30 RICHTHOFBN — =- NATURAL SYSTEM 



sequent eruptions of those belonging to other orders. At several places it has 

 been observed to intersect Eocene strata, and to expand above them. The coun- 

 try of Nagyb&iya, Felsobauya and Kapnik, the celebrated silver-bearing veins of 

 which are enclosed in propylite, offers especially conspicuous illustrations; not less, 

 from the descriptions given by G. Stache, the " Erzgebirge " of Transylvania, where 

 the same kind of rock is rich in mineral veins. In this country, hornblendic propylite 

 forms an older series, followed by eruptions of highly quartziferous varieties. In 

 both countries, but chiefly in that first named, and at several other places along the 

 southern slope of the Carpathians, andesite maybe seen intersecting propylite in large 

 massive dykes, and towering up above it in mountain ranges. Andesite composes 

 entirely the Hargitta-range, which extends over one hundred miles in length, and 

 twenty-five in width ; the Vihorlat-Gutin-range, which is of still larger dimensions, 

 and the Eperies-Kaschau-range ; all of which are densely wooded, and of a gloomy, 

 monotonous aspect. The only change observable on their summit ranges is a more or 

 less dark color of the rock, occasioned by the predominance of augite or hornblende in 

 its composition, (the augitic varieties being invariably of more recent age than the 

 hornblendic), while their slopes, and particularly their ends, present a much greater 

 variety in rocks as well as in scenery. It is here that the more silicious volcanic rocks 

 are encountered. Trachyte is of rare occurrence ; but it forms several isolated cones, 

 some of which, on account of their prominent position, were crowmed by castles in the 

 middle ages. Rhyolite is much more frequently met with, bursting forth on the 

 flanks, and skirting the foot of the andesitic ranges, particularly where they verge 

 towards the Hungarian plains, which in the rhyolitic epoch were still covered by a 

 shallow and slowly retiring sea. It projects against this in promontories, which are 

 now covered by the most celebrated of the Hungarian vineyards, those of Tokay 

 among others. The boundaries of these vineyards towards the adjoining beech forests 

 mark the dividing line between rhyolite and andesite. An interesting mode of occur- 

 rence of the former may be witnessed in large circular or amphitheatrical basins which 

 are surrounded by andesite. Such places are the theater, especially, of the volcanic 

 activity connected with the outbreak of rhyolite, and abound in endless hyaline vari- 

 eties of the same. Telkibanya is the most interesting among the localities of this 

 description. There is no lack of evidence to prove that trachyte and rhyolite are both 

 of more recent age than andesite, while the assertion that trachyte preceded rhyolite 

 in age, rests only on a few though conclusive observations. Basalt occupies a singular 

 position in the geology of Hungary. It keeps altogether aloof from the places occupied 

 by the other four orders of volcanic rocks, and forms extensive, though isolated, hills at 

 some distance from them, scattered over a wide range of country. It would be difficult 

 to determine its relative age, but for the volcanic sediments which were of formation 

 contemporaneous with the ejection of the different volcanic rocks, and have been spread 

 over wide areas at the bottom of the then existing sea, with fossils occasionally imbedded. 

 In several localities, especially in the neighborhood of Kaschau, basaltic sediments may 

 be seen, covering those composed of rhyolitic matter, while at Gleichenberg in Styria, 

 Mr. Franz von Hauer has observed fragments of rhyolite enclosed in basalt. 



The observation of these relations in Hungary and Transylvania has first given 

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