Page:Africa by Élisée Reclus, Volume 3.djvu/65

 ejected during successive marine eruptions, and round the periphery furrowed by deep valleys, which bear witness to the great antiquity of the lavas. The basalts and trachytes resting on a conglomerate of volcanic débris, called vinoso from its colour, and traversed in every direction, by dykes of injected matter, have been eroded by the rains and torrents to a depth of many hundred feet below the original surface. No distinct craters are any longer visible; the escarpments have lost their sharp scoriæ; all rugosities and rocky points have been rounded or covered with vegetable humus. Hence, despite the chasms and their steep walls, the whole surface has assumed a soft and charming aspect, even where

the rocks have not been clothed with the verdure of brushwood or forest growths. There are no indications of any surviving volcanic life, and earthquakes are of rare occurrence.

The island is traversed from end to end by a high saddle-back, broadening here and there into plateaux, and again contracting to a narrow ridge. Lateral spurs branching from the main range, and separated from each other by profound gorges, terminate on the coast in abrupt headlands, columnar basalt cliffs, and many-coloured tufas, whose brown, red, and yellow tints produce a very vivid effect. Cape Giram, one of these headlands, about the middle of the south coast,