ii8 THE GREAT BARRIER REEF. 



mentioned, and distinguished as the First Three Mile Opening and Cook's Providential Channel, 

 that of the Second Three Mile Opening occurs, almost midway between the two, in latitude 

 13" 5" S. A very little farther north than Cape Grenville, — this promontory being utilised 

 as the mainland landmark to steer for in association with it — the Raine Island entrance is 

 arrived at. This passage, it will be recollected, was referred to in an early page of this chapter as 

 the one formerly used most extensively b}' vessels bound from the south or the east for Torres 

 Strait, and as the one which H.M.S. Fly was specially commissioned to survey and define more 

 accurately. Raine Island and the immediate neighbourhood was, in consequence, made the head- 

 quarters for some little time of the surveying staff; and Mr. Jukes, the naturalist and geologist to 

 the expedition, made good use of the opportunity of examining and reporting upon its structure. 

 An abstract of Mr. Jukes' original description of this island may be here reproduced. — 



" Raine's Islet is about 1,000 yards long, by 500 wide, and in no part rises more than twenty 

 feet above high-water mark. It is formed of a plateau of calcareous sandstone, which has a little 

 cliff all round, four or five feet high, outside of which is a belt of loose sand, forming a low ridge 

 between it and the sea. Some mounds of loose sand rest upon the stones, especially at its 

 western end. The length of the island runs in about a N.N.W. and S.S.E. direction. It is 

 surrounded by a coral-reef that is narrow on the lee side, but to windward, or towards the east, 

 stretches out for nearly two miles. The surface of this reef is nearly all dry at low water, and its 

 sides slope rapidly down to a depth of 1 50 or 200 fathoms. The island is covered with a 

 low, scrubby vegetation, partly of reed-like and umbelliferous plants, and parti}' with a close 

 green carpet of a plant with succulent leaves and stem, which we subsequently found was good 

 to eat, and so went with us by the name of ' spinach.' The central part of the island had a rich 

 black soil several inches deep, and here we commenced to dig a well, having brought pickaxe and 

 spade, to try if we could find water. We dug about five feet deep, but found the rock too hard 

 and tough to allow us to proceed further. The following was the section : — 



Feet. Inches. 



Good black vegetable mould ... ... ... o 6 



Stone, brown mottled with white, hard and coarse grained o 3 



Rich moist black soil, like bog earth ... ... ... i 4 



Stone of a light brown colour, rather soft but tough, and 



yielding slowly to the pickaxe ... ... 3 o 



5 I 



" The stone was made up of small round grains, some of them apparently rolled bits of 

 coral and shell, but many of them evidently concretionary, having concentric coats. It was 

 not unlike some varieties of oolite in texture and appearance. It contained larger fragments 

 of coral and shells, and some pebbles of pumice, and it yielded occasionally a fine sand that 

 was not calcareous, and which was probably derived from the pumice. Some parts of it made 



