Page:Africa by Élisée Reclus, Volume 3.djvu/57

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TOPOGRAPHY OF THE AZORES.
39

second town in San-Miguel, and Capellas, the most frequented summer retreat of the wealthy islanders.

The waters separating San-Miguel from Terceira were the scene of violent submarine disturbances in 1720, when a temporary volcano rose for a short time above the surface. In 1867 the convulsions were renewed near the village of Serreta, at_ the western extremity of Terceira, when another heap of scoriæ was formed, without, however, reaching the level of the sea. On this occasion the ground was in a constant state of agitation for months together, as many as fifty shocks occurring more than once in a single day, some strong enough to overthrow the houses. The eruption which gave birth to the sub-marine volcano lasted seven

Fig. 17. — Central Islands of the Azores Archipelago.

days, during which the surrounding waters were coloured yellow, green, and red by the ferruginous salts in solution.

Like San-Miguel, the oval island of Terceira, or "the Third," consists of two sections, the central and eastern, with its Caldeiram, or "Kettle," and the western with its Culdeira, or "Boiler," of Santa-Barbara, belonging to different geological epochs. The Kettle is a cirque some 6 miles in circumference, encircled by volcanic cones and entirely overgrown with a thicket of brushwood. From its rim a view is commanded of all the central islands in the archipelago, and the faint outlines of San-Miguel, away to the south-east, may even be discerned in fine weather. The last eruption in the interior of Terceira occurred in 1761, the red lava streams then ejected being still nearly destitute of vegetation. A little gas