Chap. XI.] general remarks on the cuddalore group. 179 



species.* Whether this be a local form of the Cuddalore sandstone forma- 

 tion or of the more recent date of our marine alluvia, I cannot venture to 

 opine. It is not improbable that the depression evidenced by the former, 

 and the elevation of which, as I shall hereafter endeavour to show, the red 

 and black soils so frequently i-eferred to in this Memoir, are the existing re- 

 cords, may have been immediately consecutive, being the initiatory and 

 concluding events of a peiiod of widely extended marine conditions, of a 

 part of which the Tinnevelly and Ceylon deposits are also local records. 

 The full discussion of this question would, however, lead me into a review 

 of the tertiary and alluvial formations of a large portion of the Peninsula, 

 but this is a subject entirely foreign to that which forms the substance of 

 the present Memoir. 



I should, however, mention before concluding, that marine deposits 

 Marine deposits on apparently contemporaneous with those of Tin- 

 the West Coast. nevelly and Ceylon, occur in Katywar. There are 



also various superficial deposits on the West Coast, part of which, at all 

 events, may eventually be correlated with the Cuddalore sandstones, -f* 

 but these have so far, as I am aware, never been carefully examined 

 with a view to their classification, except perhaps those immediately 

 in the vicinity of Bombay, the elucidation of which we owe to 

 Dr. Carter. 



* I have seen specimens of these from Jaffna in the form of casts, in a calcareous sand- 

 stone, the whole of the shell having disappeared. It is an instructive commentary on the 

 common popular idea that the state of fossilization bears a certain relation to Geological age, 

 to contrast such specimens as these with the shells of the Trichiaopoly limestone, which 

 possess all their pristine polish, and sometimes even traces of the original coloring. 



f This has been attempted by Dr. Carter in his Summary of the Geology of the Peninsula 

 ef India. He has, however, fallen into a serious and somewhat incomprehensible error ia 

 regarding the Red Hills of Pondicherry as a formation distinct from that of Trivicary. Geo- 

 logical papers on Western India, page 753. 



