oportion. 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)."

In concluding this highly instructive and interesting memoir of the
volcanic rocks of Hungary, Professor Judd says: "The mineral veins of
Hungary and Transylvania, with their rich deposits of gold and silver,
cannot be of older date than the Miocene, while some of them are
certainly more recent than the Pliocene. Hence these deposits of ore
must all have been formed at a later period than the clays and sands on
which London stands; while in some cases they appear to be of even
younger date than the gravelly beds of our crags!"

For any one who desires to geologise in Hungary and Transylvania there
is abundant assistance to be obtained in the maps which have been issued
by the Imperial Geological Institute of Vienna, under the successive
direction of Haidinger and Von Hauer. "These are geologically-coloured
copies of the whole of the 165 sheets of the military map of the empire;
and these have been accompanied by most valuable memoirs on the
different districts, published in the well-known 'Jahrbuch' of the
Institute. Franz von Hauer has further completed a reduction of these
large-scale maps to a general map consisting of twelve sheets, with a
memoir descriptive of each, and has finally in his most valuable and
useful work, 'Die Geologie und ihre Anwendung auf die Kenntniss der
Bodenbeschaffenheit der Osterrungar. Monarchie,' which is accompanied by
a single-sheet map of the whole country, summarised in a most able
manner the entire mass of information hitherto obtained concerning the
geology of the empire."

I have given this passage from Mr Judd's paper because there exists a
good deal of misapprehension amongst English travellers as to what has
really been done with regard to the geological survey of Austro-Hungary.

[Footnote 18: A Description of Active and Extinct Volcanoes, by C.
Daubeny, p. 133. 1848.]

[Footnote 19: 'On the Ancient Volcano of the District of Schemnitz,
Hungary,' Quarterly Journal, Geo. Soc., August 1876.]

CHAPTER XXI.

A ride