In the north, the Oristanian coast starts with the white Porto Alabe beach, at Marina di Tresnuraghes, after which the high basalt cliffs, created by the eruption of Montiferru, form an evocative black wall. As you reach S. Caterina di Pittinuri the basalt rocks give way to strangely formed plastic-like rocks, the more important of these being Su Riu and S’Archittu, which forms a natural arch in the sea. Continuing on you reach Is Arenas with a 6 km. beach lying between the sea and an immense pine wood. Following the enchanting Sa Mesa Longa cove with a small island of the same name, dominated by the Capu Mannu rock. Mandriola, Putzu Idu and S’Arena Scoada seaside resorts lie on the isthmus formed by a sandy strip. Starting from Capo Sa Sturaggia, the coast suddenly opens out to show the quartz beaches of Porto Suedda and Is Aruttas, from a naturalist’s point of view among the most important in Sardinia. Continuing in a southerly direction you come across the Turr’e Seu promontory which hosts an interesting naturalistic oasis. Just past there is the S. Giovanni di Sinis beach and the Capo S. Marco promontory at the end of the Sinis peninsula. Then there is Torregrande and after the port of Oristano you come to the extensive Arborea beaches.