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ning recess; and which show the tendency, common in this sort of stone, to divide itself into fragments of even sides.

“ Above and beneath this vein there are others more narrow, one in particular, which is not above half an inch in breadth, and is prolonged, like the former, for a space of seven or eight feet. Some of the little veins show that the beds of the roche de corne have subsided, or sunk unequally, since the granite penetrated into it; for they seem to be suddenly interrupted, and to begin anew a little higher or a little lower. The broadest vein seems also to have yielded a little in some parts.

“ These veins of granite, which were then new to me, appear to throw light on the forma tion of that stone. For to any man a little versed in mineralogy, it is almost demonstrable that this granite has been formed in these veins, by mere filtration of the waters, which, in descending from the mountain of granite, which hangs over these schistose rocks, brought down the elements of that mountain, which they deposited and crystallised in these fissures. When one finds the slits of a marble, or of a slate, filled with spar or quartz, one decides, without hesitation, that these foreign bodies, or parasitical, as Linnæus calls them, have been brought by

the waters, and crystallised in these slits. Since then the elements of granite are all capable of humid crystallisation, why, as the circumstances are the same, should one hesitate to acknowledge, that it has been also dissolved and crys. tallised through the medium of water?

“ I thought then that I had made a great step towards the knowledge of the formation of granite, when I saw with so much clearness that nature could form it by the mere assistance of water. My only regret was, that the proof of this truth was concealed in the centre of the Alps, in a spot so little accessible to the greater part of the lovers of lithology.

“ But I had, towards, the end of the same year, the pleasure of finding the phenomenon in a place well frequented, and of easy access, since it is at the foot of the walls of the city of Lyons. If, without the gate of the Red Cross, you descend to the Saone, by a path which runs under the walls of the city, you will see on the right, a little beneath the fort of St. John, banks of sand, the sides of which are open to the air. Under these sands are schistose rocks, composed of white quartz and brilliant mica, sometimes red, sometimes blackish. The layers are almost perpendicular to the horizon, for they form with it an angle of 80 degrees inclining towards the west, and running from north to south.

There I found a vein of granite 21 inches in breadth, and uncovered for a length of about 18 feet. This vein, of which the sides are parallel, traverses the layers of schistose rock, under an angle of 30 degrees, and forms with the horizon an angle of 50 degrees, with the same inclination as the layers. The granite which forms this vein has shrunk, like that of Valore sine, with some rectilinear fissures, which cross each other irregularly. There are seen in the same rock other veins of granite, of a less considerable size, the largest being parallel to that which I have described, while the others run in an oblique direction.

“ I observed similar veins in the schistose rock, at the foot of the wall of the city, and under the path which accompanies that wall." One of them, about fourteen inches in breadth, is perpendicular to the horizon, like the layers of the rock. It passes under the wall, and must enter into the city. Near the Saone, and within the city, is a quarry of granite, which was wrought at the time I made my observations.

- In fine, I made at Semur, in Auxois, an observation analogous to the preceding, and which confirms the same truth that granite may be formed in the water, by the simultaneous crystallisation of two or three kinds of stone. The granite rock, on which this town is built, naturally divides itself into large masses, with plane or flat sides, and these masses are here and there separated by crevices of a certain breadth. I found in these crevices parcels of quartz, felspar, and mica, mingled as in granite, but in far larger grains, there being bits of an almost transparent quartz, two or three inches thick, traversed by leaves of mica so large that they might be called talc, or Muscovy glass ;, and the whole intermingled with large pieces of red felspar, like that of the granite, and confusedly crystallised. It could not be doubted, on seeing these heaps of large crystals, that they are the produce of the rain waters, which, passing through the granite, have dissolved and carried down these different elements, and have deposited them in these wide crevices, where they are crystallised, and have formed new stones of the same kind. The crystals of these new granites are larger than those of the ancient, on account of the repose which the waters enjoyed in the inside of these reservoirs."

Such are the remarks of this great observer, who proceeds to argue that granite was ori

ginally formed in the ancient ocean that covered the earth; that it is disposed in beds or layers, though sometimes very thick and difficult to discover, especially as those of the lower mountains are apt to split into fragments, either rhomboidal, or at least with flat sides, which he ascribes chiefly to the mixture of argil in one of his pierres de corne ; and as he mentions that it is frequent in these granites, he must mean hornblende or siderite: adding, that the absence of marine bodies in granite, gneiss, &c. affords no proof that they were not formed under water, the most ancient ocean probably having con. tained no animated matter, as a pure infusion, for example, only displays animalcules at the end of a certain time.

Scarcely a phenomenon in orology has escaped Saussure, if his work be accurately read, or rather studied, as it well deserves; and what is regarded as a new observation may be here found, namely, the elevation of the veins of granite above the clay-slate, which, in his wide field of observation, he simply accounts for by the subsidence, or shrinking, an accident common to clay; not to mention the greater softness of the substance, which may more easily be worn down by the weather. Nor is it inconceivable, on the other hand, that those, veins

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