42 FOOTE : GEOLOGY OP MADUEA AND TINNEVELLY DISTRICTS. 



Grits o£ similar colour, but finer texture, are exposed in a well-section 

 south-east of Pakaneri (Paukanary) , and about 

 1| miles north- vvtist-by- west o£ the mouth of the 

 Nambi Aru (Naut Aur). 



Some 7 miles to the south-west of the Yellava Odai section occurs 

 Tdindan Karai cliff another outcrop of typical grits in the low clifE 

 ^e<^^''on. ^^^z — 25' high) immediately east of the village of 



Idindan Karai (Iddinge Kurra) . These grits, which are mottled, are 

 rather soft, and yield much more readily to the action of the surf 

 than does the overlying hard calcareous shaly sandstone. The con- 

 sequence is that the base of the cliff gets considerably undermined, — 

 a process which continues till a cliff-fall occurs, and creates a tem- 

 porary breakwater against the surf. The base of the grits is not 

 exposed, but the bed is probably not more than 12 or 15 feet at the 

 outside, as gneiss beds show through the beach sand at a very small 

 distance to the south-west close to the village. The section is about 

 half a mile long. A small sketch showing a transverse section 

 through the cliff will be found further on (page 58). The grits appear 

 in this section as conformably overlaid by the shaly marine sand- 

 stone. 



Mottled reddish grit is exposed to a small extent in the rain gully 

 Kudung Kulam out- traversed by the path just north of the marine 

 ^^°T?- limestone plateau lying between Kudung Kulam 



and the sea. The grit bed is cut into only about 3 feet, so its thickness 

 is problematic. The shaly gritty sandstone seen eastward of Kudung 

 Kulam village is very much altered in its appearance by infiltration of 

 tufaceous lime (kankar) in large quantities. 



A gritty calcareous sandstone, of which only a few feet in thickness 



is exposed, is to be seen on the right bank of the 



Perria Manal outcrops. „ , . . / -r. thin 



estuary of the Amman Aru (or ranagudi nallah) 



a little to the north of the village of Perria Manal. The grit, which 



is unfossiliferous, is badly exposed and greatly weathered. 



Various sections reveal the presence of gritty beds under the 



( 42 ) 



