and the Clinkstone of the Schlossberg. 109 



which have left, in the innumerable basaltic summits of Bo- 

 hemia, Saxony, and Lusatia, the proofs of their activity. The 

 Mittelgebirge is entirely formed of basalt and clinkstone ,- no 

 other kind of igneous rock is met with. A red felspathic por- 

 phyry occurs at Toeplitz, at the foot of these mountains, which 

 appears to form the extremity of a continuous range extending 

 from Altenberg to Toeplitz. From this porphyry issue the 

 celebrated springs of Toeplitz : they carry to the sm-face not 

 only fragments of porphyry, but also of quartz, basalt, granite, 

 and gneiss. A marly limestone formation, analogous to the 

 pldnerkalJc of Saxony, and horizontally stratified, occurs round 

 the porphyry on which its beds rest, in such a manner as in 

 some places to show, that, from being at first horizontal, they 

 have become inclined, in consequence of the porphyritic masses 

 having been forced up : in other situations, this elevation of 

 the inferior rock has broken some, without deranging the po- 

 sition of those which remained. In the vicinity of the points 

 of contact, the porphyry is traversed by numerous hornstone 

 veins, containing fragments of porphyry, whilst fragments of 

 hornstone are seen in the porphyry next their sides. These 

 veins penetrate into the limestone from the porphyry, to the 

 depth of from six to eight feet, sometimes changing their na- 

 ture, so as to become either true flint or a more or less sili- 

 ceous marl ; but in either case, they always contain the fossils 

 of the limestone. A singular mixture of porphyry, hornstone, 

 and siliciferous limestone sometimes forms a kind of crust, with 

 a nearly scorified appearance. Thin seams of heavy spar 

 often occur in the porphyry near the junction of the two rocks. 

 It appears evident to the author, that these two rocks have 

 been at the same time in a soft or fluid state, the one being 

 igneous, the other aqueous ; and that contact under these cir- 

 cumstances could have alone produced the singular facts he 

 mentions*. 



The mountain of the Schlossberg near Toeplitz, is basaltic 

 at its lower part ; but the cone on its summit, the sides of 

 which are more steep, and which rises high above all that sur- 

 rounds it, is entirely formed of clinkstone, in thin stratified 

 beds, presenting on all sides a dip, corresponding with the 

 sides of the mountain, whilst they are horizontal at the top 

 of the cone. This kind of bell structure appears to the author 

 to show the manner in which the mountain was formed. 



H. T. D. B. 



• Here M. dc Ronnard, who, by the signature, noticed this paper in the 

 Bullelin, seems to Iiave added, " Many of'tiicse circumstances are altogether 

 analogous to those presented by the contact of the granite and lower parts 

 of the oolite foruiation in Burgundy."— 7'raw. 



XX. Plan 



