond de la mousse, et y trouvent l'humidite necessaire pour produire leurs premieres racines: celles-ci s'entrelassent dans la mousse, ou elles se conservent a l'abri du soleil, et sont alors autant de petites bouches qui pompent les sucs, que l'air, les pluies, et les rosees y deposent. Ces premieres plantes sont foibles, quelque fois meme elles ne parviennent pas a leur perfection: mais elles ont contribue a fixer la terre vegetable. En sechant et se decomposant, elles se transforment en cette terre, qui tombe au fond de la mousse, et qui prepare ainsi de la nourriture pour de nouvelles plantes qui alors prosperent et fructifient.

"Nous connoissons peu encore ce que c'est que cette terre vegetable, ce depot des pluies ou en general de l'air. Cependant, en rassemblant les phenomenes, on peut conjecturer, que la plupart des corps terrestres sont susceptibles d'etre changes en cette substance, et qu'il ne s'agit pour cette transformation que de les decomposer. J'entends par la une telle division de leurs parties, que devenant presque des elemens, elles puissent etre intimement melees a l'eau, et pompees avec elle par les tuyaux capillaires des plantes. En un mot, il semble suffisant qu'une matiere puisse entrer en circulation dans les vegetaux, pour qu'elle serve a en developper le tissu, et qu'elle y prenne la figure et les qualites que chacun de ces laboratoires est propres a produire.

"Nous pouvons accelerer de bien des manieres la transformation des matieres terrestres en terre vegetable. La fermentation, la calcination, une plus grande exposition a l'air, differens melanges, rendent propres a la vegetation, des matieres qui ne l'etoient par elles-memes: voila ce que peuvent nos soins. Mais l'air travaille sans cesse et en mille manieres. Son simple frottement sur tous les corps, en enleve des particules si attenuees que nous ne les reconnoissons plus. La poussiere de nos appartemens en est peut-etre un exemple. De quelque nature que soient les corps dont elle se detache, c'est une poudre grisatre qui semble etre partout la meme. La formation de la terre vegetable a probablement quelque rapport a celle-la. Toute la surface de la terre, les rocs les plus durs, les sables et les graviers les plus arides, les metaux meme, eprouvent l'action rongeante de l'air et leurs particules attenuees, decomposees, recomposees de mille manieres, sont probablement la source principal de la vegetation. L'air lui-meme ainsi que l'eau, s'y combinent: beaucoup d'observations et d'experiences nous prouvent que ces deux fluides fournissent leur propre substance aux parties solides des vegetaux, et par consequent a la terre vegetable qui les produit et qu'ils deposent. Quantite de plantes se nourrissent de l'eau seule, et nous laissant cependant en se sechant, un residu de matiere solide permanente. L'air aussi se fixe dans les corps terrestres, il fait partie de leur substance solide; les chimistes savent de plus en plus, et le fixer, et lui redonner son elasticite primitive, par divers procedes: et avant la multitude d'experiences qui se sont de nos jours sur cet objet interessant de la physique, le Dr. Hales avoit montre, que les vegetaux renferment une tres-grande quantite d'air, qui s'y trouve sans ressort et comme matiere constituante.

"Voila donc probablement les sources ou la nature puise peu a peu la terre vegetable dont elle recouvre la surface de nos continens. Ce sont les particules, peut-etre, de tous les corps tant solides que fluides, extraites ou fixees par des procedes qui les rapprochent de leurs premiers elemens, et leur font prendre a nos yeux une meme apparence. Ces particules sont ainsi rendues propres a circuler dans les semences des plantes, a en etendre le tissu a y prendre toutes les proprietes qui caracterisent chaque espece, et a les conserver tant que la plante existe. Ces memes particules, apres la destruction des plantes, prennent le caractere general de terre vegetable, c'est-a-dire de provision toute faite pour la vegetation.

"Les plus petits recoins des montagnes, qui peuvent arreter l'eau de la pluie, sont certainement fertilises; ce ne sont pas seulement les grandes surfaces plates, ni les pentes; ce sont meme les faces escarpees des rochers les plus durs. S'il s'y fait quelque crevasse, un arbre s'y etablit bientot; et souvent il contribue, par l'accroissement de ses racines, a accelerer la chute du lambeau de rocher qui l'avoit recu. S'il y a quelque petite terrasse, ou seulement quelque partie saillante grande comme la main, elle est bientot gazonnee. Les plus petites sinuosites se peuplent de plantes; et les surfaces les plus unies, celles memes qui sont tournees vers la bas, recoivent au moins quelqu'une de ces mousses plates, nommes lichen par les botanistes, qui ne font en apparence que passer une couleur sur la pierre. Mais cette couche est ecaillee, et elle loge bientot de petites plantes dans ses replis; de celles qui veulent l'ardeur du soleil, si le rocher est au midi, ou la fraicheur de l'ombre, s'il est au nord: c'est sur ces rochers en un mot, qui paroissent nues aux spectateurs ordinaires, que se trouve la plus grande variete de ces petites plantes, qui font les delices des botanistes, et l'une des sources les plus abondantes ou la medicine puise les secours reels qu'elle fournit a l'humanite.

"Quelle richesse dans les ressources de la nature! La pesanteur n'est pas plus prete a entrainer les pierres qui se detachent des montagnes, que l'air a fournir de semences celles qui se fixent: et des qu'une fois elles sont recouvertes de plantes, elles sont certainement fixees pour toujours, du moins contre les injures de l'air. Le fait meme nous l'annonce. Si ces ravins ou ces terreins quelconques, tendoient encore a rouler ou a se degrader, en un mot a se detruire de quelque maniere que ce fut, ils ne le recouvriroient, ni de mousses ni d'aucune autre plante. La premiere vegetation est due a quelque depot de terre vegetable; et les pluies ou l'air n'en forment que lentement; le moindre mouvement la detruite. Le terrein est donc bien certainement fixe quand il se recouvre de plantes; et s'il s'y accumule de la terre vegetable, c'est un signe bien evident que rien ne l'attaque plus: car elle seroit la premiere emportee si quelque cause exterieure tendoit a detruire le sol qui la porte."

The doctrine here laid down by our author consists in this; first, That there is a genus of plants calculated to grow upon rocks or stones; those hard bodies then decay, in decomposing themselves, and affording sustenance to the plants which they sustain. Secondly, That by this dissolution of those rocks, and the accumulation of those vegetable bodies, there is soil prepared for the nurture and propagation of another genus of plants, by which the surface of the earth, naturally barren, is to be fertilised. It is also in this natural progress of things that the solid parts of the globe come to be wasted in the operations of the surface, and that lofty rocks are levelled, in always tending to bring the uneven surface of the earth to a slope of vegetating or fertile soil.

Here we are to distinguish carefully between the facts described by this author, who has seen so much of nature, and the conclusion which he would draw from his principles. The surface of most stones are dissolved, or corroded by the air and moisture. This gives lodgement to the roots of plants, which grow, die, and decay; and these are carried away with the earthy parts of the solid stone, in order to form a vegetable soil for larger plants, growing upon some bottom or resting place to which that earth is carried. Here is so far the purpose of rocks, to sustain a genus of plants which are contrived to live upon that soil; and here is so far a purpose for certain plants, in decomposing rocks to form a soil for other plants which have been made upon a larger scale, and are adapted to the use of man, the ultimate in the view of nature.

Our author concludes thus: (p. 37.) "Le tems ne fera qu'augmenter l'epaisseur de la couche de terre vegetable qui couvre les montagnes, et qui les garantit ainsi de plus en plus de cette destruction a laquelle on les croit exposes: les pluies en un mot, au lieu de les degrader comme on se l'imagine y accumuleront leurs depots. Tel est l'agent simple qu'employe si admirablement le Createur pour la conservation de son ouvrage."

Such, indeed, is the admirable contrivance of the system, that, in the works of nature, nothing shall be destroyed more than is necessary for the preservation of the whole. But, that the whole is preserved by the necessary destruction of every individual body, and the change of every part which comes within the examination of our senses, is sufficiently evident to require no farther illustration in this place, where we are contemplating the destruction of the strongest things, by means the most effectual, though really slow, and apparently most feeble.

