KAUEHI. 15 



wider flats where sufficient material is supplied from the flats on the 

 lagoon side. 



We steamed by the large boulders of old ledge rock figured by 

 Dana, which he considers as boulders thrown up from the outer edge. 

 I am inclined to consider these huge undercut masses, many still at- 

 tached to the reef platform, as outliers, or as part of the old ledge 

 rock forming that platform ; the moi'e so, as a little farther on the 

 same beach we find outcroppings of the old ledge running from the 

 edge of the land rim across the greater part of the beach, — outcrop- 

 pings which could not be a part of the outer edge of the reef platform. 



The old ledge again crops out on the island to the north of the 

 entrance to Kauehi. This island is perhaps ten to twelve feet high, and 

 the old ledge puts out diagonally across the face of the beach from its 

 highest point a series of spurs separated by short reaches of sand. 



On the west side of Kauehi there are a great many low gaps be- 

 tween the islands and islets of the land rim opening freely into the 

 lagoon, into which the sea washes. According to the position of the 

 islands, the presence of old ledge or of boulders, either of recent corals 

 or of old ledge, or of recent conglomerate formed of both, the beaches 

 of the sea face are made up of coral sand of various degrees of fine- 

 ness, or of coral shingle of varying size. The edge of the land rim 

 is, as usual, flanked by a narrow belt of shrubs, which protects the 

 land rim against the pi'evailing winds. 



The entrance to Kauehi is very similar to the entrances into other 

 lagoons, — an opening with deep water between two low headlands, 

 flanked on the lagoon side by reef flats and islets or sand bars. Kauehi 

 is said to have on the east side a secondary lagoon similar to those which 

 we shall describe for Marokau and Ravahere, as well as to the second- 

 ary lagoons of Tahanea and Anaa. 



