MARY. How CAN this have been done?
L. There are a thousand ways in which it may have been done, the difficulty is not to account for the doing of it, but for the showing of it in some crystals and not in others You never by any chance get a quartz crystal broken or twisted in this way. If it break or twist at all which it does sometimes, like the spire of Dijon, it is by its own will or fault, it never seems to have been passively crushed But, for the forces which cause this passive ruin of the tourmaline,—here is a stone which will show you multitudes of them in operation at once It is known as "biecciated agate," beautiful, as you see, and highly valued as a pebble yet, so far as I can read or hear no one has ever looked at it with the least attention At the first glance, you see it is made of very fine red striped agates, which have been broken into small pieces, and fastened together again by paste also of agate There would be nothing wonderful in this, if this were all. It is well known that by the movements of strata, portions of rock are often shattered to pieces:—well known also that agate is a deposit of flint by water under certain conditions of heat and pressure: there is, therefore, nothing wonderful in an agate's being broken; and nothing wonderful in its being mended with the solution out of which it was itself originally congealed. And with this explanation, most people, looking at a brecciated agate, or brecciated anything, seem to be satisfied. I was so myself, for twenty years; but, lately happening to stay for some time at the Swiss Baden, where the beach of the Limmat is almost wholly composed of brecciated limestones, I began to examine them thoughtfully; and perceived, in the end, that they were, one and all, knots of as rich mystery as any poor little human brain was ever lost in. That piece of agate in your hand, Mary, will show you many of the common phenomena of breccias; but you need not knit your brows over it in that way; depend upon it, neither you nor I shall ever know anything about the way it was made, as long as we live.
DORA. That does not seem much to depend upon.
L. Pardon me, puss. When once we gain some real notion of the extent and unconquerableness of our ignorance, it is a very broad and restful thing to depend upon: you can throw yourself upon it at ease, as on a cloud, to feast with the gods. You do not thenceforward trouble yourself,—nor any one else,—with theories, or the contradiction of theories; you neither get headache nor heart-burning and you nevermore waste your poor little store of strength or allowance of time.
However, there are certain facts, about this agate-making, which I can tell you; and then you may look at it in a pleasant wonder as long as you like, pleasant wonder is no loss of time.
First, then, it is not broken freely by a blow; it is slowly wrung, or ground, to pieces. You can only with extreme dimness conceive the force exerted on mountains in transitional states of movement. You have all read a little geology; and you know how coolly geologists talk of mountains being raised or depressed. They talk coolly of it, because they are accustomed to the fact; but the very universality of the fact prevents us from ever conceiving distinctly the conditions of force involved. You know I was living last year in Savoy; my house was on the back of a sloping mountain, which rose gradually for two miles behind it; and then fell at once in a great precipice toward Geneva, going down three thousand feet in four or five cliffs, or steps. Now that whole group of cliffs had simply been torn away by sheer strength from the rocks below, as if the whole mass had been as soft as biscuit. Put four or five captains' biscuits on the floor, on the top of one another; and try to break them all in half, not by bending, but by holding one half down, and tearing the other halves straight up;—of course you will not be able to do it, but you will feel and comprehend the sort of force needed. Then, fancy each captains' biscuit a bed of rock, six or seven hundred feet thick; and the whole mass torn straight through; and one half heaved up three thousand feet, grinding against the other as it rose,—and you will have some idea of the making of the Mont Saleve.
MAY. But it must crush the rocks all to dust!
L. No; for there is no room for dust. The pressure is too great; probably the heat developed also so great that the rock is made partly ductile; but the worst of it is, that we never can see these parts of mountains in the state they were left in at the time of their elevation; for it is precisely in these rents and dislocations that the crystalline power principally exerts itself. It is essentially a styptic power, and wherever the earth is torn, it heals and binds; nay, the torture and grieving of the earth seem necessary to bring out its full energy; for you only find the crystalline living power fully in action, where the rents and faults are deep and many.
DORA. If you please, sir,—would you tell us—what are "faults"?
L. You never heard of such things?