262 "ALBATROSS" TROPICAL PACIFIC EXPEDITION. 



reef flat ; this is gradually disappearing, as we traced it on the west 

 side of Maraki. 



From the western spit of the south shore of Tai'itari extends a long 

 reach of black coral shingle forming the sea face of the southwestern 

 part of the atoll and the eastern side of the entrance to Taritari (PI. 154, 

 figs. 2, 4). The extension of the sea face of the spit is formed by a series 

 of low islets connected by ledges and covered with scrub vegetation. The 

 vegetation gradually becomes more scanty, and finally disappears from the 

 northern islets and sand bars. On the north side of the passage a stretch of 

 disconnected islets forms a barrier parallel with the western opening into 

 the lagoon (Pis. 154, figs. 1, 3 ; 224, fig. 4). To the south of the passage 

 the great expanse of the shallow lagoon is occupied by numerous shoals 

 (Pis. 151, figs. 1, 2 ; 224, fig. 4). 



When about three miles from the western edge of the passage, we turned 

 in towards the anchorage (PI. 151, figs. 1-3). On our way we passed islets, 

 shoals, flats, and bars, separated by deep lanes of blue water, the bottom 

 between them consisting of white mud formed from the disintegration of 

 the corals or NuUipores growing on the flats. The islands (PL 154, fig. 3) 

 and islets to the north of the southern ship passage are better wooded than 

 those to the south ; they form only a very imperfect barrier to the sea, 

 which sweeps into the lagoon over the whole of the wide western flat 

 (PI. 224, fig. 4). Between the shoals most intricate passages connect the 

 lagoon with the sea on the western face of the atoll (PI. 224, fig. 4). A 

 section across the land rim to the south of Butaritari shows a secondary 

 platform lagoon on the sea face of the outer reef flat edged with NuUipore 

 and Pocillipore knolls, forming a shallow sink ; the reef flat is not more than 

 150 feet in width ; it rises gradually towards the base of the beach, this is 

 fringed with beach rock and coral conglomerate and rises to a height of 

 about seven feet. From the summit the slope runs gradually to the edge 

 of the lagoon ; a narrow sink exists immediately behind the beach near the 

 sea face. At the foot of the long slope, on the lagoon side, the beach ends 

 in a low steep coral sand beach, and the face of the slope is covered with 

 weathered fragments of broken coral gradually worn into the coarse sand 

 of the beach. The sink on the lagoon face of the slope is in places changed 



