35

of the 'Vogelberg,' and which probably at the same time broke
through the triasformation with the latter. The mass of this
basalt-cone is bent in a vertical direction in many fissures and
caverns, which allow the rain water a free entrance into the inte-
rior. Probably in consequence of a successive disintegration
which took place around a protected centre, the original rock had
disjoined itself in three different concentric layers, the products of
its disintegration, which in spite of going over into each other,
were, notwithstanding, easy to be distinguished and were collect-
ed on the north-eastern end of the mountain, where a worked
stone-pit permitted it.

1.  The central mass had a black-gray color, which consisted
of a mixture of felspar and augite. Only a few crystals of olivine
were secreted in it, and which, by their brownish color, already
indicated an incipient disintegration of the stone.

2.   Upon the centre mass was lying a loose, much disjoined mass
of light-brown color.

3.  A light-yellow powder formed the outer and total disintegra-
ted layer.

The stones under 1, 2 and 3, were then analyzed, and gave
the following composition:

Silica,

Oxyds of Iron,

Clay,

Lime,

Magnesia,

Potash,

Soda,

Water,

100.07            100.72            101.12

We perceive already by this account that silica, lime, magnesia
and alkalies, were gradually washed out during the different periods
of degradation; more apparent, however, will be the relative pro-
portion of them, if we abstract from water and calculate their quan-
tities for 100 clay, under the acceptation that clay had not been
washed away, its full quantity had remained. We then proceed
to the following scheme :

1.	2.	3.
54.45	48.79	43.26
15.25	15.37	15.09
12.13	13 82	17.51
6.06	3.94	1.29
5.81	1.24	1.17
0.55	0.51	0.07
3.68	2.72	0.12
2.14	14.33	22.61

'	1.	2.	3.
Silica,	448.71	353.13	247.01
Oxyds of Iron,	125.64	111.28	86.16
Clay,	100.00	100.00	100.00
Lime,	49.92	28.51	7.38
Magnesia,	47.90	8.99	6.71
Potash,	4.27	3.71	0.35
Soda,	29.67	19.77	0.70