59 



The rocks show some diversity in character, dense and compact limestone 

 passing in some places into a somewhat quartzose stone having a calcareous matrix. 

 The hard bottom is much cut up by more or less extensive stretches of sand. Here 

 and there we meet with loose fragments of calcrete similar in composition to the bed 

 rock of the par ; dead coral is fairly common in the form either of much honey- 

 combed tabulae or of rolled and much worn broken madrepore branches, derived 

 probably by the action of backwash and under-current from the extensive coral reefs 

 that fringe the adjacent coast. 



(Thank beds lie to the south, east, and west of these banks, forming virtually a 

 girdling of chank-producing sands. 



A list of the common forms of life met with here is given on page 102 

 together with other details. 



The term Kudamuttu used in the names of these banks is significant. It 

 means literally the " Pearl Bay ", so that the shallow indentation off which these 

 banks lie and which has Hare Island, Tuticorin, and Trichendur point as its northern 

 and southern limits, with the mouth of the Tambraparni river at the centre of its 

 curve, appears to have been termed the Pearl -bay, par excelknce, from the renown of 

 the pearl fisheries held there. Kolkoi and Kayal were at the embochure of the 

 Tambraparni, so we have in Kudamuttu further indirect evidence that the towns 

 named were located near the centre of the most prolific pearl fisheries of early and 

 mediaeval times, the periods when they flourished respectively. 



9. Outer Kudamuttu Geoup. 



This is a congery of some six small banks lying due east of the Inner Kudamuttu 

 group. It measures some two miles north and south by the same from east to west, 

 with an average depth of 9 to 10 fathoms. 



Iso fishery is recorded from these banks ; neither do we know of any extensive 

 spat fall in any ypar since the inspection record begins in 1863. Time did not permit 

 of an extensive examination this year. 



10. Kadian Group. 



This collection lies about seven miles west of Pinnacoil and due south of the 

 Kudamuttu group from which it is separated by a narrow chank bed. To the south 

 it marches with the Karuwal group. In deptn it agrees with the former — 7^ to 8 

 fathoms. 



The two principal patches of rocky ground are the Kadian and Kanawa Pars, 

 each of about half a mile in diameter. The whole group covers an extent measur- 

 ing approximately two miles from north to south by one and a half from east to west. 



In its fauna, physical structure, and history, it is in close agreement with the 

 inner Kudamuttu region, and was fished in conjunction with the Kudamuttu Pars 

 in 1823. Spat falls have several times been recorded since 1861, namely in 1878, 

 1881, 1895 and 1897 when young oysters lay thick on all the rocky outcrops and 

 wherever there was any cultch, quantities being found adhering even to the valves 

 of Pinna, which are fairly abundant on the edge of the sandy ground on the western 

 margin. 



The generation of oysters seen for the first time in 1897 were reported healthy 

 and still plentiful in the following year, but in 1899 the bank was described as almost 

 bare of oysters. A very large number of byssal cables was noticed at this 1899 

 inspection, iudicatinglprobably a recent inroad by rays (Rldnoptera sp. ) upon what 

 must have been a promising bed of oysters. 



The Inspector, I observe, remarks that the presence of these byssal strands 

 '•'• shows plainly that the oysters of last year have migrated", a deduction not warranted 

 by an intimate knowledge of the habits of the pearl oyster. 



"Whenever an occurrence of this nature be met with, care should be taken to 

 ascertain the condition of the individual byssal cables ; we require to know whether 

 the majority show signs of having been broken with violence as happens normally 

 when oysters are torn away from their attachment, or if the strands of each cable 



