The sandstones which are the host wall-rock for prehistoric-art representations in Tajo Figuras (Cádiz) and Peñas Cabreras (Málaga) prehistoric-art sites show extensive alteration features damaging the paintings and engravings. These features include alteration crusts, detachment of rock-plates, alveolar surfaces and grainificalion. Climatic and geomorphic conditions, together with the compositional characteristics of the sandstones are thought to be the main factors responsible of these alteration feature
