'1^1' 



see it in mallee country. The formation of this limestone does 

 iiot prevent the growth of trees, for so long as the vegetation 

 remains alive the limestone does not form a continuous sheet 

 nor encrust the roots. The expansion of the growing roots 

 cracks the limestone, and the C02 breathed out by tlie roots 

 produces carbonic acid, which dissolves the rocks immediately 

 in contact. Should the trees die, the mechanical action of the 



