Situated in the Indian Ocean, 300 miles eastwards from Mauritius, the island of Rodriguez, like the sister Mascarene Islands, is a mass of volcanic rock. A fringing reef of coral, studded with islets, skirts it on every side, extending on the west about three miles from the land, hut at the eastern end the edge of the reef is within about a hundred yards of the beach. The island consists of a series of hills. It extreme length, from a little north of east to a little south of west, is about 11 miles and its breadth from north to south about 5 miles. Within this base the land rises towards the centre of the island, where are several peaks, none attaining any great elevation, the highest point, Mount Limon, being only 1,300 feet above the sea level. A main ridge runs along the island in a direction parallel with its greatest diameter, and rather nearer the southern shore. Its slopes rise with some abruptness from the sea on the eastern side, but on the west extend more gradually seawards, and terminate in a wide coralline limestone plain studded with elevations between Baie Topaze and Anse du Peril. The sides of the ridge as they stretch to the sea are deeply cut into ravines. The slopes on the southern side are shorter, and the ravines deeper and more numerous, than on the north. In their upper parts these ravines are bordered by lofty and inaccessible cliffs, upon which the volcanic structure of the island is well marked, and coulee is seen to succeed coulee, separated only by thin beds of cinder, agglomerate, or variously coloured clays. In some instances these cliffs are 300 feet high, and as many as 12 successive coulées may be counted on one cliff. Through these ravines the streams as they descend form in their upper parts a series of cascades, and sometimes high falls. One of the finest is the Cascade Victoire at the head of the Rivière Poursuite, where it falls over a cliff more than a hundred feet high. As the sea is approached, the ravines expand into wide valleys flanked by gently sloping and terraced ridges. These ridges too are in some places marked by lofty cliffs, on which the columnar basaltic character of the rocks is well seen. A splendid example of this is Tonnerre Cliff in the valley Riviére aux huitres, a bold perpendicular face of prismatic columns 200 feet high. At Pointe la Pouche also this structure is conspicuous.