LATERITIC FORMATIONS. 47 



old Poligar fort are entirely built of the massive rock quarried close at 

 hand. They are also very well displayed on the top of the bluff overlook- 

 ing the Pambiar valley at Neddengudij and again on the high ground 

 between Shuragudi (Shooragoody) and Karagudi, and to i,he westward 

 and south-westward of the latter place ; also in the south-eastern part 

 of the tract to the south and south-east of Amaravati. The sandy 

 form of the lateritic deposits is much less developed here than in the 

 Arrantangi tract. The sands on the eastern side measuring only from 

 2 to 3 miles across instead of 7 or 8. 



A small inlier of pale reddish sands which rises from out of the 

 alluvium of the Velldr a little south-west of Avadiar Kovil (Avadear 

 Covil), I have with great doubt mapped as of lateritic age. It rises 

 only a few feet above the surrounding alluvium^ and is of rather darker 

 colour, but presents no other special feature. 



It will be convenient to describe at this place the Tripatur tract (No. 4) 



which lies to the north and north-west of Tri- 

 Tripatur tract. i i • 



patur town, the only important place in the vici- 

 nity, and forms a narrow strip about 8 miles long and a mile or 1 j mile 

 across at its widest part. 



The dense and highly ferruginous form of the lateritic conglomerate 

 is not foand largely in this tract, but a less ferruginous and less com- 

 Chattrasingara Kotai P^ct form including large quantities of gravel 

 *'^"^°*- of gneissic origin. This description will also 



apply well to the lateritic beds seen in the Chattrasingara Kotai 

 tract (No. 5). 



The Serruvayal patch of laterities (No. 6) is also a small one lying 



between the Tripatur river and the Upparui 

 Serruvayal tract. » • • 



(Hoop Aur) . The highly ferruginous conglomera- 

 tic form is very largely developed to the north and west of the village 



^ Upparu, or " salt river," is a very common name for small rivers whose water becomes 

 very brackish before they finally dry up. There are three rivers of the name in this part 

 of Madura district : one which forms the headwater of the Tripatur river, that now under 

 reference, and a third smaller one which falls into the Vagal, 8 miles south-south-west of 

 Sivaganga. 



( 47 ) 



