208 FAUNA OF WESTERN AUSTRALIA 



that large quantities of guano have been taken from them ; 

 and this seems to have much disturbed the terns and other 

 birds which are said to have bred here formerly. The 

 entire soil of some of the islands has been removed. 

 Where we found it remaining it consisted of a mixture of 

 limestone, sand and disintegrated coral, with guano ; and 

 the rank herbage was sufficient proof of its great richness. 

 On one small island, forty or fifty acres in extent, this soil 

 had not been disturbed, and it was full of holes made by 

 the " mutton-birds," as the whalers call them, or common 

 sooty-petrel {jDssifraga gigafitea), a bird which formerly 

 bred in large numbers in these islands, probably because 

 they were seldom visited previously to the establishment of 

 the Swan River Colony. This circumstance, and the fact 

 that this group is the southernmost point in Australia, and 

 I believe in the world, where coral is found, is alone 

 sufficient to make the Abrolhos a remarkable group in the 

 eyes of a naturalist. 



The natives of Australia not using sea-going canoes 

 probably never visited these islands, as they could scarcely 

 venture so far from the mainland on the rafts they some- 

 times use. I could find no traces of them on any of them 

 except on a small islet ninety yards long by forty to fifty 

 wide, where I picked up a native spear and wommera, or 

 throwing-stick. Those, no doubt, had been brought 

 thither by some blackfellow in the company of whites, the 

 natives sometimes being employed by the fishermen and 

 wreckers, on account of their skill as divers. For though 

 the blacks are no navigators, not having advanced in the 

 art of ship-building beyond the raft-making stage, they 

 are nearly equal to the South-sea islanders in skill as 

 divers and surf-swimmers ; and I have known them swim 

 off to islands that are four or five miles from the mainland. 

 They have no fear of sharks, which they can dodge with 

 perfect ease, and indeed they often actually chase fish in 

 the water, driving them into shallows, where they can spear 

 them with the greatest ease. 



The island on which this spear was found was com- 

 posed of huge pieces of the fan-shaped coral mentioned 



