389 
these crystallizations are, in general, only among those filaments 
of wood which have entirely lost their original nature. The bark 
is distinguishable, being about four lines in thickness. There are 
two layers, one of which is of an azure blue, the other of a pale 
green, approaching to verdigris. This wood was taken from the 
mines in the neighbourhood of Souxson. Mons. D’Auteroche was 
informed, on the spot, that they sometimes found, in the strata of 
these mines, entire trees. The specimens he brought home, he took 
from a collection which occupied the greatest part of a room, which 
was more than twenty feet long. This wood, he observes, contains 
more or less copper, according to the places where it has been 
found; and displayed various appearances, with respect to colour, 
but always possesses either green, or azure blue*. 
An examination of the several specimens of fossil copper wood, 
which I am happy in possessing, shows that the impregnation is 
made by a carbonate of copper, which appears in several places in 
its most beautiful form, that of malachite. The brilliance of their 
colours, the completeness of the transmutation, and the perfect 
preservation of their original forms, place these specimens among 
the most beautiful and interesting of the vegetable secondary fossils. 
One small specimen, described at Fig. 19 in Plate VI. is highly 
interesting, on another account. On its surface, the charred wood, 
and spots of malachite, are discernible, in several parts, whilst a 
transverse section shows its substance is formed of copper pyrites, of 
a metallic lustre, displaying, by the striae and circles with which it is 
intersected, an indisputable ligneous structure. 
Whilst speaking of the impregnations of fossil wood with iron, I 
spoke of those, which, although evidently containing that metal, 
did not hold it in that proportion as to admit them to be distin- 
« Voyage en Siberie, en 1761, par M. I’ Abbe Chappe d’Auteroche. Tome i. 2'^® partie, 
p. 671. 
