The deterioration of engraved surfaces is significant to the understanding of pre and protohistorical environments in the Atlas Mountains. A better understanding of the palaeoenvironmental evolution of sites and their engraved or painted rock surfaces can be gained from the collaboration between geomorphologists and art prehistorians. Such cooperation is particularly profitable when investigating the relationships that often exist between the chronological sequence of geomorphological processes that affect rock art (or such processes that one can relate to the art), and the relative chronology presently applied to the petroglyphs or paintings. Two examples from the sub-Saharan Atlas Mountains in Algeria are examined. This study relates petroglyphs to cyclic rock exfoliation and to the generations of patination associated with it.