424 Mr Gardiner, The Coral Reefs of [Mar. 7, 



there is a very distinct beach on the lagoon sides of the islands 

 similar to the hurricane beach of the same islands. 



A hurricane beach, such as is found on the windward face 

 of the atoll, could indubitably have been formed by masses of coral 

 and reef-rock, thrown up by the waves, subsequently consolidating 

 underneath by the deposition of carbonate of lime on the evapora- 

 tion of the water at low tide, but under such circumstances the 

 strata should dip towards the ocean, which piled up the fragments 

 in the first place. The stratification is not generally visible, but 

 at the ends of the islands, especially to the south-east of the atoll, 

 it appears rather to be horizontal. At the north end of Amatuku 

 there is a section clearly visible of a small cliff about 6 feet high ; 

 the strata are horizontal, but this island is here rather broad and 

 the cliff stands well back from the sea, continuing for about 

 50 yards along the lagoon shore. The three islands, Funamanu, 

 Funangongo and Fatato, have the hurricane beach much steeper 

 than the main island ; indeed the centre one, Funangongo, has 

 towards the ocean a precipitous fall, in places almost a cliff, of 

 5 feet, succeeded by a steep boulder-covered beach. On the 

 top it is not formed of a firmly consolidated rock, but of somewhat 

 loosely aggregated blocks of coral and reef-rock ; the extreme 

 height here above high tide I measured at 6 feet. The action of 

 the sea on the coast is plainly visible in fallen shrubs and trees, 

 undermining the beach, and from the loose nature of the land 

 above continually causing slips. The beach is strewn with 

 boulders, which extend considerably below high tide level, and 

 between tide marks these seem to be joining on to the rock 

 below by the deposition of carbonate of lime on the evaporation of 

 the water left on the beach, when the tide falls. On the islands 

 lying north-east of the " pocket," a somewhat similar hurricane 

 beach is found, but it is not so steep ; it is, however, consolidated 

 to a higher level than in these islands, and the horizontal character 

 of its strata is more distinctly visible. 



Under the hurricane beach on the windward side of the atoll 

 there is an area, rarely more than 15 yards broad, of very rough, 

 ragged rock with shallow pools of water here and there at low 

 tide. Outside this is the flat of the reef and its raised outer edge; 

 these latter parts vary on this face in combined width from 40 — 

 80 yards. As I shall have occasion to refer to these zones 

 constantly, I shall call them the rough zone, the reef-flat and 

 the rim. The rock of all these three zones consists of a consolidated 

 mass of the skeletons of corals and nullipores with shells, sand 

 and the remains of various marine animals ; it is exceedingly 

 hard and rings to the hammer. On the surface where, exposed 

 to the air between tide marks, it has time to dry, it is almost 

 structureless to the unaided eye, but pieces, obtained from under 