In his 30th letter, this author describes the progress of nature, in bringing precipitous rocks to that slope and covering of soil which is to maintain plants of every kind, and to establish woods. (P. 40.) "J'ai l'honneur d'exposer a V.M. les causes qui garantissent de destruction exterieure les terreins sur lesquels la pesanteur ne peut plus agir que pour les consolider. Mais ce n'est pas ainsi que sont actuellement la plupart de nos montagnes; il en est peu qui soyent deja parvenus a cet etat permanent. Tout roc nud est attaque par l'air et les meteores, et il tend a se detruire quelle que soit sa durete. Mais ce seroit peu que cette destruction exterieure; elle pourroit meme cesser enfin totalement par l'effet seul des mousses, s'il n'y avoit pas des causes plus puissantes qui pendant quelque tems agissent dans l'interieur.

"Il n'est presque point de rocher qui offre a l'air une seule masse compacte; ils sont ou crevasses, ou formes par couches; et l'eau s'insinue toujours dans ces fentes. Quand cette eau vient a se geler, elle agit comme un coin pour ecarter les pieces entre lesquelles elle se trouve. V.M. seroit etonnee de la grandeur des masses que cette cause peut mouvoir: elle agit exactement comme la poudre a canon dans les mines; detachant toutes les pieces exterieures qui commencent a se separer, et en decouvrant ainsi de nouvelles. Chaque hiver renouvelle donc la surface de certains rochers, ou facilite l'ouvrage pour les hivers suivans.

Plusieurs autres causes agissent encore pour separer les rochers deja crevasses, qui se trouvent a l'exterieur des faces escarpees. Le petit moellon qui s'y accumule, les depots des pluies, les plantes qui y croissent, les alternatives de l'humidite et de la secheresse, les vicissitudes de la chaleur, les vents meme, sont autant de causes continuellement agissantes quand la pesanteur les seconde. Les rochers escarpes se detruisent donc par de continuels eboulemens.

"Mais toutes ces matieres qui tombent, ne sont pas perdues pour les montagnes; il s'en perd meme bien peu. Elles s'arretent au pied des rochers dont elles sont successivement detachees; et la elles s'entassent, s'elevant en forme de talus contre ces rochers eux-memes."

If the solid body of the Alps, the most consolidated masses of our land, is thus reduced to the state of soil upon the surface of the earth contrived for the use of plants, a fortiori, softer bodies, less elevated and less consolidated masses, will be considered as easily arriving at the purpose for which the surface of the earth has been intended. We only wish now to see the ultimate effect that necessarily follows from this progress of things; and how, in this course of nature, the land must end, however long protracted shall be the duration of this body, and however much economy may be perceived in this gradual waste of land;—a waste which by no means is so slow as not to be perceived by men reasoning in science; although scientific men, either reasoning for the purpose of a system which they had devised, or, deceived by the apparent state of things which truly change, may not acknowledge the necessary consequence of what they had perceived.

Let us now suppose all the solid mass of land, contained in our continent, to be transformed into soil and vegetable earth, it must be evident that no covering of plants, or interlacing of vegetable fibres, could protect this mass of loose or incoherent materials from the ravages of floods, so long as rivers flowed, nor from being swallowed by the ocean, so long as there were winds and tides. From the border of the land upon the shore, to the middle of the ocean, there is either at present an equable declivity at the bottom of the sea, or every thing tends to form this declivity, in gradually moving bodies along this bottom. But, however gradual the declivity of the bottom, or however slow the progress of loose materials from the shore towards the deepest bottom of the sea, so long as there are moving powers for those materials, they must have a progress to that end; the law of gravitation, always active, must prevail, and sooner or later the moving sea must swallow up the land.

But, along the borders of our continent, and in the courses of our rivers, there are rocks; these must be surmounted or destroyed, before the parts which they protect can be delivered up to the influence of those moving powers which tend to form a level; and we may be assured that those bulwarks waste. The bare inspection of our rocky coasts and rivers will satisfy the enlightened observator of this truth; and to endeavour to prove this to a person who has not principles by which to reason upon the subject, or to one who has false principles, by which he would create perpetual stability to decaying things, would be but labour lost.

In proportion as the solid bulwark is destroyed, so is the soil which had been protected by it; and, in proportion as the solid parts of the mass of land are exposed to the influences of the atmosphere and water, by the ablution of the soil, more soil is prepared for the growth of plants, and more earth is detached from the solid rock, to form deep soils upon the surface of the earth, and to establish fertile countries at the mouths of rivers, even in making encroachment on the space allotted for the sea. But this production of land, in augmentation of our coasts, is only made by the destruction of the higher country. While, therefore, we allow that there is any augmentation made to the coast, or any earthy matter travelling in our rivers, the land above the coast cannot be stable, nor the constitution of our earth fixed in a state which has no tendency to be removed.

M. de Luc, in his Histoire de la Terre, would make the mountains last for ever, after they have come to a certain slope. He sums up his reasoning upon this subject in these words: "L'adoucissement des pentes arrete d'abord l'effet de ces deux grandes causes causes de destruction de montagnes, la pesanteur et les eaux: la vegetation ensuite arrete l'effet de toutes les petites cause."

If all the great and little causes of demolition are arrested by the slope of mountains and the growth of plants, the surface of the earth might then remain without any farther change; and this would be a fact in opposition to the present theory, which represents the surface of the earth as constantly tending to decay, for the purpose of vegetation, and as being only preserved from a quick destruction by the solid rocks protecting, from the ravages of the floods and sea, the loose materials of the land. It will therefore be proper to show, that this author's argument does not go to prove his proposition in the terms which he has given it, which is, that those sloped mountains are to last for ever, but only that these causes, which he has so well described, make the destruction of the mountains become more slow[9].

[Footnote 9: This also would appear to be a part of that wise system of nature, in which nothing is done in vain, and in which every thing tends to accomplish the end with the greatest marks of economy and benevolence. Had it been otherwise, and the demolishing powers of the land increased, in a growing rate with the diminution of the height, the changes of this earth and renovation of our continent, in which occasionally animal life must suffer, would necessarily require to be often repeated; and, in that case, chaos and confusion would seem to be introduced into that system which at present appears to be established with such order and economy that man suspects not any change; it requires the views of scientific men to perceive that things are not at present such as they were created; it requires all the observation of a natural philosopher to know that in this earth there had been change, although it is not every natural philosopher that observes the benevolence accompanying this constitution of things which must subsist in change.]

The slope which our author gives to his mountains, in order to secure them from the ravages of time, is that which, according to his own reasoning, renders them fertile and proper for the culture of man; but fertile soil yields always something to the floods to carry away; and, while any thing is carried from the soil, the land must waste, although it may not then waste at the rate of those within the valleys of the Alps. According to the doctrine of this author, our mountains of Tweeddale and Tiviotdale, being all covered with vegetation, are arrived at that period in the course of things when they should be permanent. But is it really so? Do they never waste? Look at the rivers in a flood;—if these run clear, this philosopher has reasoned right, and I have lost my argument. Our clearest streams run muddy in a flood. The great causes, therefore, for the degradation of mountains never stop as long as there is water to run; although, as the heights of mountains diminish, the progress of their diminution may be more and more retarded.

Let us now see how far our author has reasoned justly with regard to vegetation, which, he says, stops the effects of all the little causes of destruction; this is the more necessary, as, in the present theory, it is the little causes, long continued, which are considered as bringing about the greatest changes of the earth.

Along the courses of our rivers there are plains between the mountains of greater or lesser extent; these are almost always fertile, and generally cultivated when large; when small, they are in pasture. The origin of these fertile soils, and their perpetual change, is to be described with a view to show, that vegetation, although most powerful in stopping the ravages of water, and for accumulating soil retained by this means, does it only for a time; after which the soil is again abandoned to the ravages of the running water, when no more protected by the vegetation.

