SUBMERGED PLATEAU SURROUNDING CEYLON. 77 



time, down to the coast line. The flatness of the course of the 

 streams must also greatly reduce their velocity. 



(4) Sufficient time and sufficient material, witlt transport for the 

 same having now been provided for the formation of the low-country 

 by denudation, it remains to be seen why the extension should 

 have taken place chiefly to the northward. The fact is undoubted ; 

 but the explanation of it is not at all obvious. The currents, at a 

 little distance off the shore at all events, run tliroughout the year to 

 the southward just as much as to the northward, and on the eastern 

 side with a greater velocity to the south than to the north. 



The meteorological conditions in ages past and the trend of the 

 ocean currents may have been different, when the Island of Ceylon 

 was repi'esented by the mountain country, from those now existing, 

 and in any case the gradual northward growth of the land would 

 slowly deviate the courses of the streams in the sea. 



No observations have yet been made, but it seems at least pos- 

 sible that there is, on the western plateau at all events, a steady 

 current along the bottom making to the northward. The diver em- 

 ployed in obtaining the bottom specimen from the 10-fathom bank 

 off Mount Lavinia (see above) could scarcely keep his legs, owing to 

 the strength of the north-going current over the bank, which itseK 

 had been swept bare of sand or other loose matter, no doubt from 

 this cause. 



It is this which may have formed the protecting arm of Negombo 

 lake, and the still greater one enclosing Puttalam ; and it may quite 

 possibly be the agency that covers with sand and again micovers 

 the pearl banks. The only evidence of its existence is the 

 barrenness of the plateau to the southward, and its greater 

 depth, as compared mth its sandiness northward of Colombo, and 

 shoalness. 



The shapes of the mouths of the rivers that occur on fig. I. (which 

 are presented on fig. V. on a larger scale) may be additional 

 evidence as to a north-going current of the present day, so far as the 

 western coast rivers are concerned, since all are formed with sandy 

 peninsulas across their mouths trending to the northward. 

 This is very clear in the case of Colombo, where both the interior 

 peninsula and the present exterior bar of the Kelani-ganga point 

 north, and all the points in the Colombo lake have the same 

 direction. 



At Panadure-ganga the flood water breaks out at a weak spot to 

 the southward it is true, yet the interior peninsula has grown to the 

 northward ; and there is a small lagoon northward of it again, which 

 may indicate a former mouth. The land m tliat vicinity is at 

 present occupied by the town of Moratuwa, and human agencies 

 may have been at work to make the river or lake (as it really has 

 now become) empty itself at a different spot. 



M 7(2)08 



