The rocks of the Birrimian Series in the Winneba District of Ghana have been progressively metamorphosed during the emplacement of the early and late orogenic granitic masses. The“Z”axial colours of the amphiboles generated in the hypabyssal and extrusive rocks of the Series can be broadly correlated with the grade of metamorphism as indicated by the mineral assemblages. A possible classification for amphibolites is discussed and the role of quartz indicated.