Let us suppose the river running upon the one side of the haugh (which is the name we gave those little fertile plains) and close by the side of the mountain. In this case the bed of the river is deepest at the side of the mountain, which it undermines, leaving a falling (un eboulement) on that side; on the other side, the river shelves gradually from the plain, and leaves soil in its bottom or stony bed upon the side of the haugh, in proportion as it makes advances in carrying away the bank at the bottom of the sloping mountain. The part which vegetation takes in this operation is now to be considered.

When the river has enlarged its bed by preying upon one side, whether of the mountain or the haugh, the water only covers it in a flood; at other times, it leaves it dry. Here, among the rocks and stones, the feeds of plants, left by the water or blown by the wind, spring up and grow; and, in little floods, some sand and mud is left among those plants; this encourages the growth of other plants, which more and more retain the fertile spoils of the river in its floods. At last, this bed of the river is covered perfectly with plants, which having retained plenty of fertile soil, although still rooted among the stones, opposes to the river a resistance which its greatest velocity is not able to overcome. In this state, the haugh is always deepening or increasing its soil, and has its surface heightened. At last, when this soil becomes so high as only to be flooded now and then, it becomes most fertile, as the heavier parts are carried in the bed of the river, and the lighter soil deposited upon the plain. The operations of the river, upon the plain, thus increase at the same time the height and fertility of the haugh. But this operation, of accumulated soil upon the stony bottom, has a period, at which time the river must return again upon its steps, and sweep away the haugh which it had formed. This is the natural course of things; and it happens necessarily from the deepening of the soil. Let us then examine this operation.

When no more soil is left upon the stony bottom than is sufficient for the covering of the ground, and rooting of plants which are also fixed in the solid ground or bottom of the soil, the water is not able to carry away the plants; and these plants protect the surface of loose soil. When again there is a depth of soil accumulated upon the haugh, the surface only is protected by the vegetable covering. But what avails it to the soil to be protected from above, when undermined by the enemy! The vegetable roots now no longer reaching to the bottom where solidity is found, the tender soil below is easily washed away by the continued efforts of the stream; and the unsupported meadow, with the impregnable texture of its leaves, its roots, and its fibres, falls ruinously into the river, and is born away in triumph by the flood. The water thus reclaims its long deserted bed,—only in order to pass from it again, and circulate or meander from hill to hill in varying perpetually its course.

Now this progress of the river, or this changing of its bed, is determined by the strong resistance of the new made haugh, humbly standing firm in the protection of its vegetation, while the elevated surface of the older haugh, deserted by the inferior soil which it had ceased to protect, falls a victim to its exalted state, and passes away to aggrandize another. This is the fate of haughs or plains erected by the operations of a river, and again destroyed in the natural course of things, or in the very continuation of that active cause by which they had been formed.

The water is constantly carrying the moveable soil from the higher to the lower place; vegetation often disputes the possession of these spoils of ruined mountains for a while; but, in the end, this vegetable protector, not only delivers up to the destroying cause the mineral soil which it had preserved, but, by its buoyancy in water, it facilitates the transportation of the stony parts to which this fibrous body is attached. Over and over a thousand times may be repeated this alternate possession of the transferable soil, by moving water on the one part and by fixed vegetation on the other, but at last all must land upon the shore, whether the river tends. Thus the mountain and the plain, the vegetable earth and the plants produced in that soil, must all return into the sea from whence either they themselves or their materials had come. In proportion as the mountains are diminished, the haugh or plain between them grows more wide, and also on a lower level; but, while there is a river running in a plain, and floods produced in the seasons of rain, there can be nothing stable in this constitution of things evidently founded upon change.

The description now given is from the rivers of this country, where it is not unfrequent to see relicts of three or four different haughs which had occupied the same spot of ground upon different levels, consequently which had been formed and destroyed at different periods of time. But the same operation is transacted every where; it is seen upon the plains of Indostan, as in the haughs of Scotland; the Ganges operates upon its banks, and is employed in changing its bed continually as well as the Tweed[10]. The great city of Babylon was built upon the haugh of a river. What is become of that city? nothing remains,—even the place, on which it stood, is not known.

[Footnote 10: An Account of the Ganges and Burrampooter Rivers, by James Rennel, Esquire. Philosophical Transactions, 1781.]



CHAP. VII.

The Same Subject continued, in giving a View of the Operations of Air and Water upon the Surface of the Land.

We have but to enlarge our thoughts with regard to things past by attending to what we see at present, and we shall understand many things which to a more contracted view appear to be in nature insulated or without a proper cause; such are those great blocks of granite so foreign to the place on which they stand, and so large as to seem to have been transported by some power unnatural to the place from whence they came. We have but to consider the surface of this earth as having been upon a higher level; as having been every where the beds of rivers, which had moved the matter of strata and fragments of rocks, now no more existing; and as thus disposed upon different planes, which are, like the haughs of rivers, changing in a continual succession, but changing upon a scale too slow to be perceived. M. de Luc has given a picture which is very proper to assist our imagination in contemplating a more ancient state of this earth, although in this he has a very different end in view, and means to show that the world, which we inhabit at present, is of a recent date. It is in the 32d letter of his Histoire de la Terre, which I beg leave here to transcribe.

"Des montagnes basses (comme le Jura, qui est bas comparativement aux Alpes) sont bientot fixees par ce moyen. Il ne se fait presque qu'un seul talus depuis leur sommet jusques dans les basses vallees, ou sur la plaine. Aussi l'etat de ces montagnes est-il deja presqu'entierement fixe: on y voit tres peu de rochers nuds qui s'eboulent, excepte, aupres des rivieres. C'est dans ces lieux-la que l'ouvrage tarde le plus a se finir. Le bas des talus est mine par l'eau; leur surface s'eboule donc, pour ainsi dire, sans cesse, et laisse a decouvert les rochers des sommets, qui par la continuent aussi a s'ebouler. Mais les vallees s'elargissent enfin; et les talus s'eloignant ainsi des rivieres, commencent a eprouver les influences du repos."

Here nothing can be more positively described than the natural destruction of those mountains by the operation of the rivers which run between them; and this is from the authority of matter of fact, which, on all occasions, this author faithfully describes. At the same time, we are desired to believe, upon no better authority than the imagination of a person hurried on by system, that those mountains are absolutely to come to rest. I am aware of the danger to which a spirit of systematising leads; and I wish for nothing more than to have my Theory strictly examined, in comparing it with nature.

Our author thus proceeds: "La vue seule de la chaine du Jura nous apprend donc ce que deviendroit enfin toutes les montagnes. Dans la plus grande partie de son etendue, il ne souffre plus aucun changement ruineux: la vegetation le recouvre presque partout. Les bas sont cultives de toute sorte de maniere suivant leur exposition; les sommets sont couverts de pelouses, qui forment les paturages les plus precieux. Cette gazonade s'etend aussi sur toutes les parties des pentes qui ne sont pas trop rapides, et le reste est couvert de bois.

"J'ai parcouru fort souvent le pied de ces montagnes: leur etat est presque partout tel que je viens d'avoir l'honneur de la descrire a V.M. J'ai sur-tout observe avec attention les lits des torrens qui, en descendent pour se rendre dans les lacs de Geneva, de Neufchatel et de Bienne, ainsi que dans l'Aar et dans le Rhin: et hormis ceux de ces torrens qui viennent des gorges ou les terrains sont encore escarpes, ils ne roulent plus que l'ancien gravier qu'ils out apporte autrefois.

"Mais il n'en est pas ainsi des Alpes, des Pyrenees, et des autres montagnes, qui, comme celles-la, sont beaucoup plus elevees, ou qui sans l'etre davantage ont ete livrees aux influences de l'air dans un desordre plus grand. Dans ce genre de montagnes il reste encore a la vegetation de bien grandes conquetes a faire.

"Ces montagnes ne sont pas telles que V.M. pourroit se les figurer naturellement; il faut y etre monte pour s'en former une juste idee. Ce sont des montagnes sur d'autres montagnes. De pres on ne voit que les parties inferieures; de loin tout se confond; il faut donc etre arrive sur une des premieres terrasses pour voir les secondes; sur celles-ci pour les troisiemes; et ainsi de suite.

