-- 1. In the early days of geological science, the substances which composed the crust of the earth, as far as it could be examined, were supposed to be referable to three distinct cla.s.ses: the first consisting of rocks which not only supported all the rest, but from which all the rest were derived, therefore called "Primary;" the second cla.s.s consisting of rocks formed of the broken fragments or altered substance of the primary ones, therefore called "Secondary;" and, thirdly, rocks or earthy deposits formed by the ruins and detritus of both primary and secondary rocks, called, therefore, "Tertiary." This cla.s.sification was always, in some degree, uncertain; and has been lately superseded by more complicated systems, founded on the character of the fossils contained in the various deposits, and on the circ.u.mstances of position, by which their relative ages are more accurately ascertainable. But the original rude cla.s.sification, though of little, if any, use for scientific purposes, was based on certain broad and conspicuous phenomena, which it brought clearly before the popular mind. In this way it may still be serviceable, and ought, I think, to be permitted to retain its place, as an introduction to systems more defined and authoritative.

-- 2. For the fact is, that in approaching any large mountain range, the ground over which the spectator pa.s.ses, if he examine it with any intelligence, will almost always arrange itself in his mind under three great heads. There will be, first, the ground of the plains or valleys he is about to quit, composed of sand, clay, gravel, rolled stones, and variously mingled soils; which, if he has any opportunity,--at the banks of a stream, or the sides of a railway cutting,--to examine to any depth, he will find arranged in beds exactly resembling those of modern sand-banks or sea-beaches, and appearing to have been formed under such natural laws as are in operation daily around us. At the outskirts of the hill district, he may, perhaps, find considerable eminences, formed of these beds of loose gravel and sand; but, as he enters into it farther, he will soon discover the hills to be composed of some harder substance, properly deserving the name of rock, sustaining itself in picturesque forms, and appearing, at first, to owe both its hardness and its outlines to the action of laws such as do not hold at the present day. He can easily explain the nature, and account for the distribution, of the banks which overhang the lowland road, or of the dark earthy deposits which enrich the lowland pasture; but he cannot so distinctly imagine how the limestone hills of Derbyshire and Yorkshire were hardened into their stubborn whiteness, or raised into their cavernous cliffs. Still, if he carefully examines the substance of these more n.o.ble rocks, he will, in nine cases out of ten, discover them to be composed of fine calcareous dust, or closely united particles of sand; and will be ready to accept as possible, or even probable, the suggestion of their having been formed, by slow deposit, at the bottom of deep lakes and ancient seas, under such laws of Nature as are still in operation.

-- 3. But, as he advances yet farther into the hill district, he finds the rocks around him a.s.suming a gloomier and more majestic condition.

Their tint darkens; their outlines become wild and irregular; and whereas before they had only appeared at the roadside in narrow ledges among the turf, or glanced out from among the thickets above the brooks in white walls and fantastic towers, they now rear themselves up in solemn and shattered ma.s.ses far and near; softened, indeed, with strange harmony of clouded colors, but possessing the whole scene with their iron spirit; and rising, in all probability, into eminences as much prouder in actual elevation than those of the intermediate rocks, as more powerful in their influence over every minor feature of the landscape.

-- 4. And when the traveller proceeds to observe closely the materials of which these n.o.ble ranges are composed, he finds also a complete change in their internal structure. They are no longer formed of delicate sand or dust--each particle of that dust the same as every other, and the whole ma.s.s depending for its hardness merely on their closely cemented unity; but they are now formed of several distinct substances, visibly unlike each other; and not _pressed_ but _crystallized_ into one ma.s.s,--crystallized into a unity far more perfect than that of the dusty limestone, but yet without the least mingling of their several natures with each other. Such a rock, freshly broken, has a spotty, granulated, and, in almost all instances, sparkling, appearance; it requires a much harder blow to break it than the limestone or sandstone; but, when once thoroughly shattered, it is easy to separate from each other the various substances of which it is composed, and to examine them in their individual grains or crystals; of which each variety will be found to have a different degree of hardness, a different shade of color, and a different character of form.

