With those hard and rugged coasts of Britain and Ireland, let us contrast the east coasts; What a difference between these and the west side! Upon the west side, there are no sand banks left upon the coast; the mariner has nothing there to fear but rocks. It is otherwise on the east; here we find a tamer coast, and, in many places, a sandy bottom. On the west, nothing appears opposed to the storm of the ocean except the hardest and most solid rock; on the east, we find coasts exposed to the sea which could not have remained in a similar situation on the west. Let us but compare the two opposite coasts of England, viz. the promontory of Norfolk and Suffolk upon the one side, and Pembrokeshire and Carnarvonshire on the other, both similarly exposed, the one to the north east storm of the German sea, the other to the south west billows of the Atlantic. What a striking difference! The coast in the bay of Cardigan is a hard and strong coast compared with that of Norfolk and Suffolk; the one is strong schistus, the other the most tender clay; yet the soft coast stands protuberant to the sea, the harder coast is hollowed out into a bay; the one has no protection but the sands with which it is surrounded, the other had not remained till this day but for the protection of the most solid rocks of Pembrokeshire and Carnarvonshire, which oppose the fury of the waves.

The last general observation which I shall propose, has, for its subject, a more enlarged view than those now taken of the coast, a view indeed which is not so immediately the object of our observation, but which is nevertheless to be made most evident, by means of the others now considered. We have seen that the land exposed to the sea is destroyed, and the coast wasted more or less, in proportion to the wearing causes, and to the different resisting powers opposed to those causes of decay; we are now to make our observations with regard to the extent and quality of that which has been already destroyed, a subject which can only be conjectured at from the scientific view which may be taken of things, and from the careful examination of that which has been left behind upon the different coasts.

Our land is wasted by the sea; and there is also a natural progress to be observed which necessarily takes place on this occasion; for, the coast is found variously indented, that is to say, more or less, according as the land is exposed to this wasting and wearing operation of the sea, and according as the wasted land is composed of parts resisting with different degrees of power the destroying cause. The land, thus being worn and wasted away, forms here and there peninsulas, which are the more durable portions of that which had been destroyed around; and these remaining portions are still connected with the main land, of which they at present form a part.

But those promontories and peninsulas are gradually detached from the main land, in thus forming islands, which are but little removed from the land. An example of this we have in Anglesay, which is but one degree removed from the state of being a promontory. These islands again, in being subdivided, are converted into barren rocks, which point out to us the course in which the lost or wasted land upon the coast had formerly existed.

To be satisfied of this, let us but look upon the western coast of Scotland; from the islands of St. Kilda to Galloway, on the one side, and to Shetland on the other; in this tract, we have every testimony, for the truth of the doctrine, that is consistent with the nature of the subject. The progress of things is too slow to admit of any evidence drawn immediately from observation; but every other proof is at hand; every appearance corresponds with the theory; and of every step in the progress, from a continent of high land to the point of a rock sunk below the surface of the sea, abundant examples may be found. We do not see the beginning and ending of any one island or piece of country, because the operation is only accomplished in the course of time, and the experience of man is only in the present moment. But man has science and reason, in order to understand what has already been from what appears; and we have but to open our eyes to see all the stages of the operation although not in one individual object. Now, where the nature of things will not admit of having all and every step of the progress to be perceived in one object, an indefinite progression in the various states of different objects, showing the series or gradation from a continent to a rock, must form a proof in which no deficiency will be found.

I have given for example the coast of Scotland; but all over the world where there is a coast not covered with sand, or where it is exposed to the violence of the sea, it is the same. Take the map of any country, provided it be sufficiently particular, and you will see the breaking of continents or islands, first, into promontories or peninsulas; secondly, into islands which stand on the same solid basis with the continent; and, lastly, into rocks which are related to the islands, in like manner as those parasitical islands are related to the head lands and the shore. Here is a general fact, from the simple inspection of which we must conclude one of two things; either that those rocks and smaller islands, which we have termed parasitical, are in a state of progression, by which in time they will be joined to the main land, and form one continent; or that they are in a state of degradation, by which in time they will be made to disappear. There is no other supposition to be made; and, of that alternative, there is no room to hesitate a moment which to choose. This is not a matter of mere probability, it is the subject of physical demonstration. Should we find an old manuscript in a similar condition, we could not conclude with more certainty, that the deficient or intervening places had been destroyed, than we here conclude that the part which is now wanting, between the two remaining portions of the same rock or strata, had once connected those two portions, and had been destroyed by the operation of those causes which are every day employed in still increasing the breach.

Though over all the world, where the shore is washed bare by the sea, examples are to be found which require but to be seen to give compleat conviction, it is not in every place that the eye of a naturalist has been employed in taking this view of the coast; nor is it upon every occasion that enlightened philosophers of this kind have given their thoughts upon the subject. M. de Spallanzani has given us the following observations with regard to the coast of Italy[15].

[Footnote 15: Observations sur la Physique, etc. Juliet 1786.]

"Autant l'interieur du petit bourg de Porto-venere et les rochers qui l'environnent sont a l'abri des tempetes, autant les parties exterieures sont exposees aux coups de mer les plus violens, lorsqu'elles sont en proie au deux terribles vents d'Afrique et a celui du sud-est. Ce dernier en particulier souleve les flots avec tant de violence et a une telle hauteur contre les ecueils qui servent de defense a ce petit terrain, que la mer semble menacer de l'engloutir. J'ai ete le temoin d'un de ces orages, et quoique je fusse a l'abri de tout danger, je ne pourroit vous representer l'horreur que me fit eprouver ce spectacle. J'ai voulu prendre avec exactitude la hauteur moyenne de l'elevation des flots dans les plus violens coups de vent; et quand je vous en parlerai vous serez etonne de leur force et de l'etendue de leurs effets. Les rochers qui sont a la partie meridionale de Porto-venere se rongent et se detruisent peu-a-peu de meme que les trois isles voisines Tiro, le petit Tiro, et Palmarin. On le remarque surtout dans cette dernier: les bords voisins de la terre ont une pente douce; ils sont couverts d'arbres et de plantes, tandis que la partie opposee est deserte et inaccessible couverte de precipices, de ruines et d'horreurs; les autres parties du rivage sont renfermees par la riviere du ponent et par celle du levant, de meme que celles qui s'approchent des cotes de Provence. Il me paroit que la mer a beaucoup gagne sur le terre dans ces parages; et pour parler seulement de Palmarin, la plus grande, et la plus remarquable des trois isles que j'ai nommees, je crois etre suffisamment fonde pour conclure que la meme pente facile et longue qu'on observe du cote de la terre avoit aussi existe du cote de la mer; mais que cette derniere avoit ete detruite par les orages, qui se sont succedes pendant le cours de siecles. La vue reflechie de ces trois isles me force a les regarder comme ayant ete autre fois reunies, et formant une isle seule par leur reunion, ou plutot comme une presqu'ile attenante a Porto-Venere."

We have a still more interesting observation made upon this same coast of Italy, by a naturalist to whom the world is much indebted for his excellent remarks upon what he has, by his great industry, brought to light. I mean the Chevalier de Dolomieu; where-ever he goes, natural history reaps the benefit of the most enlightened observations. We are now to avail ourselves of his Memoire sur les Iles Ponces.

The pumice islands form part of a chain of land that may be traced forming a circular line from the cape Missene to the mount Circello at the other side of the Gulf of Gaeta. The islands of Ischia and Procida, which form part of this chain of land, might, from the inspection of the map, be allowed as having once formed a continuation of the land from the continent of Italy, even without the testimony of natural history, that traces this connection from the materials of those masses which now are separated.

The pumice islands form the middle part of that chain, and are the farthest removed from that continent of which it is probable they once formed a part. They are connected with the promontory of Missene on the one hand, as being of the same or similar volcanic origin, and on the other with mount Circello, by a curious circumstance in the island Zanone, which, but a little more of the devouring operation of the sea, would have concealed from our observation.

The island of Ventotiene, which is the nearest of them to Ischia, would appear to be the ancient island of Pendataria, in which Julia was confined. The marks of degradation in this island, I would wish to give in the Chevalier's own words, (p. 52.)

"Cette isle continue a etre devoree par la mer, elle l'attaque dans toutes les parties de son contour, ou elle trouve peu de resistance, et elle ne cesse de creuser, principalement, tous les escarpemens du nord. Il paroit, par les vestiges des antiquites qui sont sur la pointe dite di Nevola, que sous l'Empire de Cesar cette isle avoit encore une etendue plus considerable. Il s'y fait journellement des eboulemens; on peut prevoir qu'elle diminuera progressivement, qu'elle se divisera, et que dans les temps a venir elle sera reduite aux rochers de laves qui la supportent, et qui seuls peuvent resister, pendant une longue suite de siecles, a tous les efforts des flots; ce ne sera surement pas la seule terre que le temps et la mer auront devoree, et que les vicissitudes de la nature ont fait disparoitre avant que l'histoire en ait pu constater l'existence."

As the island of Ventotiene connects this group of the pumice islands with the continent of Missene, that of Zanone, on the other side, connects them with the continent at mount Circello. Here is a fact of which our author now gives proper evidence.

It would appear that Mount Circello is composed of an alpine limestone. But in the north end of the island of Zanone, the Chevalier de Dolomieu finds a small part of a similar limestone in vertical strata, closely united with the volcanic materials of the islands now under consideration. It is impossible that this portion of calcareous rock could be formed in its present situation, and we have but to examine nature in order to be convinced that this limestone part had been once continued from Mount Circello. Here again I beg leave to give this author's own words, (page 141.)

