172 CRETACEOUS ROCKS OF S. INDIA. [PaRT II. § 2. 



At Tirumungalum, (Trivandipurara of the map,*) a very fiue section 

 of the beds is seen in the face of the escarpment, 

 munuagaum. .^vhich is here not less than 100 feet high. A 



hard mudstone, containing merely a trace of iron, occurs at the base, and 

 is followed by bands of sand and clay, the latter originally white, but 

 now irregularly mottled with a purple tinge, by the partial infiltration 

 of a ferruginous solution. Some of the sandstone beds are pebbly, the 

 pebbles, which are small, consisting of quartz, originally derived from the 

 gneiss. Some of the beds are very ferruginous, and about half way up the 

 section is a bed of impure ochre. The bedding is tolerably distinct, and, 

 as seen, appears to be horizontal, but the line of section nearly coincides 

 with the strike, and as seen in the turn of the escarpment, the dip of 

 the bedding appears to be at a very low angle to the Eastward. 



From Tirumungalum to Trivandipuram, and on to Cuddalore, the 



escarpment is very fine, varying from 80 to 100 feefc 



nvan ipuiam. ^^^ upwards in height {see Plate II.) But the 



face is in general too much covered with talus to admit of a good 

 sectional view of the beds. Behind the latter village, close to the point 

 from which the sketch is taken, they are, however, well seen in the 

 face of the cliff, consisting of sandstones and grits, mottled pink and 

 white, in a manner much resembling the beds at Plaunthoray, described 

 at (page 168), and owing to similar causes. About 25 feet of the upper 

 part of the section is occupied by a bed of very ferruginous clay, much 

 resembling that at Vellum (page 1 68), and half converted into laterite. 

 It appeared to belong to the Cuddalore formation, but I was unable to 

 ascertain this point to my perfect satisfaction, owing to the upper part 

 of the section being much broken and obscured by debris. At the 

 top the clay passed into a grit, and became more ferruginous than the 

 lower part, but the laterite structure was very distinct. Debris of a 

 similar rock covers the escarpment beyond, as far as Cuddalore. 



* The real village of Trivandipuram is that marked as Trivandipuram station, 5 miles from 

 Cuddalore. 



