APATAKI. 69 



numerous gaps, with shallow cuts giving more or less free communication 

 between the waters of the lagoon and the sea (PI. 38, fig. 2). 



We ran at a slight angle to the northern face of the land rim of Apataki ; 

 it possessed the same general character as the land on the west side. 

 The stretches of unbroken land rim were, however, longer, the low reaches 

 connecting them much less numerous, and there were comparatively few 

 outcrops of old ledge. 



The north face of Apataki, as far as we could see steaming along, is fairly 

 well closed up by a series of low islets and islands similar in every respect to 

 those we had seen thus far, the beaches made up of coral sand with old ledge 

 boulders and occasional old ledge outcrops. 



One of the islands of the land rim to the north of Apataki Entrance 

 has all the characteristics of the land rim of Rangiroa near Avatoru Pass. 

 It is marked by a steep white coral sand sea beach, passing into coarse 

 coral shingle (PI. 38, fig. 1) in its most exposed places, with beach rock 

 boulders cropping out at the base of the steep beach, or conglomerate 

 boulders covering a part of the old ledge reef platfoi-m ; this has a raised 

 rim of Nullipores and Pocillipores, and a diminutive reef platform lagoon 

 channel. The top of the high beach runs in loops into the bush vege- 

 tation, which at first is very meagre, but becomes quite thick beyond 

 the summit rim of the beach, where cocoanut palms cover the land rim. 



The shore platform of the lagoon is marked by two .flight but distinct 

 steps ; these would seem to indicate a very recent elevation of 12 to 18 

 inches on the lagoon side. The long stretches of sand flats in the gaps 

 and cuts which separate the lagoon from the sea (PI. 37, fig. 2) are only 

 decomposed ledge flats like the flats on the lagoon side of the land rim 

 (PI. 39). On some of these are still left the boulders or scattered rocks 

 and corals which once formed part of the old reef ledge (PI. 37, fig. 2). 



The bottom of Pakaka Pass (PI. 38, figs. 1, 3) is covered by very 

 fine masses of corals, heads of Astroeans. Porites, and the like, extending 

 down to 17 fathoms. On the island to the north of the pass, near the 

 entrance point, back of the high shingle beach facing the pass, is found 

 a small sink of brackish water. On the opposite island the shingle beach 

 at the face of the pass is from seven to eight feet high, and the outer 