"Cette reunion de deux matieres aussi differentes par leur origine que le font celles qui forment l'Isle Zanone, est une circonstance des plus singuliers. La pierre calcaire ne contient point de coquillages; sa densite sa durete; son odeur fetide annonce une origine ancienne; elle n'est point formee par un depot de nouvelle date; elle differe des pierres calcaires-coquilliere qui recouvrent les volcans du Padouan et du Vicentin, et de celles qui se sont meles avec les produits du feu dans les volcans eteintes de la Sicile: les laves ici reposent sur elle: elle paroit donc anterieure a l'epoque des irruptions qui ont eleve les isles ponces. Par sa nature elle est semblable aux pierres du Mont Circe, et a celles de l'interieure de l'Apennin; il semble que cette portion de montagne calcaire, abstraction faite des matieres volcaniques qui lui sont reunies, a appartenu a quelqu'unes des montagnes qui dependent de la chaine qui traverse l'Italie; car il n'est pas possible que ni elle ni le Mont Circe ayent ete formes seules et isoles ainsi que nous les voyons. Mais quand ont-ils ete detachees? etoient-ils deja isoles lorsque les feux ont commence la formation des isles ponces? ou seroit-ce la meme revolution qui les auroit separes du continent, et qui a opere le desordre que nous voyons dans ces isles volcanique? On ne peut former sur toutes ces questions que des conjectures bien vagues."

Our present inquiry is only with regard to the operation of those causes which we now perceive to be acting upon the coasts of the land; which must be considered as having been operating for a long time back, and which must be considered as continuing to operate. One example more I wish to give, not only as it is much to the purpose, and properly described, but because it contains the natural history of a coast well known from the circumstance of the Giant's Causeway which it contains; a coast composed of stratified chalk indurated and consolidated to a species of marble or lime-stone, and of great masses of basaltes or columnar whin-stone. Now, though our present object is not the formation of land, yet, knowing the mineral constitution of this land, the coast of which we are considering as having been worn by the action of the sea, the view here to be given, of the white marble and basaltic cliffs, is satisfactory in the highest degree. It is from Letters concerning the Northern Coast of the County of Antrim, by the Reverend William Hamilton, A. M.

"The chalky cliffs of the island of Raghery, crowned by a venerable covering of brown rock, form a very beautiful and picturesque appearance as one sails towards them; and, if the turbulence of the sea does not restrain the eyes and fancy from expatiating around, such a striking similitude appears between this and the opposite coast, as readily suggests an idea that the island might once have formed a part of the adjoining country, from whence it has been disunited by some violent shock of nature.

"You, to whom demonstration is familiar, will wonder to see two shores, seven or eight miles asunder, so expeditiously connected by such a slender and fanciful middle term as apparent similitude; and yet the likeness is so strong, and attended with such peculiar circumstances, that I do not entirely despair of prevailing even on you to acknowledge my opinion as a probable one.

"It does not appear unreasonable to conclude, that, if two pieces of land, separated from each other by a chasm, be composed of the same kind of materials, similarly arranged, at equal elevations, these different lands might have been originally connected, and the chasm be only accidental. For, let us conceive the materials to be deposited by any of the elements of fire, air, earth, or water, or by any cause whatever, and it is not likely that this cause (otherwise general) should in all its operations regularly stop short at the chasm.

"The materials of which the island of Raghery is composed are accurately the same as those of the opposite shore; and the arrangement answers so closely, as almost to demonstrate, at first view, their former union. But to explain this more clearly, it will be necessary to give you a general sketch of this whole line of coast.

"The northern coast of Antrim seems to have been originally a compact body of lime-stone rock, considerably higher than the present level of the sea; over which, at some later period, extensive bodies of vitrifiable stone have been superinduced in a state of softness. The original calcareous stratum appears to be much deranged and interrupted by those incumbent masses. In some places it is depressed greatly below its ancient level; shortly after it is borne down to the water's edge, and can be traced under its surface. By and by it dips entirely, and seems irretrievably lost under the superior mass. In a short space, however, it begins to emerge, and, after a similar variation, recovers its original height.

"In this manner, and with such repeated vicissitudes of elevation and depression, it pursues a course of forty miles along the coast from Lough Foyle to Lough Larne.

"It naturally becomes an object of curiosity to inquire what the substance is from which the lime-stone seems thus to have shrunk, burying itself (as it were in terror) under the covering of the ocean: And, on examination, it appears to be the columnar basaltes, under which the lime-stone stratum is never found; nor indeed does it ever approach near to it without evident signs of derangement.

"Thus, for example, the chalky cliffs may be discovered a little eastward from Portrush; after a short course, they are suddenly depressed to the water's edge, under Dunluce Castle, and, soon after, lost entirely in passing near the basalt-hill of Dunluce, whose craigs, near the sea, are all columnar. At the river Bush the lime-stone recovers, and skims a moment above the level of the sea, but immediately vanishes in approaching towards the great basalt promontory of Bengore, under which it is completely lost for the space of more than three miles.

"Eastward from thence, beyond Dunsaverock Castle, it again emerges, and, rising to a considerable height, forms a beautiful barrier to White Park Bay and the Ballintoy shore. After this it suffers a temporary depression near the basalt hill of Knocksoghy, and then ranges along the coast as far as Ballycastle Bay.

"Fairhead, standing with magnificence on its massy columns of basaltes, again exterminates it; and once again it rises to the eastward, and pursues its devious course, forming, on the Glenarm shores, a line of coast the most fantastically beautiful that can be imagined.

"If this, tedious expedition have not entirely worn out your patience, let us now take a view of the coast of Ragery itself, from the lofty summit of Fairhead, which overlook it. Westward we see its white cliff rising abruptly from the ocean, corresponding accurately in materials and elevation with those of the opposite shore, and like them, crowned with a venerable load of the same vitrifiable rock. Eastward, we behold it dip to the level of the sea, and soon give place to many beautiful arrangements of basalt pillars which form the eastern end of the island, and lie opposite to the basaltes of Fairhead, affording in every part a reasonable presumption that the two coasts were formerly connected, and that each was created and deranged by the same causes extensively operating over both.

"But it is not in these larger features alone that the similitude may be traced; the more minute and accidental circumstances serve equally well to ascertain it.

"Thus, an heterogeneous mass of freestone, coals, iron-ore, etc. which forms the east side of Ballycastle Bay, and appears quite different from the common fossils of the country, may be traced also directly opposite, running under Rathlin, with circumstances which almost demonstrably ascertain it to be the same vein.

"What I would infer from hence is, that this whole coast has undergone considerable changes; that those abrupt promontories, which now run wildly into the ocean, in proud defiance of its boisterous waves, have been rendered broken and irregular by some violent convulsion of nature; and that the island of Ragery, standing as it were in the midst between this and the Scottish coast, may be the surviving fragment of a large tract of country which, at some period of time, has been buried in the deep."

Besides this argument of the gradation from a continent of land to a bare rock, we have another from the consideration of those rocks themselves, so far as these could not be formed by nature in their present state, but must have been portions of a greater mass. How, for example, could a perpendicular mountain, such as St. Kilda, have been produced in the ocean? Of whatever materials we shall suppose it formed, we never shall find means for the production of such a mass in its present insulated state. Let us take examples of this kind near our coast, and of known rocks. Staffa and Ailsa, on the west coast, and the Bass, upon the east, are mountains of either whin-stone or granite, similar to many such mountains within the land; and they are perpendicular around, except perhaps on one part. It is demonstrable that such basaltic rock as contains zeolite and calcareous spar, as most of our whin-stones do, could not have been the eruption of a volcano, consequently those rocks must have been masses protruded in a fluid state, under an immense cover of earth at the time of their production; and they could not have risen immediately out of the sea, with all their various minerals, their veins and cutters, their faces and their angles.

In like manner, the east coast of Caithness is a perpendicular cliff of sand-stone, lying in a horizontal position, and thus forming a flat country above the shore. But along this coast there are small islands, pillars, and peninsulas, of the same strata, corresponding perfectly with that which forms the greater mass. Now, shall we suppose those strata of sand-stone to have been formed in their place, and to have reached no farther eastward into the sea?—It is unsupposable. Or, shall we conceive that the sea, which has made such depredations in land composed of much more solid materials, had spared this, and had not wasted much more than that now pointed out by the ruins which remain?—Impossible; we must suppose that there had once existed much land where nothing now is found but sea. But, if we are to suppose much to have been wasted, where shall we stop in this process of restoring continents? That is the question now to be discussed.

With this view, let us now turn our attention to the north-west coast of Europe, in consulting the general as well as the most particular maps. Upon the one extremity of Britain, we find Cornwall separating it as it were from the main land; and, from this promontory, the Scilly Isles pointing out what had been destroyed in that direction, which is here to be considered as the line of greatest resistance. But what a quantity of the soft materials, or less resisting parts on either side, has been destroyed! Upon the other extremity of Britain, we find the country of Scotland, forming itself into promontories and islands, and those islands and rocks pointing out to us what had been the former extent of our continent and land around. But, in following this connection of things, we cannot refuse to acknowledge that Ireland had formerly been in one mass of land with Britain, in like manner as the Orkneys had been with Scotland[16].

[Footnote 16: I have the most satisfactory evidence of this fact, in finding the schistus of Galloway and of England in the opposite coast of Ireland, corresponding to its direction in stretching from the coasts of Britain.]

It will be still less possible to refuse the junction of England with the continent of France; the testimony of that peculiar body of chalk and flint, which borders each of those opposite coasts, forms an argument which is irrefragable. Now, in order to complete our continent, we have only to connect the Shetland islands with the coast of Norway. But this is a notion which, however probable it may appear, is not proposed as a fact immediately supported by natural appearances; it is only to be considered as an enlarged view in which we may contemplate the operations of this earth upon a more extended scale; one which may be conceived as a step in our cosmogeny, and one which, while it illustrates the theory of the earth already given, is by no means required in order to confirm a theory founded upon appearances which leave no manner of doubt.



CHAP. IX.

The Theory Illustrated, with a View of the Summits of the Alps.

