Abstract: The authors first review the three parts of the Precambrian cover of the Proterozoic chains of the Anti-Atlas（Morocco）: the volcanic and molassic Precambrian III,the dolomitic Adoudounian an the Taliwinia （"lie de vin"series）which is mainly continental but develops into marine stromatolitecontaining formations in the west,enabling the transition from the Taliwinian to the Lower Cambrian to be defined. The paragraphs,that follow give a brief history of the discovery and study of the Lower Cambrian and an outline of the trilobite"stages"of the Lower Cambrian of the western Anti-Atlas. The note is accompanied by a number of paleogeographical maps of the Adoudounian,the Taliwinian and the Lower Cambrian, and a unmber of stratgraphic and structural sections.