!!)(> E. C. Andrews — The Geological History of the 



growth was changed! The plains of heavy soil were forsaken 

 gradually by the luxuriant vegetation, except for hardy outliers 

 which possessed deep roots and which were provided with 

 special devices against excessive transpiration, and such plants 

 as these even were in great danger of extermination. On the 

 coarse, hungry, sandy soils, however, the old luxuriant vege- 

 tation found means whereby many of their kind might be pre- 

 served. If, for example, during the ages involved in the 

 general and great alteration in the Australasian climate, it 

 should be found that they could utilize, or modify, certain 

 inheritances of structure or of chemical composition, so as to 

 provide against excessive transpiration, then their ancient abode 

 might still know them; if, for instance, they should secrete 

 non-volatile oils or resins, or a latex; if the old luxuriant tree 

 should be reduced to a shrub, or undershrub, or better still, 

 to an annual herb ; if the leaves should be provided with stony 

 cells, stomata, and other devices, to conserve their contained 

 moisture ; or better still, if they should dispense entirely with 

 their leaves or reduce them to linear, needle-like, spiny, pungent, 

 horny, terete types, or if their seeds should be protected so that 

 they could resist a drought extending over periods even of 50 

 or 100 years, then the safety of the family might be assured. 



The Sophorese, or at least the ancestor of the tribes Sophorese, 

 Podalyriese, and Genistese, found special facilities for survival 

 on these hungry, sandy soils which were scorched by the sum- 

 mer sun and subjected always to the menace of long continued 

 drought and desiccating atmosphere. The Leguminosse indeed, 

 as a whole are singularly liable to leaf alteration, they are also 

 singularly fortunate as regards seed protection, and as regards 

 ready fertilization. As the luxuriant arborescent forms of 

 the Sophoreee perished, one by one, on the open wastes of the 

 heavy soil, so the porous soils of the sandstones were occupied 

 by special types of the tribe, which could reduce their leaf 

 surfaces ; which could endure the gradual dwarfing process 

 to shrubs and undershrubs; and whose heritage of long tree 

 roots could be utilized in tapping the underlying moisture. 

 The nutriment supplied to individual trees of the Sophdreae 

 was limited to the area which the roots could tap, and this, 

 on barren, hungry soil, was sufficient only for small trees. 

 The leaves also underwent wonderful transformations, pinnate 

 types becoming simple, or being rolled into mere lines and 

 points, or being discarded altogether. In this way a great 

 number of individuals could live side by side on a given space, 

 because the area covered at the surface was dependent on the 



