58 FOOTE : GEOLOGY OF MADURA AND TINNEVELLY DISTRICTS. 



There can be no reasonable doubt of the northward extension in 

 former times which has been referred to above, but I had not the good 

 fortune of finding any remains of the limestone on the north side of 

 Kudung Kulam valley; but as the whole of the north side of the 

 valley is thickly covered with red soil, it is quite possible that re- 

 mains of the plateau may yet lie hidden there. As already stated above, 

 the limestone of the Kudung Kulam eastern plateau slopes gradually but 

 considerably to the east, but is unfortunately very much masked by the 

 blown sand of a small teri and by a considerable formation of impure 

 tufa underlying the teri formed by evaporation of calciferous rain-water 

 filtering down from the highest part of the ridge. Like the recent tufa 

 (travertine) described as occurring at Cape Comorin (see Records, 

 Vol. XVI, p. 30), this formation contains very large numbers of the 

 living Helix vittata in a fossil condition. This travertine extends down 

 to the slope of the ridge, and to the very edge of the low cliff which 

 Idindan Karai cliff sec- extends for about one-tbird of a mile east- ward 

 *^°"- from Idindan Karai (Iddinge Kurra) village. 



Underlying this travertine is a bed of hard calcareous sandstone of whitish 





Idindan Karai clifV (diagrammatic) i, 



( 58 ) 



