51 



coincide with a geographical position very close to Cape 

 Banks. The parting of the currents may well account for the 

 quantity of debris cast up at the spot known as the "drift" 

 mentioned by Mr. Payne. 



The localities from which the pumice may have originated 

 (judging from its known geographical occurrences) are New 

 Zealand, the Pacific Islands, the Eastern Archipelago, or, 

 possibly, a sumbarine volcano of unknown position. That 

 pumice of the size found near Cape Banks should have been 

 lost overboard by* a passing ship is also not thought to be 

 probable. 



Mr. Hedley suggests that the specimens came from the 

 Malay Archipelago, round the Leeuwin. The northerly drift 

 on the western side of the continent is against this view, but 

 it is not impossible for a floating object, starting, say, from 

 the Sunda Strait, and being caught in the equatorial current, 

 to make the round of the Indian Ocean, and, coming south, 

 enter the west wind drift, and so reach, the southern shores of 

 Australia. But that is a very long journey, and if that were 

 a source of pumice drift we might expect that it would be 

 found on shores more to the westward than Cape Banks. W 



It might again be suggested that a strong easterly wind 

 blowing through Bass Strait for several days would probably 

 have the effect of temporarily destroying the west wind drift, 

 and by reversing the current bring in the drift from the 

 Pacific through the Strait and as far westward as the southern 

 limits of South Australia. 



Ocean drifts that are dependent on prevailing winds vary 

 with the winds. They may be weak or strong, shift their 

 position, and even become for a time reversed, according to 

 seasonal variations. Pumice is a common stone in New 

 Zealand, and is likely to find its way at times to the sea. 

 The Pacific current that comes down the eastern coast of 

 Australia, and encircles the Tasman Sea, may possibly bring 

 pumice to its southern limits where it makes its return bend. 

 If under such circumstances a slight westerly drift sets in 

 from the Tasman Sea, extending to the western side of 

 Tasmania, any floating matter would then be brought within 

 the range of the drift that follows the southern coasts of 

 Australia, and might in this way become the carrier of 

 pumice from the east. 



The examples obtained from Cape Banks possess certain 

 characteristics which should assist in their identification. The 



(?) After the above was written a public notice was given of 

 a bottle, thrown overboard from a troopship at Colombo, having 

 been picked up on the beach near Cape Jervis. — See The Register, 

 June 10, 1919. 



