In many parts of the island the bottoms of the valleys ar covered in an extraordinary manner by myriads of grea loose angular fragments of the quartz rock, forming "stream of stones." These have been mentioned with surprise b every voyager since the time of Pernety. The blocks ar not waterworn, their angles being only a little blunted; the vary in size from one or two feet in diameter to ten, or eve more than twenty times as much. They are not throw together into irregular piles, but are spread out into leve sheets or great streams. It is not possible to ascertain thei thickness, but the water of small streamlets can be hear trickling through the stones many feet below the surface The actual depth is probably great, because the crevice between the lower fragments must long ago have been fille up with sand. The width of these sheets of stones varie from a few hundred feet to a mile; but the peaty soil dail encroaches on the borders, and even forms islets whereve a few fragments happen to lie close together. In a valle south of Berkeley Sound, which some of our party calle the "great valley of fragments," it was necessary to cros an uninterrupted band half a mile wide, by jumping fro one pointed stone to another. So large were the fragments that being overtaken by a shower of rain, I readily foun shelter beneath one of them.

Their little inclination is the most remarkable circumstance in these "streams of stones." On the hill-sides I hav seen them sloping at an angle of ten degrees with the horizon but in some of the level, broad-bottomed valleys, the inclination is only just sufficient to be clearly perceived. On so rugged a surface there was no means of measuring th angle, but to give a common illustration, I may say that th slope would not have checked the speed of an English mail-coach. In some places, a continuous stream of these fragments followed up the course of a valley, and eve extended to the very crest of the hill. On these crests hug masses, exceeding in dimensions any small building, seeme to stand arrested in their headlong course: there, also, th curved strata of the archways lay piled on each other, lik the ruins of some vast and ancient cathedral. In endeavouring to describe these scenes of violence one is tempted to pas from one simile to another. We may imagine that stream of white lava had flowed from many parts of the mountain into the lower country, and that when solidified they had bee rent by some enormous convulsion into myriads of fragments. The expression "streams of stones," which immediately occurred to every one, conveys the same idea. Thes scenes are on the spot rendered more striking by the contrast of the low rounded forms of the neighbouring hills.

I was interested by finding on the highest peak of on range (about 700 feet above the sea) a great arched fragment, lying on its convex side, or back downwards. Mus we believe that it was fairly pitched up in the air, and thu turned? Or, with more probability, that there existed formerly a part of the same range more elevated than the poin on which this monument of a great convulsion of nature no lies. As the fragments in the valleys are neither rounde nor the crevices filled up with sand, we must infer that th period of violence was subsequent to the land having bee raised above the waters of the sea. In a transverse sectio within these valleys, the bottom is nearly level, or rises bu very little towards either side. Hence the fragments appea to have travelled from the head of the valley; but in realit it seems more probable that they have been hurled down fro the nearest slopes; and that since, by a vibratory movemen of overwhelming force, [9] the fragments have been levelle into one continuous sheet. If during the earthquake [10] whic in 1835 overthrew Concepcion, in Chile, it was thought wonderful that small bodies should have been pitched a fe inches from the ground, what must we say to a movemen which has caused fragments many tons in weight, to mov onwards like so much sand on a vibrating board, and fin their level? I have seen, in the Cordillera of the Andes, th evident marks where stupendous mountains have been broke into pieces like so much thin crust, and the strata thrown o their vertical edges; but never did any scene, like thes "streams of stones," so forcibly convey to my mind the ide of a convulsion, of which in historical records we might i vain seek for any counterpart: yet the progress of knowledg will probably some day give a simple explanation of thi phenomenon, as it already has of the so long-thought inexplicable transportal of the erratic boulders, which are strewed over the plains of Europe.

Charles Darwin

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