NATURE OF THE ROCKS. 339 



the serpentine at Cape Lizard, on the Slicthmd 

 islands, and on the Cordillera ofthe coasts of Soutli 

 America. If we consider that the sea formerly 

 covered those countries which contain the floetz 

 mountains, which are rich in petrefaclions, and ad- 

 mit the hypothesis, that primitive mountains, which 

 were not covered by the floetz mountains, rose as 

 islands above these seas, it appears how the ser- 

 pentine of what is now tlie interior country for- 

 merly lay equally situated on the coasts ; an analogy, 

 which,if thoroughly investigated, may lead in future 

 to important conclusions respecting these and other 

 kinds of rock, in the history of the formation of the 

 surface of the earth. 



OONALASHKA. 



Dr. Langsdorff reports, in his voyage round the 

 world, that this island consists of granite and 

 porphyry, as Kamtschatka, and the whole ciiain of 

 the Aleutian islands, from the north-west coast of 

 America, contains nothing but ])rimitive rock. 

 From the beautiful series of specimens of rock 

 which have been brought from Oonalaslika, and in 

 which only the wood-stone (Lytho-vylon') is wanting, 

 which Dr. Eschscholtz, however, frequently saw 

 there, it appears that older sand formation prevails 

 with amygdaloid, porphyry, claystone, and jasper. 

 Lavender-blue and brown-red clay-iron-stone 

 forms the paste of these kinds of rocks, which 



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