Chap. V.] thichinofoly district— ootatoor group. 55 



is exposed in a little gully which cuts through the Ootatoor shales, and 



the latter are clearly seen dipping away in all directions from the boss. 



Passing to the North-east along the boundary of the Ootatoor Group, we 



meet with a few masses of limestone similar to that 

 Naicoluin ridge. 



above described on the old Madras road, about half 



way between Agaram and Naicolum, close to an old ruined temple. So far 

 as can be made out, these appear to be surrounded by the Ootatoor clays, 

 which occur quite at the base of the group, and are exposed in the gullies 

 close by. Their relations are not, however, very clearly seen, as the lime- 

 stone only is visible, except in one instance, projecting above the soil. 



Again, about a mile to the East of Naicolum, a series of lime- 

 stone rocks, showing the usual characters of 



East of Naicoliun. 



the coral Umestone, and frequently exhibiting 



the white streaks of embedded corals, extends in a line for about 



a quarter of a mile from the southern extremity of the large 



tank (see map). At this spot, to which I have already referred 



when speaking of the plant-beds, the limestone ridge (for though not 



visibly continuous above the soil, it may be considered as such,) rests 



upon the Zamia shales which dip towards it at 

 Its position, 



a low angle, while on its South-eastern flank 



the Ootatoor shales are seen in the broken ground dipping away to the 

 South-east at an angle of not more than 3 or .4 degrees. There is no 

 conglomerate at their base, the lowest beds being fine ochreous shales, 

 with ferruginous concretions, but there can be no doubt, judging from 

 their position and dip, that they rest upon the limestone. A conglo- 

 merate bed is indeed an exceptional occurrence at the base of the 

 Ootatoor Group, whatever be the nature of the rock upon which it rests. 

 In the Naicolum limestone I found, in addition to the corals, such 



as occur in the Tripatoor ridge, a Terebratula 

 Fossils of limestone. , , , -r. 



and fragments ot Fentacrimte stems ; also Belem- 



nites, and, what is very rare in the coral-reef limestone, quartz 



