Impressions of plants and some silicious wood are likewise to
be found in it."[18]
Since Dr Daubeny's time there have been many observers over the same
ground, the most distinguished being the Hungarian geologist Szabo,
professor at the University of Buda-Pest. A countryman of our own has
also taken up the subject of the ancient volcanoes of Hungary, and has
recently published a paper on the subject. Professor Judd has confined
his remarks principally to the Schemnitz district in the north of
Hungary. But the following passage refers to the general character of
the formation. Professor Judd says:[19] "The most interesting fact with
regard to the constitution of these Hungarian lavas, which in the
central parts of their masses are often found to assume a very coarsely
crystalline and almost granitic character, while their outer portions
present a strikingly scoriaceous or slaggy appearance, remains to be
noticed. It is, that though the predominant felspar in them is always of
the basic type, yet they not unfrequently contain _free quartz_,
sometimes in very large proportion. This free quartz is in some cases
found to constitute large irregular crystalline grains in the mass, just
like those of the ordinary orthoclase quartz-trachytes; but at other
times its presence can only be detected by the microscope in thin
sections. These quartziferous andesites were by Stache, who first
clearly pointed out their true character, styled 'Dacites,' from the
circumstance of their prevalence in Transylvania (the ancient Dacia).
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