Obsidian Cliff, Yellowstone Park, Wyo., U.S.A.
figureposted on 01.01.1897, 00:00 by B.L. Singley
OBSIDIAN CLIFFS, YELLOWSTONE PARK. After crossing Swan Lake Basin the first object of special interest is called Obsidian Cliffs. The sides of the cliffs rise 220 feet above the roadway, and though the general color is black, there are patches and spots that glisten in the moonlight almost like diamonds. The material of which this escarpment of volcanic outpouring consists is a true natural glass. It is mixed with volcanic ashes, but great masses of pure, translucent glass may be obtained from the thousands of fragments that form the sloping base of the cliffs. This material was used by the Indians for making arrowheads. The roadway along the base of this palisade is a true macadam, made of the crushed obsidian mingled with sand. It is the only glass roadway in the world. the general structure of the rocky cliffs is columnar, like the trap rock of the Palisades of the Hudson and the Columbia, and like the celebrated Giant's Causeway. Remarkable beaver lakes extend along the western base of Obsidian Cliffs, and the glass roadway passes between them. The combined exhibition hereabouts is most interesting.