There are two different directions in which we may observe the destruction of our land to proceed; in the one of these, the basis of our continent is diminished by the incroachment of the sea; in the other, again, it is the height of the land above the level of the sea that is lowered. We have been considering the incroachment of the sea upon the continent; let us now examine how far there may also appear sufficient documents, by which we may be led to conclude a long progress in time past, for the destruction of the solid mass of earth above the sea, without diminishing its basis.

If we shall suppose this earth composed of horizontal strata, and of one level surface, without the least protuberance remaining by which we might be informed of what had been removed by time in the operation of second causes, we should be ignorant of every thing of cosmogeny but this, That the strata of the globe had been originally formed (by the sea) in the same shape as we had found them on the surface of the land. But this is not the shape of the surface of our continent: We have every where abundance of eminences, sufficient to give us great information with regard to what had passed in former periods of time, if the strata of the globe were in that regular shape which they had originally assumed in being deposited at the bottom the sea.

The strata, however, are not in that regular shape and position from whence we might learn, by examining the remaining portions, what had been carried away from the surface in general; they are found variously inclined to the horizon; and this we find both occasioned from the fracture and flexure of those bodies, thus changed from their natural horizontal state. Thus, though there are in many places immense masses of strata cut off abruptly, and exposed to view, without the remainder appearing, we cannot from hence form any estimate of the general quantity of destruction; at the same time, it must be evident, from a general inspection, that there has been an immense quantity removed; and that an immense time had been required in bringing about those revolutions of things, which are not done by violent changes, but by slow degrees.

Besides that general conclusion with regard to the destruction of the strata, there is also in many places a demonstration of that fact, from a measured minimum of the quantity which had been removed. It is to the mining business chiefly that we are indebted for that demonstration of which we now shall give an example.

The coal strata, about Newcastle upon Tyne, dip to the south-east at the rate of one in twelve, or thereabouts. This is but little removed from the horizontal position; at the same time, the strata come all up to the soil or surface in a country which is level, or with little risings. But in those strata there is a slip, or hitch, which runs from north-east to south-west, for 17 or 18 miles in a straight line; the surface on each side of this line is perfectly equal, and nothing distinguishable in the soil above; but, in sinking mines, the same strata are found at the distance of 70 fathoms from each other. Here therefore is a demonstration, that there had been worn away, and removed into the sea, 70 fathoms more from the country on the one side of this line, than from that on the other. It is far from having given us all the height of country which has been washed away, but it gives us a minimum of that quantity.

The examination of what is commonly called a secondary country is not sufficient to give us an idea of the immense operation of time in wearing the surface of this earth. It is not that those countries of inferior hardness and elevation have been spared in the course of time, but because we have not, in those levelled countries, such great remainders, by which we are to judge the quantity of what is lost. In the alpine country, again, though it be the same system of things with that which takes place in the lower country, the revolution of things is more marked for our view; and the ravages of time, in destroying the solid parts of the globe, in order to make soil of that which is removed, may be seen in all the steps of that important operation; whereas, in the more level countries, the scale of elevation is imperceptible, and that of time is so slow as renders our examination fruitless. It is the Alps, therefore, chiefly that we are to take for an example, in tracing this operation of nature upon the surface of this earth, and forming some idea of the course of time that must have flowed during that operation in which the height of our land had been diminished.

On whatever side we approach the Alps, we find some great river discharging the waters which had been gathered above, and with that water all the waste of earth and stone which had been made among those lofty masses of decaying rock. Now, we find this river running in a valley proportioned, in general, to this vehicle, in which is travelled the wreck of ruinous mountains. Spacious plains attend those mighty streams; and, tho' sometimes we find the greatest rivers much confined between approaching hills of solid rock, the valley opens again, and, on the whole, is always corresponding to the current of water which has successively run in all the quarters of this plain. Here a question occurs; Has this valley been made by the operation of the river itself, or has it been the effect of other causes? Let us now resolve that question.

If the valley was made for the river by any other natural cause, either we should tell by what means this work had been performed, or all reasoning upon the subject is at an end, and fancy substituted in its place. If again the river be considered as the means employed by nature in making this valley, then all the solid parts between the bounding mountains must have been removed, and the fertile plains must have been formed by the water depositing those materials which we find in the soil, and which had come originally from the solid mountains. There is no occasion to enter into any argument to prove this fact; nobody that examines the matter will find any reason to doubt; and it would be as unreasonable for those to doubt who have not examined, as for those who find no reasonable subject of doubt to disbelieve.

We are now to suppose the great river to have formed the valley and extensive plain in which the water runs,—a valley corresponding to the grandeur of the river by which it has been formed. But, as we ascend this great valley, we find other valleys branching from this main valley; and, in all those subordinate valleys, we find rivers corresponding in like manner with the magnitude of the valley. Here, therefore, is infinitely more than a single river, and a valley corresponding to the river; here is a system of rivers and of valleys, things calculated in perfect wisdom, or properly adapted to each other.

Now it is just as easy, by our theory, to explain this system of rivers and valleys, as it is to understand the single appearance of a river and a valley. But it is only in this manner that such a complicated operation, of a series in rivers and their valleys, is to be explained; and we can neither suppose the land to be formed with this intention by a supernatural cause, nor imagine any other natural cause so arranging things, upon the surface of the earth, as to form this perfect system, which holds of nothing but itself; a system in which is manifested wisdom, so far as all the parts are properly adapted to each other, and thus made to answer that intention which is so visible in the economy of this world.

The direction of the principal valleys of the Alps, or every mountainous region of the globe, may be considered as proceeding from the centre of that region to the plain country in which each river is to terminate; each secondary river with its valley then branches from the primary as from a stem, consequently runs in a direction perpendicular or inclined to the other. But the secondary rivers also have their branches; and subordinate branches still are branched. In thus tracing rivers and their branchings, we come at last to rivulets that only run in times of rain, and at other times are dry. It is here I would wish to carry my reader, in order to be convinced, with his proper observation, of this great fact,—that the rivers, in general, have hollowed out their valleys.

The changes of the valley of the main river are but slow, the plain indeed is wasted in one place, but it is repaired in another, and we do not perceive the place from whence that repairing matter had proceeded. Therefore, that which here appears does not immediately suggest to the spectator what had been the state of things before the valley had been hollowed out, or before that plain, through which the river runs so naturally as being in the lowest place, was made. But it is otherwise in the valley of the rivulet; no person can examine this subject without seeing that the rivulet carries away matter which cannot be repaired except by wearing away some part of the mountain, or the surface of that place upon which the rain, which forms the stream, is gathered. In those rivulets, or their little plains, we see the detached parts remaining in the soil, and also the place from whence those detached parts were taken. Here we need no long chain of reasoning from effect to cause; the whole operation is in a manner before our eyes. In this case, it requires but little study to replace the removed parts; and thus to see the work of nature, resolving the most hard and solid masses by the continued influences of the sun and atmosphere. In this state of things, we are easily made to understand how heavy bodies are travelled along the declivity of the earth, by means of water running from the height.

Such is the system of rivers and their valleys; nor is there upon the continent a spot on which some river has not run. But, in the Alps of Switzerland and Savoy, there is another system of valleys, above that of the rivers, and connected with it. These are valleys of moving ice, instead of water. This icy valley is also found branching from a greater to a lesser, until at last it ends upon the summit of a mountain, covered continually with snow. The motion of things in those icy valleys is commonly exceeding slow, the operation however of protruding bodies, as well as that of fracture and attrition, is extremely powerful.

To illustrate those operations of excavating the valleys of rivers and of thus undermining mountains which fall by their proper weight, I shall transcribe some descriptions of what is to be found among the Alps. But first I would wish to carry my reader to the summit of that country, to examine the state of that part which nothing can have affected but the immediate influences of the sun and air. After having thus formed some idea of the summit of this wasting country, we shall next examine the valleys through which the materials of the degraded summit must have travelled.

In order to give a proper idea of this central part of the Alps, which is so interesting a part in the natural history of the earth, M. de Saussure, in the plates of his Voyages dans les Alpes, tom. 2. has given us two views, the one in profile, the other in face, of the Mont-Blanc. I have caused copy those plates, which are necessary to be consulted in reading the following description of this centre of the Alps.

This author has taken much pains to form, to himself a proper idea of the object which we have now in view; and he gives a description of the Mont-Blanc as seen from the top of the Cramont. It is that description which I am now to transcribe[17].

[Footnote 17: Voyage dans les Alpes, tom. 2.]

Sec. 910. "Le premier objet de mon etude fut le Mont Blanc. Il se presente ici de la maniere la plus brillante et la plus commode pour l'observateur. On l'embrasse d'un seul coup-d'oeil, depuis sa base jusqu'a sa cime, et il semble avoir ecarte et rejete sur ses epaules son manteau de neiges et de glaces pour laisser voir a decouvert la structure de son corps. Taille presqu'a pic dans une hauteur perpendiculaire de 1600 toises, les neiges et les glaces ne peuvent s'arreter que dans un petit nombre d'echancrures, et il montre partout a nud le roc vif dont il est compose.

"Sa forme paroit etre celle d'une pyramide, qui presente au sud-est du cote du Cramont une de ses faces. L'arrete droite de cette pyramide du cote du sud-ouest, monte au sommet, en faisant avec l'horison un angle de 23 a 24 degres. L'arrete gauche du cote du nord-est, monte au meme sommet sous un angle de 23 a 24 degres, en sorte que l'angle au sommet est d'environ 130 degres.

