Palaeomagnetic results are reported from three formations from the late Precambrian to lower Paleozoic sedimentary sequence of L'Adrar de Mauritanie, on the West African Craton. Each of the formations recorded complex magnetizations, the sequence of which could only be resolved after detailed thermal and chemical cleaning. Most of these complexities have arisen from post depositional hematite coating on both magnetic and non-magnetic grains. Formation I2 with a probable age of 1020 Ma records an early, presumably original remanence directed along D = 034°, I = +60° (α95 = 6°) and a later remanence D = 336°, I = +37° (α95 = 11°). Specimens from formations CO8 and CO10 (Cambro–Ordovician boundary) record a common late phase remanence at D = 128°, I = +24° (α95 = 8°). The CO10 early phase remanence is D = 033°, I = +61° (α95 = 7°), whereas the poorly isolated early phase remanence of CO8 approximates D = 060°, I = +51° (α95 = 20°).