"La plupart de ces terrasses successives sont de grandes plaines, dominees par des rochers qui s'eboulent, et forment des talus. Si dans la succession des siecles, les eboulemens de ces bandes de rochers en amphitheatre finissoient sans emporter les plaines qu'ils soutiennent, et que les torrens eussent creuse leur lit pendant ce tems la a quelque distance des talus tout seroit fini par cette premiere operation. Mais il y a peu de hautes montagnes ou les arrangemens soient si simples: souvent ces bandes empietent les unes sur les autres en s'eboulant, et alors le repos est bien differe.

"Supposons que ces terrasses soient etroites, et que leurs murs, c'est-a-dire les rochers qui les soutiennent, soient fort eleves. Les terrasses alors ne suffiront pas pour recevoir les eboulemens qui doivent se faire sur elles car le dessus de chacune d'elles s'etrecit de plus en plus par la destruction du rocher qui la soutient. Il pourra donc arriver que ce talus, s'etant etendu jusqu'au bord de la terrasse, se trouve reposer sur une base qui s'eboule encore; et meme cela arrive tres souvent; de sorte qu'a chaque retrecissement de la base, le talus lui-meme s'eboule. Ainsi deux talus, qui etoient peut-etre deja en pleine vegetation par la lenteur des eboulemens des rochers qui les formoient, pourront etre fort recules a cet egard; le talus superieur, parce que la surface fertilisee glissera en bas; et le talus inferieur, parce que la sienne sera ensevelie sous de nouveaux decombres.

"Les montagnes qui sont dans ce cas seront proportionnellement plus abaissees que les autres; parce que leurs talus se confondant ainsi et devenant par la fort etendus demeureront longtemps a devenir solides. Les eaux partant de fort haut, auront le tems de s'y rassembler et de devenir destructives vers le bas. Au lieu que dans les montagnes ou les terrasses subsisteront encore apres que tous les rochers se seront eboules, les eaux etant recues par reprises, perdront beaucoup de leur rapidite. Elles se rassembleront dans les enfoncemens des petites vallees superieures, elles s'y formeront des lits qu'elles ne rongeront presque point; et la vegetation restera tranquille partout."

Let us now consider the height of the Alps, in general, to have been much greater than it is at present; and this is a supposition of which we have no reason to suspect the fallacy; for, the wasted summits of those mountains attest its truth. There would then have been immense valleys of ice sliding down in all directions towards the lower country, and carrying large blocks of granite to a great distance, where they would be variously deposited, and many of them remain an object of admiration to after ages, conjecturing from whence, or how they came. Such are the great blocks of granite which now repose upon the hills of Saleve. M. de Saussure, who has examined them carefully, gives demonstration of the long time during which they have remained in their present place. The lime-stone bottom around being dissolved by the rain, while that which serves as the basis of those masses stands high above the rest of the rock, in having been protected from the rain. But no natural operation of the globe can explain the transportation of those bodies of stone, except the changed state of things arising from the degradation of the mountains.

Every thing, therefore, tends to show that the surface of the earth must wear; but M. de Luc, although he allows the principles on which this reasoning is founded, labours to prove that those destructive causes will not operate in time. Now, What would be the consequence of such a system?—That the source of vegetation upon the surface of the earth would cease at last, and perfect sterility be necessarily the effect of allowing no farther degradation to the surface of the earth; for, What is to supply the matter of plants? Water, air, and light alone, will not suffice; there are necessarily required other elements which the earth alone affords. If, therefore, this world is to continue, as it has done, to form continents of calcareous strata at the bottom of the ocean, the animals which form these strata, with their exuviae, must be fed. But, on what can they be fed? not on water alone; the consequence of such a supposition would lead us to absurdity; nor can they be fed on any other element without the dissolution of land. According to my views of things, it is certain that those animals are ultimately fed on vegetable bodies; and it is equally certain, that plants require a soil on which they may not only fix their fibrous roots, but find their nourishment at least in part; for, that air, water, and the matter of light, also contribute, cannot be doubted. But if animals, which are to form the strata of the earth, are to be fed on plants, and these are to be nourished by the matter of this earth, the waste of vegetable matter upon the surface of the earth must be repaired; the exhausted soil must be transported from the surface of the land; and fertility must be restored by the gradual decay of solid parts, and by the successive removal of soil from stage to stage. What a reverie, therefore, is that idea, of bringing the earth to perfection by fixing the state of its vegetable surface!

The description of those natural operations, which M. de Luc has given with a view to establish the duration of the mountains, is founded upon nothing but their destruction. These beds of rivers, which, according to our author, are hardly to be wasted any more, will not satisfy a philosopher, who requires to see no degree of wasting in a body which is to remain for ever, or continue without change. But, however untenable this supposition of a fixed state in the surface of this earth, the accuracy of the natural philosopher may still be observed in the absurdity of the proposition. "L'etat des montagnes sera fixe, partout ou les rivieres seront arrivees au point de n'emporter pas plus de limon hors de leur enceinte, que l'air et les pluies n'y deposeront de terre vegetable, et voila enfin quel sera le repos, l'etat permanent de la surface de notre globe. Car alors il y aura compensation entre les destructions et les reparations simultanees, et les montagnes surement ne s'abaisseront plus."

Surely, if there is in the system of nature wisdom, we may look for compensation between the destroying and repairing operations of the globe. But why seek for this compensation in the rest or immobility of things? Why suppose perfection in the want of change? The summit of the Alps was once the bottom of the sea; the existence of our land depended then upon the change of seas and continents. But has the earth already undergone so great changes, and is it not yet arrived at the period of its perfection? How can a philosopher, who is so much employed in contemplating the beauty of nature, the wisdom and goodness of Providence, allow himself to entertain such mean ideas of the system as to suppose, that, in the indefinite succession of time past, there has not been perfection in the works of nature? Every material being exists in motion, every immaterial being in action and in passion; rest exists not any where; nor is it found in any other way, except among the parts of space. Surely it is contrary to every species of philosophy, whether ancient or modern, to found a system on the inutility of repose, or place perfection in the vacuity of rest, when every thing that truly exists, exists in motion; when every real information which we have is derived from a change; and when every excess in nature is compensated, not by rest, but by alternation.

M. de Luc allows the rivers to carry matter always to the sea; but then, at a certain period, this matter carried by the floods is to be compensated to the mountains by the vegetable earth received from the air and rains. Here is a proposition which should be well considered, before it be admitted as a principle, which shall establish the perpetuity of these mountains, if it be true; or, if false, assure us of their future demolition. Let us now examine it.

If from air and rain there is produced earth which cannot afterwards be resolved by the operation of those elements, and thus again dissolved in the air and water of the land, then this author might have had some pretext, however insufficient, for alledging that it might be possible to compensate the loss of mineral substances, carried off the surface of the earth, by the production of this vegetable matter from the air and rain; but, when there is not sufficient reason to conclude that any substance, produced in vegetation, can resist the continued influences of the air and water, without being decomposed in its principles, and at last entirely dissolved in water, the cautious argument here employed by this author, for the permanency of mountains, must appear as groundless in its principle as it would be insufficient for his purpose, were it to be admitted; but this will require some discussion.

That which preserves vegetable bodies so long from dissolution in water, is what may be called the inflammable or phlogistic composition of those bodies. This composition is quickly resolved in combustion; but it is no less surely resolved by the influences of the sun and atmosphere, only in a slower manner. Therefore, to place the permanency of this earth, or any of its surface, upon a substance which in that situation necessarily decays, is to form a speculation inconsistent with the principles of natural philosophy[11].

