Las Pilas ravine is located in the southern foothills of the Ajaches massif. This is a basin carved on lava flows and pyroclastic outcrops with radiometric ages of between 14.5 and 1.5 m, corresponding to Dominio de Ajaches. The main canyon basin called Las Pilas fits into its middle and final section on the marine Pliocene rasa, characteristic of a warm coastal environment, since this sector extends to the area of Punta del Papagayo-Las Coloradas. This rasa and in contrast to the Miocene outcrops, developed sandstone deposit biodetritical, marine conglomerates, with frequent rounded edges of basalts and abundant fossil content among which the Strombus coronatus developed. In the upper reaches of the ravine, wind deposits of Miocene / Pliocene that make the fossil dunes the highest in the Canary Islands (160 m a.s.l.).
This geosite is a primary concern of sedimentological type. With additional paleontological and stratigraphic interest. In this geosite, sandstones have been exploited for the manufacture of stone distillers, which were used as water filters and blocks of lintels. This geosite is included in the Monumento Natural de Los Ajaches and has been declared ZEPA (Spanish acronym, Natural Protected Area).