HOUTMAN ABROLHOS ISLANDS. 135 



at Ceylon, and in particular to that of Stanley Gardiner at the Laccadive 

 and Maldive Islands. We have found the reports of Stanley Gardiner's 

 expedition, both on the fauna and the formation of the islands, of very 

 great service. 



GENERAL DESCRIPTION OF THE ISLANDS. 



The islet group of the Abrolhos extends betweeu 28° 15' and 29° S. lat. 

 and consists of a large number of islands, the smallest of which are only a 

 few square yards in area and generally uncharted. There is urgent need of 

 a survey, for the maps of the islands leave much to be desired and we often 

 had evidence of the inefficiency of the charts. 



The archipelago (for such it might be termed) is about 50 miles in length, 

 and the islands occur in four groups. The most northerly group consists, 

 however, of a single island, North Island, whilst the others (the Wallaby, 

 Easter, and Pelsart Groups) comprise a number of islets which according io 

 our views are closely related to one another. These four collections of 

 islands are separated by channels whose depths are approximately the same 

 as those between the entire Abrolhos Group and the mainland. 



It may be noted as a characteristic feature, that all the islets occur on a line 

 running roughly N.N.W.-S.S.E. Furthermore, if an island is much longer 

 than it is broad (and this is frequently the case), the long axis usually runs 

 almost north and south. The submerged reefs are often found to be running 

 in the same direction. 



It is usual to leave Geraldton about midnight or early in the morning, so 

 that the islands will not be reached before the sun is well up. It is difficult 

 to observe submerged reefs if the sun's rays are striking the water very 

 obliquely. As a matter of fact, on each occasion that I have visited the 

 islands the night start was quite unnecessary, for unfavourable winds and 

 rough sea prevented us sighting the islands until late in the following 

 afternoon. 



Owing to the low elevation of the islands (usually about S feet above sea- 

 level), with the exception of some to be mentioned presently, they are not 

 seen until one is quite close. The picture presented is somewdiat uninteresting, 

 for the vegetation covering them is very scanty and consists of low bushes. 

 No palm trees occur whatever, the largest, plants being mangroves, but these 

 are by no means common and occur on the lagoon flats, so that they are 

 rarely visible from the sea. The gorgeous pictures made by the living coral 

 below the glass-like surface of the water of the lagoons more than makes up 

 for the uninteresting appearance of the surface of the islands. Coral is 

 everywhere in evidence and appears to be growing luxuriously, although the 

 Abrolhos are situated on the extreme southern limit of coral-reef formation. 



The islands would be quite uninhabited were it not for a few guano 

 workers wdio come over for the summer months only, and frequent some 