"Cette pyramide paroit elle meme composee de grands feuillets triangulaires ou pyramidaux. Trois de ces grands feuillets ont leurs bases dans l'Allee-Blanche, et forment ensemble tout l'avant corps de la base de la pyramide. Chacun de ces feuillets, vu de l'Allee-Blanche, paroit une grande montagne, je les ai decrits dans le chapitre precedent sous le noms de Mont-Peteret, Mont-Rouge, et Mont-Broglia, Sec. 830, 831, 834. Mais du haut du Cramont, on voit plus nettement leur forme, et leur ensemble, on distingue, par exemple, qu'ils sont eux-memes composes de grandes feuilles pyramidales; on voit que les injures du temps ont detruit la pointe du Mont-Rouge, tandis que celles des deux autres pyramides sont demeurees entieres.

"Ces trois feuillets ne s'elevent pas jusqu'a la moitie de la hauteur du Mont-Blanc; d'autres feuillets plus petits, situes derriere et au-dessus d'eux, et places sur deux lignes principales qui convergent au sommet, achevent de couvrir la face de cette grande pyramide. Ces feuillets sont tous de forme pyramidale; les plus petits sont les plus aigus; j'en ai mesure plusieurs, dont l'angle au sommet n'etoit que de 70 degres. Tous, absolument tous, ont leurs plans paralleles a l'Allee-Blanche, et par consequent diriges du nord-est au sud-ouest.

"Sec. 911. Quant a la matiere dont est composee cette grande et haute montagne, toute sa cime et toute sa base, tant au centre que du cote du nord-est, sont indubitablement de granit; mais le cote sud-ouest de la base, ou le Mont-Broglia que nous avons vu de pres, Sec. 834, est d'une pierre moins dure, melangee de schorl, de feldspath, de mica, de quartz gras et de pyrites.

"On voit tres-bien du haut du Cramont que cette partie de la base n'est point du granit; sa couleur est d'un brun rougeatre, elle ne se termine point par des arretes vives et nettes, n'est point composee de grandes tables planes. Ce font cependant des feuillets pyramidaux, mais petits et presses les unes contre les autres; a mesure qu'ils s'approchent du sommet, et par cela meme du coeur de la montagne, ils perdent leur couleur rouge, leurs angles deviennent plus vifs, leurs tables plus grandes et plus planes, et enfin pres de la cime, et a la cime meme, ce sont de vrais granits parfaitement caracterises. On peut donc conclure, que le corps entier du Mont-Blanc, et meme ces bases avancees du cote de l'Italie, sont toutes de granit, excepte la base de l'arrete exterieure du cote du sud-ouest.

"Sec. 912. La montagne qui touche le Mont-Blanc du cote du nord-est, et qui, vue de Geneve, forme en quelque maniere le premiere escalier en descendant de la cime, est aussi composee de tables de granit qui paroissent dirigees du nord-est au sud-ouest. Mais la sommite qui suit celle-ci en tirant toujours au nord-est, et qui forme le second escalier, paroit avoir quelques feuillets tournans autour de son corps pyramidal, comme les feuillets d'un artichaux, et comme j'ai depeint l'aiguille du Midi, tome I. pl. 6. En tirant plus encore au nord-est, on reconnoit les Jorasses que nous avons vues du haut du Talefre, Sec. 637, elles paroissent d'ici, apres le Mont-Blanc et ses escaliers, les sommites les plus elevees de toute cette chaine, et elles semblent resulter de l'assemblage de plusieurs suites de feuillets pyramidaux convergents vers leur sommet. En general toutes les cimes elevees que l'on peut distinguer dans cette chaine, depuis le Mont-Blanc jusqu'au col Ferret, sont soutenues par des augives composees d'une ou de plusieurs suites de feuillets pyramidaux appuyes les uns contre les autres; les exterieures ont leurs bases dans le fond de la vallee, et les interieures remontent par degres jusqu'au haut des cimes. Les deux escaliers du Mont-Blanc sont les seules sommites qui n'aient pas des augives de ce genre.

"Sec. 913. Je demande a present quelle idee on peut se faire de l'origine de ces feuillets plans et de toutes ces pyramides grandes et petites qui resultent de leur assemblage, si on ne les considere pas comme les restes ou les noyaux les plus durs des couches qui out resiste aux ravages du temps, tandis que les parties intermediaires, qui les lioient entr'elles, out ete detruites par ces memes ravages.

"Mais jusqu'a quel point la crystallization a-t-elle contribue a determiner ces formes pyramidales? doit-on considerer le Mont-Blanc ou telle autre de ces aiguilles, comme un enorme crystal? C'est une question de theorie que j'examinerai ailleurs. Quant a present je me contenterai de conclure, que la face meridionale de la chaine centrale des Alpes est, comme la face septentrionale de cette meme chaine, composee, pour la plus grande partie, de couches de granit a-peu-pres verticales, et dirigees pour la plupart du nord-est au sud-ouest."

This theoretical question of our author is so properly connected with the natural history which he has here given us, that it is not difficult to resolve it in the most satisfactory manner.

Here is an enormous mass of granite, the origin of which we are not now inquiring after, but the causes of its present form. The internal part of this granite subsists in a state of the most perfect solidity; the external again is evidently in a decaying state. This is a fact which we learn from the nature of feldspar, of which granite is in part composed; this crystallised substance is every where decomposed, where long exposed to the atmosphere. But it is not this gradual decay of the mass of granite perishing equably from its external surface, and resolved into some of its component parts, that we are here to consider; it is only mentioned to show that the mass of granite is subject to decay, when exposed to the influence of the atmosphere, like every other compound mineral body, and to lose that perfect solidity which we find in the centre of the mass.

We find the granite masses not only subject to decay from the external surface, by the decomposition of the feltspar, or the dissolution of its constituent parts, but also liable to be separated into blocks of different degrees of regularity, commonly rectangular or approaching to the rhombic shape. This is the consequence, either of larger veins and fissures, filled with matter which is still more dissolvable than is the substance of the granite, or else by imperceptible crevices or cutters, into which the atmospheric influences gradually insinuate, and form at last a visible separation.

In examining the tops of granite mountains, or where this rock is exposed to the weather, we may perceive those two species of decay proceeding together. The external surface of the stone, where there is a sufficient mixture of feltspar, is separating into grains which form a species of sand, being nothing but the particles of granite separating by means of the decaying sparry part. But a similar progress may be observed, from the external surface penetrating in lines the mass of solid rock, and dividing that mass into the rectangular blocks into which those exposed places are gradually resolved.

Now the tops of all those mountains are formed into an assemblage of pyramids, declining in height from the central pyramid; and all those pyramids are again in like manner subdivided into lesser pyramids. But the smallest of those pyramids are no other than the rectangular blocks into which those granite masses always separate by the influence of the atmosphere.

It will now be evident, that those mountains, thus resolving into separate blocks, must acquire this series of pyramidal constructions; for, in every particular mass of mountain, there must be a central part, from which the separated blocks cannot be removed, while those around, or towards the sides, are detached by the swelling water upon freezing, and separated from the more central masses which are thus the latest of being removed.

It is impossible to see this series of pyramidal relics, without at the same time perceiving that manner of formation, by the gradual resolution of the solid mass of granite, as it comes to be exposed in succession to the influences of the atmosphere, which M. de Saussure has termed les ravage du temps.

But if it be in this manner, that time wastes the solid masses of this globe; and if all the solid masses of the earth have acquired their solid state by the same means, i.e. by heat and fusion, as is maintained in the present theory, we should find similar pyramidal mountains formed of different materials. Now there can be nothing more different than masses of lime-stone and those of granite. But pyramidal mountains are equally formed of those two different materials. In plate V, under the letter B, may be seen the calcareous pyramids which are near the col de la Seigne, and which in plate VI. are represented under the letter G.

Here is a view of the summit of the Alps, from whence we may be allowed to draw the most important conclusions in favour of our theory.

This summit is of solid granite, a mass in which there is no stratification, such as is to be perceived in all the other masses of those alpine regions. With regard again to the extent of this mass of granite, its basis is about two leagues in breadth, by at least thrice that space in length; and now we are to consider in what shape this mass of granite presents itself to our view.

The summit of Mont Blanc, which may be considered as in the centre of this mass, is a pyramid; and this great central pyramid is surrounded by a number of other great pyramids of the same kind. The points of those pyramids are extremely lofty; and, having sides often vastly steep, if not perpendicular, those colossal pyramids rise from the icy valleys in such a shape as has given occasion to their being named needles. Thus we find the whole space of this granite mass consisting of a mixture of icy valleys, and pyramidal rocks on which hardly any thing rests.

Now, these lofty rocks or pointed mountains must have been either originally formed of that shape, or posteriorly hewn out by the hand of nature, gradually wasting mountains in the course of time, and operations of the surface. If it is by the first that we are to explain the present state of things, then observation is superfluous, and our reasoning is at an end; for, when even observation should not contradict the proposition, which it actually does, it would be useless, as it can afford no data from a former state, which is supposed to have been no other than it is at present; and reasoning cannot be admitted if we have no data. Therefore, if we are to reason upon the subject, we are obliged to admit, that nature must have hollowed out of the solid rock all those pyramidal mountains, and a system of inclined valleys carrying the ice from the summits.

Let us now reason from our principles, in order to see how far the present appearances of things would naturally result from those wasting causes acting upon a mass of granite, of a given basis and of sufficient height, during a space of time which is unlimited.

We are to suppose our mass of granite without any structure except that of the veins and cutters, formed by the contraction of the solid mass in cooling. Now, those separations will naturally give direction to the operation of the wasting causes, whether we consider these as chymical or mechanical. Hollow tracts would thus be formed in the solid mass; in those hollow ways would flow the water, carrying the detached portions of the rock; and those hard materials, by their attrition upon the solid mass, would more and more increase the channels in which they move. Thus there would be early formed a system of valleys in this rock, and among those valleys a number of central points, or summits over which no running water would carry hard materials to operate upon the solid rock over which it flows.