But this examination will not enable the observer to comprehend the method either of their formation or aggregation, at least by any process such as he now sees taking place around him; he will at once be driven to admit that some strange and powerful operation has taken place upon these rocks, different from any of which he is at present cognizant; and farther inquiry will probably induce him to admit, as more than probable, the supposition that their structure is in great part owing to the action of enormous heat prolonged for indefinite periods.

-- 5. Now, although these three great groups of rocks do indeed often pa.s.s into each other by imperceptible gradations, and although their peculiar aspect is never a severe indication of their relative ages, yet their characters are for the most part so defined as to make a strong impression on the mind of an ordinary observer, and their age is also for the most part approximately indicated by their degrees of hardness, and crystalline aspect. It does, indeed, sometimes happen that a soft and slimy clay will pa.s.s into a rock like Aberdeen granite by transitions so subtle that no point of separation can be determined; and it very often happens that rocks like Aberdeen granite are of more recent formation than certain beds of sandstone and limestone. But, in spite of all these uncertainties and exceptions, I believe that unless actual pains be taken to efface from the mind its natural impressions, the idea of three great cla.s.ses of rocks and earth will maintain its ground in the thoughts of the general observer; that whether he desire it or not, he will find himself throwing the soft and loose clays and sands together under one head; placing the hard rocks, of a dull, compact, h.o.m.ogeneous substance, under another head; and the hardest rocks, of a crystalline, glittering, and various substance, under a third head; and having done this, he will also find that, with certain easily admissible exceptions, these three cla.s.ses of rocks are, in every district which he examines, of three different ages; that the softest are the youngest, the hard and h.o.m.ogeneous ones are older, and the crystalline are the oldest; and he will, perhaps, in the end, find it a somewhat inconvenient piece of respect to the complexity and accuracy of modern geological science, if he refuse to the three cla.s.ses, thus defined in his imagination, their ancient t.i.tle of Tertiary, Secondary, and Primary.

-- 6. But however this may be, there is one lesson evidently intended to be taught by the different characters of these rocks, which we must not allow to escape us. We have to observe, first, the state of perfect powerlessness, and loss of all beauty, exhibited in those beds of earth in which the separated pieces or particles are entirely independent of each other, more especially in the gravel whose pebbles have all been _rolled into one shape_: secondly, the greater degree of permanence, power, and beauty possessed by the rocks whose component atoms have some affection and attraction for each other, though all of one kind; and lastly, the utmost form and highest beauty of the rocks in which the several atoms have all _different shapes_, _characters_, and _offices_; but are inseparably united by some fiery process which has purified them all.

It can hardly be necessary to point out how these natural ordinances seem intended to teach us the great truths which are the basis of all political science; how the polishing friction which separates, the affection which binds, and the affliction that fuses and confirms, are accurately symbolized by the processes to which the several ranks of hills appear to owe their present aspect; and how, even if the knowledge of those processes be denied to us, that present aspect may in itself seem no imperfect image of the various states of mankind: first, that which is powerless through total disorganization; secondly, that which, though united, and in some degree powerful, is yet incapable of great effort or result, owing to the too great similarity and confusion of offices, both in ranks and individuals; and finally, the perfect state of brotherhood and strength in which each character is clearly distinguished, separately perfected, and employed in its proper place and office.

-- 7. I shall not, however, so oppose myself to the views of our leading geologists as to retain here the names of Primary, Secondary, and Tertiary rocks. But as I wish the reader to keep the ideas of the three cla.s.ses clearly in his mind, I will ask his leave to give them names which involve no theory, and can be liable, therefore, to no great objections. We will call the hard, and (generally) central, ma.s.ses Crystalline Rocks, because they almost always present an appearance of crystallization. The less hard substances, which appear compact and h.o.m.ogeneous, we will call Coherent Rocks, and for the scattered debris we will use the general term Diluvium.

