108 CRETACEOUS ROCKS OF S. INDIA. [PaUT II. § 1. 



an inexplicable unconformity which baffles all his attempts to trace it 

 out, and which is yet of such magnitude, that it is only after the con- 

 stant repetition of such failures, that he can convince himself that he 

 has to deal with the local irregularities of a drifted deposit. The difficul- 

 ty of gaining a clue to the real state of things is the greater that, in the 

 area within which these irregularities are the greatest, fossils are scarce, 

 and those met with are by no means characteristic, belonging to such 

 species as are either common to other groups, or so closely resemble 

 Ootatoor and Arrialoor species, that without a more critical knowledge 

 of them than can be gained in the field, it is impossible to accept them 

 with confidence as indicative of the Trichinopoly group. As regards 

 lithologic character, there is but little to distinguish these from the 



underlying Ootatoor beds, or from the lowest beds 

 Lithological characters. 



of the Arrialoor group, except in one peculiarity, 



which the conglomerates of the Trichinopoly series have in common with 



the Arrialoor beds, but which is not met with in those of the Ootatoor 



group. 



I have described in a former place * the granitic band which runs 



Peculiarity of Trichino- along the North boundary of the Cauvery allu- 

 poly and Ai-rialoor con- 

 glomerates, vium. Of the rocks composing this ridge, 1 have, 



with a single exception,-f- never met Avith any fragments in the 

 conglomerates of the Ootatoor group, which consist exclusively of the 

 debris of the gneiss and coral-reef limestone, and it is probable 

 on this, as on other grounds, that the Ootatoor sea therefore stretch- 

 ed far up the present^ Cauvery Valley, and that if the granite was 

 exposed anywhere in the land of the epoch, it must have been too far 



* Sae ante, page 30-31. 



f In a thin band of sand intercalated in the shales near Muddam, some minute fragments of 

 quartz and felspar resembling those of the Thutchuncoorchy granite were met with. This 

 band was close to the base of the Ootatoor beds, and it is probable that when it was formed, 

 some portion of the granite remained unsubmerged. The fi-agments were very small and 

 much rolled. With this exception, the remark in the text holds good for the whole of the 

 Ootatoor group. 



