406 PASSAGE OF CORDILLERA. MarcL^ 1835. 



the newer horizontal beds on the shores of the Pacific. From 

 this resemblance I expected to find silicified wood^ which is 

 generally characteristic of those formations. I was gratified 

 in a very extraordinary manner. In the central part of the 

 range^ at an elevation probably of seven thousand feet^ on a 

 bare slope^ I observed some snow-white projecting columns. 

 These were petrified trees, eleven being silicified, and from 

 thirty to forty converted into coarsely-crystallized white cal- 

 careous spar. They were abruptly broken off ; the upright 

 stumps projecting a few feet above the ground. The trunks 

 measured from three to five feet each in circumference. They 

 stood a little way apart from each other, but the whole formed 

 one distinct group. Mr. Robert Brown has been kind enough 

 to examine the wood : he says it is coniferous, and that it 

 partakes of the character of the Araucarian tribe (to which 

 the common South Chilian pine belongs), but with some 

 curious points of affinity with the yew. The volcanic sand- 

 stone in which they were embedded, and from the lower part 

 of which they must have sprung, had accumulated in succes- 

 sive thin layers around their trunks ; and the stone yet re- 

 tained the impression of the bark. 



It required little geological practice to interpret the mar- 

 vellous story, which this scene at once unfolded; though I 

 confess I was at first so much astonished that I could scarcely 

 believe the plainest evidence of it. I saw the spot where a 

 cluster of fine trees had once waved their branches on the 

 shores of the Atlantic, when that ocean (now driven back 

 700 miles) approached the base of the Andes. I saw that 

 they had sprung from a volcanic soil which had been raised 

 above the level of the sea, and that this dry land, with its up- 

 right trees, had subsequently been let down to the depths of 

 the ocean. There it was covered by sedimentary matter, and 

 this again by enormous streams of submarine lava — one such 

 mass alone attaining the thickness of a thousand feet ; and 

 these deluges of melted stone and aqueous deposits had been 

 five times spread out alternately. The ocean which received 

 such masses must have been deep ; but again the subterra- 



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