Here therefore, in the nature of things, is placed the rudiments of our needles, those colossal pyramids which acquire height gradually as the valleys widen, and whose apices may arrive at an angle of a certain degree of acuteness. But what a waste of rock to have formed all those needles which we find rising from the icy valleys round Mount Blanc!

Upon the supposition that this had been the origin of those pyramidal mountains, it must be evident, that there is a ne plus ultra of acuteness to which the apex of a pyramid would in time arrive; and that then the decaying summit would tumble by the lump alternately, and regain the acuteness of its point. Now, if this be the case, although we cannot see the process, which is too slow for human observation, we should actually find them in all the stages of this progress. But this is precisely the state in which the summits of those mountains are to be found. M. de Saussure gives a view of one of those pyramids, which will serve to illustrate this subject in the most perfect manner. It is from the Montanvert that this object is to be perceived. (Voyages dans les Alpes, vol. 2.).

These high peaks of solid rock demonstrate the manner in which those enormous masses of mountains are degraded, and also the means which are employed by nature for that purpose; but this scene, however well represented, is too far removed, in its appearance, from the ordinary mountains of this earth, to satisfy the doubts of every reader or to generalise a principle which must be universal in the system of this earth. We therefore have occasion for a mean, by which the extreme of those alpine summits shall be generalised or connected with our low inclined plains; and, on this occasion, I will give M. de Saussure's most excellent description of the Breven. Nothing can better suit our present purpose than the subject of this natural history; and I am persuaded that most readers will be better informed by the description of this naturalist, than they would be by their own observation.

"Sec.. 639. J'ai deja plusieurs fois nomme cette montagne, qui est situee immediatement au-dessus du Prieure de Chamouni, du cote du nord-ouest: elle est liee par sa base avec les Aiguilles-rouges, dont j'ai aussi parle dans le premier volume. Mais sa cime est nue, isolee, arrondie sur les derrieres, et coupee a pic du cote de Chamouni. C'est a tous egards une des montagnes les plus interessantes pour un naturaliste.

"J'y montai pour la premiere fois en 1760, et je ne crois pas qu'aucun naturaliste l'eut visitee avant moi; j'y retournai l'annee suivante; j'y allai encore en 1767, et j'y montai enfin pour la derniere fois en 1781, afin de verifier mes anciennes observations, et de me mettre en etat d'en donner une description plus exacte.

"Sec. 640. On peut du Prieure monter au sommet du Breven et redescendre dans le meme jour, mais c'est une course penible, car il faut au moins cinq heures pour monter, et la pente est extremement rapide. On peut cependant faire a mulet le premier tiers de cette montee. Comme je voulus avoir le tems d'observer tout avec soin, j'y destinai deux jours, et j'allai coucher le premier jour dans un chalet, nomme Plianpra, qui, en partant du Prieure, est aux deux tiers de la hauteur totale de la montagne.

"En montant a Plianpra, on fait pres des trois quarts du chemin sur des debris tombes et roules du haut de la tete du Breven. La colline meme sur laquelle est bati le village du Prieure n'est composee que des debris de cette montagne; ces debris ont debouche par une gorge que nous traversons en montant, et se versant ensuite a droite et a gauche, ils ont pris la forme d'un cone, dont le sommet est au milieu de cette gorge. Les collines de ce genre et de cette forme se rencontrent bien frequemment dans les vallees bordees par de hautes montagnes.

"Ces debris, qui ne viennent pas seulement de la tete du Breven, mais de ses flancs et de sa base, sont des roches feuilletees melangees de quartz, de mica et de feldspath dans toutes les proportions imaginables. De ces differentes proportions naissent differens degres de durete, depuis le granit feuillete le plus dur jusques a la roche micacee la plus tendre.

"Sec. 641. Les rochers au pied desquels on passe avant de gravir la montee rapide et herbee qui aboutit a Plianpra, sont composes d'une roche feuilletee assez dure, dont les couches bien paralleles aux veines interieures de la pierre, suivent la direction de l'aiguille aimantee et sont tres-inclinees a l'horison.

"Le chalet de Plianpra est situe au milieu d'une assez grande prairie en pente douce du cote de la vallee de Chamouni, et dominee du cote oppose par les rocs nus qui forment les sommites de la chaine du Breven. Du bord de cette prairie, on a une tres-belle vue du Mont-Blanc, de la vallee de Chamouni et des glaciers qui y aboutissent. Ces memes objets se presentent avec bien plus d'eclat de la cime du Breven; cependant la vue de Plianpra meriteroit bien que ceux qui n'auroient pas la force ou le courage d'aller jusques a la cime, montassent du moins jusque la pour s'en former une idee.

"Comme je ne voulois monter sur le Breven que lendemain, j'employai le reste de la journee a observer les environs du chalet. J'examinai surtout avec soin des rochers situes a une demi-lieue au nord au-dessus du chalet, qui de loin paroissent colores en rouge, comme plusieurs sommites de cette chaine: c'est par cette raison qu'elle porte le nom d'Aiguilles-rouges.

"Sec. 642. Je trouvai que c'etoient encore des granits veines, melanges de quartz, de feldspath, de mica et de fer qui colore la pierre en se decomposant au-dehors: cette teinte penetre meme quelquefois assez avant dans l'interieur. Ces rochers sont divises par couches bien distinctes, a-peu-pres verticales, et dans la direction de l'aiguille aimantee, comme celles que j'avois observees au-dessous du chalet. Ces couches sont coupees par des fentes a-peu-pres perpendiculaires a leurs plans, et qui sont pour la plupart paralleles a l'horison, de maniere que ces rochers se trouvent ainsi divises en grandes pieces de forme a-peu-pres rhomboidale. Les veines memes interieures de la pierre sont aussi tres-bien prononcees, et exactement paralleles a ses couches; observation generale et de la plus grande importance, parce qu'elle prouve que ces couches sont bien de vraies couches, et non point des fissures produites fortuitement par la retraite ou par un affaissement inegal des parties du rocher. Ces veines sont dessinees sur le fond blanc de la pierre des feuillets minces de mica noiratre; elles sont tantot planes, tantot ondees, mais toujours regulieres et paralleles entr'elles, excepte la ou il se rencontre des noeuds; encore reprennent-elles leur direction apres en avoir fait le tour. Comme le mica s'y trouve en petite quantite, la pierre est dure, et ne se brise qu'a grands coups de marteau. Lorsqu'on l'observe de pres dans sa cassure, on voit que les petites lames ou ecailles de mica sont constamment couchees dans le sens des veines de la pierre. Ces memes ecailles n'ont presque aucune adherence entr'elles, en sorte que les feuillets dont la pierre est composee, n'adherent entr'eux que par les points ou il ne se trouve point de mica.

"Sec. 643. Je me demandois a moi-meme, en observant cette pierre, s'il etoit possible qu'elle eut ete formee dans cette situation verticale; si ces ecailles incoherentes auroient pu venir s'attacher a ces murs verticaux, et si le mouvement des eaux, clairement indique par le tissu feuillete de la pierre, n'auroit pas du les detacher et les faire tomber a mesure qu'elles se formoient. Je me demandois encore, si les fentes qui coupent ces feuillets, perpendiculairement a leurs plans, ne dateroient point d'un tems ou ces couches auroient ete horisontales, et n'auroient point ete produites alors par le poids et l'affaissement inegal des parties de la pierre. Mais pour admettre cette supposition, il faudroit expliquer comment ces bancs, d'abord horisontaux, ont pu se redresser; pourquoi ce redressement a ete si frequent, si regulier, etc. etc. Je reserve pour un autre tems la discussion de ces grandes questions; mais je ne crois pas inutile de faire apercevoir la liaison qu'ont avec la theorie des observations si minutieuses en apparence.

"En faisant ces reflexions, je retournai au chalet de Plianpra ou je passai la nuit sur de la paille que j'avois fait etendre aupres du feu, parce que la soiree etoit extremement fraiche.

"Sec. 645 On commence a monter par de jolis sentiers peu inclines, pratiques le long d'un grand rocher semblable a ceux que j'avois observes la veille. On a ensuite le choix de monter, ou par des pentes couvertes de rocailles un peu fatigantes, ou par des gazons extremement rapides. Ceux-ci paroissent d'abord plus agreables et moins penibles; cependant ces gazons sont si serres et si glissans, qu'ils en deviennent dangereux, au moins pour ceux qui n'ont pas l'habitude des montagnes. Ces rocailles sont debris de roches feuilletees, semblables a celles que l'on rencontre en montant du Prieure a Plianpra.

"Sec. 646. B. Au bout d'une heure de marche, on arrive au pied d'un rocher assez escarpe, qu'il faut escalader pour parvenir a la cime de la montagne. C'est une roche micacee, mais qui contient cependant assez de quartz pour avoir de la consistance. Elle se separe par feuillets si decides, que sans employer d'autre instrument que mes mains, j'en detachai une dalle, qui avoit sept pieds de hauteur sur quatre de largeur, et a peine un pouce dans sa plus grande epaisseur.

"J'avois quelque desir de descendre de-la au pied des grandes tables verticales qui composent la tete du Breven, pour les observer de pres et comparer ainsi leur base avec leur cime; mais de cet endroit la chose est impossible, la pente est d'une telle rapidite qu'une pierre mediocrement grosse, que je mis en mouvement, roula avec beaucoup de vitesse, en entraina d'autres, celles-ci d'autres, et elles formerent enfin un torrent de pierres qui se precipita avec un fracas mille fois repete par les grands rochers du Breven.

"Comme donc je ne pouvois pas descendre, je montai par le passage ordinaire, qui est une espece de couloir ou de cheminee ouverte, adossee a un rocher presqu'a pic, de 40 ou 50 pieds de hauteur. Bien des curieux sont venus jusques au pied de ce passage sans oser le franchir; mais je vis en revenant qu'a un demi-quart de lieue plus au nord, on trouve un autre passage extremement commode, qui mene au meme but, et qu'il faut par consequent toujours preferer.

