DESCRIPTION OF SMALL ISLANDS OF THE ATOLL. 103 



continuous with the lagoon edge of most of the " headlands " of breccia on the lagoon side. Just where 

 the breccia ceases is a lai'ge block of Pontes, apparently /;; situ, protruding through it. 



Regarding these three islands as a whole, we have seen in them a breccia defence all along the ocean 

 side, but broken in ^jlaces ; there a breach is forming or has formed through which the S.E. gales sweep 

 over a portion of the island to the lagoon, carrying away the fragmental material of which it is largely 

 composed, undermining the trees, creating channels or enlarging any already made, and eroding deep into 

 the breccia sheet, so that these channels once made become enlarged more and more. On its east end 

 severe corrosion is taking place, removing the breccia sheet and corroding deeply into the floor of the 

 reef itself. Thus denudation, solution, corrosion and violent erosion are combining to remove, on almost 

 every hand, the material of the surface and every side of these three islands, except at the few relatively 

 small areas indicated, where sand is accumulating and may for long so continue to do, until it may 

 possil^ly form the nucleus of a sand island farther out on the lagoon platform, when these older present 

 islands have been all removed except perhaps a thin mantle of the breccia sheet. 



Indeed, though to understand the history and destiny of the islands on this atoll every available piece 

 of evidence obtainable is necessary, and even more would have been welcomed, yet these southern reefs 

 and islands appeared to me to supply the index or key to most of the islets on the atoll, especially since 

 they exhibit some of the more intense phases of erosion and the manner in which it operates in nearly 

 all its stages. 



TEFOTA. 



Tefota (Plate 5) is a tiny islet situated on the south-east corner of the atoll. Its importance arises not 

 from its size, but its position and relation to the larger land on either side. Its elevation is but about 3 feet 

 6 inches above high water ; its surface is composed of foraminiferal sand mingled with a little rubble and 

 beach cUhris like that on the islands on either side of it. There is but little Hurricane Bank and that 

 chiefly on its west side. There are no breccia buttresses or low clifi's to defend it from the encroachments 

 of the waves. It rests upon the breccia sheet, which slopes away steeply to the canoe channel in the 

 breach on the east side, and but gradually to the breach or channel on the west, and to the sea on 

 the south, in which direction it is very rough and jagged. 



This island though so small and exposed would appear to be fairly stable and to have retained its 

 surface material. It has probably continued as a remnant of the land which at one time formed a single 

 island. It must have remained as now for a very long time, for besides several cocoanut trees less 

 than the usual height it has two quite tall ones. The erosion in the breach on the east side has been 

 considerable ; the canoe channel in it can be used till about half tide, and consequently admits of the 

 passage of a large stream of water at ebb and flow. The west breach is shallower and is only covered 

 as high water is approached. The fact that so large a surface of the breccia sheet on the jolatform 

 and in the breaches at this corner is partly removed, affords a good opportunity to observe its com- 

 position and general features. It is composed of usually angular and flattish coral rubble lying at all 

 angles, but generally conforming approximately to the horizontal, and I fancied inclined more to the sea 

 than otherwise, the interstices being occupied by smaller fragments of coral and some sand. On the 

 underside of some of the recently overturned large flat sheets or cakes of breccia near this island, smaller 

 sized and less worn and fractured parts of coral were commonly found, many of which were observed 

 to be Reliopoi'a. 



Among this breccia was one very large and a few smaller corals of the strong form of ilontijMra 

 species, apparently embedded in the breccia as it grew, having been but very slightly injured by con- 

 tact with the drift coral of the breccia sheet, which appears to have grown during the deposition of 

 that sheet, then to have been covered over by it, and at last to have l)een again exposed by the recent 

 removal of its upper part. I had occasionally seen coral in a similar position which struck me as l:)eing 



