its gaseous fumaroles, and the flames thrown out with a loud roaring noise from one gloomy cavern in its side, this volcano may still be considered active.  Its white calcined crater is clothed in some places with green shrubs, particularly with luxuriant sage, myrtle, and white heather; but an eruption took place in it so late as 1198, during which a lava current, a rare phenomenon in this district, flowed from its southern edge to the sea, destroying the ancient cemetery on the Via Puteolana, and forming the present promontory of Olibano.  The ground sounds hollow beneath a heavy tread, reminding one unpleasantly that but a thin crust covers the fiery abyss which might break through at any moment.  With the exception of Vesuvius, this is the only surviving remnant of the fierce elemental forces which have devastated this coast in every direction.  The whole region is one mass of craters of various sizes and ages, some far older than Vesuvius, and others of comparatively recent origin.  They are all craters of eruption and not of elevation; and in their formation they have interfered with and in some cases almost obliterated pre-existing ones.  Some of them are filled with lakes, and others clothed with luxuriant vineyards, and wild woods fit for the chase, or encircling cultivated fields.  To one looking upon it from a commanding position such as the heights of Posilipo, the landscape presents a universally blistered appearance.  Hot mineral springs everywhere abound, often associated with the ruins of old Roman baths; and the soil is a white felspathic ash, disposed in layers of such fineness and regularity that they look as if they had been stratified under water, the sea and the shore having alternately given place to each other.  Of the white earth abounding on every side, which has given to the place the old name of Campi Leucogaei, and is the result of the metamorphosis of the trachytic tufa by the chemical action of the gases that rise up through the fumaroles, a very fine variety of porcelain—­known to collectors as Capo di Monti—­used to be made on the hill behind Naples, and it has been supposed that the china clays of Cornwall and other places have been produced from the felspars of the granites in a similar way.  The whole of the Solfatara crater has been enclosed for the purpose of manufacturing alum from its soil.  On the hillside to the north there are several caverns, called stufe, from whence gas and hot steam arise, and these are used by the inhabitants as admirable vapour baths.  So late as the year 1538 a terrible volcanic explosion, accompanied with violent earthquakes, happened not far from Puteoli, which threw up from the flat plain on which the village of Tripergola stood, a mountain called Monte Nuovo, four hundred and forty feet high and a mile and a half in circumference, consisting entirely of ashes and cinders, obliterating a large part of the celebrated Leucrine Lake, elevating the site of the temple of Serapis sixteen feet, and then depressing it, and generally changing the old features of this locality.  This eruption gave relief to the throes of Lake Avernus, which henceforth ceased to send forth its exhalations, and became the cheerful garden scene which we now behold.