708 Mr. Edwin Ashby on the [Ibis, 



lake at (Jalabona in South Australia and the survival in a 

 shady gorge of the Mac Donald Ranges of a species of Fan 

 Palm and a Macrozamia, both representatives and survivals 

 o£ a long-distant past when luxuriant vegetation grew there, 

 conclusively support this contention. 



A botanist of high standing has advanced tlie opinion that 

 the " Mallee," a group of" Eucalypts that brancli from the 

 base and no longer grow into a timber-tree, are the survivors 

 of an ancient forest. Therefore the thousands of square 

 miles of Mallee now existing are the remains of an immense 

 aberrant forest, dwarfed and stunted during the ages because 

 of the steady decrease in the rainfall. 



It is quite certain that the spare, stiff, cardboard-like 

 leaves of these Eucalypts and the vei-y dry character of the 

 districts in which they grow, absolutely preclude the possi- 

 bility of the generation of sufficient heat by fermentation to 

 hatch such eggs that may be deposited there. I therefore 

 judge that in the long-distant past the Le'ipoa, in common 

 with its congeners^ Megapodius and Alectnra, gathered 

 together the leafage and debris that must then have thickly 

 strewn the ground under the trees of the luxuriant forests 

 of those distant days. 



But slowly and surely the climate changed, the atmosphere 

 grew drier and drier, the forest-trees diminished in size, until 

 we have the dwarf forms of Eucalypts which wc know to-day 

 as Mallee. 



If we accept this statement of probable facts as correct — 

 the evidence is so strong that it is well-nigh impossible to 

 deduce otherwise, — we may till in an unwritten page of the 

 past history of Australia's Mound-building Birds. 



Instead of their method of incubatino- their et»os beina' a 

 survival of an old reptilian habit of simply scratching a hole 

 in the sand and leaving the future of their eggs to the influ- 

 ence of solar heat and chance, we have a group of birds 

 who have acquired highly specialised habits in connection 

 with the incubation of their eggs. 



It is impossible to tell whether their progenitors had, in 

 common with most birds, been " nest-makers," hatching their 

 ;s by means of body-heat, and then adopted the method of 



