Page:Africa by Élisée Reclus, Volume 3.djvu/99

 TENERIFFE. 73 Sierra de Teno, dating from a primitive geological period, and consequently similarly eroded at its base by the sea. Between these two sections towers the lofty cone of the comparatively recent volcano, larger than both the other systems combined, and connected with them by lava-streams and intervening volcanoes. The juxtaposition of three independent groups belonging to successive ages has imparted to TenerifPe a general aspect very different from that of the other islands belonging to the same geological epoch. Instead of developing a circular contour like Gran Canaria, Gomera, and so many other islands of like origin, Teneriffe has the outlines of an irregular triangle, the apex of which belongs to recent and the other two angles to older formations. It is thus an Atlantic Trinacria, like the Mediterranean Sicily, the land of ^tna. Most of the island consists of ashes and scoriae with steep rocky escarpments. But it also presents some romantic valleys, all on the north slope, exposed to the trade winds, as well as some cirques whose rich vegetation presents a striking contrast to the gloomy walls of encircling lavas. Thanks to these productive oases of verdure, Teneriffe is able to support a relatively dense population, although its chief resources, wine and cochineal, now yield but slight returns. The hills, which begin in the north-east corner, near Cape Anaga, do not constitute a continuous chain, although their rocky peaks, one of which rises to a height of 3,420 feet, follow in succession from east to west as far as the plateau of Laguna. At the Anaga headland now stands a first-class lighthouse, and the plateau is crossed at a height of 1,870 feet by the main highway of the island between Santa Cruz and Orotava. The uplands of the Laguna terrace are inter- rupted by a sudden gap, b; yond which the land again rises, developing a regular chain commanded by the heights of Guimar, and again interrupted by a profound depression. Beyond this depression stands a volcano which rose in 1705, dis- charging a stream of lava eastwards nearly to the coast. It is the first cone of the encircling wall, which develops a semicircle east and south of the Peak of Teyde, and which presents on a far larger scale the same aspect as the wall of La Somma round Vesuvius. It is the largest known formation of this class on the surface of the globe, having a total length of 33 miles and a height of over 6,700 feet, above which several of its peaks, such as Azidejos and Guajarra, rise to 9,000 feet and upwards. The concave side of the chain facing the peak of Teyde com- mands a plateau of lava and scoriae lying some 1,000 feet lower down, while on the outer side all the narrow and deep crevasses of the crest, hence known as the Circo de las Cailadas, are disposed in deep barrancas descending in diverging lines to the coast. The western extremity of this system merges in a " mal pais," or chaos of lavas strewn with volcanoes, one of which, the Chahorra, attains an elevation of 8,270 feet. Farther west the cones are so numerous that the inter- vening lava-streams ramify in all directions like a vast labyrinth. The outer edge of the mass rising above the Teno heights ends in the Montana Bermeja, or "Red Mountain," whence was ejected a stream of lava in the year 1706. Thus recent lavas mark both extremities of the enclosure wh'ich encircles the base of the dominating volcano, the Echeyde of the old inhabitants, now known as the Peak 69— AF