Stone Trnj)lements in lateritic formations. 



9 



argument in favour of the two deposits being of different 

 ages, were it not that about two miles N. W. an equally 

 high level spread of conglomerate near Goompolliam, 

 from which Implements were obtained, is quite as largely 

 made up of pebbles as any part of the beds in the Atram- 

 pakkam nullah. 



Unfortunately no section could be found to clear up the 

 relation of the lateritic conglomerate in the valley of the 

 Atrampakkam nullah to that on the top of this high ground 

 E. of Nelway, and I am rather doubtful whether to consider 

 them as part of one and the same series or to regard, the lower 

 lying beds as subsequently formed and mainly from the 

 debris of the higher lying ones. Dr. Oldham and Mr. King 

 inclined to think these low level beds younger than the 

 typical laterite and derived from it, in fact a local allu- 

 vium. 



It is not impossible that the laterite of the valley and the 

 high ground in question might belong to one and the same 

 formation, which accommodated itself to the greatly eroded 

 surface of the plant-bearing series, a phenomenon which 

 on a smaller scale, may be well observed in hundreds of 

 places in the many sections occurring in this part of the 

 country. 



On a far -larger scale is such a conformity of the laterite 

 with the shape of the surface traceable in the valley of the 

 Ingawarpolliam nullah 5 or 6 miles E. of Sattaveclu, where 

 the laterite passes down from the high ground, disappears 

 under the local alluvium and re-appears again on the op- 

 posite side of the valley. A similar phenomenon is stated 

 to be of common occurrence in the laterite of Bancoorah 

 District in S. W. Bengal(l). This point must remain for 



(1) Note. — See Report on the Geological Structure and Physical Fea- 

 tures of the Districts of Bancoorah, Midnapore and Orissa. Bengal 

 Memoirs— Geol. Survey of India— Vol. I, page 270. 



