Chap. XI.] ouddalore sandstones. 160 



calcareous infiltrations have resisted the absorption of the coloring 

 fluid. The rock, in consequence of the unequal resistance of its parts, 

 weathers into a roughly mammillated mass, bearing a rude resem- 

 blance to great masses of coral, wherever, as in the neighbourhood 

 of nullahs, the surface is laid bare, and much exposed to the action 

 of raio. Higher up, on the high ground between the two villages 

 of Plaunthoray, some of the sandstones are silicious ; but these are 

 exceptional. 

 Of the beds to the Eastward I have seen but little, for the reasons 



-p * rw J- IV noted above. The rock thrown up from an 



East of W odiarpoUiam. '■ 



ancient irrigation channel about 4 miles beyond 

 Jahenkoondasholapooram (East of Wodiarpolliam^ is a fine soft argilla- 

 ceous sandstone, mottled grey and yellow, and un distinguishable from 

 much of the Cretaceous rocks. Indeed but for its position I should 

 have considered it to be Cretaceous. 



To the North of the Vellaur, the Cuddalore sandstones are met with in 



the immediate neighbourhood of Verdachellura, and 

 At Verdacliellxmi. . 



are exposed in some quarries, almost the only 



excavations deserving the name in this part of the country, and situated half 



a mile to the East of Velur (Wurnaur of the Atlas map). The rock consists 



of a massive yellow sandstone, tolerably hard,and well adapted for buildino-. 



The surface has been very unevenly eroded, and it is covered with from 



6 to 20 feet of red soil, at the base of which is a layer of rounded quartz 



pebbles. No bedded structure is discernible, but the rock is intersected 



by 2 series of regular vertical joints, at right angles to each other. The 



quarries are situated just above the little escarpment or steep rise, which 



runs from near Velur for some miles to the North-east, and along which the 



beds are exposed at two or three places. At Koviraveram a section is 



seen in a small gully draining the high ground : the rock is a mottled 



sandy clay, not unlike that of the Cretaceous beds to the Westward, but 



containing some very characteristic bands of ferruginous grit. The 



