Chap. II.] alluvial deposits and fjlown sands. 31 



the country round about; the soil is exactly like that formed in the 

 great Mercanura tank or back-water deposit lying to the north ol" Pon- 

 dicherry, as well as the deposits formed and now forming in the beds of 

 all the tanks about this part of the country. 



A distinct boundary exists, however, between this soil as an alluvial 

 deposit of the Vellaur basin and the cotton-soil of the higher grounds 

 to the westward ; and therefore we have included it among the alluvial 

 deposits of the river, and refrained from classing it as cotton-soil proper, 

 until the subject of the different soils of India has been more fully 

 worked out. 



The surface of the alluvial flat north of Chellunbrun is more 

 elevated than that nearer the Coleroon; for the Vel- 



^^'^ ?naghirf ^^'°'''" ^^^^^* ™^^ i" ^ ^^^^P ^^d with stccp banks, forming, 



at Bhowanaghiri, regular cliffs, at the base of which 



the upper beds of the Cuddalore sand-stones are exposed. At Tolum, 



where there is a Government ferry station, and beyond which place 



the tide extends, there is a bed of peat exposed only at ebb tide. The 



peat consists mainly of leaves and fruits of dico- 

 'Peat' at Tolum. ^ ... 



tyledonous trees, still preserving, in great measure, 



their characteristic shape. Here, likewise, the river runs between cliffy 



banks, 20 feet or more in height. 



The Vellaur does not form a delta, discharging its waters into the 



Bay of Bengal by one mouth at Porto Novo. 



North of Chellunbrun, on the west side of the road, is a small ridge 



of blown sand running north by east to within a 



few yards of the Vellaur. It is overgrowTi by 



numerous larg-e Palmj-ra palms. Excepting those two patches of 



blown sand south of Anagara Chuttrum, this is the most westerly 



of aU the blown sands along the coast, from which it is distant fully 



G miles. 



(253) 



