103 
, "-The higli ridges to tlie west of the Two-mile Creels are of granite. . The granite 
ends ronnd to the east about a quarter of a mile up the crook, and crossing the creek, 
eiins the range that divides the Two-milo Creek waters from those of Biggenden or 
^egilbo Creeh. 
“Prom the foot of the S 2 )ur up to the mine, a distance of about 10 chains, 
® rock consists entirely of siliceous slates, which dip very steeply to the north- 
west. Above the mine is a bed of limestone about 70 feet in thickness, and 
^ eve that again the slates occur, together ■with an altered sedimentary rock, con- 
S'ining quartz, felsqoar, hornblende, and olivine. lioc.ks of the same character 
®ecur on the ridge north-east of the gully, and right away on to Mount Biggenden 
Itself. 
“ The Mount Biggenden deposit consists of an irregular mass of magnetite, 
Somewhat semicircular in shape, bounded on the north by the slates and on the south 
y the bed of limestone. 
“The following is a description of the deposits and workings: — 
,. “ Cutting No. 1 has been driven into the spur in a southerly direction for a 
^®tance of 95 feet. The cutting is situated at the tojs of an inclined tramway, which 
down the hill to the Two-milo Creek. 
g “ The first 12 feet of the cutting is in a light-grey soil with a few boulders of a 
ne-gja^jj^gd felsqiathic rock in it. The next 12 feet is of hard altered rock containing 
® minerals schorl, chlorite, and olivine. Then comes 6 feet of a decomposed dioritic 
’which has decomposed in concentric rings around kernels of the undecom- 
hosed rock. Next to this there is 9 feet of decomposed granite, and then 7 feet of 
white kaolinite. Prom this point to the face of the cutting, which is 35 feet 
eight, is a mass of magnetite, lying in more or less horizontal layers. Near the 
^ee, above the magnetite, there is a siliceous rock containing a large amount of 
'^^^enical pyrites. ^ 
, The magnetite contains numerous cavities, the sides of which are generally lined 
.^'®ll'formed octahedral crystals of that mineral; some of these cavities are filled 
■Vfli' 1 ' °"®de, while others are lined with decomposed radiating iirtsmatic crystals, 
I believe were originally hornblende. 
g . "In aud around the calcite there are also cavities containing a black powder 
cWnfly of the biuoxide of manganese. The oxide of manganese is generally 
oxide and carbonate of bismuth. 
of ®wd of the cutting in the western corner there is a mass of this calcite 
bis^^^'*?" 15 feet in length and 3 feet in height, in -which some fine specimens of 
^uthiuite (sulphide of bismuth) have beeji obtained. 
I'as h Magnetite contains a little bismuth throughout it. A large amount of ore 
6en taken and stacked for treatment from this cutting, but owing to the difficulty ■ 
^^^°*^'^®^li’ating it up to a sufficiently high percentage of bismuth, it has not been sent 
froru *lifficuity lies in the separation of the oxides and carbonates of bismuth 
Stav'f ^ ®®'§Detite, as their specific gravities arc so much alike ; the average specific 
11*® oxide of bismuth being 4'3, carbonate of bismuth 6'5, and that of 
“giietite 5-2. 
of -^fter washing a dishful of this ore as carefully as possible, 700 out of 900 qiarts 
were of magnetite, and could bo extracted with a magnet. This 
o^^"as not being worked. 
the ea | ^ is situated about 100 feet south-east of the mouth of No. 1, on 
^ cpn fall of the spur, and at 15 feet higher level than No. 1. 
