KWAJALONG. 801 



Many of tlie gaps on the west face of Menschikov are comparatively 

 shallow, judging from the color of the water, but occasionally a light or even 

 a dark blue streak indicates a deeper passage for boats or small vessels. 



North of Enniigenliggelap (Pis. 169, fig. 2; 227, fig. 2), between it and 

 Boggen Island, stretches an extensive reef flat on which long sand spits have 

 been thrown out on the lagoon side of the shingle beach of those islands. 

 This reef flat is covered with green water, showing that the pass is compara- 

 tively shallow. On the lagoon flat two lines of breakers, parallel to the 

 outer reef, indicate the position of sand bars which are in the near future to 

 form a double line of islands and islets. A little north of this we came on 

 a still more instructive reef flat, where there is not only a second, but also a 

 third line of sand bars indicated by breakers on the wide reef flat. On the 

 very edge of the outer reef flat are two small sand islands ; the lagoon flat 

 extends eastward from twelve to fifteen hundred feet, then a narrow line of 

 blue water separates the inner edge of this flat from the second and third 

 line of islands and sand bars. Still further in the lagoon a fourth line of 

 breakers shows the piling up of sand in the shallow i)art of the lagoon. 

 Opposite passages and gaps the breakers usually throw up islands, islets, and 

 bars, wherever a considerable body of water flows across the reef flats. The 

 width of the reef flat of Menschikov atoll varies greatly. Sometimes it is 

 narrow, nothing but a shallow beach line, on the one side of which beat the 

 lagoon breakers, and on the other the rollers on the sea face, the land rim 

 forming only a narrow sand dam separating perhaps the deepest part of the 

 lagoon from the deep water off the sea face. Where the reef flats are wide, 

 they are usually cut into intricate channels and dotted with sand bars, as 

 near Gehh and Tengeli. 



Similar lagoon reef flats are developed north of Oniimak Island, imme- 

 diately south of the adjoining pass. At Wotje Pass we strike one of the 

 finest examples of lines of secondary islands and lagoons (Pis. 170, figs. 3, 4 ; 

 227, fig. 2), separated by strips of deeper water than is usual on reef flats 

 where sand bars are readily formed. At Wotje Pass we again found high 

 sand dunes, blown over on the outer reef flat from the lagoon side, which 

 have nearly overwhelmed the beach rock on the sea face. Here sand dunes 

 exist not only on the two outer islands flanking the north and south side 



