94 DR BOUE^ ON THE GEOGNOSY OF GERMANY. 
3. Fhetz Rocks, 
The Floetz period begins with the Old Red Sandstone, 
{Gres rouge). This sandstone is ordinarily red, generally 
coarse at first, and afterwards finer : it appears often to be 
chiefly derived from the disintegration of porphyries, sye- 
nites, and granites. In it (as in Silesia), under it (Valley 
of Tharandt, near Dresden), or upon it (in the Palatinate), 
occur more or less extensively the coal-sandstones, or coal- 
measures, having some fresh water shells, and sometimes salt 
and fresh water organic remains, in different parts of the 
deposit, but never together in the same bed. In some in- 
stances, the sandstone of the coal-formation occupies the 
greatest part of this formation, as in the Prussian and Ba^ 
varian Rhine provinces. 
Upon this deposit rests the Zechstein, or Magnesian 
Limestone, or Calcaire Alpiri * ; for all these denomina- 
tions, and the deposits which they indicate, are identical, 
their various masses and their petrifactions being the same. 
The Asche of the Germans, and their Limestone, with 
Sparry Iron-ore (Schmalkalden), is the Calcaire Alpin of 
the south of France, near Figeae, for instance, a locality 
described long ago by Cordier {Journal des Mines), 
The Zechstein of the country of Swarzburg, Kamsdorf, 
Gera, &c. is precisely the Magnesian Limestone, with 
flustr^, &c. of Sunderknd, and also the Calcaire Alpin 
Magnesien of the south of France. In Germany, the low- 
est part of this deposit contains ores, which, in France, are 
found in the uppermost part of the Old Red Sandstone, as 
* I do not mean by this term the Limestones of the Alps, which have 
sometimes been so named without sufficient certainty- 
