54 GEOLOGY OF TRICHINOPOLY^ &C. [ChAP. IV. 1. 



Naivailie, 16 miles to the nortli-west of Trichinopoly ; also at Thutcli- 



umcoorchy,'^ 3 miles north-east of Culpolliam^ on the Trichinopoly and 



Madras Road. 



At Mootum the rock is only seen for about a mile along- the surface, 



as a bed of 10 feet in width _, striking east-south- 

 Mootum beds. . . ^ 



east J and having a dip of 45 to the N. N. E. 



It is covered up by the alluvium at its eastern end, and crops out 



to the west. The stone is generally of a pink colour, and varies much 



in its texture. To the north and to the south of this, granite veins are 



very numerous, but there is no gneiss visible close at hand, similar to 



that which is associated with the limestone at Polliam. 



At Naivailie,t limestone crops out between beds of quartzite and 



hornblendic gneiss, which strike to east-north-east. 

 Naivailie beds. i i • 



To the east of the tank there is a spread of 



alluvial soil, under which the limestone disappears, but it is again seen 

 in the same direction for a short distance, when, together with the beds 

 of the gneiss, it turns up to the east-north-east, apparently in conse- 

 quence of the intrusion of a great mass of granite to the south. After 

 maintaining the latter course for some distance, the band of limestones 

 bifurcates, and encloses a large boss of hornblendic gneiss, beyond which 

 one of the arms of the divided band spreads out into a slightly farrowed 

 surface, some 50 yards in width. It then narrows again, and ultimately 

 joins another thin band coming from the north side of Naivailie village : 

 after the junction, it decreases its width, and about one mile to the east- 

 ward, it dies out. Throughout this course the beds are vertical. 



The different colours of this limestone are nearly the same as those 

 seen south of Caroor, and there are the same differences in the texture 

 and the stone, excepting that the very coarse variety which we have 



* Memoirs of the Geological Survey of India, Vol. IV, Part 1, p. 204. 

 t A notice of these beds by Mr. King was published in the Madras Jo\u-nal of Litera- 

 ture and Science, Vol. XXI, p. 272, 1859. 



(276 ) 



