MODE IV. FELSITE. 173 



parations into large plates and ill-formed pillars. 

 Examples of such grotesque rocks, are the Biliner- 

 stein, near Belin, and the Engelhaus-berg, not far 

 from Carlsbad. 



" To complete the history of this stone, I must 

 briefly notice an opinion which has of late been in 

 vogue, and even now seems to have its abettors. 

 I mean, that the klingstone-porphyry, as well as 

 the basalt, the amygdaloid (mandelstein), and 

 other trap mountains, have been considered as 

 volcanic productions, or lavas. It does not be- 

 long to the object of the present inquiry to repeat 

 and to examine what on both sides of the question 

 has been argued, and sometimes with violence 

 disputed. I shall only mention, that in the se- 

 veral attentive inspections with which I examined, 

 in the middle mountains of Bohemia, the sites of 

 basalt and klingstone-porphyry, I could not dis- 

 cover the least vestige of a crater, or other signs 

 of a volcanic nature ; no more than any other un- 

 prejudiced observer would have been able to find. 



" To these short geognostic remarks I shall 

 now add the description of the external characters 

 of the mass, which chiefly constitutes the kling- 

 stone-porphyry. 



" The colour of the klingstone is grey, now and 

 then a little inclining to the green. It occurs 

 only massive. It has a fine grain, an uneven, 



