I&4 HOLLAND: CHARNOCKITE SERIES. 



The other feature of interest displayed near Tirrupur is the 

 production of banding by lit-par-lit injection of the non-felspathic 

 forms along the foliation planes of the basic types. That this is the 

 correct explanation of the well marked banding in this neighbourhood 

 is shown by the fact that the non-felspathic " bands" sometimes 

 break across the foliation planes, and sometimes actually bifurcate 

 (see plate IX). The ultra-basic (non-felspathic) bands often weather 

 with formation of onion-like shells and with deposition of calcareous 

 kankar along the cracks. A good case is badly represented in the 

 photograph forming plate X. 



The charnockite series here, as they often are, are associa- 

 ted with quartz iron-ore beds, and in other parts of the same district 

 also with crystalline limestones. 



NiLGlRlS. 



The civil district of the Nilgiris, which is very nearly coinci- 

 dent with the hill ranges known as the Nilgiris and Kundas, is 

 practically made up of members of the charnockite series. The 

 plateau, which forms such a conspicuous feature in the south of 

 India, measures 42 miles long and 15 miles broad, covering an area 

 of about 750 square miles. In a large number of places it exceeds 

 8,000 feet in height, and attains its maximum altitude of 8,760 feet in 

 Dodabetta, a rounded hill near Ootacamund (lat. 1 1° 24' $'40"; long. 



The characteristic scenery of a charnockite area is typically 

 developed in the Nilgiri Hills. The rounded peaks and grass- 

 covered undulating " downs " of the plateau are features charac- 

 teristic of a country in which the inequalities developed by 

 uninterrupted weathering have completely obliterated all the physi- 

 cal features originally formed by earth-movements. The scenery 

 of the Nilgiris contrasts very strikingly with the deep narrow 

 gorges of the Himalayas, where the rapid erosion, following the 

 geologically recent elevation of the mountain range, has left the 

 slopes so near the angle of repose of the broken rock, that landslips 

 ( 66 ) 



