Between Santo António and São Roque do Pico, the old cliff was covered by several more recent basaltic lava flows that advanced the coastline and consequently expanded the island. This fossil cliff extends from Ginjal (to the west), including the Furna area and the Camp Site, to Cais do Pico – Ribeira de Dentro (to the east), covering a total length of about 4.5 km. The old cliff is composed of aa-type basaltic lava flows, often covered by very fluid pahoehoe flows from Pico Mountain, which gave rise to spectacular lava cascades. In this geosite, there’s an old exploitation of ankaramitic basalt (rock with abundant and large phenocrysts of pyroxene and olivine), which was used in the construction of the São Roque harbour. The coastal area of Furna has high and steep cliffs, small islets, and some submerged caves. This geosite has several bathing areas, such as the Furna and Cais do Pico pools, and São Roque’s rock pools, as well as areas for diving and two hiking trails. This is a geosite of regional relevance with scientific, educational, and economic uses.
