Chap. XVI.] 
UPPER SILURIAN OF THE HARZ. 
391 
rope, the geographical direction of the Harz is from north-west to south- 
east ; and thus, like that of the Thiiringerwald, as before noticed (p. 314), 
its appearance upon a map is not derived from its ancient mineral nucleus, 
but from the unconformable and enveloping younger strata. 
Just as many of the slaty fossiliferous rocks and limestones of the Harz 
are known to be of the same age as those of Devonshire (the Coccosteus 
of the Scottish Old Eed having been found associated therewith), so 
another suggestion * of Sedgwick and myself has been verified, and the 
rocks of these eastern hills are now proved to be of older date. In the 
tracts around Harzgerode, and in spots near Ilsenburg, as well as in the 
Lauther-Thal in the Western Harz, fossils have been found by M. Bischof, 
M. Jasche, and M. Adolf Homer which leave no doubt that these districts 
are occupied by Upper Silurian rocks ; and, although the fossils of these 
tracts are nearly all of species unknown in Britain, they belong, as a 
whole, to Barrande's uppermost Silurian zone of Bohemia. 
Having elsewhere shown f the general relations of the strata which I con- 
sidered to be of Upper-Silurian age in the Eastern Harz, I would only add 
that, on revisiting that tract in 1857, accompanied by Professor Hupert Jones, I 
was confirmed in the accuracy of that view. It is, I reaffirm, quite true that 
the schistose rocks with intercalated fossiliferous limestones near Magdesprung, 
Harzgerode, and Alexis Baden rise out conformably from beneath a vast 
thickness of superincumbent strata which, ranging towards Blankenrode, and 
dipping to the east, must be considered of Devonian age. 
The fossils of these underlying rocks, many of which had been previously 
figured |by Ad. Homer J, have been recently well compared and identified by 
C. Giebel of Halle §. They consist, according to the latter, of Trilobites of the 
following eight genera — Harpes, Proetus,Cyphaspis, Phacops, Dalmania, Lichas, 
Acidaspis, and Bronteus. On the whole, these Crustaceans, though bearing a 
very close resemblance to those of the Upper Silurian of Prague, are not, in 
Giebel's opinion, absolutely identical. An Orthoceras and a Serpulite are 
also of new species. The genus Acroculia gives 13 species j Tentaculites, 2 
species ; Pterinea, 2 species j Lima, Venus, and Ctenodonta, each 1 species ; Spi- 
rifer, 9 species ; Atrypa, 2 species ; Hhynchonella, 8 species, including the well- 
known Rh. Wilsoni; Pentamerus, 3 species, including P. Knightii, Sow., 
and P. galeatus, Dalm. ; Orthis, 3 species ; Strophomena depressa, Dalm., and 
another species ; Leptsena, 5 species ; Chonetes, 1 species ; Discina, 3 species. 
The Crinoids are Actinocrinus laevis, Mill., and a Hhodocrinus. The Zoo- 
phytes are of the genera Aulopora, Pleurodictyum (?), Palaeocyclus, Cyatho- 
phyllum, Alveolites, Dania, Chaetetes, and Beaumontia, with Graptolithus and 
Hetipora. Besides these fossils, three undescribed species of Fishes and three 
or four species of Plants are enumerated, one of which is of large size ; but 
whether these latter are of land or marine origin has not been determined. 
In his conclusion respecting the age of the ninety-six fossils which he specifies, 
M. Giebel makes the following classification. Of decided Devonian species, or 
those known in other places, there are five species only, and two others which 
are common to Silurian and Devonian ; whilst eighteen are identified as Upper- 
* Trans. G-eol. Soe. Lond. ser. 2. vol. vi. p. 300. § Zeitschriffc fur die gesammten Naturwissen- 
t Quart. Journ. G-eol. Soc. Lond. vol. xi. p. 431. schaften, Jan. 1858, no. 1 : Halle. 
I Dunker und von Meyer's Palaeont. vol. ii. 