[Footnote 11: It is from inadvertency to this fact in natural history, the consuming of vegetable substances exposed to the influences of the atmosphere, that M. de Luc, in his Histoire de la Terre, has pretended to determine the past duration of the German heaths as not of a very high antiquity. He has measured the increase of the vegetable soil, an increase formed by the accumulation of the decayed heath; and, from the annual increase or deposits of vegetable matter on that surface, he has formed a calculation which he then applies to every period of this turfy augmentation, not considering that there may be definitive causes which increase with this growing soil, and which, increasing at a greater rate in proportion as the soil augments, may set a period to the further augmentation of that vegetable soil. Such is fire in the burning of those parched heaths; such is the slower but constant and growing operation of the oxygenating atmosphere upon this turfy substance exposed to the air and moisture. This author has very well described the constant augmentation of this vegetable substance in the morasses of that country, as it also happens in those of our own; but there is a wide difference in those two cases of peat bog and healthy turf; the vegetable substance in the morass is under water, and therefore has its inflammable quality or combustible substance protected from the consuming operation of the vital or atmospheric air; the turfy soil, on the contrary, is exposed to this source of resolution in the other situation.]

But even supposing that the degradation of mountains were to be suspended by the pretended compensation which is formed, by the rivers carrying mineral mud into the sea, and the air and rain producing vegetable earth; in what must this operation end? In carrying into the sea, to be deposited at its bottom, all the vegetable earth produced by the air and rain. But our cosmologist, in thus procuring an eternal station to his mountains, has not told us whether this transmutation of the air and rain be a finite operation, or one that is infinite; whether it be in other respects confident with the natural operations of the globe; and whether, to have the air and water of the globe converted into earth, would ultimately promote, or not, that perfection which he wishes to establish. Here, therefore, in allowing to this philosophy all its suppositions, it would be necessary to make another compensation, in preserving mountains at the expense of air and rain; and, the waste of air and water, which are limited, would require to be repaired.

It is not in our purpose here to treat of moral causes; but this author having endeavoured to fortify his system by observing, that the world certainly cannot be ancient, since men have not ceased as yet to quarrel and fight, (Lettre 34.) it may be proper to observe, that the absolute rest of land, like the peace among mankind, will never happen till those things are changed in their nature and constitution, that is to say, until the matter of this globe shall be no more a living world, and man no more an animal that reasons from his proper knowledge, which is still imperfect. If man must learn to reason, as children learn to speak, he must reason erroneously before he reasons right; therefore, philosophers will differ in their opinions as long as there is any thing for man to learn. But this is right; for, how are false opinions to be corrected, except in being opposed by the opinions of other men? It is foolish, indeed, for men to quarrel and fight, because they differ in opinion. Man quarrels properly, when he is angry; and anger perhaps is almost always ultimately founded upon erroneous opinion. But, in nature, there is no opinion; there is truth in every thing that is in nature; and in man alone is error. Let us, therefore, in studying nature, learn to know the truth, and not indulge erroneous notions, by endeavouring to correct, in nature, that which perhaps is only wrong in our opinion.

Having shown that every thing, which is moveable upon the surface of the land, tends to the sea, however slowly in its pace, we are now to examine, what comes of those materials deposited within the regions of the waves, still however within the reach of man, and still subservient more immediately to that soil on which plants grow, and man may dwell.

As, from the summit of the land, the natural tendency of moveable bodies is to fall into the water of the sea, so, from the borders of the land or coast, there being a declivity towards the deepest bottom of the sea, and there being currents in the waters of the ocean occasionally rendered more rapid on the shore, every moveable thing must tend to travel from the coast, and to proceed alone; the shelving bottom of the sea into the unfathomable deep, when they are beyond the reach of man or the possibility of returning to the shore.

But it is not every where upon the coast that those materials are equally delivered; neither is it every where along the shore that the currents of the ocean are equally perceived, or operate with equal power in moving bodies along the shelving bottom of the sea. Hence in some places deep water is found washing rocky coasts, where the waste of land is only to be perceived from what is visibly wanting in the continuity of those hard and solid bodies. In other places, again, the land appears to grow and to encroach upon the space which had been occupied by the sea; for here the materials of the land are so accumulated on the coast, that the bottom of the sea is filled up, and dry land is formed in the bafon of the sea, from those materials which the rivers had brought down upon the shore.[12]

[Footnote 12: We are not however to estimate this operation, of forming soil by the muddy waters of a river depositing sediment, in the manner that M. de Luc has endeavoured to calculate the short time elapsed in forming the marshlands of the Elbe. This philosopher, with a view to show that the present earth has not subsisted long since the time it had appeared above the surface of the sea, has given an example of the marsh of Wisebhafen where the earth, wasted by inundation, was in a very little time replaced, and the soil heightened by the flowings of the Elbe, and this he marks as a leading fact or principle, in calculating the past duration of our continents, of which he says, we are not to lose sight (Tome 5, p. 136.) But here this philosopher does not seem to be aware, that he is calculating upon very false grounds, when he compares two things which are by no means alike, the natural operations of a river upon its banks, making and unmaking occasionally its haughs or level lands, that is to say, alternately making and destroying, and the artificial operations of man receiving the muddy water of a tide-way into the still water of a pond formed by his ramparts; yet, it is by this last operation that our author forms an estimate which he applies to the age of this earth, in calculating how long time might have been required for producing the marsh lands of the Elbe.

I would here ask if he can calculate what time it may have required to hollow out the bed of the Elbe from its source to the sea; and to tell how often the marsh-lands, which he now sees cultivated, had been formed and destroyed by the river before they were cultivated in their present state; or if there is any security that they shall not again be taken away by the river, and again formed in the same place. If this is the case, that the river is constantly changing the fertile lands, which it forms by its inundation, what judgement are we to form by calculating the quantity of sediment in a certain measure of its muddy water.]

Holland affords the very best example of this fact. It is a low country formed in the sea. This low land is situated in the bottom of a deep bay, or upon the coast of a shallow sea, where more materials are brought by the great rivers from the land of Germany than what the currents of the sea can carry out into the deep. Here banks of sand are gathered together by streams and tides; this sand is blown in hillocks by the wind; and those sand hills are retained by the plants which have taken root and fixed those moving sands. Behind that chain of hillocks, which line the sea shore, the waters of the rivers formed a lake, and the bottom of this lake had been gradually filled up or heightened by materials travelling in the rivers, and here finding rest. It grew up until it became a marsh; then man took possession of the soil; he has turned it to his own life; and, by artificial ramparts of his forming, preserves it in the present state, some parts above the level of the sea, others considerably below the ordinary rise of tides. M de Luc, who has given a very scientific view of this country in his Lettres Physiques et Morales, has there also furnished us with the following register of what had been found by sinking in that soil. It was at Amsterdam at the year 1605 in making a well.

"Voici la designation des matieres qui furent trouvees en partant de la surface.

51 pieds, meles de sable tourbeux, de fable des dunes pur et d'argile ou limon.

22.—-de meme sable des dunes pur, et d'argile bleuatre.

14.—-du meme sable pur.

87 pieds.—Ou rien encore n'indiquoit la presence de la mer.

55.—-de sable marin, et de limon, meles l'un et l'autre de coquilles dans plusieurs couches.

142 pieds.—Soit la plus grande profondeur, ou s'est manifestee la presence de la mer.

49.—-Argille dure sans melange de coquilles, soit que ce soit une couche argilleuse continentale, ou les premiers depots des fleuves; ce qu'il est difficile de Determiner.

191 pieds.

13.—-Sable mele de pierres; qui est enfin surement le sol vierge continental.

28.—-Sable pur; continental encore; car j'ai remarque partout dans la Geest, que c'est dans la couche superieure, a une petite profondeur que se trouvent les pierres; au-dessous le sable est pur.

232 pieds.—C'est a cette profondeur, ou dans la masse de ces deux dernieres couches, que se trouva l'eau douce, et par consequent le vrai sol continental."

The light that we have from this pit which has been made in the soil, according to my view of the subject, is this, that here is the depth of 232 feet in travelled soil, and no solid bottom found at this distance from the surface or level of the sea. How far this depth may be from the bottom of these travelled materials is unknown; but this is certain, that all that depth, which has been sunk, had been filled up with those materials[13].

