30 GEOLOGICAL MEMOIRS. 
formations in general, which are less permeable to humidity than 
limestones, emerged peat-mosses are not uncommon on highly in- 
clined slopes. ‘They rise even to the culminating point of the 
Brocken. This important fact proves that they do not originate in 
any particular acid, or in any other agent prepared beforehand. It 
is the most positive proof possible of the hygroscopic action of the 
sphagnum, both in absorbing water and favouring the preservation 
of the woody fibre in the moistened tufts. 
Many of the vast peat-mosses in the plains of Northern Germany, 
that of Neumiinster, for instance, near Kiel, show the two forma- 
tions superimposed. The peat has first grown in a basin several feet 
deep, and on reaching the surface of the water the emerged forma- 
tion has commenced. This fact is easily proved, both by the nature 
of the fuel and by the plants found in these different portions. 
A third mode of growth has been observed in some parts of the 
Vosges, but more especially in Scania and Denmark, where in deep 
basins of small extent the peat-forming plants have begun to grow 
at the surface of the water, and the basin been gradually filled by 
the immersion of the floatmg turf, continually thickened by the 
growth of new plants. Such abysses, concealed by verdure, have 
often proved dangerous ; and these kinds of peat-mosses in the north 
are filled with numerous bones and instruments of various kinds, 
both ancient and modern, which may aid in establishmg different 
epochs in their formation. 
The relation between the mimeral combustibles, coal, lignite and 
peat, is shown, according to the author, by the dépdéts of lignite of 
the Rhon mountains and of Thuringia, and by the coal of Ilmenau. 
The lignites of Bischoffsheim, iclosed in basalt, are a mass of semi- 
carbonized wood, dug out with hatchets. The beds of clay on which 
they rest, or by which they are covered, frequently exhibit impressions 
of the leaves of the elm, the birch, the willow, or other trees. The 
lignites of Machsterstadt are mixed with an immense number of pine 
cones. Those of Liitzen, which should rather be described as peat, 
are covered by a bed of sand and gravel thirty feet thick. The com- 
bustible matter is black and brittle, some fragments of aquatic mosses 
may still be recognised in it, and it lies above trunks of trees, of 
which the wood, completely blackened, is reduced to a soft paste 
like clay. It is in a state of decomposition intermediate between 
peat, properly so called, and the lignites or coals. This softening of 
the largest vegetables explains perfectly the flattening of all the re- 
mains of plants that can be recognised in mineral fuel. 
Some curious observations have been made relative to the great 
antiquity of certain peat-mosses in the environs of Helsingor, where 
excavations have exposed three forests placed one above the other, — 
and separated by beds of peat of considerable thickness. The author 
explains this singular pheenomenon by successive sinkings of the over- 
loaded surface, and its renewal by the growth of the peat. But these 
formations must have required a considerable space of time, smce 
of these three forests, each composed of different species of trees, one, 
of oaks, shows trunks not less than two or three feet in diameter. 
