BEAUTIES OF THE UNDER-GROUND WORLD.

It has often happened that in the course of excavations in search of minerals, the workmen have come upon some singular hollows or openings in the rock, caused by convulsions of the earth or earthquakes, or caverns through which torrents have flowed in former ages, and have left them for nature to ornament in the most beautiful and fantastic manner.

You will understand how the natural caverns are formed that you may have seen on the sea-coast; the moving waters, carrying with them gravel and sand, enter the cracks and crevices in the rocks, and increase their size by wearing away portions of the rock until caverns are formed. Some of these are of immense size, and the extent of many is unknown.

Many caverns are lined with beautiful crystals, called calcareous spar, or substances containing much lime, and generally colored by the impurities of the water that has dropped on them. Sometimes these crystals are of a pure white, and have, when the cave is lighted up, a richness and transparency that can scarcely be imagined. Others have the appearance of stone, moss, and shells, in every variety of color.

Caverns of enormous extent occur in Iceland; that of Gurtshellir being forty feet in height, fifty in breadth, and nearly a mile in length. It is situated in the lava that has flowed from a volcano. Beautiful black stalactites hang from the spacious vault, and the sides are covered with glazed stripes, a thick covering of ice, clear as crystal, coating the floor. One spot in particular is mentioned by a traveller, when seen by torch-light, as surpassing anything that can be described. The roof and sides of the cave were decorated with the most superb icicles, crystallized in every possible form, many of which rivalled in delicacy the clearest froth or foam, while from the icy floor arose pillars of the same substance, in all the curious and fantastic shapes that can be imagined. A more brilliant scene, perhaps, never presented itself to the human eye.