169 
be seen, but from the information given me by the manager (Mr. L. A. 
Samuels), it would seem that it may be the fault reef or crosscourse pre¬ 
viously referred to. Both these reefs have been worked northward to a 
massive lunate-shaped body of quartz, apparently associated with the cross¬ 
course, but what amount of work has been done on the latter cannot be 
determined until the present company has cleaned out and repaired the 
old levels. 
Mr. Samuels, who is a keen geological observer, and who, 
while directing the operations of re-opening these workings, has had 
opportunities of noting features now hidden from view, sees a peculiarity 
in the form of the quartz deposits in this mine, and advances an in¬ 
teresting speculation on the subject. While not sharing it, I can per¬ 
fectly comprehend Mr. Samuels’ opinion, which is that the North 
Langdon shaft is sunk in centre country (anticlinal) through the cap of 
a saddle reef pitching to the north at an angle of 80 deg. “ Consequently 
the company’s shaft, which has hugged the cap of the reef for a con¬ 
siderable distance, is equivalent in its relation to an ordinary reef forma¬ 
tion to a level driven in centre country just under the cap, or in the 
saddle of the latter. In practical working, it is obvious, therefore, that 
levels driven on either the east or west legs represent the equivalent of 
winzes or rises on ordinarily situated formations, as they are driven either 
north, in a direction towards the cap, or south in the opposite direction. 
A level driven in centre country will represent a centre country winze, 
unless the folding of the strata should resume its normal position, but 
there are indications on the surface, though not very well defined, that 
similar formations exist in a northerly direction from the North Langdon 
shaft. ” 
A plan of the workings tends to confirm Mr. Samuels’ con¬ 
jecture, but having made a careful examination of the country surround¬ 
ing the mine, I feel sure that no anticline exists between the Thistle 
anticline and the Langdon syncline, between which the North Langdon 
Mine is situate. The attached plan and section show the position of the 
workings in relation to the structure of the country. The main west leg 
is a leg, properly so called, of a trough reef, the cap of which will be 
found at a depth of about 370 or 380 feet below the surface. The so- 
called east leg is probably the continuation of the crosscourse seen on 
the surface. Making due allowance for the pitch of the country, it is 
probable, as pointed out by me in notes on the Langdon lines, sent in on 
6/4/08, that the main west leg in this mine is the west dipping leg of 
the trough reef, of which the reef being worked in the Langdon Mine is 
the east dipping leg. The massive quartz styled by Mr. Samuels the 
cap is probably a development newer than the leg quartz, and is geneti¬ 
cally connected with the crosscourse. It is* of greyish-white colour, 
cavernous, much fractured, and is mixed with seams of slate and sulphide 
which are not always parallel with the country. On the other hand, the 
quartz forming the leg reef is of a bluish colour, and evenly laminated 
parallel to the walls. The transition from the one class of quartz to the 
other is abrupt, and it would seem that while the deposition of the leg 
quartz was a gradual process (as implied by its regularly laminated struc¬ 
ture) that of the other was not so gradual, was later, and was the im¬ 
mediate result of the disturbing influence of the crosscourse. The beds 
exposed in this mine belong probably to the Castlemaine series. Some 
fossils collected from the locality were identified by Dr. Hall. (See 
p. 189.) 
[.Report sent in 20.11.0S .] 