-- 8. All these substances agree in one character, that of being more or less soft and destructible. One material, indeed, which enters largely into the composition of most of them, flint, is harder than iron; but even this, their chief source of strength, is easily broken by a sudden blow; and it is so combined in the large rocks with softer substances, that time and the violence of the weather invariably produce certain destructive effects on their ma.s.ses. Some of them become soft, and moulder away; others break, little by little, into angular fragments or slaty sheets; but all yield in some way or other; and the problem to be solved in every mountain range appears to be, that under these conditions of decay, the cliffs and peaks may be raised as high, and thrown into as n.o.ble forms, as is possible, consistently with an effective, though not perfect permanence, and a general, though not absolute security.

-- 9. Perfect permanence and absolute security were evidently in nowise intended.[42] It would have been as easy for the Creator to have made mountains of steel as of granite, of adamant as of lime; but this was clearly no part of the Divine counsels: mountains were to be destructible and frail; to melt under the soft lambency of the streamlet; to shiver before the subtle wedge of the frost; to wither with untraceable decay in their own substance; and yet, under all these conditions of destruction, to be maintained in magnificent eminence before the eyes of men.

Nor is it in any wise difficult for us to perceive the beneficent reasons for this appointed frailness of the mountains. They appear to be threefold: the first, and the most important, that successive soils might be supplied to the plains, in the manner explained in the last chapter, and that men might be furnished with a material for their works of architecture and sculpture, at once soft enough to be subdued, and hard enough to be preserved; the second, that some sense of danger might always be connected with the most precipitous forms, and thus increase their sublimity; and the third, that a subject of perpetual interest might be opened to the human mind in observing the changes of form brought about by time on these monuments of creation.

In order, therefore, to understand the method in which these various substances break, so as to produce the forms which are of chief importance in landscape, as well as the exquisite adaptation of all their qualities to the service of men, it will be well that I should take some note of them in their order; not with any mineralogical accuracy, but with care enough to enable me hereafter to explain, without obscurity, any phenomena dependent upon such peculiarities of substance.

1. CRYSTALLINE ROCKS.

-- 10. 1st. CRYSTALLINE ROCKS.--In saying, above, that the hardest rocks generally presented an appearance of "crystallization," I meant a glittering or granulated look, somewhat like that of a coa.r.s.e piece of freshly broken loaf sugar.

Are always Compound.

But this appearance may also exist in rocks of uniform and softer substance, such as statuary marble, of which freshly broken pieces, put into a sugar-basin, cannot be distinguished by the eye from the real sugar. Such rocks are truly crystalline in structure; but the group to which I wish to limit the term "crystalline," is not only thus granulated and glittering, but is always composed of at least two, usually three or four, substances, intimately mingled with each other in the form of small grains or crystals, and giving the rock a more or less speckled or mottled look, according to the size of the crystals and their variety of color. It is a law of nature, that whenever rocks are to be employed on hard service, and for great purposes, they shall be thus composed. And there appear to be two distinct providential reasons for this.

-- 11. The first, that these crystalline rocks being, as we saw above, generally the oldest and highest, it is from them that other soils of various kinds must be derived; and they were therefore made a kind of storehouse, from which, wherever they were found, all kinds of treasures could be developed necessary for the service of man and other living creatures. Thus the granite of Mont Blanc is a crystalline rock composed of four substances; and in these four substances are contained the elements of nearly all kinds of sandstone and clay, together with potash, magnesia, and the metals of iron and manganese. Wherever the smallest portion of this rock occurs, a certain quant.i.ty of each of these substances may be derived from it, and the plants and animals which require them sustained in health.

The second reason appears to be that rocks composed in this manner are capable of more interesting variety in form than any others; and as they were continually to be exposed to sight in the high ranges, they were so prepared as to be always as interesting and beautiful as possible.

And divisible into two cla.s.ses, Compact Crystallines and Slaty Crystallines.

