137 



the conflagration. The passage of a light fire is, however, 

 favourable to the dispersion and germination of the seeds of 

 Acacia, Hakea, Grevillea, Banksia &c. The scrub is burnt 

 usually in March, at a time when the vegetation is dry and 

 has disseminated its seeds. If this periodic denudation of the 

 scrub by fire be persisted in, disastrous results must indubitably 

 follow ; the scrub shields the loose sandy soil from the action 

 of the wind and rain ; remove this, and these agents will in 

 time bring about a transformation in the aspect of the vegeta- 

 tion — the sand will be swept from the tops and slopes of the 

 rises, laying bare the subjacent rock, and will be drifted on to 

 the clayey flats, thus converting the whole into stony wastes 

 surrounded by sandy deserts. In an arid country an appreciable 

 change would at once be discernible, but as Kangaroo Island 

 is favoured with a humid atmosphere, the chief disturbing agent 

 is not so active. Concurrent with the change in its surface 

 conditions there will be one in its vegetation. 



General Botanical Features. 



Kangaroo Island in its botany presents almost a unity, as it 

 is only over very limited areas, that there is any marked 

 departure from one type of vegetation. The subordinate 

 features are more or less referable to the nature of the 

 subjacent rock. The prominent groups of vegetation are — 



1. That oftJie Heathy Scruh- Lands. — In my geological sketch 

 I have stated, that the major part of the island is covered by 

 sand and fine ironstone-gravel, derived from the waste of 

 metamorphic rocks in place. It is upon these soils that the 

 most characteristic and varied of the vegetation of Kangaroo 

 Island exists. The vegetation is comprised of a dense thicket of 

 shrubs and shrubby states of trees, and opposes an almost 

 effectual barrier to both man and horse. This scrub varies 

 in stature and somewhat in nature, according as the soil is a 

 dry or moist sand, or gravel, or a loam. Interspersed are clay- 

 flats which are fed by surface flow of water from the 

 surrounding higher ground ; they are soft and boggy in 

 winter, but are level and dry, almost indurated, in summer. 

 The soil is for the most part devoid of water, but in a few 

 instances, where clay underlies a thin covering of sand, as 

 towards D'Estrees Bay and near Karatta, the heathy ground 

 yields water by digging for the whole year. Leschenault* 

 attributes " the vigour of the vegetation, which is not impaired 

 by the sterility of the soil, to the impervious nature of the 

 rocks which underlie the sands, and by which the infiltrated 

 pluvial waters are arrested and retained." In general, the 



* Peron's " Voyage aux Terres Australes," vol. ii., p. 366. 



