Chap. V.] trichinopoly district — ootatoor group. 69 



one is certainly identical with a species characteristic of those limestones, 

 while another closely resembles a species from the Ootatoor Group, which 

 is not found in the Trichinopoly beds, and a third (a Belemnite) belongs 

 to a genus which I have only met with either in the Ootatoor Group, or 

 the reef limestones of the same epoch. 



Ind. — No coral-reef limestone, that I have met with elsewhere, belongs 

 even probably to any other than the Ootatoor period, nor (except 

 in the immediate neighbourhood of Ootatoor reef limestones) do the conglo- 

 merates of the Trichinopoly beds contain fragments of such rock as might 

 lead us to believe in the former local existence of Trichinopoly reefs. 



Src?.-^The beds on which the Cullygoody Hmestone rests are of doubtful 

 age, but it is more probable that they belong to the Ootatoor than to any 

 later group, inasmuch as they contain Belemnites, and that the Trichino- 

 poly beds rest on them with greater and more decided unconformity 

 than can be accounted for by local irregularity of bedding. I have shown 

 in the preceding pages that the Ootatoor reef limestone occasionally rests 

 on the first-formed beds of the group. 



I lay no stress on the fact that a boulder-bed, such as that underlying 

 the Cullygoody limestone, nowhere occurs at the base of the Trichino- 

 poly Group, inasmuch as the bottom beds of that group are very vari- 

 able ; and if, as I have reason to infer, the boulder-bed at the base of 

 the Ootatoor Group is a remnant of the plant-beds, there would be 

 no d priori improbability of its occurring occasionally at the base 

 of the Trichinopoly Group under similar conditions. Neither do I 

 insist with any great emphasis on the fact that neither the boulder-beds 

 nor the associated grits contain any fragment of older sedimentary depo- 

 sits, while the Trichinopoly conglomerates generally are full of fragments 

 of the Ootatoor beds. Although of some little value as negative evidence, 

 the Trichinopoly conglomerates offer too many exceptions to the above 

 rule, to admit of the absence of Ootatoor pebbles being taken as a crite- 

 rion of age. I think, however, that in the absence of any evidence to 



