MANGA REVA. 63 



central ridge on the pass leading from Rikitea to Kirimiro on the west side 

 of Manga Reva, as well as from the pass leading to Taku. On both these 

 passes we obtained excellent views of the encircling reef to the west, north, 

 and east of the Gambier Islands (Pis. 63, fig. 1, 66, 69-71). We could trace 

 in the panorama before us the western reef extending in a northeasterly 

 direction parallel to the general trend of Manga Reva Island for a distance 

 of about five and a half miles (PI. 69). 



From the northern horn to nearly opposite Kirimiro Bay the barrier reef 

 (PI. 14) has only three small islets ; it is narrow, of uniform width, about 

 one-third of a mile, plainly defined, submerged in places, and forms the 

 western boundary of a large northern bight with from 7 to 11 fathoms, 

 dotted with numerous interior coral patches from a quarter of a mile to a 

 mile in diameter or length. The southern part of the western barrier 

 lagoon off Manga Reva is irregularly dotted with many small patches of 

 reef, with an occasional deep hole of from 15 to 20 fathoms near Manga 

 Reva Island. From the terminal islet of the western reef to tlie west of 

 Kirimiro there are but few coral patches, indicating a reef which dips 

 gradually in a distance of a mile to a deep channel of from 4 to 6 fathoms, 

 which separates the northern and western reef from the great reef fiat 

 lying to the southwest of Tara-Vai. This flat has a width of nearly two 

 miles, is about four and a half miles long, and is marked at its soutlnvest 

 extremity by a series of low islets arranged in a somewhat circular line, 

 formed by three deep bays and spurs from the outer line of islets, as so 

 frequently occurs on a wide reef flat in atolls of the Pacific. 



This part of the reef is called Tokorua(Pl. 14). It shelves very gradually 

 from 3 J- to 4 fathoms on the west face to 7, and connects with the plateau 

 upon which stands Tara-Vai and Aga-kanitai. From Tokorua the reef 

 extends in an indefinite narrow ridge eight miles long, with from 3 to 8 

 fathoms, in a southeasterly direction. The western edge is steep to, and 

 the eastern face passes gradually into, the lagoon, which at that point has 

 a general depth of 8 to 20 fathoms. The deepest part of this region is at 

 the foot of Mount Mokoto, between it and Tara-Vai, though Tara-^'ai is 

 united with Manga Reva Island by a plateau varying in depth from 3^ to 

 4|- fathoms. 



At the southeastern point of the reef it passes into a wide plaloau with 

 from 9 to 10 or If) fathoms. This plateau is about nine miles wide southwest 

 of Tekava (PI. 14). That part of the atoll has not been well surveyed, so 



