CHAP, xxxiii.] PHTSICJl OmGRAPBT. 



485 



whose names are Vorkai and Maykor, are said to be very 

 similar in geiierrtl character; but they are rather near 

 together, and have a number of cross channels intersecting 

 the Hat tract between them. On the south aide of Maykor 

 the banks are very rocky, aud from thence to the southern 

 extremity of Am is an umntemipted extent of mther 

 elevated and very rocky country, penetrated Ijy numerous 

 small streams, in the high Emestone cliffs bordcrmg wliich 

 the edible bii-ds' nests of Ani are chiefly obtained. All 

 my informants stated that the two southern rivers are 

 iai^er than Watelal 



The whole of Aru is low, but by no means so flat as it 

 has been represented, or as it appears from the sea. Most 

 of it is dry rocky groimd, with a somewhat undulating 

 surface, rising here and there into abrupt hillocks, or cut 

 into steep and narrow ravmes. Except the patcliea of 

 swamp which are fomid at the mouilis of most of the 

 small rivers, there is no absolutely level ground, although 

 the greatest elevation is probably not more than two 

 hundred feet. The rock which everywhere appears in the 

 ravines and brooks is a coralline limestone, in some places 

 aoft and pliable, in others so hard and crystalline as to 

 resemble our mountain limestone. 



The small islands which surround the central mass are 

 very numerous but most of them are on the east side, 

 whei*e they form a fringe, often extending ten or fifteen 

 miles from the main islands. On tlie west there are very 

 few, Wamma and Pnlo Babi being the chief, with Ougia 

 and Wassia at tlie north-west extremity. On the east side 

 the sea is everywhere shallow, and full of coral ; and it is 

 here that the pearl-shells are found which form one of the 

 chief staples of Ai-u trade. All the islands are covered 

 with a dense and very lofty forest 



The physical features here described are of peculiar 

 interest, and, as far as I am aware, are to some extent 

 unique ; for I have b(^en unable to find any other record 

 of an island of the size of Aru crossed by channels which 

 exactly resemble true rivers. How these channels origi- 

 nated were a complete puzisls to me, till, after a long consi- 

 deration of the whole of the natural phenomena presented 

 by these islands, 1 arrived at a conclusion which I will now 