-- 12. These crystalline or spotted rocks we must again separate into two great cla.s.ses, according to the arrangement, in them, of the particles of a substance called mica. It is not present in all of them; but when it occurs, it is usually in large quant.i.ties, and a notable source of character. It varies in color, occurring white, brown, green, red, and black; and in aspect, from shining plates to small dark grains, even these grains being seen, under a magnifier, to be composed of little plates, like pieces of exceedingly thin gla.s.s; but with this great difference from gla.s.s, that, whether large or small, the plates will not easily break _across_, but are elastic, and capable of being bent into a considerable curve; only if pressed with a knife upon the edge, they will separate into any number of thinner plates, more and more elastic and flexible according to their thinness, and these again into others still finer; there seeming to be no limit to the possible subdivision but the coa.r.s.eness of the instrument employed.

[Ill.u.s.tration: FIG. 3.]

-- 13. Now, when these crystals or grains, represented by the black spots and lines in Fig. 3, lie as they do at _a_ in that figure, in all directions, cast hither and thither among the other materials of the stone,--sometimes on their faces, sometimes on their sides, sometimes on their edges,--they give the rock an irregularly granulated appearance and structure, so that it will break with equal ease in any direction; but if these crystals lie all one way, with their sides parallel, as at _b_, they give the rock a striped or slaty look, and it will most readily break in the direction in which they lie, separating itself into folia or plates, more or less distinctly according to the quant.i.ty of mica in its ma.s.s. In the example Fig. 4, a piece of rock from the top of Mont Breven, there are very few of them, and the material with which they are surrounded is so hard and compact that the whole ma.s.s breaks irregularly, like a solid flint, beneath the hammer; but the plates of mica nevertheless influence the fracture on a large scale, and occasion, as we shall see hereafter, the peculiar form of the precipice at the summit of the mountain.[43]

The rocks which are dest.i.tute of mica, or in which the mica lies irregularly, or in which it is altogether absent, I shall call Compact Crystallines. The rocks in which the mica lies regularly I shall call Slaty Crystallines.

[Ill.u.s.tration: FIG. 4.]

COMPACT CRYSTALLINES.

-- 14. 1st. Compact Crystallines.--Under this head are embraced the large group of the granites, syenites, and porphyries,--rocks which all agree in the following particulars:--

Their first characteristic. _Speckledness._

A. Variety of color.--The method of their composition out of different substances necessitates their being all more or less spotted or dashed with various colors; there being generally a prevalent ground color, with other subordinate hues broken over it, forming, for the most part, tones of silver grey, of warm but subdued red, or purple. Now, there is in this a very marvellous provision for the beauty of the central ranges. Other rocks, placed lower among the hills, receive color upon their surfaces from all kinds of minute vegetation; but these higher and more exposed rocks are liable to be in many parts barren; and the wild forms into which they are thrown necessitate their being often freshly broken, so as to bring their pure color, untempered in anywise, frankly into sight. Hence it is appointed that this color shall not be raw or monotonous, but composed--as all beautiful color must be composed--by mingling of many hues in one. Not that there is any aim at _attractive_ beauty in these rocks; they are intended to const.i.tute solemn and desolate scenes; and there is nothing delicately or variously disposed in their colors. Such beauty would have been inconsistent with their expression of power and terror, and it is reserved for the marbles and other rocks of inferior office. But their color is grave and perfect; closely resembling, in many cases, the sort of hue reached by cross-chequering in the ground of fourteenth-century ma.n.u.scripts, and peculiarly calculated for distant effects of light; being, for the most part, slightly warm in tone, so as to receive with full advantage the red and orange rays of sunlight. This warmth is almost always farther aided by a glowing orange color, derived from the decomposition of the iron which, though in small quant.i.ty, usually is an essential element in them: the orange hue forms itself in unequal veins and spots upon the surfaces which have been long exposed, more or less darkening them; and a very minute black lichen,--so minute as to look almost like spots of dark paint,--a little opposed and warmed by the golden Lichen geographicus, still farther subdues the paler hues of the highest granite rocks. Now, when a surface of this kind is removed to a distance of four or five miles, and seen under warm light through soft air, the orange becomes russet, more or less inclining to pure red, according to the power of the rays: but the black of the lichen becomes pure dark blue; and the result of their combination is that peculiar reddish purple which is so strikingly the characteristic of the rocks of the higher Alps. Most of the travellers who have seen the Valley of Chamouni carry away a strong impression that its upper precipices are of red rock. But they are, without exception, of a whitish grey, toned and raised by this united operation of the iron, the lichen, and the light.

