26 FOOTB : GEOLOGY OF MADURA AND TINNEVELLY DISTRICTS. 



the thickness o£ the local superficial dejoosits. At the eastern end of 

 the ridge also the bed cannot be followed up for a considerable distance, 

 but it apparently re-appears in the low but well-marked ridge running 

 north-east by north from Kistnapuram to Pareikulam. The dip of 

 the granular quartz rock in both ridges is northerly. The eastern 

 extension of the Sevandipuram-Saugani band is also obscure aud doubt- 

 Sevandipiu-am-Sangani f^l ; the probability is, however, that it thins out 

 ^^^^^- greatly and is represented in a small ridgy outcrop 



running nortli-east-by -north parallel with tbe Kistnapuram ridge about 

 a mile to the eastward. This may be the true correlation of the beds, 

 but a gap some 2 miles in length exists between the Sevandipatti hill 

 and the north-easterly ridge, and it is not impossible the real extension 

 eastward of the band might be found in the Karunkulam hill which 

 forms an inlier of granular quartz rock rising out of the alluvial flat of 

 the Tambraparni. 



Another very important show of granular quartz rock is to be studied 

 Melpattam granular ^^ great advantage in the Melpattam (Maillapan- 

 quartz rock ridges. ^^^^ Trigonometrical Station hill ^ miles north- 



east of Palamcotta. The rocks here form a large and very well marked 

 liorse-shoe curve open to the north. The western arm of the horse-shoe 

 seems to re-appear north of the alluvium of the Tambraparni valley and 

 to join the great band of granular quartz rock forming the Taliyuttu- 

 Pottai ridge. The actual junction of these beds has, however, not as 

 yet been traced out. 



A moderately large well marked bed of granular quartz rock lies close 



^ , ^ , in to the military cantonment at Palamcotta. 



Granular quartz rock "^ 



band east of Palamcotta This bed runs nearly due eastward for about 2 1 



cantonment. , . . , • i f> i 



miles when it is lost sight of under a great spread 



of gritty red soil. 



The most southerly outcrop of the granular quartz rock is the south- 

 South Vallanad grauu- Westerly extremity of the great Vallanad hill 

 lar quartz rock beds. ^^^^^ ^^^^^ ^^ ^^^^ y[\\agQ of Viralaperi. The 



gneiss region lying southward of this point shows an absolute prcdomi- 

 ( 20 ) 



