136 
Excursion to the 
long-continued drought; which cannot apply to those 
on the rises out of reach of floods : nor can it arise, as 
others believe, from the soil, the dead trees occurring in 
every kind of soil, from the best to the worst. So like¬ 
wise it cannot be from too much, nor too little, moisture, 
as they are seen both in dry and moist situations. 
Another cause suggested is an insect, which, by eating 
the wood next the bark, forms furrows, and thus interrupts 
the free circulation of the sap. This seems highly 
probable, but is still attended by difficulties; and a 
gentleman who has endeavoured to ascertain if such be 
the case tells me it cannot be, or he must have discovered 
it. There is, however, no doubt that some of them have 
been killed by an insect; though it seems scarcely 
credible that any insect would commence its devastations 
simultaneously on the mountain chains, and on the low¬ 
lands, and at spots so distant from each other as is the 
case. Near the east coast I saw on a plain thousands 
of Eucalypti all dead, but still standing. On inquiry of 
the neighbouring settlers if they knew the cause, I was 
informed that nine or ten years ago there was a tremendous 
storm of thunder and lightning, and that shortly after¬ 
wards the trees were observed to be dead. My informants 
were unable to say, with any certainty, whether this took 
place in consequence of the storm, or from some other 
cause. I know myself that in several instances the trees 
at certain spots have flourished until cattle and sheep have 
been depastured upon the ground where they grew, and 
then the trees died; but whether this is attributable to 
the eating down of the grass, and thus in some degree 
exposing the roots, which unquestionably are often very 
superficial, I will not venture to say. 
The tree most commonly found dead is known as the 
black-butted or curly gum, which, unlike the blue 
gum ( E . globulus ), grows spirally to the branches. 
