196 
In the lower portions of their courses both the Morass Creek and the 
Deep Creek have cut their way deep through the basalt into the underlying 
Silurian rock. So* also ha's the Mitta, and a long portion of the spur between 
the Mitta and the Gibbo towards its extremity is free from basalt. In my 
examination I had the advantage of the assistance and information of 
Mr. De Jarlais and Mr. Toland, both successful prospectors, who know 
every inch of the country and are well conversant with the general rock 
formations. 
Of the source or sources of the basaltic flow, there appears no indication; 
it is as unknown as that of the similar older basalt flow of the Dargo High 
Plains. 
From where the road comes down on the Gibbo, a short portion of the 
t>asalt plateau extends as a fringe about a couple miles up stream. It lies 
on the south-east side of the river some hundred feet above the water and 
flanking the slopes of the higher Silurian range at the back. An isolated 
remnant similarly occurs about 3 miles up, but beyond this, on either side 
of the river, not a vestige of basalt was seen by me, nor could I learn of 
any from the gentlemen abovenamed. There is a small patch of basalt on 
the north-west side of the Gibbo about 2 miles up from where the road 
comes down on the river, and a still smaller one on the north of the river 
between that point and the junction with the Mitta, but further continuity 
is broken down to the patch—2 or 3 miles below the junction on the east side 
of the Mitta—to which mv attention was directed bv Mr. E. J. Dunn. 
Owing to the difficulty of access on foot or horseback I did not go down to 
this patch, but can rely upon Mr. De Jarlais 7 information that it is only a 
short length of basalt some two or three hundred feet above the river, 
fringing the slope of the mountain behind, and underlaid in part by 
heavy gravel wash, a slipped portion of which Mr. De Jarlais worked but 
with poor results, while in the wash under the basalt he only got unpayable 
returns. 
Down to the northernmost occurrence of basalt noted by Mr. Dunn, 
which De Jarlais recognised, he states that there are only a few insignificant 
vestiges of basalt. 
There are various places where wash occurs under the basalt as at the 
furthest patch up the Gibbo and on the sides of the Morass Creek, but in 
no case where tested have they proved payable. In the Deep Creek, where 
it cuts into the Silurian, it is said that very small prospects of gold have 
been got, but nothing payable. The only chance for a portion of unbroken 
lead is under the basalt of the Morass Creek, and here, from all other 
evidence, the probability of payable gold being found is remote. 
The conclusion I have arrived at- is that the ancient lead covered by 
basalt ran down where the Morass Creek and Mitta Valleys now exist and 
was almost wholly eroded by the latter, so that the gravel contents were 
concentrated in the deepened river bed and nothing but flanking vestiges of 
basalt left remaining. As to the Gibbo I regard the basalt there as vestiges 
of an upstream flow for a short distance from the main one, very possible 
up the old valley of the Gibbo, which has since cut its wav to a deeper 
level. 
Mr. Toland took me to the limestone belt on the spur between the Mitta 
and the Gibbo and showed me a small vein containing copper ore, not 
payable in size as now visible, but possibly indicating the proximity of a 
larger body; also a great lode of calcite in the Gibbo River containing 
somewhat sparsely disseminated galena. 
