Chap. V.] trichinopoly district — ootatoor group. 67 



ridge terminates somewhat abruptly, and tlie Trichinopoly beds are 



exposed in one or two little nullahs dipping away 

 At Culljgoody, 



from it usually at a high angle. Adjoining the 



camping ground at Cullygoody, at a distance of about 200 yards from 



the main ridge, we meet with another small ridge of limestone on 



which the village is partly built, consisting, in part, of the coralliferous 



form of the limestone. A break of about a mile then intervenes, 



which is occupied by the boulder-bed, and we then come to the 



Vadoogapaitty ridge, which extends for about a 

 Vadoogapaitty ridge. 



mile to the bank of the Palumbaddy nullah. 



The rock of this ridge is much concealed by the soil, and the summit 



close to the village, which is the most elevated point for many miles 



round, is thickly covered with an isolated patch of ferruginous sand 



similar to that which occupies the high ground of the Wodiarpolliam 



jungles. Some of the rock is, however, exposed on the Western slope, and 



close to the village, the same variation in the character of the rock is 



observable, which, as I have remarked, obtains 

 Structure of rock. 



elsewhere. The coralliferous form of the lime- 

 stone occurs only at the base of the ridge, where the corals are very- 

 abundant, and the rock massive in structure and honey-combed on the 

 surface. The upper part, on the other hand, exhibits, when viewed on the 

 ground, a decided bedded structure ; and when broken, a sub-crystalline 

 fracture, being composed of broken corals, shells, &c., cemented into a 

 compact limestone. 



At the base of this ridge a peculiar rock of a pisolitic structure occurs 



in great quantity. It is made up of small pisi- 

 Pisolitic limestone. 



form nodules, formed by the deposition of succes- 

 sive coats of calcareous matter round fragments of the limestone, and 

 cemented together by similar material, generally into a compact stone, 

 with occasional irregular cavities. It is probably formed in part 

 beneath the soil, where the latter is thin, for, in a section exposed in 



