Chapter III. — Post-cretaceous rocJcs, — (Cuddalore Sandstones.) 



This name has been assigned by Mr. Henry F. Blanford to an 

 important series of rocks, resting" immediately on the cretaceous formations 

 found in the South Arcot and Trichinopoly districts. 



This series of rocks occurs in four distinct areaSj separated by the 



valleys of the Punniar^ Vellaur, and Cauvery rivers. 

 Four areas. 



The four areas are, in all probability^ parts of a great 

 continuous deposit over the eastern side of the Carnatic, which was cut 



through, and in great part denuded away during 



Originally continuous. 



the formation of the valleys now occupied by the 

 abovenamed rivers. 



The four areas have the form of low table-lands or plateaux termin- 

 ating in low but abrupt headlands on their northern and eastern sides, 

 around which the beds of the present alluvium have been deposited. 



On the south side of the Cauvery, the Cuddalore series appears to 

 rest immediately on the metamorphic rocks, the cretaceous beds, if they 

 ever covered those parts, having been in great part, if not entirely, denuded 

 away previously to the depositions of the post-cretaceous formations."^ 



Owing to the absence of any fossil remains, excepting some tree-stems 



found at Tiruvakary, near Pondicherry, the exact 

 Age undecided. '' *' 



age of this rather extensive formation is as yet un- 

 decided ; fossil trees not offering sufficient data whereby to refer these beds 

 to well-determined horizons amongst the recognised tertiary or quarternary 

 formations. 



As indicated by the name '' Cuddalore Sandstones," this series of 

 rocks consists mainly of more or less ferruginous sandstones associated 



* Since the country south of the Cauvery was examined by us, fossiliferous beds under- 

 lying the Cuddalore series ai'e reported to have been exposed near Tanjorc, in cuttings made 

 during the construction of the Railway from Negapatam to Trichinopoly ; but we have been 

 unable to procure any of the fossils from these rocks, which are probably of cretaceous age. 

 No outcrops of the cretaceouis rocks hare as yet been observed anywhere south of the Cauvery. 

 (356) 



