15 
At one time, each of the beds of these four series was widespread as a 
continuous sheet; and the more recent beds were probably all at a higher 
level than the underlying Jurassic sandstones. But by a great series 
of faults the continuity of the sheets has been broken; great bands of 
the upper beds have been dropped to a lower level till they form the 
floors of the valleys, which are of the type of rift valleys. The recog¬ 
nition of these faults is essential to anv understanding of the geology of 
this area, and to any attempt to determine the range of its coal and 
mineral deposits. 
The best general account of the geoloev of this area is by J. H. Wright 
{Prog.. Rep. Geol. Surv., Viet., No. VIII.), who has described many of 
the chief faults. 
Economic Geology. 
The two chief economic products of this area are coal and iron. 
Scarlett’s seam of black coal is onlv a few miles south of Mirboo North, 
and the presence of coal in many of the creeks of this districts is widely 
reported. But no coal is being worked, and I did not see any of the 
Coal Measure rocks between Mirboo North and the iron deposit. 
Iron is widely distributed in the district. I examined two outcrops. 
One at Mr. Gilfeddar’s paddock, just east of the eastern boundary of the 
township of Mirboo North. There are some concretionary masses of 
limonite, overlying mottled clays. The masses are associated with 
boulders of ferruginous quartzose conglomerates, which outcrop for a few 
chains on the hill side. But there is no evidence of any outcrop of ore 
on a commercial scale. 
The second outcrop is that on Funston’s paddock, and is held bv the 
Mirboo Coal and Iron Syndicate. The ore is exposed by a landslip, on a 
steep hill slope, down to one of the tributaries of the Little Morwell 
River. The rocks exposed on the hill slope are mainly the mottled clays 
of the uppermost series. They are repeated at various levels by land¬ 
slips. The limonite occurs below the ordinary mottled clay, and above 
the larger oc'hreous clay. Apparently below, it is a bed of fine-grained 
quartzose, ferruginous conglomerate. At the foot of the hill, in the 
creek, are two shafts, which I was told were dug by Mr. J. H. Wright 
in search of coal. No undoubted coal measures are now exposed, though 
some decomposed shales may belong to them. I was told that the coal 
measures are exposed in the next creek to the north, where a seam of coal 
is said to occur in them. 
The limonite is in concretionary masses in the mottled clay series; the 
amount exposed is too small to be of practical use. There is no sign 
of any lode, or any prospect of the occurrence of a lode. The adjacent 
rocks are stained with iron, and, as not infrequently occurs in such condi¬ 
tions, the percolation of water through the rocks has caused the concen¬ 
tration of some of the iron into nodular masses. The prospects of the 
occurrence of ores in sufficient quantitv for working depends on whether 
the limonite forms a widespread bed, or occurs in small patches where 
the drainage escaped on the surface in springs. If the ore is in a wide¬ 
spread bed, it should be easily found bv searching along the hill side, 
both north and south of the outcrop, and also on the western slope 
down from Lydiard’s track. A cut back into the hill, at the outcrop, 
would probably suffice to show whether the ore is in a thick regular bed 
or in irregular patches. Hence I should advise the syndicate, before 
proceeding further, to dig back into the hill, at the point where the ore is 
exposed, and also to search the cleared ground along the hill slopes, to 
the north and south, for any continuation of the ore. 