[Footnote 13: An interesting map for the use of natural history would be made by tracing the places (behind this country of loose or travelled soil) where the solid strata appear above the level of the sea. We should be thus able to form some notion of the quantity of materials which had been deposited in the water of this sea. But, though we might thus enlarge our views a little with regard to the transactions of time past, it would only be in a most imperfect manner that we would thus form a judgment; for, not knowing the quantity of sand and mud carried out by the currents from the German sea into the Atlantic, we could only thus perceive a certain minimum, which is perhaps a little portion of the whole.]

It will thus appear of what unstable materials is composed the land of that temporary country. It will also be evident, that, by removing the sand banks of this coast, the whole of this low country would be swallowed by the sea, notwithstanding every effort that the power of man could make. But it may be alledged, that those sand banks are increasing still with the alluvion of Germany, instead of being in a decreasing state. I should also incline to believe that this is truly the case; but, though we may acknowledge the growth of land upon the coast of Holland, we must deny that a stable country can be formed in the bed of the sea by such means. For, however increasing may be the sand in the German sea, and however great additions may be made of habitable country to the coast of Holland, yet, as the islands of Great Britain and Ireland are worn by attrition on the shores, and are wasted by being washed away into the ocean, the causes for the accumulation of sand in the German sea must cease in time, when, in this progress of things, the sand banks, on which depends the existence of Holland, must diminish, and at last be swept away, in leaving the solid coast of Germany to be again buffeted by the waves, as is at present the coasts of Ireland, France, and Spain.

This reasoning is, indeed, very far removed from that which is commonly employed for the purpose of conducting human operations, or establishing the political system of a nation; it is not, however, the less interesting to man, in that it cannot direct him immediately in his worldly affairs; and it is the only way of reasoning that can be employed in order to enlighten man with a view of those operations which are not to be limited in time, and which are to be concluded as in the system of nature, a system which man contemplates with much pleasure, and studies with much profit.

Thus we have shown, that, from the top of the mountain to the shore of the sea, which are the two extremities of our land, every thing is in a state of change; the rock and solid strath dissolving, breaking, and decomposing, for the purpose of becoming soil; the soil travelling along the surface of the earth, in its way to the shore; and the shore wearing and wasting by the agitation of the sea, an agitation which is essential to the purposes of a living world. Without those operations, which wear and waste the coast, there would not be wind and rain; and, without those operations which wear and waste the solid land, the surface of the earth would become sterile. But showers of rain and fertile soil are necessarily required in the system of this world; consequently, the dissolution of the rocks, and solid strata of the earth, and the gradual, flow, but sure destruction of the present land, are operations necessary in the system of this world; so far from being evils, they are wisely calculated, in the system of nature, for the general good.



CHAP. VIII.

The present Form of the Surface of the Earth explained, with a View of the Operation of Time upon our Land.

It is not to common observation that it belongs to see the effects of time, and the operation of physical causes, in what is to be perceived upon the surface of this earth; the shepherd thinks the mountain, on which he feeds his flock, to have been always there, or since the beginning of things; the inhabitant of the valley cultivates the soil as his father had done, and thinks that this soil is coeval with the valley or the mountain. But the man of scientific observation, who looks into the chain of physical events connected with the present state of things, sees great changes that have been made, and foresees a different state that must follow in time, from the continued operation of that which actually is in nature.

It is thus that enlightened natural history affords to philosophy principles, from whence the most important conclusions may be drawn. It is thus that a system may be perceived in that which, to common observation, seems to be nothing but the disorderly accident of things; a system in which wisdom and benevolence conduct the endless order of a changing world. What a comfort to man, for whom that system was contrived, as the only living being on this earth who can perceive it; what a comfort, I say, to think that the Author of our existence has given such evident marks of his good-will towards man, in this progressive state of his understanding! What greater security can be desired for the continuance of our intellectual existence,—an existence which rises infinitely above that of the mere animal, conducted by reason for the purposes of life alone.

The view of this interesting subject, which I had given in the first part, published in the Transactions of the Edinburgh Royal Society, has been seen by some men of science in a light which does not allow them, it would appear, to admit of the general principle which I would thereby endeavour to establish. Some contend that the rivers do not travel the material of the decaying land;—Why?—because they have not seen all those materials moved. Others alledge, that stones and rocks may be formed upon the surface of the earth, instead of being there all in a state of decay. These are matters of fact which it is in the power of men who have proper observation to determine; it is my business to generalise those facts and observations, and to bring them in confirmation of a theory which is necessarily founded upon the decaying nature and perishing state of all that appears to us above the surface of the sea.

Nothing is more evident, than that the general effect of mineral operations is to consolidate that which had been in an incoherent state when formed at the bottom of the sea, and thus to produce those rocks and indurated bodies which constitute the basis of our vegetable soil; but, that indurating or consolidating operation is not the immediate object of our observation; and, to see the evidence of that operation, or the nature of that cause, requires a long chain of reasoning from the most extensive physical principles. Our present subject of investigation requires no such abstract distant media, by which the effect is to be connected with its cause; the actual operation in general is the object of our immediate observation; and here we have only to reason from less to more, and not to homologate things which may, to men of narrow principles, appear to be of different kinds. But even here we find difficulty in persuading those who have taken unjust views of things; for, those who will not deny the truth of every step in this chain of reasoning, will deny the end to which it leads, merely because they are not disposed to admit the progress of that order which appears in nature.

In the last chapter, I have been using arguments to prove that M. de Luc has reasoned erroneously, in concluding the future stability of a continent; and I have been endeavouring to show that our continent is necessarily wasted in procuring food to plants, or in serving the various purposes of a system of living animals. We have now in view to illustrate this theory of the degradation of the surface of the earth; a theory necessarily leading to that system of the world in which a provision is made for future continents; and a theory explaining various natural appearances which otherwise are not to be understood. A door may thus be opened for the investigation of natural history, particularly that which traces back, from the present state of things, those operations of nature which are more immediately connected with what we take much pleasure to behold, viz. the surface of the earth stored with such a variety of beautiful plants, and inhabited by such a diversity of animals, all subservient to the use of man.

There are two ways in which we may look for the transactions of time past, in the present state of things, upon the surface of this earth, and read the operations of an ancient date in those which are daily transacted under our eye. The one of these is to examine the soil, and to trace the origin of that which we find loose upon the surface of the earth, or only compacted by the soft and cohesive nature of some of its materials. In thus studying the soil we shall learn the destruction of the solid parts; and though, by this means, we cannot form an estimate of the quantity of this destruction which had been made, we shall, upon many occasions, see a certain minimum of this quantity which may perhaps astonish us.

The second method here proposed, is to examine the solid part of the earth, in order to learn the quantity of matter which had been separated from this mass. Here also we shall not be able to compute the quantity of what had been destroyed; but we shall every where find a certain minimum of this quantity, which will give us an extensive view with regard to the operation of the elements and seasons upon the surface of this earth. We shall now examine more particularly those two ways of judging with regard to the operations of time past, and the changes which have been made upon the surface of our land, by those active causes, which, being in the constitution of this earth, must continue to operate with undiminished power, and tend to preserve the whole amidst the destruction of its particular parts.

The quality of the soil or travelled earth of the globe is various; because the solid parts, from the destruction of which the soil is formed, consist of very different substances, in the different portions of each country. Thus, in one part of a country, the soil will be calcareous, or containing much of that species of substance; in another, again, it will be argillaceous; in another sandy, where the prevailing substance is siliceous. These are the original soils; other substances may be considered as adventitious to this soil, though natural to the surface of the earth, which is covered with plants and animals. The substance of those animal and vegetable bodies, mixed with the soil, adds greater fertility to the earth, and gives a soil which is still more compounded in its nature, but still composed of those materials now enumerated.

We have been now supposing the solid parts below, or in the same field, as furnishing materials of which the soil is formed; this soil then partakes of the nature of those solid parts, whether more simple or more compound. There is, however, another subject of variety, or still greater composition in soils; this is the transportation of materials from a distance; and this, in general, is performed by the ablution of water, in following the declivity of the surface. But sand is sometimes travelled by the wind, and proceeds along the surface of the earth, without regard to the declivity, and changes the nature of soil in those places which happen to be exposed to this accident.

