SECTION OF CORAL REEF. 353 



soundings gradually decreased with a soft muddy 

 bottom, as we approached the eastern shores of 

 the bay ; which is so large and free from shoals, 

 that a vessel not wishing to anchor might pass the 

 night standing off and on with perfect safety. 

 There is over the head of this bay a remarkable 

 level topped hill, called by Captain Cook, Janes's 

 table land ; rendered the more conspicuous from the 

 low nature of the surrounding country. In the 

 evening we anchored a mile from the S. W. side of 

 a small detached reef, marked F. in the chart, and 

 distant 22 miles from Cape Flinders ; the solitary 

 position of this reef, it being four miles from the 

 inner edge of the Great Barrier, and nine from the 

 nearest part of the main, gave us a good oppor- 

 tunity of making a section, with a view of illustrating 

 the progressive structure of coral edifices, in the 

 still waters within the barrier reef; we accord- 

 ingly visited the spot in the evening, and being an 

 interesting object, we here give a drawing of the 

 section. 



Section of a detached coral reef in hat, 14o S,, within the Barrier Reef of 



Australia. 



G 70 6(i C D 66 C!) 



The point C (on the edge of the reel' C) stuuds two feet above water line 

 G, and the point D IJ feet above it. The depth of water in lagoon exag- 

 gerated ill section. Figures on line denote depth of water in feet beneath. 

 — G. level of sea in a mean state. 



It proved a good specimen of the circular or 

 lagoon reef. One young mangrove was growing on 

 the elevated part marked C in the wood- cut. The 



VOT. I. 2 a 