-- 15. I have never had an opportunity of studying the effects of these tones upon rocks of porphyry; but the beautiful color of that rock in its interior substance has rendered it one of the favorite materials of the architects of all ages, in their most costly work. Not that all porphyry is purple; there are green and white porphyries, as there are yellow and white roses; but the first idea of a porphyry rock is that it shall be purple,--just as the first idea of a rose is that it shall be red. The purple inclines always towards russet[44] rather than blue, and is subdued by small spots of grey or white. This speckled character, common to all the crystalline rocks, fits them, in art, for large and majestic work; it unfits them for delicate sculpture; and their second universal characteristic is altogether in harmony with this consequence of their first.

Their second characteristic. _Toughness._

-- 16. This second characteristic is a tough hardness, not a brittle hardness, like that of gla.s.s or flint, which will splinter violently at a blow in the most unexpected directions; but a grave hardness, which will bear many blows before it yields, and when it is forced to yield at last, will do so, as it were, in a serious and thoughtful way; not spitefully, nor uselessly, nor irregularly, but in the direction in which it is wanted, and where the force of the blow is directed--there, and there only. A flint which receives a shock stronger than it can bear, gives up everything at once, and flies into a quant.i.ty of pieces, each piece full of flaws. But a piece of granite seems to say to itself, very solemnly: "If these people are resolved to split me into two pieces, that is no reason why I should split myself into three. I will keep together as well as I can, and as long as I can; and if I must fall to dust at last, it shall be slowly and honorably; not in a fit of fury." The importance of this character, in fitting the rock for human uses, cannot be exaggerated: it is essential to such uses that it should be hard, for otherwise it could not bear enormous weights without being crushed; and if, in addition to this hardness, it had been brittle, like gla.s.s, it could not have been employed except in the rudest way, as flints are in Kentish walls. But now it is possible to cut a block of granite out of its quarry to exactly the size we want; and that with perfect ease, without gunpowder, or any help but that of a few small iron wedges, a chisel, and a heavy hammer. A single workman can detach a ma.s.s fifteen or twenty feet long, by merely drilling a row of holes, a couple of inches deep, and three or four inches apart, along the surface, in the direction in which he wishes to split the rock, and then inserting wedges into each of these holes, and striking them, consecutively, with small, light, repeated blows along the whole row.

The granite rends, at last, along the line, quite evenly, requiring very little chiselling afterwards to give the block a smooth face.

-- 17. This after-chiselling, however, is necessarily tedious work, and therefore that condition of speckled color, which is beautiful if exhibited in broad ma.s.ses, but offensive in delicate forms, exactly falls in with the conditions of _possible_ sculpture. Not only is it more laborious to carve granite delicately, than a softer rock; but it is physically impossible to bring it into certain refinements of form.

It cannot be sc.r.a.ped and touched into contours, as marble can; it must be struck hard, or it will not yield at all; and to strike a delicate and detached form hard, is to break it. The detached fingers of a delicate hand, for instance, cannot, as far as I know, be cut in granite. The smallest portion could not be removed from them without a strength of blow which would break off the finger. Hence the sculptor of granite is forced to confine himself to, and to seek for, certain types of form capable of expression in his material; he is naturally driven to make his figures simple in surface, and colossal in size, that they may bear his blows; and this simplicity and magnitude are exactly the characters necessary to show the granitic or porphyritic color to the best advantage. And thus we are guided, almost forced, by the laws of nature, to do right in art. Had granite been white, and marble speckled (and why should this not have been, but by the definite Divine appointment for the good of man?), the huge figures of the Egyptian would have been as oppressive to the sight as cliffs of snow, and the Venus de Medicis would have looked like some exquisitely graceful species of frog.

