S86 



is constituted, and will be likely to deposit, in its substance, an 

 oxide, so nearly at its minimum of oxidation, as to approach nigh 

 to the hardness, gravity, and lustre of a metal. Such, indeed, ap- 

 pears to be the constitution of those specimens of ferruginous wood 

 to which I here allude. That part which was originally ligneous 

 appears to have become the most solid and metallic, whilst the 

 cavities appear to have been filled by a rust-like precipitate. 

 Among the boggy iron ores, are frequently found specimens which 

 illustrate the manner, in which this kind of metallized wood is 

 formed ; and also show that it has been by an operation carried on 

 near the surface. In these, which are often in large masses, broken 

 twigs of trees, grass, and other vegetable matters, are found, consi- 

 derably changed, and indurated, and connected together by a fine 

 yellow, or yellowish brown, oxide of iron. But the following account, 

 from an intelligent observer, will serve to give you a more correct idea 

 of the^effects resulting from this important natural process. 



Mr. Tooke, remarks, that one of the principal curiosities, among 

 the mountains of Russian Lapland is in the martial waters of Us- 

 sona, Muun-ozero, &c. Here are seen, he says, a vast quantity of 

 stems, branches, twigs, leaves, and roots of birch trees, and other 

 exuviae of vegetables, entirely mineralized by iron, with the diverse 

 texture of the rotten wood plainly visible ; in which mineralizations 

 the tender white rind, known to be in the highest degree incorrupt- 

 ible, is preserved quite in its natural appearance ; the soil is changed 

 into a rich ferruginous earth, and the grassy sod into iron ore. The 

 like transmutations are seen in all the low spots and pits that incline 

 towards the Muun Lake, but particularly near the Martial Waters, 

 and over against the village Buijova. Here lies the iron ore in a 

 wide extended valley, forested apart with birch-trees, and with 

 gently-rising hills on both sides. In this valley, though not in its 

 deepest bottom, issue the Martial Springs, which, in 1716, by com- 

 mand of Peter I. were fitted with accommodations for public use. 



