~ 
748 _ STRATIGRAPHICAL GEOLOGY. [Boox VI. 
1. Lower or main coal-bearing (Saarbriicken) beds, 5200 to 9000 feet thick, 
with 82 workable and 142 unworkable coal-seams, or in all between 350 
and 400 feet of coal. Abundant plants of the middle and lower zone of 
, the upper coal flora. 
Among the small coal-fields of Germany are those of Ibbenbiiren and 
Presberg, Halle, Harz, and Thiiringer Wald. That of Zwickau, in 
Saxony, contains about 1700 feet of strata with 12 chief seams of coal, 
one of which (Russkohle) is sometimes 25 feet thick. Geinitz, adopting 
the order of succession of the fossil plants as his guide, has proposed to 
subdivide the Saxon Coal-measures as follows in descending order: 
3. The Fern zone, marked by the profusion of its ferns (Sphenopteris, Hymeno- 
phyllites, Schizopteris, Odontopteris, Neuropteris, Cyclopteris, Alethopteris, 
Caulopteris). ‘This is underlaid by 
2. The Sigillaria Zone, containing many species of Sigillaria, also Lepido- 
dendron, Calamites, Asterophyllites, aud a few ferns. 
1. The Lycopod Zone, abounding in Sagenaria (Lepidodendron) veltheimiana, 
with Sphenopteris distans, Calamites transitionis, &c. This zone is com- 
pared by Geinitz with the Culm. According to Grand’Eury the Saxon 
Coal-measures belong to the upper group of the middle coals and lower 
group of the upper coals. 
? 
Eastern Europe.—lIn Moravia, Silesia, Poland, and Russia, the Car- 
boniferous Limestone reappears as the base of the Carboniferous system, 
but not in the massive calcareous development which it presents in 
Belgium and England. One of its most characteristic phases is that to 
which the name “Culm” (applied originally to the inferior slaty coal 
of Devonshire) has been given, when it becomes a series of shales, sand- 
stones, greywackes, and conglomerates, in which the abundant fauna 
of the limestone is reduced to a few molluscs (Productus antiquus, 
P. latissimus, P. semireticulatus, Posidonomya Becheri, Goniatites spheericus, 
Orthoceras striatulum, &c.). ‘The Posidonomya particularly characterizes 
certain dark shales known as Posidonia schists. About 50 species of 
plants have been obtained from the Culm, typical species being Calamites 
transitionis, Lepidodendron. velthemianum, Stigmaria ficoides, Sphenopteris 
distans, Cyclopteris tenuifolia. ‘This flora bears a strong resemblance to 
that of the Calciferous Sandstones of Scotland. 
The coal-field of Pilsen in Bohemia occupies about 300 square miles. 
It consists mainly of sandstone, passing sometimes into conglomerate, and 
interstratified with shales and a few seams of coal which do not exceed 
a total thickness of 20 feet of coal. In its upper part is an important 
seam of shaly gas-coal (Plattel, or Brettelkohle), which, besides being 
valuable for economic purposes, has a high paleontological interest 
from Dr. Fritsch’s discovery in it of a rich fauna of saurians and 
fishes. The plants above and below this seam are ordinary typical 
Coal-measure forms, but these animal remains present such close 
affinities to Permian forms, that the strata containing them may 
belong to the Permian system (see p. 754). What are believed to 
be true Permian rocks in the Pilsen district seem to overlie the coals 
unconformably. 
In Russia the Scottish type of the Carboniferous system reappears. 
In the central provinces the coal-field of Tula, said to occupy an area of 
13,000 square miles, lies conformably on the Old Red Sandstone, and 
a gf > ‘ 
