The El Hoyo Formation js located at the boundary: between the Obejo-Valsequil/o-Puebla de la Reina Domain and the Badajo/.-Córdoba Shear Belt. This serie is composed by quartz-schists and mica-schists, finé grained quartzites, coarse grained arkoses with conglomerates and medium grained arkoses. This Formation defines a transcurrent duplex with ÑE mergences of the cartografie sketch. This Formation age is still unknown, in this paper, Lower-Middle Cambrian age is proposed for correlation with other areas of Ossa-Morena Zone and Massif Iberian