46 



discovered small undamaged fora minif era in the desert sand of Barmar and 

 Bikanir, which must have reached the heart of the desert by wind trans- 

 portation over a distance of 500 miles from the coast of Cutch. 



This interesting observation gave the first clue to the remarkable work 

 organized by T. H. Holland, 1 to explain the origin of several intermittent 

 saline lakes in the Rajputana desert, in which the quantity of salt stored 

 is in excess of the amount that could be accumulated by normal freshwater 

 rivers acting within any reasonable geological period under present physio- 

 graphic conditions. The Rann of (.hitch dries up in the hot dry season, to 

 be covered with a thin incrustation of salt. This salt is transported by 

 strong winds from the south-west, which blow regularly from April to June, 

 to be followed by the rainy season, when the salt, deposited on the surface 

 of the desert, is washed in solution into convenient hollows, forming small 

 lakes. It was found, as a result of this investigation, which should be widely 

 known amongst botanists, that during four months of the hot season of 1908 

 the amount of wind-borne salt passing a front of 300 km. broad and 100 m. 

 high must have been something of the order of 1HO,000 tons. 



Recently our airmen 2 operating in Mesopotamia have found the " dust 

 chokes the engines and the sand above blows as high as 4000'." Further 

 interesting proof of the constant direction of air-currents is afforded in the 

 first report on upper air research in Australia, 3 when difficulties were 

 encountered owing to the fact that Melbourne is on the south coast of 

 Australia, and the prevailing winter winds, as well as the upper currents in 

 advance of cyclonic disturbances, are from a northerly direction, and thus 

 carry the balloons out to sea. Material carried by wind is deposited on 

 reaching contrary currents, when should the seeds carried be precipitated on 

 to a suitable habitat germination takes place (12, i. 220). 



Cross-currents would be most likely met with on the summits of high 

 mountains, where conditions in the tropics would alone be favourable to 

 ombrophobous plants requiring temperate conditions. We have now sufficient 

 evidence to prove that the area of high open country on the immense chains 

 of mountains in New Guinea must carry an enormous number of species of 

 this type of plant. The summits of Mt. Kiuabalu in Borneo, Mt. Halcon 

 and others in the Philippines, and Bonthain Peak in Celebes, would offer 

 the only suitable habitat for such plants between New Guinea and the 

 Himalayas in the west monsun region of distribution. 



In those cases where not only the suitable area but also the fauna is much 

 restricted, though identical conditions of temperature and rainfall prevail, 



1 T. H. Holland : successive Annual Reports of the Geological Survey of India published 

 in Recordt G.S.I, during 1904-09; "Discussion on the Physiography of Arid ' Lands," 

 Report Brit. Asaoc. Adv. Sci. for 1914, 363 (1915). 



a Candler, Edmund, ' Daily Mail,' Dec. 19, 1916. 



Commonwealth Bureau of Meteorol., Bull. 13 (Melbourne, 1915). 



