68 



in breadth, it lies from 6 to 10 miles off the coast, south-east of Manapad and 

 about 5 miles south-west of the southern extremity of the Manapad group of pars. 

 No information is given in the inspection summary of the character of the bottom. 

 It would be advisable if the Inspector be instructed to pay special attention to this 

 group during the next few inspections in order to obtain data for comparison of 

 these banks with the better-known ones of the Central division. 



Historical evidence as already quoted points to some at least of these banks being 

 occasionally productive. 1 know of no physical reason why such conditions should 

 cease. 



Northern or Kilakarai Division. 



The limits of the banks comprised in this category lie between Vaipar on the 

 south and the Island of Edmesvaram on the north, a distance of 60 miles. In the 

 past considerable attention has been devoted to their examination, very much more 

 indeed than that given to those of the Southern division which are more deserving of 

 such care. 



All these northern pars suffer from the excessive turbidity of the sea which 

 prevails during stormy weather. The proportion of mud present in their sand is much 

 greater than in the case of either the Central or the Southern division, and as 

 a consequence pearl oysters exist in a condition of chronic starvation, are stunted from 

 an early period and never survive to a fishable age, if we may judge by the records of 

 the past 100 years and from the effects I have noticed in those experiments where 

 I have kept oysters under circumstances simulating a like condition of silt-laden 

 water. 



Much of this mud is derived from the rivers entering the sea between Vaipar and 

 Pamban, mud which moves north-east up the coast during the south-west monsoon 

 period. In several places eddies caused by the deflection of the current by the 

 presence of the chain of islands lying parallel with this part of the coast conduce to 

 the formation of mud deposits at definite localities, one of which we found between 

 Nallatanni Tivu and Upputanni Tivu Pars ; other mud deposits are marked on the 

 Admiralty chart. 



Between Kallatanni Tivu and Pamban the banks have all the useless character- 

 istics of the Ceylon banks immediately south of Mannaar island and are distinguished 

 by an inordinate luxuriance in growth and variety of Algae, such as Luurencia, 

 Polyziphonia, Corallina, Chrysymenia uvaria, Halimida tuna, and Kallymenia perforata. 



Such pars are, I fear, uniformly valueless and unworthy of inspection oftener 

 than once in four years. 



Greater attention is required in the southern portion of the division where there 

 exists the possibility, rendered somewhat definite by the presence of the remains of a 

 fishery camp on Nallatanni Tivu, of oysters some day maturing. The prospect is not 

 hopeful but is sufficient to justify an inspection in alternate years. The pars requiring 

 the most attention are the Upputanni Tivu, the Nallatanni Tivu and the Vembar 

 Periva Pars. The two first lie four miles off the coast south and south-east of 

 Yalinukam Point, the last south-east of Vembar village. 



The rocky bottom on all these pars is the usual brownish dense limestone calcrete, 

 while the sand is in most cases rather finer than that from the Central and Southern 

 divisions and the amount of mud mingled with it is very markedly greater in quantity. 



When inspection of this ground be made, diving and dredging traverses should be 

 made over the whole of the ground at depths between 7J and 10 fathoms to the south 

 and east of the two Tanni Tivu and Vembar Pars. Some of the ground we met here 

 was distinctly promising, and being further from land and at greater depth the bottom 

 is more free from mud than on the inshore banks. 



The characteristic organisms of the Tanni Tivu Pars are sponges in great abund- 

 ance (see page 28 for names), various Gorgonoids, notably Juncclla juncea, an occa- 

 sional Astraeid, the tubes of Eunice tuhifex and numbers of Pinna ; Modiola harbata 

 (suran) generally absent. 



Kumulam Par is valueless, as are also Valinukam and "Valinukam Tundu Pars 

 and some others in shallow water between Valinukam and Vembar. 



