to the east the river Marosch from Toplitza upwards, the Aluta from Varosch to Tuschnad and Kasson; to the west, a line passing through Kasson, Tulle, Udyarhely, Parayd, Libonfalva and Pata. It is for the most part composed of various kinds of trachytic conglomerate, of which the best sections are presented along the course of the Marosch, for elsewhere a most impracticable forest of pines 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 mostly 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 nowhere observed, although black trachyte abounds. Distinct craters are only seen at the southern extremity of the chain. One of the finest observed by Dr. Boué was to the south of Tuschnad; it was of great size and well-characterized, surrounded by pretty steep and lofty hills composed of trachyte. The bottom of the hollow was full of water. The ground near has a very strong sulphureous odour. A mile in a S.S.E. direction from this point there are on the table-land two large and distinct “maars,” like those of the Eifel, that is to say, old craters, which have been lakes, and are now covered with a thick coat of marsh plants; the cattle dare not graze upon them for fear of sinking in.

Some miles farther in the same direction is the well-known hill of Budoshegy (or hill of bad smell), a trachytic mountain, near the summit of which is a distinct rent, exhaling very hot sulphureous vapours. The heat of the ground is such as to burn the shoes. A deposition of sulphur has taken place there, and the rock is converted into alum-stone by the

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action of the vapours upon the constituents of the trachyte. In this manner hollows are formed in the rock. At the base of the hill are some very fine ferruginous sulphur springs, much resorted to for various diseases by the inhabitants, who encamp near them in the open air during summer. Chalybeate sulphur springs generally abound at the base of this volcanic range, and chalybeates with carbonic acid still more. Some of these appeared as good as those of Pyrmont, and the most famous, that of Borsah, a bathing-place much resorted to by the Transylvanian nobles, contains more carbonic acid than Pyrmont water itself.

The craters last described have thrown out a vast quantity of pumice, which now forms a deposit of greater or less thickness along the Aluta and the Marosch from Tuschnad to Toplitza. Impressions of plants and some siliceous wood are likewise to be found in it, as is the case in Hungary. These fragments of pumice have been deposited under water. Some, says Dr. Boué, might be disposed to set down a more considerable portion of Transylvania as trachytic than I have done, but I have satisfied myself that many rocks which may appear to be trachyte are nothing but some of the newer transition or coal-sandstone porphyries, which are here and there more scorified than elsewhere, or of which the scorified portions have stood the action of the weather better than the rest. This may be the case with the most recent porphyries of the two great deposits of that formation, the one of Marmorosch, the other in the Gespannschaft (comitat) of Hunyad and the Stuhl of Muhlenbach.

To this account of the volcanic rocks of Transylvania I have only to add that a basaltic cone is mentioned by Beudant as occurring in Schlavonia near Peterwaradin, and that I myself saw in the possession of Professor Schuster at Buda, specimens from that province, and probably from the same locality, which from their scoriform aspect I should judge to be of modern formation.

Dr. Boué also informs me that between Ober-Pullendorf and Stoop, near Güns in Hungary, south of the lake of Neu

del, is a flat conical hill about 100 feet in height, half a league in its greatest diameter, and a quarter of a league in

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its smallest, which rises from the midst of the upper tertiary deposits, or amongst the marly beds lying above the blue shelly marl common to Austria and the Apennines. The rock itself is composed of a blackish or greyish felspathic basalt, which is sometimes compact, and contains oval nodules, partly of mamillary or botryoidal iron ore, and partly of arragonite; sometimes very porous, and with the cavities either entirely empty, or coated with globules of sphærosiderite.

The direction of the cells is from E.N.E. to W.S.W., and the same is the direction of the range itself. It is decidedly a tertiary basaltic cone, having its base only covered by recent marls.

CHAPTER VII.

VOLCANIC ROCKS OF STYRIA.

Volcanos of Styria.— Trachyte of Gleichenberg near Grätz.-Age of the

beds surrounding it.-Mode of accounting for the position occupied by

the trachyte.— Trachyte of Cilli. On my way from Vienna into Italy in 1823, I deviated a little from the direct road, in order to look at some rocks of a volcanic nature that occur near Friedau in Styria, a little to the south-east of Grätz, of which the only account that had been published was a short one by Von Buch, in the Transactions of the Academy of Berlin.

The formation in question may be briefly stated as consisting of a central nucleus of trachyte, which constitutes the lofty conical hill called the Gleichenberg, round which on all sides apparently are mantle-shaped strata of volcanic tuff, alternating with beds belonging to the tertiary class.

The tuff consists in general of a congeries of very minute fragments of volcanic matter, which seem to have been immediately ejected from the volcano, mixed up and loosely agglutinated with small quartzy pebbles. In the midst of it are fragments of cellular and compact basaltic lava, sometimes containing nests of olivine. Masses of the same substance of a globular form, not imbedded in any matrix, are found also distributed amongst the tuff. Specimens of augite, and of a substance looking like altered granite, likewise occur. The tuff, becoming more and more mixed with particles of clay and sand, passes at length into a loamy earth, at first dark, and afterwards, where it is unmixed with volcanic matter, of an ash-grey colour. The constituents are in a state of very fine division, and a number of minute specks of silvery mica impart a sparkling lustre to the general mass, and give it the appearance of a bed of silt deposited tranquilly at the bottom of a lake.

At a village called Khelig, a little to the south of the former

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locality, I observed that the tuff, which here contained decided scoriæ, was superimposed on a rock which nowise differed from ordinary basalt, except in the existence of minute internal pores. It formed a number of concentric lamellar concretions, of which the external have become decomposed, whilst the internal retain their solidity. The exterior surface of the balls is coated with asphaltum. The whole rests upon a bed of marl without any traces of volcanic matter.

We find, at a somewhat greater distance from the central trachyte, strata of limestone full of shells, belonging to the most recent order of deposits, amongst which the miliolite occurs, but which consists in a great degree of a conglomeration of little oval concretions, which give to the rock exactly the appearance of the colite of our own country.

Professor Sedgwick and Sir Roderick Murchison, who in the year 1829 visited this district, consider the above-mentioned rocks as belonging to the newest of the three groups into which they divide the tertiary formations of Styria and Austria.

But Mr. Lyell sees no sufficient reason for separating the beds which belong to this newest division from those of the miocene period, and consequently regards the principal eruptions of volcanic matter which took place in that province as having begun at the same epoch.

Respecting the age at which the igneous causes ceased, these authors offer no conjecture. We do not find traces of their action since the sea retired from the bays of Lower Styria, as no igneous rocks follow the direction of the valleys or inclined planes presented by the existing surface of the country. On the contrary, they rise in steep insulated masses, formed, evidently, before the rivers drained through their present channels; and they offer most emphatic proofs of the enormous degr::dation and waste of the country since the formation of one of the newest regular deposits known in geology

Two hypotheses present themselves with respect to the age of the trachyte of the Gleichenberg; for it may either be said, that having been first thrown up by volcanic action, the beds of tuff and of marl collected by degrees around its base; or that after the latter had been formed in a position approach