Note 5 — Chapter I · ST. JAGO, IN THE CAPE DE VERDE ARCHIPELAGO.
Reading edition
The sides of this gorge, where the upper basaltic stratum is intersected, are almost perpendicular. The lava, which has since filled it up, is attached to these sides, almost as firmly as a dike is to its walls. In most cases, where a stream of lava has flowed down a valley, it is bounded on each side by loose scoriaceous masses.