6o 



HOLLAND: MICA DEPOSITS OF INDiA, 



to forty miles (fig. 15). Geologically this field is composed of a central 



80°| E. 



N^ N > ^ > V^ NVN> N V WSJ " * ' \\\\ 



GEOLOGICAL 



MAP 



f.'!!! CtaHators snfl. Recent. So ale, 



E=3 fjuddapah. rooks, Hn B= 32 m. 



CkS GnelsBose Granites. 



&§§ gchigtS -sriEh. Pegmatites. 



HH Sat&ftsj -mtihons Pegmatites. 



Fig. 15. 

 V-shaped fundament of well-foliated gneisses, the angle of the V being 

 situated nearVojili (see fig. 15), one of the arms passing nearly due 

 north past Nellore and Kavali, while the other arm goes in a north-west 

 direction past Saidipuram and Udayagiri, and between this schist 

 complex and the Bay of Bengal the surface rocks are of comparatively 

 recent origin, none being older than the Rajmahal plant beds. On the 

 west the gneisses are bounded by an area of igneous rocks, gneissoid 

 granites and traps, cr by the Cuddapah system of formations which 

 make up the Veligondas. The eastern half of the schist complex is 

 traversed by a large number of intrusive sheets and lenses of pegmatite 

 often very rich in muscovite of great economic value. This constitutes 

 ( 50 ) 



