Caderno Lab. Xeolóxico de Laxe Coruña. 1995. Vol. 20, pp. 117-122 Presencia de pirofilita en reemplazamientos de conchas de espiriféridos (Brachiopoda) del Devónico de la zona centroibérica. (Macizo Hespérico, España) Appearance of pyrophyllite as replacements of spiriferids (Brachiopoda) Shells of the devonian in the Central-Iberian zone (Hesperic Massif, Spain). PARDO ALONSO, M. v.; LÓPEZ BUENDÍA, A. M.; SERRANO,]. YBASTIDA,]. A macroscopicpyrophyllite bearing mineralization related to shells ofspiriferids has beeen found in the Herrera Formation (southern Central-Iberian Zone, Hesperic Massif, Spain). The observed mineral asociation is pyrophyllite + nacrite + quartz + calcite + anhydrite, and it is interpreted as resulting from the substitution of initial carbonatic shell by a Si, Al, S rich hydrothermal solution. Key words: pyrophillite, fossil diagenesis, hydrothermal, brachiopods, Devonian, Hesperic Massif, Spain. PARDO ALONSO, M. V.; LÓPEZ BUENDÍA, A. M.; SERRANO,]. Y BASTIDA,]. Departamento de Geología. Universitat de Valencia (Estudi General). 46100 Burjassot (Valencia).