There cannot be any extensive, great, or distant travelling of sand or soil by means of the wind, except in those places which are sterile for want of rain, and thus are destitute of rivers and of streams; for, these running waters form every where a bar to this progressive movement of the soil, even if the sterility or dryness should permit the blowing of the sand. But the operation of streams and rivers, carrying soil and stones along the surface of the earth, is constant, great, and general over all the globe, so far as a superfluity of water, in the seasons of rain, falls upon the earth.

From the amazing quantity of those far travelled materials, which in many places are found upon the surface of the ground, we may with certainty conclude, that there has been a great consumption of the most hard and solid parts of the land; and therefore that there must necessarily have been a still much greater destruction of the more soft and tender substances, and the more light and subtile parts which, during those operations of water, had been floated away into the sea. This appears from the enormous quantities of stones and gravel which have been transported at distances that seem incredible, and deposited at heights above the present rivers, which renders the conveyance of those bodies altogether inconceivable by any natural operation, or impossible from the present shape of the surface. This therefore leads us to conclude, that the surface of the earth must have been greatly changed since the time of those deposits of certain foreign materials of the soil. Examples of this kind have been already given. I shall now give one from the Journal de Physique.

"Les bords du Rhone aux environs de Lyon, et sur la longueur de quarante lieues, et de plus, des montagnes entieres, dans le meme pays, sont formes de pierres dont on ne trouve les analogues que dans la Suisse. Ce fait presqu'incomprehensible est accompagne de beaucoup de circonstances qui meritent d'etre detaillees dans un discours plus longue que celui-ci. Il y a cependant une que je ne peux pas m'empecher de rapporter ici, comme une suite de ce que je viens de dire.

"Dans cette grand catastrophe, a laquelle j'attribue le transport de ces matieres alpines, il se fit de grandes echancrures dans le Jura; les plus profondes que j'aie vues sont celles de Jougue de Sainte-Croix, du val de Mousthier Travers, de Someboz au val de Saint-Inver, une cinquieme aux environs du village de Grange, trois lieues plus bas que Bienne, et une sixieme a quatre a cinq lieues plus bas que Soleure, a l'endroit dit la cluse. Cette derniere est la plus profonde, et se trouve de niveau avec les eaux de l'Aar. Beaucoup de ces matieres etrangeres au Jura, ont passe par ces echancrures, et sans doute, par bien d'autres et se sont repandues, dans plusieurs de ces vallees. J'en ai vu un suite bien marquee qui a passe par Jougue, par Saint-Antoine, part Mont Perreux, les Grangettes, les Granges Friards, Oye, et qui est allee jusqu'aux plaines de Pontarlier. Cette suite est en ligne droite vis-a vis l'echancrure de Jougue, et la direction de la vallee qui est au bas de ce village. On en trouve quelques morceaux a Metabiefs, mais je n'en ai point vu aux Longevilles, ni a Roche-Jean. Il y en a au-dessus de Saint-Croix ou d'autres ont pu passer aussi pour aller de meme aux environs de Portarlier. Il y en a dans le val de Mousthier-Travers jusqu'au dessus de village de Butte; elles ont meme passe les roches de Saint-Sulpice du cote des Verrieres de Suisse, ou l'on a ete oblige d'en faire sauter de gros blocs avec de la poudre pour degager la grande route; il y en a dans les vallees de Tavannes, et de Delemont; on en trouve bien plus loin, j'en ai vu pres de Roulans, et je ne douterois pas que les pierres meulieres de Moissez et des environs n'eussent la meme origine."

M. de Saussure, who has so well observed every thing that can be perceived upon the surface of the earth, gives us the following remarks which are general to mountainous countries. (Voyages dans les Alpes, tome 2d Sec. 717).

"Dans le haut des vallees entourees de hautes montagnes, on ne voit point de cailloux roulees, qui soient etrangers a la vallee meme dans laquelle on les trouve; ceux que l'on y rencontre ne sont jamais que les debris des montagnes voisines. Dans le plaines au contraire, et a l'embouchure des vallees, qui aboutissent aux plaines et meme assez haut sur les pentes des montagnes qui bordent ces plaines, on trouve des cailloux et des blocs que l'on diroit tombes du ciel, tant leur nature differe de toute ce que l'on voit dans les environs."

Here are facts which can only be explained in supposing that the valleys have been hollowed out of the solid mass, by the gradual operation of the rivers. In that case stones, travelled from a far, will be found at considerable heights, upon the sides of the valleys at their under end, or where, as our author says, they terminate in plains.

We have a striking example of the operation of time and the influences of the atmosphere, in wasting the surface of the rocks, and forming soil upon the earth; this is the kaolin of the Chinese, or the true porcelain earth, which is the produce of granite countries. The feldspar of the granite rock exposed to the atmosphere is corroded very slowly indeed, by the effects of air and moisture, and in having the soluble earth or calcareous part of its composition dissolved; the surface of this stone, thus, in a long course of time, becomes opaque in having the white siliceous earth exposed to view, and thus appears like a calcined substance. The snows and rain detaches from this surface of the rock the white earth, which being deposited in the plain below, forms a stratum of kaolin more or less pure, according to the circumstance of the place.

As this operation of the atmosphere upon the surface of granite is so extremely slow as to be altogether unmeasurable to man; and as there are in many places of the earth inexhaustible quantities of this kaolin, notwithstanding a small portion only of the ablution of the rock had been retained upon the surface and deposited by itself, it must appear that much time had been required for amassing those beds of kaolin, and that these operations, which in the age of a continent is nothing, or only as a day, are, with regard to the experience of man, unmeasurable.

For approbation of this theory, it is not necessary to show, that wherever there is granite found, there should be also kaolin observed; but it is necessary that wherever kaolin is found, there should be also granite or feldspar to explain its origin; and to this proof the theory is most willingly submitted. The following are the places which have come to my knowledge. First Loch Dune in the shire of Ayr; this lake receives its water from the granite hills which are at its head. Secondly, some small lakes which receive the washings of the granite mountain, Crifle, in East Galloway. Thirdly, Cornwall, a county in which I have not been, but which is sufficiently known as possessing kaolin and granite.

Another example from a very distant country we have both from M. Pallas, in the Oural mountains, and from M. Patrin, who has given a mineralogical notice of the Douari, Journal de physique, Mars 1791. Here we find the following observation.

"Parmi les chose interessantes qu'offrent les rives de Chilea, on remarque au dessous de la fonderie, des collines de petunt-fe blanc comme la neige, parseme de mica argentin de la plus grande tenuite. Dans le voisinage de ce petunt-fe est une argile micacee, qui en est peut-etre une decomposition: on essaya en ma presence d'en faire de la poterie qui avoit tous les caracteres du meilleurs biscuit de porcelaine."

We have now been endeavouring to illustrate the wasting and washing away of the solid land, in the examples of decayed rocks and water worn stones, all of which are traceable, though at a great distance, to their source; we are now to consider another species of substance, which is still more particular as to the place of its production, or to its original situation, this being only in the veins of the earth. Among all the various productions of mineral veins, we have only now in view some particular metallic substances which do not seem to waste and be dissolved, as many of them are, in being long exposed to the influence of air and rain. When, therefore, the solid parts of the land are wasted in time, and carried away from the surface of the earth, the contents of the veins, which are occasionally found in those decayed parts of the land, are also carried away in the stream; but as the specific gravity of those metallic contents is much greater than the other stony materials moved in the stream, they sink to the bottom, and tend much more to be deposited upon the land, than those stones which had moved with them from their place. Hence it is, that deposits, rich in those metallic substances, are formed in certain places of the soil; and these are sought for, upon account of the value of their contents. Thus, stream tin, which in the time of the Romans formed a subject of traffic, is still found in the soil of Cornwall, even in great profusion, at this day.

