Notices of Memoirs — C. W. Andrews — On Christmas Island. 21 



The next highest hill (Eoss Hill) is over South Point. It also has 

 a flat top covered with dolomitio limestone, in which traces of 

 gastropod shells are visible. On its outer side there is a low cliff, 

 and below this a long steep slope covered with blocks of limestone 

 in the wildest confusion, and thickly overgrown with creepers and 

 brushwood. Towards the plateau also the descent is rather abrupt. 



Over North-East Point is another elevation (Phosphate Hill), 

 which, though not so high (900 feet), is particularly interesting on 

 account of the extensive deposit of phosphate of lime which is found 

 there. This substance is strewn over the surface in blocks of all 

 sizes, and in some places it is found to a considerable depth ; in 

 others, however, it can be seen to rest directly on an irregular 

 surface of dolomitio limestone, occasional pinnacles of which project 

 through it. At the northern end of the hill the phosphate is found 

 on both outer and inner slopes, but farther south on the plateau side 

 only, the outer being occupied by a reef of limestone, which descends 

 to the terrace beneath in a low cliff. The area actually covered by 

 this thick deposit of phosphate of lime is about half a mile long by 

 a quarter broad, but an immense quantity occurs in the form of 

 irregular nodules and blocks scattered over all the slopes and 

 terraces of this part of the island. There are other less extensive 

 beds over Flying Fish Cove, and also at several points along the 

 eastern edge of the plateau. Probably, when the islands were still 

 low and not covered with forest, they formed the homes of myriads 

 of sea birds, and the guano thus formed, after undergoing alteration, 

 mainly through loss of its organic matter, gave rise to the hard 

 phosphatic rock now existing. At the same time the limestones on 

 which it rests have often been phosphatized, and lumps of coral 

 consisting mainly of phosphate of lime are sometimes found. The 

 extensive accumulations of guano which must have taken place point 

 to a time when the rainfall was much less than at the present 

 day, a condition which may, at least in part, have been dependent 

 on the circumstances that the islands were low and probably free 

 from forest. 



On the eastern rim, between Phosphate Hill and Eoss Hill, there 

 are several smaller elevations, all presenting similar characters, 

 viz. : having on their seaward side a steep talus slope or low 

 cliff, a flat top, and a moderate declivity on the inland side. 

 Between the hills both on the north and east coasts, the rim of the 

 plateau varies a good deal in character. As a rule, its outer edge 

 is marked by a kind of rampart of lines of limestone pinnacles 

 Separated by channels, but sometimes it descends by a gentle slope ; 

 in either case, beneath the cliff or the slope there is always a steep 

 talus-strewn declivity passing down to the first terrace. 



The northern part of the plateau within the elevated rim is 

 particularly characterized by the presence of numerous low hills 

 (about 50 feet), with more or less flat tops covered with blocks 

 and pinnacles of limestone. Further south there are several step- 

 like ridges, running in a generally east-and-west direction ; their 

 southern face is covered with blocks of limestone, composed mainly 



