At the base of the tunnel we found ourselves on the threshold of an immense, almost circular cave, with a diameter of some fifty meters, rising overhead into a regular vault or dome about twenty-seven meters in height. The entrance to the cave is so large that plenty of daylight is admitted, and the whole cave easily examined. The rocks are of a yellowish brown hue, and I could not help thinking of Nibelheim in Richard Wagner's Rheingold. [Illustration: Fig. 1.[2] Vertical Section of Chaux-les-Passavant.] [2] The figures in this book are rough sketches, without pretense at accuracy of measurement, and are only explanatory of the text. The bottom of the cave was entirely covered with a flooring of ice. How thick this flooring was there was no means of judging, as there were no holes, but it must have been at least two or three meters thick in places. At the back of the cavern, directly facing the entrance, one magnificent frozen water fall streamed from a fissure. It was perhaps five meters high, and began to take the fan shape from its origin. The base was about four meters wide, and did not rest on the ice floor, but on a sloping rock extending out from the side of the cave. Perhaps the most remarkable feature of all, were six or seven great ice stalagmites, shaped like cones or rough pyramids, which rose on the floor of the cave. One of these was at least five meters in diameter and six in height, and seemed perfectly solid. In the case of two of the others, however, the cones were broken on one side, revealing in each the stem and branches of a young pine tree. These evidently had been planted in the ice and round them the columns had grown. Whether all the ice cones were thus artificial in their origin I could not determine, but it seemed probable that they were the result of years of undisturbed accretion and growth. In both the cones where the break on the side gave a view into the interior, the dark blue-green color of deep glacier crevasses was present. A pool of water, perhaps thirty centimeters in depth and three or four meters in diameter, lay at one place on the ice floor. The whole cave was damp and the ice in places decidedly slushy, in fact all the signs showed that it was thawing. In the case of this glacière as well as in those of the Mont Parmelan, it seemed clear that it must be in the winter months that the formation of ice takes place. [Illustration: ICE STALAGMITES, CHAUX-LES-PASSAVANT. From a Photograph by E. Mauvillier. ] DÓBSINA JEGBARLANG.