A still more famous Norwegian cataract is the Sarp-fos in the Stor-Elven, formed by the junction of the Lougen and Glommen, the largest of the Norwegian rivers. Like the Riunkan-fos the stream is greatly contracted in a rocky gorge, and at the edge of the cliff is divided into two channels which, however, soon unite in a fall of one hundred feet upon huge masses of rock, through and over which it rushes tumultuously for a short distance, and then flows quietly into the sea. The volume of water is unusually large for a purely mountain river, being in the gorge at the top of the fall one hundred and fifty feet wide and forty feet deep. The massive and intensely white column contrasted with the dark green foliage of the solemn pines, and the darker rocks about it, and the deep blue water into which it falls, produce a vivid impression on the mind of the beholder. The Stor-Elven here presents the curious phenomenon of a stream changing, not from a perpendicular fall to a rapid, but the reverse, from a rapid to a perpendicular fall. A great portion of the right bank of the river at the fall, and for a considerable distance below, is chiefly composed of a stiff blue clay, and the river once flowed past Sarpsborg, a mile below, in a succession of magnificent rapids. At that time a superb mansion with numerous out-buildings stood at the termination of the rapids. On the 5th of February, 1702, the mansion, together with everything in and about it, sunk into an abyss six hundred feet deep, and was entirely buried beneath the water. The walls of the house were of unusual strength and thickness, with several high towers, but the whole was buried out of sight. Fourteen persons and two hundred head of cattle were also engulfed. The catastrophe was caused by the washing out of the blue clay, and the undermining of the bank, which then toppled over into the watery chasm. [Illustration: UPPER FALLS OF THE YELLOWSTONE] In Switzerland is the Staubbach--dust-stream--a well known fall in the canton of Berne. It has a sheer descent of nearly nine hundred feet, in which the water is converted into spray that is easily moved by the wind, thus giving it a singularly beautiful resemblance to a white curtain floating in the air.