Natural History. • 423 



Mr. Schoolcraft adds, that the serpentine rock is not in situ, 

 nor is it so found in any part of the region he visited. He 

 thinks that the source of this copper, and that found in the 

 region of the Ontonagon, is the Porcupine Mountains. These 

 are situated 30 miles westward of the river, and are supposed 

 to be the seat of extinguished volcanoes, that have thrown 

 forth these masses of native copper. This opinion is supported 

 by the fact of the mountains being composed (as far as is 

 observed) of granite, probably associated with other primary 

 rocks, and among them serpentine; that the red sandstone- 

 rock at their base is highly inclined towards the mountains, so 

 as to be ahnost vertical, being apparently thrown up by the 

 granite ; and also by the height C1800 feet above the lake) of 

 the peaks, their conical and rugged forms, and other appear- 

 ances of volcanic mountains. 



!Mr. Schoolcraft then states the occurrence of native copper 

 in islands on the other lakes and localities, but forming part of 

 the same region. He concludes by stating it as his opinion, 

 that though the alluvial soil along the banks of the Ontonagon 

 up to its source, and in the contiguous region, contains very 

 frequent, and some most extraordinary imbedded masses of 

 copper, yet there is no body of it sufficiently extensive to 

 become the object of mining operations; but he thinks that a 

 mineralogical survey of the rock formation skirting the Ontono- 

 gon, would lead to the discovery of very valuable mines of the 

 sulphuret and carbonate of copper, the working of which 

 would be rendered still more advantageous by the occasional 

 occurrence of masses of native copper. — American Journal, 

 iii. 201. 



3. Mont Brasier. — There is a mountain called Mont Brasier, 

 situated between Senes and Larogne, in the Alps, which has 

 been reported from time to time to emit noises and flame. This 

 report has been verified by M. Dubois-Ayme, who, when in the 

 neighbourhood in 1818, examined the mountain, collected evi- 

 dence of the flames having been seen, and himself heard deto- 

 nation in the mountain. On examining the mountain, he found 

 that in the strata of limestone that formed its sides were beds 

 of pyritous chalk, marly schists, radiated sulphuret of iron, bitu- 

 minous substances, &c., and he concludes that the flames and 

 noises arc produced by the accidental firing of hydrogen libe- 

 rated by the action of water on these substances, it is to 

 be remarked that the detonations are most frequent when the 

 wind is in one direction, an effect probably due to the mixture 

 that then takes place of air with the hydrogen within the cre- 

 vices of tlie mountain. — Ann, dc Chim., xviii., p. 158. 