"Ce rocher une fois escalade, on monte par une pente douce, sans danger et sans fatigue, jusqu'au sommet du Breven.

"Sec. 646. C. En montant le long du bord, du cote de Chamouni, j'eus un plaisir inexprimable a contempler les magnifiques tables de granit dont est composee toute la tete de cette montagne. Car bien que les ecailles du mica noiratre dont cette roche est melangee, soient paralleles entr'elles et lui donnent ainsi quelque ressemblance avec une roche feuilletee, cependant la quantite de quartz et de feldspath qui entrent dans sa composition, son extreme durete, le peu de disposition qu'elle a a se fondre dans le sens de ses feuillets, la placent, sinon pour le nomenclateur, du moins pour le naturaliste, dans la classe des vrais granits[18]; et le parfait parallelisme de ces feuillets avec les faces des grandes tables, ou des grandes divisions du rocher, demontre que ces tables sont des couches, et non des parties separees par des fissures accidentelles."

[Footnote 18: "La denomination de granit veine que j'ai, a ce que je crois, employee le premier, a paru tres-heureuse a quelques naturalistes, et a, au contraire, souverainement deplu a quelques autres. Un de ces derniers pretend que ce que je nomme granit veine n'est qu'un amas de gravier graniteux, et par consequent une espece de gres grossier. Mais je voudrois que ceux qui de bonne foi pourroient croire que j'aie commis une erreur aussi grossiere et aussi frequemment repetee, observassent les granits du Breven; et j'en enverrais volontiers a ceux d'entr'eux que le souhaiteroient. Lorsqu'ils verroient que les parties de quartz et de feldspath qui entrent dans leur composition, ont tous leurs angles vifs et tranchans, que ces parties sont intimement unies entre elles et empatees les unes avec les autres, comme dans les granits en masse; que leur coherence est aussi grande que dans ces derniers granits, et que cette roche n'en differe absolument, comme je l'ai deja dit, que par le parallelisme qu'observent entr'elles les lames rares de mica dont elle est melangee: je suis persuade qu'ils reconnoitroient qu'elle a tous les caracteres essentiels du ranit, qu'elle doit avoir la meme origine, et qu'en un mot elle est au granit proprement dit, ce qu'une pierre calcaire feuilletee est a une pierre calcaire dans laquelle on ne distingue point de feuillets."]

"L'extreme regularite de ces tables acheve de demontrer que ce sont de veritables couches. Leurs plans qui sont ici a decouvert dans une hauteur perpendiculaire de plus de 500 pieds, sont parfaitement suivis, comme tailles au ciseau, diriges tous comme l'aiguille aimantee, et verticaux, a quelques degres pres dont ils s'appuyent contre le corps de la montagne. On s'assure en montant que cette structure est celle de la montagne entiere; on voit les profils d'une infinite de ces couches, on passe sur les sommites de ces tranches verticales, et on les voit se prolonger dans cette meme direction tout au travers de la montagne. Or je demande si un naturaliste qui aura observe cet ensemble et ces details pourra regarder cette montagne comme le produit du concours fortuit de grains de sable agglutines entr'eux.

"Ces tables sont coupees un peu obliquement a leurs plans par des fentes dont la plupart sont a-peu-pres horizontales et d'autres tres-inclinees a l'horizon. La pierre se trouve ainsi tres-frequemment coupee en parallelepipedes obliquangles. Ces memes fentes rendent raison, d'une observation que j'avois faite en 1776. En examinant avec une bonne lunette, depuis une fenetre du Prieure, les faces verticales des couches de la sommite du Breven, j'avois remarque un grand dieze bien nettement ecrit sur la face de la montagne, je le vis de pres en 1781, et je reconnus qu'il etoit forme par quatre de ces fentes qui se coupoient obliquement.

"Sec. 647. La cime de la montagne est une pointe mousse, coupee a pic du cote de la vallee de Chamouni et arrondie de tous les autres cotes. Cette tete est entierement couverte de debris et de blocs confusement entasse. On est etonne de trouver la ces debris, car cette cime est absolument isolee, et separee par de larges et profondes vallees des sommites qui la surpassent en hauteur: il semble que ces debris n'aient pu tomber que du ciel; mais quand on les examine avec soin, on voit qu'ils sont du meme genre de pierre que la montagne elle meme; et que tous leurs angles font vifs, leurs faces planes et leur forme souvent rhomboidale. On reconnoit donc par la que les parties superieures de la montagne, qui sont plus exposees aux injures de l'air et qui ne sont pas assujetties par des masses situees au-dessus d'elles, se delitent et se separent. Je trouvai cependant sur la cime une pierre d'une espece differente; c'etoit une roche composee de schorl noir en aiguilles, de quartz et de grenats; sa forme etoit exactement rhomboidale. Mais ce genre de pierre se rencontre assez souvent en filons dans les roches feuilletees et dans les granits veines; il est donc vraisemblable que le filon auquel ce fragment avoit appartenu s'est detruit avec la partie superieure du rocher, du moins n'en ai-je pu trouver aucun indice dans la partie solide de la montagne.

"L'admirable regularite des couches de cette cime elevee merite l'attention des amateurs de la geologie, et la vue qu'elle presente dedommageroit seule de la peine d'y monter.

"Sec. 648. Mon but principal dans la premiere course que je fis au Breven etoit de prendre de la une idee juste des glaciers de la vallee de Chamouni, de leur forme, de leur position, et de l'ensemble des montagnes sur lesquelles ils sont situes. Comme cette montagne est postee a-peu-pres au milieu de la vallee de Chamouni, en face du Mont-Blanc et vis-a-vis des principaux glaciers qui en descendent, c'etoit certainement un des meilleurs observatoires que l'on put choisir dans cette intention. J'y montai par le jour le plus beau et le plus clair; c'etoit mon premier voyage dans les hautes Alpes, je n'etois point encore accoutume a ces grands spectacles; en sorte que cette vue fit sur moi une impression qui ne s'effacera jamais de mon souvenir.

"On decouvre tout-a-la-fois et presque dans un seul tableau les six glaciers qui vont se verser dans la vallee de Chamouni, les cimes inaccessibles entre lesquelles ils prennent leur naissance; le Mont-Blanc surtout, que l'on trouve d'autant plus grand, d'autant plus majestueux, qu'on l'observe d'un lieu plus eleve. On voit ces etendues immenses de neige et de glaces, dont, malgre leur distance, on a peine a soutenir l'eclat, ces beaux glaciers qui s'en detachent comme autant de fleuves solides qui vont entre de grandes forets de sapins, descendre en replis tortueux, et se verser au fond de la vallee de Chamouni; les yeux fatigues de l'eclat de ces neiges et de ces glaces se reposent delicieusement ou sur ces forets, dont le verd fonce contraste avec la blancheur des glaces qui les traversent, ou dans la fertile et riante vallee qu'arrosent les eaux qui decoulent de ces glaciers."

Our object at present is not to see the degradation of that great mass of granite out of which have been hewn, by the hand of time and influences of the atmosphere, these lofty pyramids which surround Mont-Blanc; it is to see the degradation of that immense mass of vertical or highly inclined strata, out of which that great mass of granite rises; and it is to understand the conical and rounded forms which are to be perceived more or less in all the inferior mountains, where apparently the degradation has come to a stand, and where the surface is actually employed in vegetation, or in maintaining the system of living bodies in this world.

How high those vertical strata may have been erected, or how much may have been wasted of that mass in forming the mountains and their valleys, is a question which it is impossible to resolve: It is evident, however, that this quantity must have been very great. In the Mont-Rosa we find those strata at present in the horizontal situation, as high as the summits of those granite pyramids that overlook the mass of vertical strata which we are now considering; and, in those mountains of Rosa, the valleys are most profound. It is therefore most reasonable to suppose, that the mass out of which the Breven and all the other mountains had been formed, was once as high, at least, as the summit of Mont-Blanc. It is altogether inconceivable, that this mass of vertical and horizontal strata could have been formed, either originally, or by any mineral operation, into the present shape of things; therefore, we must look out for another cause.

Let us now suppose them degraded by the hand of time, and all their moveable materials transported in the floods; In what state would they be left for our examination?—Here is a question that must decide the theory of those mountains; for, if it is not possible to conceive the present appearances as arising from any other cause than this gradual degradation which we see operating at present, we must conclude that this is the system of nature established for the purpose of this world. But this is the very state in which they are found; every where the solid parts are going into decay, and furnishing those heaps of earth and stones that form the slopes by which we ascend from step to step. Wherever earth and stones may lie, there they are found to form a bank for vegetation; whenever these loose materials are carried away to a lower; station, the more solid parts above are still decaying in order to furnish more. There is not one step in all this progress, (of the summit of the solid mountain forming earth and stones, and travelling to the sea) that is not to be actually perceived, although it is only scientifically that man, who reasons in the present moment, may see the effect of time which has no end.

The summit of the granite pyramids of Mont-Blanc, the summit of the Breven, that of the Saleve[19], and of every little hillock upon the surface of the earth, attest this truth, that there is no other natural means by which this end may be attained. It is true, indeed, that geologists every where imagine to themselves great events, or powerful causes, by which these changes of the earth should be brought about in a short space of time; but they are under a double deception; first with regard to time which is limited, whereas they want to explain appearances by a cause acting in a limited time; secondly, with regard to operation, their supposition of a great debacle is altogether incompetent for the end required. How, for example, accumulate the debris of the Breven, as we have now seen, upon the summit of that mountain, by the force of running water? But this is only one of a thousand appearances that proves the operations of time, and refutes the hypothesis of violent causes.

[Footnote 19: See Part II. chap. 30.]

