ailleuses ne font point du mica, ce sont de lames minces
du petrosilex dont j'ai deja parle."

Here is evidently what I would call petuntze strata, or porcelane stone,
that is, strata formed by the deposits of such materials as might come
from the _detritus_ of granite, arranged at the bottom of the sea, and
consolidated by heat in the mineral regions. We have precisely such
stratified masses in the Pentland hills near Edinburgh. I have also a
specimen of the same kind, brought from the East Indies, in which there
is the print of an organized body. I believe it to be of some coralline
or zoophite.

Sec. 1048. "Cette roche melangee continue jusqu'a ce que le rocher
s'eloigne un peu du grand chemin. La, ce rocher se presente coupe a
pic dans une grande etendue, et divise par de grandes fentes obliques,
a-peu-pres paralleles entr'elles. Ces fentes partagent la montagne en
grandes tranches de 50 a 60 pieds d'epaisseur, que de loin semblent etre
des couches. Mais lorsqu'on s'en approche, on voit, par le tissu meme
de la pierre feuilletee, que ses vraies couches font avec l'horizon des
angles de 70 a 75 degre, et que ces grandes divisions sont de vraies
fentes par lesquelles un grand nombre de couches consecutives sont
coupees presque perpendiculairement a leurs plans. Les masses de rocher,
comprises entre ces grandes fentes, sont encore divisees par d'autres
fentes plus petites, dont la plupart sont paralleles aux grandes,
d'autres leur sont obliques; mais toutes sont a tres-peu-pres
perpendiculaires aux plans des couches dont la montagne est composee."

Here is a distinct view of that which may be found to take place in all
consolidated strata, whatever be the composition of the stratum; and
it is this appearance which is here maintained to be a physical
demonstration, that those strata had been consolidated by means of
heat softening their materials. In that case, those stratified
bodies, contracting in cooling, form veins and fissures traversing
perpendicularly their planes; and these veins are afterwards filled with
mineral substances. These are what I have here distinguished as the
_particular_ veins of mineral masses; things perfectly different from
proper mineral or metallic veins, which are more general, as belonging
to immense masses of those strata; and which had been formed, not from
the contraction, but from the disrupture of those masses, and by the
forcible injection of fluid mineral substances from below. No