M. Beudant on the Pitch$tone Snxony, ^69 
CM* less numerous. What is very remarkable is^ that these frag- 
ments occur not only in the argillaceous mass, but also in the 
pitchstone itself; thus proving, by a raineralogical character that 
the two rocks, however different in external appearance, belong 
to the same formation. 
Considerable masses of claystone also occur to the south-west 
of Freyberg, about the small town of Chemnitz. Here the vi- 
treous retinite, in so far as I know, is not found ; but, in the 
midst of the porphyritic claystone, we observe porphyritic rocks, 
having a basis of compact felspar, with a somewhat resinous 
lustre, of a brown or reddish colour, sometimes mixed with a 
little green, which include very small crystals of lamellar felspar, 
and which have a very striking resemblance to certain earthy va- 
rieties of the porphyritic pitchstones of Tribisch. The same por- 
phyries still occur at Planitz, near Zwickau, which is not far dis- 
tant from Chemnitz, and in the midst of the same formation (ter- 
rain), which, in this part, occupies a considerable extent. This 
porphyry forms kidneys in the middle even of the pitchstone, 
which has been, found here, either in the sandstone of the coal 
formation (gres houiller), or between it and the red sandstone 
lying immediately above it, and which is itself covered, in this 
part, by amygdaloids. 
The result of these data is, that the pitchstone is found in im- 
mediate connection with the claystone deposits ; but these de- 
posits are themselves a part of the red sandstone formation 
(Both liegende), which in this country covers a considerable ex- 
tent, and they would appear to occur sometimes above and 
sometimes beneath the quartzose arenaceous deposits, of which 
it is formed. Thus the pitchstones of Saxony belong to the red 
sandstone formation, and would appear to occupy the place of 
the porphyries with a basis of compact felspar, which occur in 
many localities, and which even appear in an evident manner 
at Chemnitz, where they are solitary, and at Planitz, where they 
form kidneys even in the midst of the pitchstones. But it is 
jcnown farther, that it is universally in the red sandstone that the 
pitchstone occurs. It is in this position that these rocks appear 
in Scotland, according to the descriptions given by Professor Jame- 
son, Dr MacCullochj and Dr Bone ; it is still in the same manner 
fh^t they occtir at Grantola, on the Lago Maggiore, ydiere X yisit- 
