250 CEYLON MARINE BIOLOGICAL REPORT.S. 



foiuid to bo silting over. A recent examination sliowcd that the whole area was covered with a layer 

 of coarse sand, with mud, and a sandy shoal which existed (stretching in an east-north-easterly direction 

 into the bay from near the beacon) lias extended out to, and partly over, the oultclied area. Thi.s sand 

 shoal is not showii on tlie original chart. It has formed on a .small rocky patch, and of late has grown 

 out into the bay and threatens to almost close the entrance. The shoal is a dangerous one, having only 

 3 feet on it at low wat<>r. It rises out of 3 fathoms of \\ater, and is very abrupt on the north side. 

 There are other striking changes taking place in Dutcli Bay. Several vei-y interesting characteristics 

 were noted in Part III., " Ceylon Marine Biological Reports," June, 1909. 



The severance of Ipanti-\Ti island from Karativu has , taken place of late years. A shoaJ now 

 marks the subsidence, and a sheet of water 2 miles in breadth separates the islands. Another remark- 

 able change, concurrent probably with the subsidence, is that at the south-west extremity of Karativu 

 full-grown trees of 3 feet circumference now stand in 9 feet of water at a distance of a cable and 

 a halt from the shore. As these trees do not appear to be more than twenty years old, it is evident that 

 the subsidence is recent, and probably still going on, for when Dutch Bay was visited last it was fomid 

 that a new channel had formed north of the present southern extremity of Karativu, so that the island 

 is again divided. 



The other striking change noted in the above Report was the formation of a channel, now a mile 

 broad, cutting off Dutch Bay Land from Mutwal Island. The channel is still broadening, much to the 

 sorrow of an enterprising Sinhalese fisherman, who has planted a coconut tope, which is slowly and 

 surely being washed away by each succeeding monsoon. This new channel on the south probably 

 accounts for the segregation of sand on groimd hitherto kept clean by the velocity of the ebb and flow 

 of tide, as doubtless a smaller volume of water passes through the main entrance now than formerly, 

 when only one channel existed. 



In the face of such rapid and striking changes Dutch Bay cannot be recommended as a safe 

 anchorage, and should be entered with great caution. It is only available for vessels of very hght 

 draught — not over 12 feet. The entrance to the bay must be approached from the south of the Bar reef, 

 the passage between the reef and Karativu not being safe, as sandy shoals form there. 



Native craft frequently water from Ipantivu Island, where weUs have been sunk at the north-west 

 extremity, off which a depth of 12 feet is found at a distance of four cables. The water is good. 



Portugal Bay affords anchorage sheltered from the south-west monsoon in 4 fathoms of water, with 

 good holding groimd, the bottom being stiff mud. This bay has no hidden danger, and the soundings are 

 very even. It is ordy useful as an anchorage. 



Marichchukaddi, 4 miles furtlier north-east — the fishery headquarters — affords good anchorage for 

 hght draught vessels in 3 fathoms of water, and is sheltered from the fuU force of the south-west 

 monsoon, although there is a very steep sea and considerable surf on the beach during the height of the 

 south-west monsoon. 



A good leading mark when approaching Marichchukaddi is the northern bimgalow of the three 

 built on a chff , in hne with a large conspicuous tree bearing east. This gives a leading line over Karativu 

 shoal in 3 fathoms of water. The bimgalows are very conspicuous, more so than Dixon's tower, which 

 latter stands three cables north. The top of the tower is 95 feet above low water. Both form conspicuous 

 marks over the East and West Cheval Paar. 



At Marichchukaddi there is a good supply of fresh water from two reservoirs, one a quarter and 

 the other three-quarters of a mile from the beach, but the water is not so good as that found at Silavatarai, 

 which is obtained from concrete wells smik close to the beach, and from which water can be readily 

 pumped into a water boat. 



Silavatarai Anchorage lays three cables south of an iron beacon erected lately on the Silavatarai 

 coral reef, and is only used when calling for water. Of late a nursery — formed of expanded metal — has 

 been erected under the shelter of this reef. The ground is flat rock covered with a little sand, and is not 

 u safe anchorage. 



