400 Notes, principally Geological, [No. 162. 



The bed of the river near Kistapatam is apparently about 500 yards 

 broad, and sandy. A bar of sand obstructs the mouth, against which 

 the surf beats in white breakers. The Collector's bungalow stands on 

 the N. bank of the river. 



Nellore. Circumstances prevented my examining the tract between 

 the sea at Kistapatam and Nellore; but as far as could be judged from 

 rapidly passing over it, it resembles in flatness (sloping gently sea. 

 wards) the rest of the maritime plains of the Coromandel Coast, and 

 abounds with small tanks. At Nellore the usual granitic and hypo- 

 gene rocks of this coast are covered by beds of laterite, which are seen 

 in cliffs about 16 feet high fringing the Pennaur river. About three or 

 four miles from Nellore, on the Northern bank of the river, quarries of 

 the laterite occur at the village of Kohor, in a deposit of this rock about 

 20 feet thick near the tank. Both at Nellore and the surrounding 

 villages, it is extensively employed as a building stone, and in other 

 repairs of the roads. Blocks, about one foot thick and two long, are sold 

 at the rate of 12 for the rupee. Small springs are seen oozing out at 

 the bases of the laterite cliffs on the S. bank of the river at Nellore. 

 These cliffs are divided by perpendicular and horizontal seams ; the 

 rock composing them is less quartzy than the Kohor laterite. In the 

 vertical fissures I observed fragments of earthenware broken by the 

 natives in coming for water. These bits of pottery often become 

 impacted in a lateritic alluvial cement, which must not be mistaken, 

 as has been the case, for the true laterite, and hence its origin 

 ascribed to the recent or historic period. Some of the oldest pagodas 

 and structures in South India are built on this rock. Both the 

 laterites of Nellore and Kohor consist of a rock resembling the 

 Malabar laterite, but containing more angular fragments of quartz. 

 The surface of the laterite is often covered by a modern lateritic 

 debris, more or less consolidated, which must not, as said before, be 

 confounded with the true laterite. 



As in the Beder laterite the water often passes from the surface of 

 these cliffs by the tubular cavities in its structure which are enlarged, 

 emptied of their clay and lithomarge, and modified by its passage 

 downwards, until stopped in part by the clayey barrier it has assisted 

 to accumulate. The water here forms reservoirs, and in overflowing 

 finds its way out by fissures in springs. The bed of the Pennaur near 

 Nellore is sandy, and apparently about 800 yards broad. 



