Page:Africa by Élisée Reclus, Volume 3.djvu/109

 Santa-Luzia, Ilheo Branco, Ilheo Razo, Sam-Nicolau, whose hills or mountains all runina direct line, thus constituting quite a separate group, which from a distance looks like a single island indented with deep inlets. Farther east Sult and Bõa-Vista, continued south-westwards by the Bank of Joam Leitano, form a second group at the eastern verge of the semicircle. Lastly the southern section comprises Maio, Sam-Thiago, Fogo, Brava, and a few islets. All the northern islands, including Salt and Bõa-Vista, take the collective name of Barlovento, or "Windward," the four others that of the "Leeward" Islands.

The Cape Verd archipelago seems to belong to an older geological epoch than the almost exclusively volcanic Canaries and Azores. All the islands have no doubt their craters and eruptive rocks, while Santo-Antam and Fogo consist exclusively of scoriæ and lavas. But in the others are also found crystalline rocks, granites, syenites, and "foyaite," so called from Mount Foya in Algarve. Fine metamorphic marbles and sedimentary rocks also occur, and Maio is especially remarkable for the relative extent of its non-igneous formations, a fact which certainly favours the theory of an Atlantic continent formerly occupying these waters.