40 GEOLOGICAL MEMOIRS. 



On the LiASSic Flora o/*Bayreuth. By Dr. Braun. 



[Proceedings of the Imp. Geol. Institute of Vienna, Nov. 28, 1854.] 



The new genus Kirchneria, Braun, is found in the lower liassic sand- 

 stone around Bayreuth, and bears a close resemblance to the forms 

 found in the carbonaceous liassic sandstone of Steierdorf in Banat, 

 and described by C. von Ettinghausen *. The analogy of Kirchneria 

 with the Thinnfeldia of Ettinghausen is very remarkable, notwith- 

 standing that the former is a fern, and that the latter is ranked 

 amongst Conifers. The forms described by Dr. Braun likewise 

 offer considerable analogies with those discovered by M. A. de Zignof 

 in the Jurassic strata of the Venetian xllps ; of these, a fern, on which 

 M. de Zigno has founded his new genus, Cycadopteris, bears the 

 nearest resemblance to Kirchneria. 



Dr. Braun' s researches prove that the liassic sandstones of Bayreuth 

 bear a striking agreement with those of Steierdorf in Banat, Fiinf- 

 kirchen in Hungary, and Lilienfeld, Lunz, and Grossau in Lower 

 Austria, all of them belonging to the same subdivision of the liassic 

 group. [Count M.] 



On the Mining District o/" Pribram. By M. Kleszcznski, 



Mining Surveyor at Pribram. 



[Proceedings of the Imp. Geol. Institute of Vienna, Nov. 21, 1854.] 



The rich lead and silver veins so extensively worked at the Birken- 

 berg near Pribram, at Drkolnow, and near Bohutin belong to the 

 lower portion of the grauwacke formation which occupies exclusively 

 that portion of Central Bohemia which is situated between Prague 

 and Klattau. Not far from Pribram crystalline rocks, especially 

 granite, range continuously along the grauwacke through Neuknin, 

 Dubenitz, and Sliwitz. Here the grauwacke comprises broad zones 

 of alternating grauwacke and slates, with intercalated subordinate 

 bands of clay-slate and quartzite, frequently passing into the sur- 

 rounding rocks. The strike is generally S.W. and N.E. ; the dip, 

 N.W. or S.E. 



The grauwacke of the Birkenberg contains the metalliferous veins, 

 from which a large quantity of argentiferous galena is extracted, 

 together with very fine mineral specimens well known in collections. 

 Veins of greenstone occur both in connection with the metalliferous 

 veins, and independent of them. A clay-bed (called Lettenkluft), 

 running parallel to the grauwacke beds, and dipping N.W. (in an 

 opposite direction to the grauwacke), marks the limit between the 

 grauwacke and the slates overlying it. The metalliferous veins 

 become richer, or separate into several branches, as they approach 

 this clay-bed, and at last are totally cut off by it, no trace of them 

 being found beyond it. It is still a question, however, whether the 

 veins really terminate at the clay-bed, or whether they are shifted 



* Abhandl. K. K. Geol. Reichsanstalt, vol. i. 



t Leonh. u. Bronn's N. Jahrb. 1854, p. 31 ; and Quart. Journ. Geol. Soc, 

 vol. X. part 2, Miscell., p. 13. 



