APEIL- 1858.] 



Fossil Wood. 



49 



era and eastern limits in the neighbourhood of Trivicary, but to the 

 north it dies away gradually, and the sandstones themselves disap- 

 pear beneath a thick covering of soil, and are only occasionally 

 visible when laid bare in the beds of the small water- courses. A 

 thick deposit of sandy soil laps in a similar manner, round the foot 

 of the eastern bluffs and conceals the underlaying rock, except in 

 the immediate neighbourhood of the river, where gneiss is seen in 

 situ, and from its position, is evidently cropping out from beneath 

 the sandstones. Cretaceous rocks resembling those at Verdoor are 

 no where seen in contact with these beds except that at one point 

 an isolated block of yellow sandstone containing cretaceous fossils, 

 which from its appearance, I judge to have been recently dug up, 

 from the soil on the spot on which it rests, is seen at what appears, 

 to be the boundary of the sandstones. No cretaceous rocks what- 

 ever are here seen in place. 



There is great reason to believe, judging from the color and ap- 

 pearance of the soil* that from Trivicary, the tree-bearing sand- 

 stones extend for some distance to the East and overlap a portion 

 of the cretaceous rocks, as shown in the accompanying map and 

 section, but as in the absence of any sections on any rock whatever 

 seen in situ over this tract of country, it is impossible to prove the 

 fact, we must seek elsewhere for reliable proofs of superposition, 

 and to do this, we pass to the country between Verdoor and Pon- 

 dicherry. 



About two miles N. W. of Pondicherry, the Madras road as- 

 cends and passes for about three miles over a tract of elevated coun- 

 try, characterized by a red sandy soil, from beneath which a late- 

 ritic gravel is dug in places to metal the road. This elevated tract 

 extends from the south east corner of the great Oosatary tank, four 

 miles west of Pondicherry to the village of Mundakuppam on the 

 coast 10 miles north of Pondicherry and along the greater part of 

 its boundary is terminated by a small escarpment of about 30 feet 

 average elevation. The streams which carry off the drainage of 

 this little plateau have cut deeply into the rocks composing it at 

 several places along the escarpment, and expose Oosatary gritty sand- 



* This character, vague and unreliable as it may appear, has been found to be 

 an excellent indication of the presence of certain rocks throughout the district. 



