I20 THE GREAT BARRIER REEF. 



myriads of birds mentioned b}' IVIr. Jukes, whose habits are so graphically described in the 

 foregoing quotation, have accumulated, during the countless centuries in which they probably 

 enjoyed unmolested occupation, and lived and bred there, a vast deposit of guano little inferior in 

 quality and value to the far-famed Peruvian variety. The essential chemical difference between the 

 two is that, whilst the Peruvian guano abounds in ammonia as well as in phosphates, that obtained 

 from Raine Island is composed of phosphates only. The difference is accounted for by the 

 fact that the guano imported from the South American coast-line is derived from a permanently 

 arid and rainless district, whilst the site of the Raine Island accumulations is necessarily 

 exposed to the heavy rainfall during the north-west monsoon. For many agricultural pur- 

 poses this conservation of the pure phosphates only possesses advantages. Dealing with 

 the subject of guanoes, it may be recorded that hopes originally ran high respecting the 

 possible utilisation of the vast deposits of bat excreta in caves in the Rockhampton (Keppel 

 Bay) district of Queensland, although to all appearance resembling guano of the highest class, 

 it is found on analysis to be altogether destitute of phosphates, and has so far been turned 

 to no practical account. Concerning the Raine Island guano, it may be observed that the 

 deposits occur under three distinct conditions : Firstly, in layers some fifteen inches thick, 

 immediately beneath the upper crust of coral conglomerate, which constitutes the encircling 

 plateau described by Mr. Jukes ; secondly, in pothole-like hollows in the same location ; and 

 thirdly, in trench-like depressions in the central black earth basin. The deposits are so 

 extensive that the present proprietors have found it worth while to import a locomotive and 

 all the plant requisite for tramways over which to convey the material to the landing jetty. The 

 work of collecting and shipping the guano began in the 3'ear 1882, and the supplies are 

 apparently far from being exhausted. 



The birds that have been noticed in Raine Island, in addition to those mentioned in the list 

 given by Mr. Jukes, include, as notified to the author by the present proprietor of the works, 

 three white and one blue varieties of cranes, and a few stray pelicans. The main object of H.M.S 

 Flys first visit to Raine Island, 1843, was the charting of the passage, through the Barrier at 

 this point, that was most frequently followed by vessels bound for Torres Strait. The undertaking 

 was accomplished. The subsequent year the Fly repaired thither again for the purpose of 

 erecting a substantial and conspicuous beacon on the island, that should assist vessels in making' a 

 straight course for the passage from the outer ocean. The beacon was constructed of square blocks 

 of coral concrete, quarried from the east end of the island, the lime for the mortar used being 

 compounded on the spot by burning the large shells of Tridacna and Hippopus, which could be 

 obtained in abundance from the reefs at low water. The general plan of the beacon, which is still 

 standing, is that of a circular stone tower, forty feet high and thirty feet at the base, with 

 walls five feet thick. Erected on the highest ground of the island, its summit is fully seventy feet 

 above low-water mark. This Raine Island beacon was, unfortunately, not destined to fulfil 