Their third characteristic. _Purity in decomposition._

-- 18. The third universal characteristic of these rocks is their decomposition into the purest sand and clay. Some of them decompose spontaneously, though slowly, on exposure to weather; the greater number only after being mechanically pulverized; but the sand and clay to which by one or the other process they are reducible, are both remarkable for their purity. The clay is the finest and best that can be found for porcelain; the sand often of the purest white, always l.u.s.trous and bright in its particles. The result of this law is a peculiar aspect of purity in the landscape composed of such rocks. It cannot become muddy, or foul, or unwholesome. The streams which descend through it may indeed be opaque, and as white as cream with the churned substance of the granite; but their water, after this substance has been thrown down, is good and pure, and their sh.o.r.es are not slimy or treacherous, but of pebbles, or of firm and sparkling sand. The quiet streams, springs, and lakes are always of exquisite clearness, and the sea which washes a granite coast is as unsullied as a flawless emerald. It is remarkable to what extent this intense purity in the country seems to influence the character of its inhabitants. It is almost impossible to make a cottage built in a granite country look absolutely miserable. Rough it may be,--neglected, cold, full of aspect of hardship,--but it never can look _foul_; no matter how carelessly, how indolently, its inhabitants may live, the water at their doors will not stagnate, the soil beneath their feet will not allow itself to be trodden into slime, the timbers of their fences will not rot, they cannot so much as dirty their faces or hands if they try; do the worst they can, there will still be a feeling of firm ground under them, and pure air about them, and an inherent wholesomeness in their abodes which it will need the misery of years to conquer. And, as far as I remember, the inhabitants of granite countries have always a force and healthiness of character, more or less abated or modified, of course, according to the other circ.u.mstances of their life, but still definitely belonging to them, as distinguished from the inhabitants of the less pure districts of the hills.

These, then, are the princ.i.p.al characters of the compact crystallines, regarded in their minor or detached ma.s.ses. Of the peculiar forms which they a.s.sume we shall have to speak presently; meantime, retaining these general ideas touching their nature and substance, let us proceed to examine, in the same point of view, the neighboring group of slaty crystallines.

FOOTNOTES

[42] I am well aware that to the minds of many persons nothing bears a greater appearance of presumption than any attempt at reasoning respecting the purposes of the Divine Being; and that in many cases it would be thought more consistent with the modesty of humanity to limit its endeavor to the ascertaining of physical causes than to form conjectures respecting Divine intentions. But I believe this feeling to be false and dangerous. Wisdom can only be demonstrated in its ends, and goodness only perceived in its motives. He who in a morbid modesty supposes that he is incapable of apprehending any of the purposes of G.o.d, renders himself also incapable of witnessing his wisdom; and he who supposes that favors may be bestowed without intention, will soon learn to receive them without grat.i.tude.

[43] See Appendix 2. Slaty Cleavage.

[44] As we had to complain of Dante for not enough noticing the colors of rocks in wild nature, let us do him the justice to refer to his n.o.ble symbolic use of their colors when seen in the hewn block.

"The lowest stair was marble white, so smooth And polished that therein my mirrored form Distinct I saw. The next of hue more dark Than sablest grain, a rough and singed block, Cracked lengthwise and across. The third, that lay Ma.s.sy above, seemed porphyry, that flamed Red as the life-blood spouting from a vein."

This stair is at the gate of Purgatory. The white step means sincerity of conscience; the black, contrition; the purple (I believe), pardon by the Atonement.