The Cheri Hill in the Madras type area of charnockites, shows on careful mapping the folding of bands of leptynite and basic charnockites. The mineralogy of the basic types gives striking evidences of the metamorphic origin of charnockites. The rocks have been subjected to some little retrograde metamorphism and are ascribed to the almandine-diopside-hornblende subfacies of the amphibolite facies. A quantitative idea of the influx and efflux of ions is worked out on the lines of Barth, in the process of replacement of the norite to the associated garnetiferous-diopside-granulite.