Chap. YI.] trichinopoly district — ootatoor group. 97 



one or two specimens, and tliese in bad condition, and generally so firmly imbedded in 

 the matrLx, that it was impossible to procure them without the expenditure of more time 

 than I could conveniently devote to them. The following list includes all the species 

 here met with. 



Ostrea. 1 species, very abundant, apparently peculiar to this deposit. 



Ti'igonia. 2 species, that above described, and a larger species with 



longitudinal ribs and a smooth posterior area, resembling T. 

 semisericea, both peculiar to these beds. 

 Natica. 1 large species, of which I saw and obtained one specimen 



only ; peculiar. 

 Ammonites. 1 specimen only seen in section, about 9 inches in diameter. 



Belemnites. 1 species, resembling in form and size the B. stilus of the 



Ootatoor Group. 



Total, 6 species — Mollusca. 

 Fossil Wood. 



About two miles South of Cullygoody the boulder-bed is seen in a small nullah close to the 



village of Vadoogapaitty, and may be traced for about the same 



Boulder-bed at Vadoosapaitty. ,-,-,, , o.i ■ ■, „ ■,■ , ,., 



distance along the Jiastern edge ot the ridge ot limestone which 



commences at that village. It is not very extensively exposed, but that it is a continuation 

 of that to the North of Cullygoody, is proved by the occurrence of the nodulose-ribbed Tri- 

 gonia, in some masses of gneissose conglomerate exposed in the nullah. In the same conglo- 

 merate I also found a Belemnite and a small turbinoliform coral, the former resembling the spe- 

 cimen seen in the calcareous grits to the North of Cullygoody, but like it not sufficiently well 

 preserved to be determinable. 



I have detailed at page 61 — 64 my reasons for regarding these Cullygoody deposits, and tho 

 associated coral-reef limestone as of Ootatoor age, and need not repeat them here. I shall there- 

 fore proceed to summarise the principal facts deducible from the foregoing description with 

 respect to the physical conditions of the Ootatoor Group. 



Summary of the preceding. 



The age of the Ootatoor Group, as compared with the minor groups 



in the Cretaceous series, acknowledged by European 

 Ageof Ootatoor Group. . . i . i ■ 



Geologists, IS a subject upon which it would be pre- 

 mature to pronounce here. The problem of determining the respective age 

 of minor sub-divisions in distant quarters of the Globe, the intervening 

 area being unknown, or at least imperfectly explored, is at all times one 

 demanding the utmost critical acumen of the Palaeontologist for its solu- 

 tion, and until the fossil fauna of the group in question has been 