From the top of those decaying pyramids to the sea, we have a chain of facts which clearly demonstrate this proposition, That the materials of the wasted mountains have travelled through the rivers; for, in every step of this progress, we may see the effect, and thus acknowledge the proper cause. We may often even be witness to the action; but it is only a small part of the whole progress that we may thus perceive, nevertheless it is equally satisfactory as if we saw the whole; for, throughout the whole of this long course, we may see some part of the mountain moving some part of the way. What more can we require? Nothing but time. It is not any part of the process that will be disputed; but, after allowing all the parts, the whole will be denied; and, For what?—only because we are not disposed to allow that quantity of time which the ablution of so much wasted mountain might require.



CHAP. X.

The Theory illustrated with a view of the Valleys of the Alps.

Such is the summit of the Alps, a body wasting by the influence of the elements, slowly changing, but in actual decay. This mass of granite is arrived at such a perfect state of degradation as leaves no trace of its original shape or height, from whence we might compute the quantity which has been lost, or time which had flowed in bringing about that event. We are now to take a view of the valleys that are formed at the same time that the mountains are degraded.

To the valleys of ice succeed those formed by water upon the same principle by moving the hard materials procured from the summits. Let us now begin at the bottom of one of those fertile valleys, and ascend, tracing the marks of time and labour in those operations by which the surface of the earth is modified according to the system of the globe.

(M. Bourrit[20], Nouvelle Description des Alpes.) "Saint-Maurice est entre le Rhone et une montagne; "Quoique la situation de Saint-Maurice paroisse l'exposer au malheur d'etre un jour ensevelie sous les ruines des montagnes, cependant on ne vit pas ici avec moins de securite qu'ailleurs: ce qu'il y a de plus a craindre, c'est la submersion du pays; ce malheur pourrait arriver si l'une ou l'autre des montagnes qui forment la gorge, venoit a tomber soit par un tremblement de terre, soit par des affaissemens considerables: cette gorge etant etroite, le Rhone ne pourroit plus s'ecouler il s'etendroit necessairement au large, bientot toute la vallee jusqu'a Martigni, Sion meme, rentreroit sous les eaux qui l'ont autrefois couvert, et tout ce pays ne formeroit plus qu'un lac, a moins que le Rhone ne se fit jour sous les rochers renverses, comme il passe au travers de ceux qui semblent lui disputer le passage a cinq-lieues au-dessous de Geneve."

[Footnote 20: M. Bourrit, etc.]

"Avant de penetrer dans le Vallais, il convient d'en donner une idee generale: il forme cette partie des Alpes connue sous le nom d'Alpes Pennines; il contient non-seulement les plus hautes montagnes des Alpes, mais encore la plus longue vallee qui il y ait en Europe, puis qu'elle a trente-quatre lieues depuis Saint-Maurice jusqu'a-la source du Rhone, qui la traverse dans toute cette etendue: sa largeur est depuis demi-lieu jusqu'a une lieue et demie; sa direction suit le soleil. Outre cette vallee, il y en a d'autres qui y viennent aboutir dans diverses directions: celle-ci sont enclavees dans les deux chaines de montagnes qui bordent la grande vallee; quelques-unes remontent a quatre lieues et meme a six, dans les sinuosites que forment les rochers qui bordent les deux cotes du fleuve."

To give an idea of these valleys which proceed to the icy tops of mountains, or to the high valleys of ice, I shall transcribe some descriptions of this country from the Tableaux de la Suisse Discours, etc. page 21.

"Route au Mont-Saint Bernard.

"On passe par Martigny pour aller au Mont du grand Saint-Bernard; cette ville est un depot pour les marchandises qui vont et viennent d'Italie. Le chateau a cote de cette ville est situe sur des rochers calcaires qui bordent la Drance dans cette partie; ce torrent prend sa source au Mont Saint-Bernard. On compte huit lieues de Martigny a l'Hospice situe sur ce mont; a une demie-lieue on commence a monter insensiblement; le chemin est beau et peut se faire en voiture jusqu'au bourg Saint-Pierre.

"Le vaste base de ces monts accumules n'est qu'un compose des debris des montagnes superieures; on rencontre ici des granits roules, composes de quartz, de feld-spath, et de mica; des graviers et des sables provenant de la decomposition des granits des pierre calcaire grise, puis de grosse masses de granit arrondies, dont il seroit difficile d'assigner l'origine, puisque toutes les montagnes a portee de la vue et qui forme cette gorge sont absolument de pierres micacees par lits et par couches, ou schisteuses melees de gros et petits rognons, de filons et de veines de quartz; elles font en general toutes feu avec le briquet. Le chemin et la Drance qu'on passe et repasse plusieurs fois, occupent tout le fond de la vallee qui devient fort etroite. On rencontre des pierres schisteuses, quartzeuses et sablonneuses, seules sans melange d'autre especes.

"Saint-Branchier, bon village, est situe entre des montagnes tres-hautes et tres-escarpees composees des memes especes des pierres schisteuses micacees que les precedentes; elles sont de couleur bleuatre, vue en grandes masses et inclinees a l'horison; cette inclinaison suivant la meme direction de ce cote ci de la Drance, et les couches se correspondant l'une a l'autre, on voit que ce torrent s'y est creuse un passage. En avancant, on trouve de l'ardoise feuilletee bleue avec des veines de spath calcaire, ensuite une grande quantite de granits et de pierres calcaires roulees, sans que les montagnes environnantes changent d'especes; les montagnes a l'est sont bien cultivees, rapportent differentes sortes de grains, avant et apres avoir passe orsiere; on retrouve de l'ardoise entre ce village et Liddes et les derniers granits roules.

"La Drance est ici fort resserree et tres encaissee; ce n'est pas sans fremir qu'on s'appercoit, quand on est sur deux morceaux de bois jetes d'une roche a l'autre, appelles ici pont, qu'on a un gouffre de plus de trois cent pieds au dessous de soi, il faut etre sur cette espece de pont pour s'en apercevoir et distinguer les differents sinuosites tracees sur chaque cote de cette roche du haut jusqu'en bas; ce sont autant de preuves des differentes hauteurs ou l'eau a passe avant de parvenir a sa profondeur actuelle.

"La dernier village qu'on rencontre, avant d'arriver au Saint-Bernard, est le bourg Saint-Pierre, on mont insensiblement jusqu'a ce village, et on ne peut plus se servir de voitures pour aller au-dela. Les montagnes sont plus rapides, il n'y a plus de chemin fait, et on n'en peut point pratiquer, moins a cause de la quantite des rochers dont toute cette partie est couverte que par la difficulte de les entretenir ou de les renouveler chaque annee, parce que les torrens et les avalanches les detruiroient; de plus on ne pourroit y travailler que trois ou quatre mois de l'annee, les huit ou neuf autres mois le pays, au dela du bourg, etant presque toujours couvert de neige. La truite ne remonte pas au-dela du bourge Saint-Pierre, elle se trouve arretee par les cascades et chutes trop considerables de la Vassoree qui va se jetter dans la Drance. Ce torrent sort encaisse et resserre dans le lit qu'il s'est creuse, provient d'un glacier qu'on rencontre en montant le Saint-Bernard qui porte le meme nom. L'entree du valais est fermee et defendue de ce cote par le lit de la Vassoree; c'est le fosse le plus profond et le plus escarpe qui existe. Des ouvrage creneles et une porte sont places a l'entree du bourg Saint-Pierre, nous avons donne un dessin de la chute de ce torrent, on voit le travail des eaux dans le rocher qu'il a mine et ou il s'est ouvert un passage.

"On compte trois lieues de ce bourg a l'Hospice, sur le haut du Saint-Bernard; c'est le passage le plus frequente pour communiquer du Bas-Vallais en Italie par le Piemont et la vallee d'Aost; le transport des marchandises ne se fait qu'a dos de mulets et de chevaux; c'est du produit de ces transports que vivent la plupart des habitans qui sont des deux cotes de ce mont; celui des fromages, qui est la principale production de ces hautes Alpes, fait le plus fort article. On ne rencontre sur cette route que des rochers entasses les uns sur les autres, entre lesquels on passe par mille detours, en suivant les petits vallons qu'ils forment. Des torrents des eaux y roulent et s'y precipitent de tous cotes; on voit dans ces bas, de bois de sapins meles de quelques pins et puis des melezes; ils diminuent insensiblement, leurs vegetation est moins vigoureuse, les arbres sont plus rares les derniers qu'on rencontre sont des melezes a une heure de Saint-Pierre. Plus loin, on ne voit plus que des buissons bas et rabougris; au bord de quelque ruisseau ou torrent ce sont des aulnes ou vergnes; le dernier arbrisseau que nous avons vu, entre les melezes et les aulnes, est un sureau sans fruit. Les paturages, l'herbe et le gazon suivent la meme progression. Ce n'est-que dans quelques endroits, d'ou les eaux n'on pas entraine une restant de terre vegetale, qu'il se voit un gazon fin, menu et serre; de petites fleurs, aussi bases que ces gazons, nuancees des plus belles et des plus vives couleurs, y forment des groupes de la plus grande beaute; des mousses non moins curieuses que variees, couvrent et colorent quelques parties de rochers; le reste n'offre a l'oeil que d'enormes masses de rochers, entrecoupes de fentes, de crevasses; des pierres culbutees et amoncelees dans les fonds, qui font en partie couverts de neige.

