ARI. 105 



Off the western face of Digura we found only fine and coarse coral sand, 

 but none of the sticky ooze so characteristic of the bottom of the lagoons of 

 the Pacific atolls. To the north of our anchorage off Didu we saw a large, 

 most regularly elliptical faro fully a mile in length. Immediately to the 

 west of Digura Pass are a number of large faros of various shapes, with very 

 regular rim flats and some with lagoons of considerable depth. Some of 

 the banks we passed have no veins indicated on the chart; it is difficult to 

 say that this is an error of the survey, or betokens a change, as is suggested 

 by Mr. Gardiner for North and South Nilandu.* In one of the faros we 

 find from six to seventeen fathoms, in another from four to ten ; another 

 has a greatest depth of nine, and several have depths of five to six fathoms. 

 We did not check these soundings, yet we could see that these faros had 

 undergone only slight changes since they were surveyed in 1834. In areas 

 protected from the action of the monsoons a faro with a deep lagoon and 

 well-submerged rim must change slowly; its rim increases very gradually 

 in width and height, and its lagoon fills at a very insignificant rate. 



The horn of the eastern face of the south pass into Ari, as well as of the 

 western face of the pass, is edged with large boulders, and a mass of coral 

 rubble is thrown up on the flats of Ariadu, on the southern face of the 

 island. 



To the west of Mamigeli a number of sand-bars have been thrown up on 

 the south side of the eastern, irregularly shaped lagoon of the faro. The 

 northern rim of the lagoon is a mere narrow flat ; its slope and summit are 

 covered with a magnificent growth of corals. The western islands of Mami- 

 geli Faro are separated from the terminal lagoons by a wide green flat 

 covered with from two to six feet of water. The northern horn of this faro 

 is sharp, and is separated by a pass with not more than six fathoms from the 

 faro to the north of it, the first link of the chain of large faros flanking the 

 western face of Ari ; six of these are at least four miles in length ; they are 

 quite irregular in outline. 



At the northwest angle of Ari is Matiwari, an irregularly shaped faro 

 resembling Dugati, at the southeast angle of Ari, only the reef flat area 

 is more extensive in the northern faro ; like the southern faro it seems 



1 Loc. cit., p. 405. 