Nothing can tend more to illustrate this travelling of the wasted surface of the solid land, than the contents of those mineral veins suffering in the general destruction of things, but partly saved from that total ablution by which so much of the solid parts had been made to disappear; and nothing can, in a more beautiful manner, show this order of things, than the method practised by the Cornish miners in quest of the original country of that metal, by shoding, (as it is called) upwards in running back the tract in which the stream tin had been conveyed. This is done by trying parcels of the soil, in always mounting to see from whence the mineral below had come.

Gold is thus found almost in every country but it is only in the most sparing manner that it may thus be in general procured, by reason of the few veins in which gold is found, and the small quantity of this metal contained in those veins. America, however, affords an example of veins rich in gold, and it is also there that quantities of stream gold is found in the soil, bearing a due proportion to the number and riches of the veins.

I shall give an example concerning the situation in which this stream gold is found in Peru (Voyage au Perou, par M. Bouguer, page 49.)

"Cette Cordeliere occidentale contient beaucoup d'or de meme que le pied de l'orient, et celui d'une autres chaine tres-longue qui s'en detache un peu au sud de Popayan, et qui apres avoir passe par Santa Fe de Bogota, et par Merida, va se terminer vers Caracas sur la mer du nord; outre que l'or en paillettes occupe toujours des postes assez bas a l'egard du reste de la Cordeliere, on ne peut aussi jamais le decouvrir qu'en enlevant presque toujours deux couches de differentes terres qui le cachent. La premiere, qui est de la terre ordinaire, a trois ou quatre pieds d'epaisseur et quelquefois dix ou douze. On trouve souvent au dessous une couche moins epaisse qui tire sur le jaune, et plus bas est une troisieme qui a une couleur violette, qui a souvent trois ou quatre pieds d'epaisseur, mais qui n'a aussi quelquefois qu'un pouce, et c'est cette troisieme dans laquelle l'or est mele. Au dessous la terre change encore de couleur, elle devient noire comme a la surface du sol, et elle ne contient aucun metal. D'ailleurs on ne creuse pas indistinctement par tout. On se determine a chercher en certains endroits plutot qu'en d'autres par la pente de terrain. On agit comme si l'or avant que d'avoir ete couvert par les deux couches superieures, avoit ete charrie par des eaux courantes. On s'est assure aussi que les terres une fois lavees ou depouillee de leurs richesses n'en produisent point d'autres; ce qui prouve que l'or y avoit ete comme depose."

Therefore, whether we consider the quantity or the quality of the materials which are found composing the soil upon the surface of the earth, we must be led to acknowledge an immense waste of the solid parts, in procuring those relicts which indicate what had been destroyed.

We have now to examine what is left of that solid part which had furnished the materials of our soil; this is the part which supports the vegetable or travelled earth, and this earth sustains the plants and animals which live upon the globe. It is by this solid part that we are to judge concerning the operations of time past; of those destructive operations by which so great a portion of the earth had been wasted and carried away, and is now sunk at the bottom of the sea.

Man first sees things upon the surface of the earth no otherwise than the brute, who is made to act according to the mere impulse of his sense and reason, without inquiring into what had been the former state of things, or what will be the future. But man does not continue in that state of ignorance or insensibility to truth; and there are few of those who have the opportunity of enlightening their minds with intellectual knowledge, that do not wish at some time or another to be informed of what concerns the whole, and to look into the transactions of time past, as well as to form some judgment with regard to future events.

It is only from the examination of the present state of things that judgments may be formed, in just reasoning, concerning what had been transacted in a former period of time; and it is only by seeing what had been the regular course of things, that any knowledge can be formed of what is afterwards to happen; but, having observed with accuracy the matter of fact, and having thus reasoned as we ought, without supposition or misinformation, the result will be no more precarious than any other subject of human understanding. To those who thus exercise their minds, the following remarks may furnish a subject for some speculation. Now, though to human policy it imports not any thing, perhaps, to know what alterations time had made upon the form and quantity of this earth, divided into kingdoms, states, or empires, or what may become of this continent long after every kingdom now subsisting is forgotten, it much concerns the present happiness of man to know himself, to see the wisdom of that system which we ascribe to nature, and to understand the beauty and utility of those objects which he sees.

There are two different operations belonging to the surface of this globe which we are now to consider, and by which we shall be enabled to form some computation of what had been in space and time, from that which now appears. Moving water is the means employed in both those operations; but, in the one case, it is the water of the sea; in the other again, it is the water of the land. The effect of the one operation is the wasting of the coast, and the diminution of that basis on which our land and soil depends; of the other, again, it is the degradation of our mountains, and the wasting of our soil. In the course of this last operation, there is also occasionally land formed in the sea, in addition to our coast.

With regard to the wearing of the coast by the agitation of the waves, this is an operation of which some understanding is to be formed from the surest of all records, from a careful examination of our shores which are in this decaying state, and by observing what has been removed from those portions which we find remaining. Few people have either the skill or the opportunity of thus judging of the state of our earth from that which actually appears; but there is no person, who studies this science of geology, that may not satisfy himself with regard to the truth of this theory, by looking into our maps and charts, and making proper allowances for causes which cannot appear in the maps, but which may be understood by a person of knowledge making observations on the spot. In order to assist this study, the following observations may be made.

It is a general observation among mariners, that a high coast and rocky shore have deep water; whereas a low coast, and sandy shore, are as naturally attended with shallow water. The explanation of this fact will appear by considering, that a steep rocky coast is occasioned by the sea having worn away the land; and, when that is the case, we are not to expect sand should be accumulated upon that shore, so as to make the sea shallow. Look round all the coasts of Great Britain and Ireland that are exposed to the wide ocean, as likewise those of France and Norway, deep water, and a worn coast, are universally to be acknowledged. If again the coast is shallow, this is a proof that the land affords more materials than the sea can carry away; consequently, instead of being impaired, the coast may here increase and be protruded from the land. Such is the case in many places along the coast of North America, where several reasons concur in accumulating sand upon that coast; for, not only is the shore plentifully provided with sand from the rivers of that continent, but also the sand of the Mexican Gulf would appear to be carried along this coast with the stream which flows here towards the north, and which has thus contributed to form the banks of Newfoundland.

The second general observation is to be considered as respecting the shape of coasts, in like manner as the first had in view their elevations. Now, it is plain that the shape of the coast, in any part of the land, must depend upon a combination of two different causes. The first of these is the composition of the land or solid parts of the coast; if this be uniform and regular, so will be the shape of the coast; if it is irregular and mixed, consisting of parts of very different degrees of hardness and resistance to the wasting operations, the coast will then be, cet. par. irregular and indented. The second, again, respects the wearing power. If this wearing power shall be supposed to be equally applied to all the coast; and, if every part of that coast were of an equal quality or resisting power, no explanation could be given, from the present state of things, for the particular shape of that coast, which ought then to be wasted in an equable manner by the sea. But neither is the coast, of any extensive country at least, composed of such uniform materials; nor is the application of the wearing power to the coast an equal thing; and this will form the subject of another observation. The third general observation, therefore, regards the operations of the sea upon the coast, and the effects which may be perceived in consequence of that cause, independent of the qualities of the coast, or supposing them in general to be alike. Here, according to the theory, we should expect to find deep water and an indented coast upon a country, in proportion as that coast is exposed to the violence of the sea, or is open directly to the ocean. We have but to look along the west coast of Norway, the north-west of Scotland, the west of Ireland, and the south-west of England and of France; and we shall soon be convinced that the sea has made ravages upon those coasts in proportion to its power, and has left them in a shape corresponding to the composition of the land, in destroying the softer, and leaving the harder parts[14].

[Footnote 14: M. de Lamblardie, ingenieur des ponts et chaussees, has made a calculation, seemingly upon good grounds, with regard to the wasting of a part of the coast of France, between the Seine and the Somme. This coast is composed of falaises, (or chalk cliffs, like the opposite coast of England), which are 200 feet high above the level of the sea, composed of strata of marl, separated by beds of flint. This coast is found to be wasted, at an average, at the rate of one foot per annum. We may thus perhaps form some idea of the time since the coast of France and that of England had been here united, or one continued mass of those strata which are the same on both those coasts.]