485 
tion of the Porphyry, which on the southern and south-eastern limits 
of the tract is associated with the newest Coal strata and the oldest 
beds of the New red system (Rothe todte liegende). 
The Thuringerwald is considered to exhibit the same succes- 
sion of the older strata as the Rhenish provinces and the Hartz, the: 
central masses being equivalents of the Silurian and possibly of 
the Upper Cambrian group; but the authors, having passed ra- 
pidly over these parts, attach importance only to their observations 
on the southern limits of that region, near the foot of the Fich- 
telgebirge, where they indicate a clear descending series, from the 
true Mountain-limestone with large Producti into lower fossiliferous 
limestones and slaty rocks, the fossils of which have been elabo- 
rately described by Count Munster, and which they place in the 
parallel of the Devonian system. 
The authors express their very great obligations to Mr. Lonsdale, 
whose intimate knowledge of the Devonian fossils has enabled them, 
to speak with confidence, and whose advice has often dispelled ob- 
securities which must ever attend the elimination of the order of 
succession of rocks which have been so extremely dislocated, and in 
many instances so much altered. They also acknowledge the valu- 
able cooperation of their friend M. de Verneuil, who accompanied 
them during a portion of the time devoted to this laborious survey, 
and to whose intimate acquaintance with the older fossils they are 
largely indebted ; and who, uniting with his countryman M. d’Ar- 
chiae, will describe the Mollusca of these regions asa sequel to the 
geological memoir of the authors. 
Mr. Murchison’s recent journey over large tracts of Russia was 
intended to test the accuracy of the new classification of the pale- 
ozoie rocks upon a still wider scale than any to which it had been 
applied. Believing from the works of Strangways, Pander, and 
Eichwald, that some members of these formations occur near St. 
Petersburgh, and pronipted by the suggestions of M. Von Buch, 
that the threefold succession of Carboniferous, Old red, and Silurian 
systems would be found to’ prevail in Livonia and North-western 
Russia, Mr. Murchison, accompanied by M. E. de Verneuil, has 
made during the last summer a most extensive and instructive tour 
in Russia. The principal results of this journey were offered to the 
Geological Section of the British Association in September last at 
Glasgow, showing that the Silurian rocks occupy several islands in 
the Baltic and large parts of Livonia and Courland, and range by 
St. Petersburgh to the W.N.W. Qn the south they are overlaid by 
a great red formation which was formerly supposed to be the New 
red sandstone on account of its saliferous and gypseous beds, but 
which is now proved to be the Old red sandstone by containing the 
Ichthyolites which characterize that deposit in the British Isles; these 
fishes, Holoptychius, Coccosteus, Diplopterus, &e., are associated _ 
with Mollusca similar in species to some of the fossils of the Devonian. 
rocks of England, Belgium, and the Rhine. The old red or De- 
vonian rocks of Russia, spreading over a very wide area, are sur- 
_ mounted in the Waldai Hills by Mountain or Carboniferous lime- 
VOL. Ill. PART Il. ZS 
