386 
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, appears to be the con- 
stitution 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, considerably 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 Ussona, 
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 incorruptible, 
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 1^16, by command 
of Peter 1. were fitted with accommodations for public use. 
