422 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [Apr. 4, 



to the Rothe-todte-liegende that we are surrounded on all sides 

 with porphyry, and as this period of turbulence was followed by 

 one of beach action and quiescent marine deposits, to which we 

 shall presently advert, it is quite manifest, that all the breccias and 

 coarse conglomerates, however composed of mixed materials, were 

 formed during a period of igneous action, perhaps more intense than 

 any to which an appeal can be made in the history of other German 

 formations. In fact, it was in this, the earlier part of the Permian 

 sera, that those grand eruptions took place from N.E. to S.W. which 

 obscured the ancient physical direction of the rocky and slaty masses 

 that trend from N.E. to S.W., and determined the axis or watershed 

 to be at right angles to the original outline of the ridges. 



As we shall have to speak of a similar phsenomenon in the Harz, 

 we reserve for awhile our inferences concerning the condition of the 

 earth's surface during the tumultuous period of the earlier of the 

 Permian deposits, when such vast physical changes occurred. 



In the meantime we may indeed truly say, with M. Credner, that 

 the northern portion of the Thiiringerwald is essentially a porphyritic 

 chain ; since nearly all its highest central summits, from the Kahle 

 Berg and the Inselsberg, the latter 3096 English feet, to the Schnee 

 Kopf or highest point, about 3300 English feet above the sea, con- 

 sist of red porphyries, which ranging from N.E. to S.W. constitute 

 what is locally termed the Rennsteig or central ridge, which deter- 

 mines the axis or watershed to which all the rock-masses of the chain 

 have in a geographical sense been rendered subordinate. 



No organic remains have been found in the Rothe-todte-liegende of 

 the Thiiringerwald, as might indeed be expected from the mineral 

 structure and condition of the rocks, except certain hard silicified 

 stems of fossil plants, PsaronicE, &c. 



In the environs of Zwickau, Chemnitz, Dresden, &c., however, 

 where very finely laminated claystones are intercalated in the middle 

 of the conglomerate series, Colonel Gutbierhas collected and described 

 about sixty species of Calamarice^ Filices, Selagines, and Coniferce ; 

 of these forty are considered by the author to be peculiar to the Per- 

 mian, three of them being also found in the Permian group of Russia 

 {Calamites gigas, Sphenopteris erosa^ and S. lobatd). On the other 

 hand, seven of the sixty species described are considered to be forms 

 known in the Coal-measures*. 



In relation to the adjacent region of Saxony, we think it right 

 here to allude to various outbursts of porphyry, and to wide exten- 

 sions of the Rothe-todte-liegende and its subjacent coal strata, as 

 existing near Zwickau, Chemnitz, and other parts of Saxony, where 

 the coal, on the authority of Prof. Geinitz, lies invariably beneath 

 every stratum to which the term " Rothe-todte-liegende " can be ap- 

 plied. In these tracts, as well as in the environs of Dresden, the lower 

 division of the red rocks is composed of sandstones and shale, and 

 the upper portion alone near Dresden (according to Geinitz) is a 

 coarse conglomerate. In traversing the country from Freiberg to 



* Versteinerungen des Permischen Systemes in Sachsen, von A. v. Gutbier. 

 Dresden and Leipsig, 1849. 



