STONE AGES OF CEYLON. 113 
of ancient manufacture. Presumably these white sand heaps 
belong to Neolithic days. They do not seem to be encroaching 
much upon the jungle now. 
Ancient red earth dunes are to be found buried beneath 
those of more modern dates and lighter colour in the Jaffna 
peninsula. From some of the former, at Kalmunai, I have 
gathered quartz flakes. 
Denudation has accomplished so much since the red earth 
was laid down that the present outcrops are mere scattered 
remnants. One traces them over the lowlands and up the 
valleys of the permanent rivers.* And here I would call 
attention to the difference between permanent rivers, such as 
the Kelani and the Kalu-ganga, for example, with their 
buried bottoms and ancient history, and the modern streams 
which have no such buried bottoms. The latter have all been 
formed since red earth times, and the great majority (though 
not all, I should suppose) rise in the low-country, and run dry 
in the rainless seasons ; whereas all the permanent rivers rise 
in the mountain zone. 
I have already made reference to the occurrence of red earth 
dunes below more modern ones at Kalmunai and elsewhere. 
The former have been preserved of course by the latter, which 
protect them from denudation. Blown sand is a fine pro- 
tection, for as fast as it is removed, either by the wind or rain, 
it is replaced with fresh material; but its action is often 
limited to a zone a few hundred yards in width around the 
coast. So one finds high rims of sedimentary rocks and plateau 
beds along the coast which separate flat country, standing 
but a very few feet above sea-level, from the ocean. An 
excellent example of this is seen at Minihagalkanda in the 
Southern Province. In this instance elevation has gradually 
raised the plateau beds above the influence of the blown sand, 
and now denudation is ‘playing its usual part. From the 
present distribution then of plateau deposits and their typical 
occurrence on the summits of low hills, it follows that the 
geography of the low-country is distinctly different to-day 

* In the case of the Maha-oya this can be traced with comparative 
ease, and I have no doubt whatever that some of the higher gravels of 
the Kelani river are part of the flaked series, 