"A une demie lieue de l'Hospice dans une vallon assez large pour une pareille hauteur, nomme les Envers des Foireuse, on rencontre une enorme quantite de pierre roulees qui remplissent presque tout le haut de ce vallons. Cet amas de pierres provient des glaciers et des hauteurs qui descendent du Mont-Velan, qui est la partie la plus elevee du groupe de montagnes, qui forment le grand Saint Bernard. La sont des neiges et des glaciers de cette partie, fournit aussi la Drance qui va se jetter dans le Rhone au dessous de Martigny. On ne voit de ces pierres roulees qu'en cet endroit, elles viennent directement des glaciers, elles ont ete charriees par les eaux qui en viennent, et ne peuvent avoir pris leur forme que par les meme causes, dont nous avons parle ci-devant dans l'observation faite en Savoie sur les pierres roulees; elles sont toutes, ainsi que les rochers au-dessus, d'ou-elles proviennent, composees de parties micacees-argilleuses, plus ou moins melees de partie de rognons, de veines et de filons de quartz, par lits et par couches irregulieres, plus ou moins epaisses. Les parties micacees de ces pierres sont variees de differentes nuances, tirant sur le gris, le bleu, le verd, et le jaune; ces nuances sont quelquefois melees. Tous les rochers composans ce cote de montagne tourne au nord, sont de la meme espece. Nous n'y avons pas vu un seul granit, c'est-a-dire, une pierre composee de petites masses irregulieres de quartz, melees et agglutinees, avec des parties micacees argilleuses, et quelquefois melanges de feldspath. Parmi ces pierres, il y en a quelques-unes provenant du meme filon, qui contiennent de la pyrite cuivreuse dans un filon de quartz.

"Nous avons dit precedement que c'etoit entre Orfiere et Liddes que nous avions vu des derniers granites roules, on n'en rencontre plus dans toute le reste de la route jusqu'au haut du Mont Saint-Bernard. Les rochers, qui dominent ce sommet, ne sont pas composes de granites, et quoiqu'on ne puisse aborder jusqu'a leurs plus grands elevation, on peut juger de leurs especes, par les masses qui s'en precipitent.

"(Page 35.) Malgre la chaleur qu'il avoit fait le jour de l'arrivee au Saint-Bernard, la nuit fut froide; le lendemain (31 Juillet) le haut de la montagne etoit enveloppe de nuages epais, mais tranquilles, il n'y avoit point d'agitation dans l'air on assuroit qu'il faisoit beau au-dessous de ce sommet; nous fumes visiter le revers meridional de la montagne qui conduit au val d'Aost; apres une demie heure de marche, nous fumes hors de cet atmosphere sombre et humide, le soleil etoit chaud, le ciel pur et serein: on voyoit dans le lointain les sommets des plus hautes montagnes enveloppes dans les nuages comme le Saint-Bernard: les sommets les plus a portee etoient decouverts et eclaires par le soleil; ces rochers termines en pointe, en pyramides et en aiguilles, sembloient s'elancer dans la region pure de l'ether: des vallons profonds, des ecueils, et des precipices effrayants les entouraient. Toutes ces masses sont, comme dans la partie opposee de la montagne, des pierre schisteuses, argilleuses et micacees: le plupart schisteuses, c'est-a-dire par feuillets, par lits ou par couches differemment inclinees, le toute mele de veines et de parties quartzeuses, de couleurs variees, mais les verdatres dominent: il y a de plus sur la hauteur de ce revers des masses et des blocs prodigieux, sans melange, de quartz blanc et grenu a sa superficie, lesquels, au premier coup-d'oeil, paroissoient etre de marbre de Carare; a quelque distance c'est un chaos immense de blocs de pierres de toutes grandeurs, jetes, culbutes, entasses dans la plus grand confusion; c'est la meme espece de pierre micacee; il faut que des sommets, des rochers prodigieux se soient ecroules pour avoir produit un pareil desordre qui ressemble a la destruction d'un mond.

"(Page 40.) On trouve aux environs du couvent quelques schistes argilleux ou ardoises grises feuilletees detruites a moitie. On ne voir nulle part de ces ardoises sur pied ou formant des masses attachees au sol; il faut que les couches ou les lits de ces ardoises, qui avoient ete formes et places sur ces hauts, ayent ete detruits et renverses par le temps.

"Enfin toute cette montagne, une des plus hautes des Alpes Poenines, qui conserve des neiges et de glaces permanentes, est composee en general de pierres et de roches schisteuses, dont les couches et les lits sont plus on moins sensibles et inclines, et d'une grande durete. Leurs parties constituantes sont un mica argilleux dont les lames ou les parties sont plus ou moins grandes et brillantes et diversement colorees: elles sont traversees de filons et de veines meles de rognons et de globule de quartz ordinairement blanc, quelquefois vitreux, transparent, opaque ou grenu: nous n'y avons vu des granits que sur le penchant de la montagne; ils y etoient isoles et roules. Quelqu'un qui aura plus de temps, plus de loisir, decouvrira peut-etre d'ou ces masses proviennent[21]."

[Footnote 21: M. de Saussure, in his 2d volume of Voyages dans les Alpes, has shown the origin of these travelled granites, and traced the way by which they have come.]

We have here a picture of one of those valleys which branch from, or join the main valley of the Rhone. In this subordinate valley, there is the most evident marks of the operations of water hollowing out its way, in flowing from the summits of the mountains, and carrying the fragments of rocks and stones along the shelving surface of the earth; thus wearing down that surface, and excavating the solid rock. On the summit of the mountain, again, there is an equal proof of the operation of water and the influences of the atmosphere continued during a long succession of ages. It is impossible perhaps to conjecture as to the quantity of rock which has been wasted and carried away by water from this alpine region; the summits testify that a great deal had been above them, as that which remains has every mark of being the relicts of what had been removed, and moved only by those operations which here are natural to the surface of the earth. Let us now abstract any consideration of that quantity above the summits of those mountains, as a quantity which cannot be estimated; and let us only consider all the cavity below the summits of those ridges of mountains to have been hollowed out by those operations of running water which we now have in view.

In taking this view of the mountains on each side which supply the water of the Rhone, what an immense quantity of stones, of sand, and fragments of rock, must have travelled in the bed of that river, or bottom of that valley which receives the torrents coming from the mountains! The excavation of this great valley, therefore, will not be found any way disproportionate to that which is more evident in the branches; and, though the experience of man goes for nothing in this progress of things, yet, having principles in matter of fact from whence he may reason back into the boundless mass of time already elapsed, it is impossible that he can be deceived in concluding that here is the general operation of nature wasting and wearing the surface of the earth for the purposes of this world, and giving the present shape of things, which we so much admire in the contrast of mountains and plains, of hills and valleys, although we may not calculate with accuracy, or ascribe to each particular operation every individual appearance.

With a view to corroborate what has been here alledged of the valley of the Rhone, I would beg leave to transcribe still more from the same author. From the immense masses of horizontal strata remaining upon both sides of the valley of the Rhone, with a face broken off abruptly, we shall find the most perfect evidence of that which had been carried away in the course of time, and in the forming of those valleys.

"(Page 49.) Route au Bains de Loiche. Nous quitterons un moment les bords du Rhone pour visiter les bains de Loiche, afin de ne pas revenir sur nos pas. De Sierre on passe par Clare et Salge, en laissant le Rhone sur la droite; tout ce terrain est calcaire et fort pierreux. A Faren (villages qui ne font point sur les cartes) on commence a monter la montagne de Faren; le chemin est fort rapide et mauvais, et dure une bonne heure et demie; on trouve sur le haut de cette montagne de blocs de granit composes de quartz, de feld-spath, et de mica, d'ou viennent-ils? On ne voit que des roches calcaires et point de montagne plus elevee au-dessus; on passe par un bois de pins, on parvient enfin a un escarpement a pic, dont on n'a point d'idee pour la hauteur; on reste stupefait de voir le gouffre qu'on a devant soi, et on ne prevoit pas trop comment on parviendra dans ce fond, ou la vue a peine a distinguer la Dala, gros torrent qui y precipite ses eaux. On a taille a grands frais un sentier tortueux dans cette roche toute calcaire; On a eu soin de garnir le cote scabreux du sentier avec des pierres ou des garde fou, pour rendre ce passage moins effrayant; ces precautions ne peuvent guerir de la crainte de voir tomber d'enormes quartiers de rochers suspendus au-dessus de soi, ils sont fendus et crevasses partout, et menacent de se precipiter a chaque instant; on ne peut meme s'empecher de remarquer qu'il y en a qui sont tombes nouvellement! Ce sont des mineurs Tiroliens qui ont fait cet ouvrage, ainsi que le passage du Mont-Gemmi.

"Quand on est descendu au tiers environ de cet enorme fond, on passe sur les decombres de cette vaste montagne, et par un bois de pins et de sapins; la vue ne perce pas dans ce fond tenebreux, on entend plutot le bruit du torrent qu'on ne l'appercoit. Ayant eu occasion de voir et d'examiner par la suite ces bas et le pied de cette etonnante montagne calcaire, nous avons vu dans plus d'un endroit qu'elle pose, et que ces fondements sont un lit de schistes argilleux ou d'ardoises feuilletees sans melange, que ce lit est detruit et se detruit dans differens endroits, qu'il est incline et affaisse dans d'autres, et que c'est la destruction qui a occasionne la chute d'une partie de cette montagne; elle est par-tout a pic de ce cote, et a subi successivement ces renversements qui paroissent plus anciens les unes que les autres, car ces debris sont plus ou moins couverts de bois, d'arbres, et de productions vegetales.

"On continue la route a mi cote au travers de ces debris. Le sommet de ces montagnes eclaires par le soleil, etoit peint de rouge, de jaune, de blanc, de bleu, et de noir, dans les endroits ou les eaux avoient coule par-dessus, ils ressemblent de loin a des murailles, des tours, des forts, et des fortifications de differentes formes placees pour se defendre contre des ennemis qui viendroient par les airs. Les neiges qu'on appercoit dans differents endroits, produisent des chutes d'eau, des cascades, dont partie se reduit en vapeurs avant d'atteindre le bas: le haut des montagnes qu'on voit de l'autre cote de ce vallon, est egalement calcaire, elles sont plus basses, couverts d'arbres et de sapins; au lieu que celles dont il est question sont nues et arides; elles sont le sejour des neiges et sont partie de la Gemmi.