‘NOTES OF A JOURNEY ON THE DARLING. 43. 
Supposing the soil to contain a large quantity of salt, which, to 
judge by the salt nature of the vegetation and the number of salt 
wells, seems very probable, would not the effect of the rainfall be 
to wash the salt out of the surface soil and carry it down to the 
subsoil, and then the surface-rooting plants might flourish and 
deep-rooting plants which could not bear a salt soil would perish ? 
course in sandy country, where the water could percolate freely, 
the salt would be carried to a greater depth than in clay soils, 
and so we find the salt-bushes almost without exception growing 
on clay soils that are not subject to inundation. is would 
account for the fact of the rivers having a fringe of gum and 
ges as they are called, although in many cases there seems to be 
no ridge but only a change from clay to sand, and in the only 
place in which I saw a section of the strata the clay was overlying 
the sand. 
After leaving Walgett I went up the Darling (or Barwon) to 
the Queensland boundary, and noticed that in all the country on 
the lower Namoi, and all up the Barwon to Queensland, there isa 
remarkable absence of stones or rocks of any kind. There is a 
ind of rock showing in the Barwon River in one or two places, 
more particularly at Bundinbarrina Falls, but the appearance 1s 
rather that of burnt clay than of what one might call a genuine 
rock. I brought a specimen from Bundinbarrina Falls, and after- 
wards, on examining the Fishery as it is called at Brewarrina, 
which is about 160 miles lower down the Darling, I saw that the 
exactly the same in both places, the river descending not ina single 
a ; but in a series of rapids by which in about 100 yards it falls 
eet. 
murrillo means ant-hill— is, the red cone-shaped ant-hill that 
1s found in all the northern and wes parts of New South 
sex ese ant-hills nearly always built on the high 
: are 
gtound in that part of the Colony, to avoid floods, and as the 
