Near Sable in Anjou, a source, or rather a pit from eighteen to twenty- four feet in diameter, well known in the country under the name of the Bottomless Fountain (_Fontaine-sans-fond_) sometimes overflows its brink, and then casts forth a large quantity of fish, so that it is evidently a mere aperture in the vault of a large subterranean pool. In the department of the Haute Saône, another pit, called the Frais Puits, presents a similar phenomenon. After abundant rains, the water gushing forth from its mouth inundates the neighbourhood, and on its retiring, pikes are not seldom found scattered over the surface of the flooded fields or meadows, a sure proof that the Puits must communicate with a large subterranean cavity. Nothing is more common in limestone districts than the engulfment of rivers, which, after holding a subterranean course of many miles, escape again by some new outlet. The Guadiana loses itself in a flat country in the midst of an immense savannah, and hence the Spaniards, when the magnificent bridges of London or Paris are mentioned to them, boastfully reply that they have one in Estramadura on which more than a hundred thousand oxen graze at a time. In the vast limestone formation which, under various names, extends through Carinthia, Carniola, Istria, Dalmatia, Albania, and Greece, the whole country is perforated like a sponge by an intricate system of subterranean water-courses. In the more elevated districts of the Morea there are many deep land-locked valleys or basins inclosed on all sides by mountains of cavernous limestone. When the torrents are swollen by the rains, they rush from the surrounding heights into these basins; but, instead of forming temporary lakes, as would be the case in most other countries, they are swallowed by chasms, which are sometimes situated in the middle of the plain, constituting the bottom of the closed basin, but more commonly at the foot of the surrounding escarpment of limestone. During the dry season, which in Greece alternates almost as distinctly as between the tropics with a period of rain, these chasms are the favourite retreats of wild animals. Sometimes, in the limestone formation, the same stream repeatedly gushes forth from some cavernous recess, and then again disappears. The caves of Adelsberg, Planina, and Upper Laibach in Carniola are traversed by the same river, which, losing its name every time it plunges into a new subterranean channel, is called, first, the Poik, then the Unz, and finally the Laibach. In the same manner the Temenitz, an affluent of the Save, thrice disappears under the earth, and thrice emerges as a new- born river with another name.