Cabeço das Laranjas (Ilhéu de Cima)

Geosite, at the north-western tip of Ilhéu de Cima, 81 m above the sea. The outcrop concentrates fossil calcareous algae — structures built by calcareous red algae — dated to 15–14 million years, from the phase when the island had not yet emerged. They lie between a submarine volcanic complex (18.8 to 13.5 million years) and a subaerial one (14 to 10.2 million years), which makes this point a marker for dating the island's emergence.