42 CATALOGUE OF MINERALS ; 
traversed by siliceous veins, and containing some angular fragments of the 
‘country rock,’ the members of the series leaning more and more fan 
fashioned to the west as they recede from the central vertical bands. At 
the end of the cutting is a mass of magnesia and aluminous silicates, 
which is probably the prolongation of the dyke seen in the upper quarry. 
Mr. Lyle, the manager, informed me that he got ‘ prospects’ in every part 
of this cutting, with the exception of the siliceous earth at the magazine. 
This was corroborated by my own observations. I ground and washed a 
great number of specimens (of my own selection) from both the upper and 
lower cutting, and from every variety of material, and was surprised and 
delighted with the prospects obtained, in most cases frem stuff which 
miners would regard as most unpromising. 
‘Mr. Staiger’s assays of characteristic samples selected from the lower 
cutting yielded gold as follows :— 
Brown hematite, 3 ozs. 6 dwts. per ton. 
Red hematite, 6 oz. 16 dwt. per ton. 
Aluminous rock from west of dyke, no gold. 
Siliceous sinter from among the aluminous rock, 3 oz. 15 dwts. 
per ton. 
“ Down the hillside to the north, west, and south a similar deposit is 
everywhere met with—a frothy or spongy matrix, sometimes aluminous and 
sometimes siliceous, generally ironstained and occasionally associated with 
large masses of red and brown hematite; but the gold has as yet been 
only obtained from a few places away from the hill-top, although naturally 
there has been vigorous prospecting (so far as possible in an unusually 
dry season) wherever the ‘formation’ resembled that of Mount Morgan. 
Perhaps the deposit on the slopes is more aluminous and less siliceous, and 
contains less of iron oxides than on the hill-top; but these are the chief 
differences, and the formation has evidently one origin throughout. 
‘““ After a careful study of the whole formation, I have come to the 
conclusion that nothing but a Thermal Spring in the open air could have 
deposited the material under consideration. The frothy siliceous sinter 
agrees in every respect with the deposits of New Zealand and Iceland 
geysers, and of the still more wonderful hot springs of the Yellowstone 
National Park, so graphically and scientifically described by Dr. A. C. 
Peale (Twelfth Annual Report of the United States Geological and 
Geographical Survey of the Territories, Part II., Section 2, Onthe Thermal 
Springs of Yellowstone National Park, Washington, 1883). The ‘frothy’ 
and cavernous condition of the siliceous sinter of Mount Morgan may be 
accounted for by the escape of steam, while the silica was yet (after its 
deposition on the evaporation of the water) in the gelatinous condition so 
frequently observed in the deposit of hot springs. The aluminous silicates 
represent the peculiar outbursts and flow of mud. The iron oxide appears 
to have been deposited in some cases along with the silica and alumina, 
and in others to have been deposited later—its solvent fluid having been, as 
it were, injected into the interstices, vescicles, and caverns of the silica and 
alumina. In some cases it may have been originally pyrites, as it now and 
then occurs in cubical hollows. Calcareous sinter is very common in 
siliceous springs, and its absence from Mount Morgan must needs imply 
the local absence of limestones among the rocks from which the spring was 
