HOUTMAK ABROLHOS ISLANDS. 



163 



obviously part of it. They rise from the same reef-flat and show distinct 

 signs of having been cut off comparatively recently by erosion. All agree 

 in formation and in appearance. Rat Island itself is flat-topped and almost 



Text-figure 8. 



28 «' 



28 20' 



everywhere exactly 8 feet high. The margins take the form of an undercut 

 cliff, which overhangs very considerably in most places. Here and there are 

 great masses which have fallen and now are being removed by the sea at 



