26 Mr Gardiner, The Atoll of Minikoi. 



The lagoon, as is commonly the case in small atolls, is shallow 

 and much broken up by shoals. It has a sand flat against the 

 rough zone of the reef, especially broad to the south ; this can be 

 waded nearly everywhere at low tide. The central deeper part is 

 evidently enlarging in all directions at the present day. The 

 following give evidence of this :— (1) there is a marked cliff all 

 round from one to about three fathoms ; (2) the shoals have all 

 precipitous sides often overhanging ; (3) coral growth is absent 

 from the bottom ; (4) the depths show a slight general increase 

 as compared with the chart ; (5) there are no foraminiferal 

 deposits, the sand being the same everywhere, exceedingly fine, 

 evidently for the most part much broken and triturated coral 

 fragments. 



Tracing back the history of the atoll the island would appear 

 to have been formed entirely by either an elevation of the whole 

 atoll, or more probably by a change of level in the surrounding 

 ocean. The highest point of land is 19 feet above the low tide 

 level, and such an height is only found in one position, and may 

 be partly artificial. Allowing amply for denudation, it is fair to 

 suppose a change of about four fathoms. When first the altera- 

 tion in relative level took place, it is probable that the island 

 extended round the atoll, except perhaps where the present ships' 

 passage exists, the presence of pinnacles at any part being taken 

 as evidence of the existence of former land. The sandy part of 

 Minikoi island was probably mainly an after formation, due to 

 washing up from the lagoon. 



At the present day the reef of the atoll is indubitably grow- 

 ing outwards on every side — the carious formation to the north- 

 east being due to special local conditions— and the lagoon is 

 deepening and broadening. There is no evidence of a former 

 central island, such as is commonly found in the Fiji Group, nor 

 is there any indication of subsidence throughout the Laccadives. 

 Indeed it would appear more probable that this atoll has been 

 formed sui generis, has perhaps grown up as a flat reef on some 

 mound on the sea floor, subsequently attaining its present ring 

 shape. On this view the numerous deep banks of the Laccadives 

 represent incipient stages in the formation of reefs, while its 

 islands and reefs exemplify the changes which finally produce the 

 perfect atoll. In all this region however there was probably a 

 change of level of the reefs in respect to the sea, which has 

 modified them considerably, but the main features certainly 

 remain. 



A full report on the atoll is in preparation and will shortly be 

 published. The foregoing account was read at the recent meeting 

 of the British Association at Bradford. 



