Stone Implements in lateritic formations. 13 



bles upward to masses a yard or more in diameter, generally 

 cemented together by a coarse dark red brown or purple fer- 

 ruginous sandy cement, more rarely by a calcareous cement. 

 The nearer we approach to these centres whence the quart- 

 zite pebbles were derived, the coarser and more shingly do 

 the lateritic conglomerates become, and finally where they 

 abut on the old Sattavedu conglomerates, the lateritic 

 material is far less than the included masses of quartzite in 

 quantity, and can only be regarded as a cementing material. 

 The cementing material of the old conglomerates being also 

 generally more or less ferruginous, renders it exceedingly 

 difficult and often impossible to distinguish between them 

 and those recent laterite conglomerates where the two are 

 at all much weathered. 



The compact laterite generally shows the characters of a 

 true conglomerate, the contained pebbles being rounded and 

 water- worn ; but not unfrequently small patches of a few 

 square yards in extent, present all the characters of a breccia 

 all or very nearly all the included stones being sharply 

 angular fragments. No reason for this change was apparent 

 in any case noticed. 



The thickness of the lateritic formations so far as they 

 have yet been examined in this part of S. India is not by 

 any means large. Even if the Cuddalore Sandstones and 

 grits be bond fide a member of the lateritic series as they 

 appear to be both at Cuddalore and the Red Hills (near 

 Madras) the utmost aggregate thickness most likely falls 

 far short of 150 feet. The section in which they are most 

 fully exposed is, that in the cliffs on the south bank of the 

 Corteliar near Yermootapolliam about 2 miles west by S. of 

 the ford by which the Madras Nellore road crosses that 

 river. The cliffs there are from 30 to 60 feet in weight. 



The Implements have as yet only been discovered in the 

 laterite which is the uppermost member of the whole series 



