[Illustration:  CRATER AND LAKE ON TOP OF THE MOSENBERGE.]

After having made these observations, we descend from the height which afforded us the view of the Vinrt Valley.  A clear brook flows through green meadows and variegated fields stretch along the mountain sides, while modest little villages are scattered among the fruit trees.  On the other side of the valley rises the Herchenberg, an extinct volcano.  As we climb its sides we see traces of the former devastation.  Loose ashes cover the ground, bits of mica glittering in the sun, and on the summit we find enormous masses of stone which were melted and then baked together.  In the center lies the old crater, a quiet, barren place bearing very little vegetation, but from its wall an excellent view of the surrounding country can be obtained.  Not far from this mountain lies the mighty Bausenberg, with its immense, well preserved crater, only one side of which has been broken away, and which is covered with a thick growth of bushes.  The ledges of this mountain are full of interest for the mineralogist.  Nearer to Lake Laach are the Wahnenkopfe, the proud Veitskopf, and other cone-shaped peaks.  To these we direct our steps, and after a long tramp over the rolling, cultivated plateau, we climb the wood-covered sides of the great basin in whose depths the Laachersee lies.  From the shore of this lake rise the high volcanic peaks which tower above all the other mountains.

[Illustration:  LAKE GEMUNDEN.]

Tired from our climb through the ashes, which are heated by the sun, we rest in the shade of a beech-wood, looking through the leaves into the valley below us, with the old cloisters and the high Roman church which the monks once built on the banks of the lake.

[Illustration:  THE CRATER OF THE HERCHENBERGES.]

To the south of the lake rise other volcanoes, lying on the border of the fertile Maifeld, which gradually descends to the valley of Neuwied.  Here, at the southern declivity of the group of volcanoes which surrounds the Laachersee, remarkably large streams of lava were ejected, covering the surface of the plateau with a thick layer.  The largest of these streams is that from the Niedermendig, which consists of porous masses of nepheline lava.  In the time of the Romans millstones were made from this mass of rock, and the industry is carried on now on a larger scale.  It is a strange sight which meets one’s eyes when, after descending through narrow passages, he finds himself in large, dark halls, from which the stone has been cut away, and in which there are well-like shafts.  The stones are raised through these shafts by means of gigantic cranes and engines.  Because of the rapid evaporation of the water in the porous stone, these vaults are always cool, winter and summer, and therefore they are used by several brewers as storehouses for their beer, which owes its fame to these underground halls.

[Illustration:  THE MILLSTONE GALLERIES IN THE LAVA BEDS OF NIEDERMENDIG.]