NOTES OF A JOURNEY ON THE DARLING. 45 
out on to the western plain ; but the thing which strikes one at 
60 yards in width and 20 or 25 feet deep. 
On examining the country round and making inquiries, I found 
that there was a very large area of country (of which Cawarra 
Plain is the lowest part) surrounded by ridges, and only open to 
the north towards the Narran River, and it seems probable that 
this used in times of flood to be filled from the Narran, and that 
the point in which Grawin Water is now found was the lowest 
place where the water broke over the ridge and escaped from the 
lake which must have covered those plains at that time. Of course 
if this theory is correct it is easy to understand how the water, 
after rising to the top of the ridge, with a fall of about 20 feet in 
about half a mile, would have force to cut a channel for itself and 
the then flooded state of the country, to find out where the water 
came from, but the probability is that it was the overflow of the 
arran. 
The murrillo conglomerate shows in the banks oP amt comet 
and is lying on a white rather soft rock, almost as light ‘ss “meer 
schaum, of which I brought specimens with me. In some places this 
underlying rock is so soft as to be easily cut with a knife, and in 
others as hard as flint.* ? 
* Within the last few days I have been informed by Mr. Bagot, of Gun- 
dabline, who has been Ponidiedlt on the Moonie River, near the Queensland 
re known to him are the murrillo conglo ; some, of 
ing above the like those of Gerrarra, only coming to the 
ey ve the surface and some, | ee 108 aay oe 
continent, an t : ‘ 
a sort of bar which obstructs the flow of the underground water to the south- — 
West and so causes it to rise up to or near the surface in many places, 
