A layer of hard rock, most likely a several meters thick conglomerate layer, makes the flat summits of the tabular geomorphology. The erosion of the soft rocks just below, most likely mudstones, outlines the resistant rock layer on top. As the basement is lost, the hard rock layer of the summit is projected out until big, roughly poligonal as a result of former crevices, blocks of rock fall down. The number of conglomerate blocks in the slope fell down from the summit layer. Additional blocks will fall in the future. The image is taken in the south slope of Santa Cecília de Grevalosa (Castellfollit del Boix) hermitage. [photo Jordi Badia]