Chap. IL] alluvial dki'Osits and blown sands. 29 



the pretty equal effect of the monsoons ;* tor, thougli the north-east 

 monsoon blows on this coast with much greater force than the south- 

 west, its transporting- powers are negatived by the heavy rains, wliich, 

 by saturation for a considerable time effectually bind the loose parti- 

 cles of sand. From Trimelwassel southwards, it was frequently observed 

 that a dense jungle of Screw-palm or Pandanus intervened between the 

 sand ridges and cultivated ground, offering a perfect barrier to the 

 advance of the sand. In the Screw-palm jungle, small but beautiful glades 

 covered with short fine turf occur not unfrequently. South of Nega- 

 patam, there are some very fine sand-hills, having a steep slope facing 

 the sea. On ascending there, the landward side was found to be quite 

 steep and backed-up by a thick jvmgle of trees and Palmyra palms. 

 Further south the ridges are lower, and the tree jungle ceases, so 

 that the sand extends further inland, until stopped by the Pandanus 

 jungle. t That there is, however, some advance, is shown by the rapid 

 silting up of a canal running northward from Trimelwassel parallel 

 to the beach-line. 



The Alluvmm of the Vellaur. — The alluvial flat of this river may be 

 said to commence from its junction with the Ellayaur, — a large stream 



* This explanation is strongly confirmed by the observation of several residents on 

 this Coast, among whom Messrs. Norfor and William Underwood, Junior, informed us that a 

 particular sand-hill near Porto Novo regularly encroached on and covered a certain road 

 during the north-east monsoon, and was as regidarly driven back by the south-west 

 monsoon, and the road opened again to traffic. 



On various occasions, while engaged in mapping this line of sand-hills during the 

 prevalence of the south-west monsoon,) immense quantities of sand were observed on 

 dry windy days to be blown into the sea : this waste must of course be replaced, or the 

 sand ridges would soon entirely disapear. 



t West of Outlay, a village on the south bank of the Cauvery, just below the junction 

 with the Ambrawutty, is a hill of blown sand, raised most likely when the river is low and 

 its wide sandy bed in great part dry. Another such hill occurs just within the apex of the 

 angle caused by the junction of those two rivers, while on the nortli Ijank of the Cauvery, 

 a few miles west of Moganoor, blown sand-hills are being formed on a small scale. 



