QQ GEOLOGY or TRICHINOPOLYj &C. [ChAP. IV. 1. 



extent in the thick jungles, are of fair richness, and shoAv here and 



there a considerable degree of decomposition into a lateritic peroxide. 



Within the area of the great curve, hut standing in very obscure 



relation to it, is a lai'ge and strangely contorted 

 Mabclavy hill beds. 



bed of magnetic iron, to be adverted to presently 



as forming part of the Mahdavy (Mahadevi) hill lying in the eastern 

 part of the valley which divides the KolymuUays from Tullamullay and 

 its subsidiary ridges. The iron bed is only moderately rich, the quan- 

 tity of iron probably not exceeding one-third of the mass of the bed, the 

 remainder being impure quartz, and here, as at Vaulavandy, the surface of 

 the out-crop shows much lateritic peroxide formed by weathering. The 

 south-eastern end of the double curve formed by this iron bed is lost under 

 the superficial soil a few hundred yards east from the Pagoda or Maha- 

 devi hill. The north-eastern, or LutchmepoUiam end of the bed, is 

 probably continued below the surface beyond that village and towards 

 Keddiputty, as the ground west of the Reddiputty tank is thickly strewed 

 with weathered fragments of the iron ore, though none was met with 

 in situ between the two villages in question. 



3;y/. The Bmgipoor am group of heels. — The beds forming this group 



occupy a position about 4 miles south of the Go- 



Singipooram series. 



dumullay peak. They appear to form a synclinal 

 fold, having, if followed from west to east along the strike from Vullala- 

 condam, a course varying from west and east to north-east by east and 

 then trending to east-north-east and east by north. In length they ex- 

 tend for about 10 miles. 



There are three principal beds, separated from each other by inter- 

 vening beds of hornblendic and quartzo-felspathie 

 Number of beds. 



gneiss of very considerable thickness. Ey far the 



greatest visible development of the beds is along the northern side of the 

 synclinal fold, the greatest length of which is stated above. On the south 

 side the three beds were traced only for much shorter distances to the 



(288) 



