Notice of Active and Extinct Volcanos. 251 



3d, the pumiceous conglomerates, composed of fragments of pumice 

 and obsidian, agglutinated either immediately, or by the inter- 

 vention of some cement more or less earthy. 



4th, the porphyritic conglomerates, resulting from the decomposi- 

 tion of the pumice. 



5th, the aluminous beds, consisting of tufaceous or conglomerated 

 rocks impregnated with alum." 



Transylvania. 



Professor Daubeny, derives his knowledge of the rocks of 

 Transylvania from a private communication of Dr. Boue, of 

 whose geological labors there is a notice from the pen of Dr. 

 J. W. Webster. See vol. 6, p. 185, of this Journal. 



Unfortunately, Dr. Boue's contemplated journey through 

 the Bannat and the provinces of the Austrian empire as far 

 as Trieste, was prevented by " a severe illness occasioned by 

 the villany of a servant, who attempted to poison him in 

 order the more readily to make off with his money and prop- 

 erty." 



In the eastern part of Transylvania there are volcanic 

 rocks of undoubted tertiary formation. 



" They are for i*he most part composed of various kinds of 

 trachytic conglomerate ; of which the best sections are presen- 

 ted along the course of the Marosch, for elsewhere a most im- 

 practicable forest of pine and oaks covers it nearly throughout. 

 From the midst of these vast tufaceous deposits, the tops of the 

 hills composed of trachyte, a rock which forms all the loftiest 

 eminences, here and there emerge. Of these the most elevated 

 is called Kelemany; the other principal ones are Fatatschion, 

 Pritzilasso, Hargala, Barot, the hills south of Tuschnad, &c. &c. 

 The trachyte is ordinarily reddish, greyish, or blackish ; it most- 

 ly contains mica. In the southern parts, as near Tschik Sereda, 

 the trachyte incloses large masses, sometimes forming even small 

 hillocks, of that variety of which millstones are made, having 

 quartz crystals disseminated through it, and in general indurated 

 by siliceous matter in so fine a state of division that the parts are 

 nearly invisible. The latter substance seems to be the result of 

 a kind of sublimation, which took place at the moment of the 

 formation of the trachyte. 



" Basalts were no where observed, although black trachyte 

 abounds. Distinct craters are only seen at the southern extremi- 

 ty of the chain. One of the finest observed by Dr. Boue was 

 to the south of Tuschnad ; it was of great size, and well charac- 

 terized, surrounded by pretty steep and lofty hills composed of 



