16 
SURVEY OP THE INTERTROPICAL 
1821 . gray trepang; a small chama gigas, a a/prwa, 
June 19. a pretty azure-coloured species of aster ia, and a 
few bivalve shells. The few birds that fre- 
quented the reef were very shy, and flew away 
at our approach : they were principa;lly pelicans 
and terns. 
20. After weighing the next morning, we steered 
N.|W., a course farther to seaward than we 
had previously taken, in order to see the reefs 
more distinctly, and to prove the width and ex- 
tent of this part of the channel ; but the sun was 
shining in the direction of our course, and the 
shadows of the clouds upon the water were at 
times so deceptions that, whilst they often 
caused appearances of reefs where none existed, 
they concealed others that, for the same reason, 
were not seen until we were close to them. 
Having now the charge of two merchant-vessels, 
it was necessary to proceed with caution, and 
therefore we steered nearly over our last year’s 
track, but notwithstanding, we now discovered 
several new reefs, and informed ourselves of the 
extent and shape of others which had escaped 
our previous observation. 
As we were rounding the two islands that 
lie close to the south side of Lizard Island, a 
native was seen in a canoe, paddling towards , 
another who was sitting on the rocks watching 
