1922] MADRAS PEARL FISHERIES 8$ 



dives gave tenacious black mud similar to that taken between 

 Uppu Tanni Tivu and Nalla Tanni Tivu Pars. 



The par is all a more or less pure limestone, mostly of fine grain. 



Viewed by the nature of the bottom and the depth of water, 

 I am very doubtful if the locality inspected is the Vembar Periya 

 Par ; I believe the ground examined in reality lies seaward of the 

 par so named. This Vembar Periya bank at all times must be 

 difficult to find from want of good land-marks ; there are indeed 

 no charted land-marks observable from this position at sea, though 

 several remarkable trees and clumps can be seen and might be 

 utilized for lack of something better. To do this sketches of the 

 relative positions of these trees and clumps should be made from 

 different bearings and the positions of the principal objects 

 marked accurately on the chart. 



Fortunately this is the only bank in any way difficult to locate, 

 all others that are equally far from land being within sight of such 

 conspicuous land-marks as beacons, lighthouses and pagodas. 



On the evening of May 14th we returned to Tuticorin, the 

 unsettled and threatening character of the weather making it 

 doubtful if we should be able to do any further work at sea. 



Pending a decision upon this question, I occupied part of this 

 stay ashore in endeavouring to locate any bed of window-pane 

 oysters [Placuna placenta) that there might be in the neighbourhood. 

 I had found prior to this several young individuals thrown up by 

 the tide along the shore to the south of the town, and from the 

 muddy character of the bottom I thought it useful to investigate 

 further. Accordingly taking two fishermen I proceeded south 

 along the coast and passed the salt factory scrutinizing as we 

 proceeded the eroded edge of the low sandy land on the one side 

 and the face of the littoral on the other. Along the shore of the 

 bay-like estuary south of the salt factory large quantities of dead 

 Placuna shells are observable in two places accumulated in dense 

 masses and embedded in the sand some little distance below high- 

 water mark. The shells appear as densely packed as those in the 

 great heaps which mark the sites of former fisheries of this shell-fish 

 along the shores of Lake Tampalakam near Trincomali in Ceylon. 



Close by I saw others embedded in the adjacent sand hum- 

 mocks, showing up wherever a section was exposed. In some 

 places a depth of sand of fully 18 inches lay upon the shells. 

 Meanwhile the fishermen had been wading about in the shallows 



