366 



nien's Land is not farflier from Australia, nor Sardi- 



nia from Italy; yet all these countries present difle- 



rences more or less marked in their faunas; tliey pos- 



sess eacli their peculiar species, and sometimes evcii 



peculiar genera. Ahnost the only islands possessing a 



rich fauna, bet identical with that of the adjacent 



continent, are Great Britain and Sicily, and that cir- 



cumstance is held to prove that they have been once 



a portion of such continents, and geological evidence 



shows that the separation had taken place at no di- 



stant period. We must, therefore, suppose Aru U 



have once formed a part of New Guinea, in order to 



account for its peculiar fauna, and this view is sup- 



ported by the physical geography oT the islands ; for, 



while the fathomless Molucca sea extends to within i 



few miles of them on the west, the whole space east- 



ward to New Guinea, and southward to Australia, b 



occupied by a bank of soundings at a uniform dept.i 



of about 30 or 40 fathoms. But there is another cir 



cumstance still more strongly proving this connexion 



the great island of Aru, 80 miles in length from nortl 



to south, is traversed by three Avinding channels d" 



such uniform width and depth , tliough passing througi 



an irregular, undulating, rocky country, that the 



seem portions of true rivers, tliough now occupiei 



by salt water, and open at each end to the entranc 



of the tides. This phasnomenon is unique, and w 



can account for their formation in no other way tliai 



by suppossing them to have been once true rivers , ha- 



ving their source in the raountains of New Guinea, 



and reduced to their present condition by the subsi- 



dence of the interveniiig land. 



