52 i'OOTE : GEOLOGY 01-' MADURA AND TIXNEVELLY DISTRICTS. 



there the reddish sands of ordinary type prevail with one or two small 

 patches o£ hard dark coloured highly ferruginous laterite conglomei'ate. 



A considerable area of the gueissic country north-west of the Parn- 

 Ovitlying gravel beds ^^^^ tract IS covered with a broken and disconti- 

 at Mautapa Sale. nuous sheet of gravel and shingle of lateritie age, 



which covers a small plateau extending from the great tank at Paral- 

 lache, north-westward to a little beyond the American Mission station at 

 Mantapa Sale (Mundagashaulay). Here and there the gravels are ce- 

 mented by a ferruginous conglomerate into a true coarse conglomerate, 

 but in general they are non -compacted. The mass of the gravel consists 

 of granular quartz rock well rolled, but with a fair sprinkling of other 

 pebbles of gneissic origin. A considerable number of rude flakes and 

 some good-sized angular lunftps of a brown or greenish brown chert with 

 almost very smooth surfaces were also noted. 



In the southern part of the Parnalli tract only a few tank and well 

 Pale gravels at Par- sections show a pale granular quartz gravel. The 

 ^^ ' most important of these exposures, and really very 



trifling ones, per se, occur at and a little to the west of Parnalli village, 

 and a slight terrace rise of the ground which sweeps round both north- 

 east and south-west of the village appears to show the emergence of this 

 gravel from below the great alluvial spread to the south. 



Occasional traces of similar pale yellow or cinnamon coloured gravels 

 Pale gravels near show at intervals over the gneissic tract westward of 

 Velati Kuiam. ^j^g Parnalli lateritie tract, but there also the face of 



the country is greatly masked by thick cotton soil, and the gravels are ex- 

 posed only in artificial sections as wells, tank bottoms and the ballast pits 

 along the high road to the north of Velati Kulam (Vullauticolum). The 

 gravels are often largely mixed with gravelly kankar (small nodular tufa). 



South of the Vaippar (Vypar) there is a long stretch of country over 

 which no sections exhibiting gravels were met with, though they very 

 likely occur in detached patches under the surface of the wide spreading 

 sheets of cotton soil which cover so large an area in Eastern Tinnevelly. 



The first show of gravels noted south of the Vaippar occurs at 

 Timmarajapuram, south-south-west of Meltattappai'ai station on the 

 ( 52 ) 



