SECTIONAL TRANSACTIONS.—C, 383 
basins as Lake Timiskaming, the Montreal River, and Trout Lake. The pro- 
nounced alteration, which has now been traced downwards in the Keeley work- 
ings to a depth of 600 ft., is limited to the southern part of the mine workings, 
where various minor pre-mineralisation faults join the main fault occupied by 
Woods’ vein. The alteration may be described as a pre-glacial ‘ fossil,’ having 
been protected from glacial erosion by the narrowness of the southern portion 
of the valley, which forms the surface expression of Woods’ vein. In other 
words, in this section the glacier seems to have been forced locally by topo- 
graphical conditions to deposit rather than erode. 
MINERALOGICAL SUMMARY. 
Unaltered Material. No. 3 No. 8 No. 9 Average 
Cobaltite....... eco ederceeccs CoAsS 8-13 11-48 2-32 7-31 
Leellingite ...............665 FoAs, 63:35 37-37 22-42 41-05 
Rammelsbergite ......... NiAs, — —- 20-50 6-83 
Safflorite......006i..0.se000e CoAs, 24-45 10-87 5:22 13-51 
Skutterudite ............... CoAs, 3-52 40-90 49-10 31:17 
99-45 100-62 99-56 99-87 
The metallic minerals present in the analysed samples from the unaltered 
portions of the mine include lellingite, skutterudite, safflorite, cobaltite, and 
rammelsbergite, in that order of prevalence. It will be noted that lcellingite 
and skutterudite are the most constant constituents, while the safflorite and 
rammelsbergite vary in quantity, and cobaltite is a minor constituent, seldom 
exceeding 10 per cent. of the section. 
Altered Material. No. 1 No. 6 No. 6B No. 7 Average 
Cobaltite ......... CoAsS 4-82 4-98 3:44 30-2 10-43 
Gersdorffite ...... NiAsS —- _ — 39-4 10-28 
Leellingite......... FoAs, 13-89 82-0 13-09 17-92 42-30 
Skutterudite...... CoAs, 38-16 — 80-57 11-93 32-67 
Chloanthite ...... NiAs, 35:06 — — — 8:77 
Smaltite ......... CoAs, 7:94 11-10 1:05 _— 5:02 
Tetrahedrite ...Cu,Sb,S, 0-84 = = 0-21 
The metallic minerals in the analysed samples from the partially altered 
parts of the Keeley include lellingite, skutterudite, cobaltite, gersdorfiite, 
chloanthite, smaltite, and tetrahedrite, in that order of prevalence. The first 
three named are the most constant in quantity, with the remainder in minor 
and varying amounts. 
A comparison of these two tables shows that the three constituents, leellingite, 
skutterudite, and cobaltite, are the most constant both in the unaltered and 
the partially altered material. They appear to be the least susceptible of the 
metallics and might be expected to survive the alteration processes to a very 
large extent. The rhombic diarsenides, on the other hand, which are prevalent 
in the unaltered material, disappear entirely in the altered portions, being 
replaced by the corresponding cubic representatives. This significant feature 
may be accidental or may be the result of a radical change in the molecular 
structure of these constituents. In any case, the order of susceptibility to 
alteration of the mineral constituents would appear to be: rammelsbergite, 
safflorite, chloanthite, smaltite, lcellingite, skutterudite, and cobaltite. 
It is believed that the alteration has resulted in considerable elemental 
migration, a marked change in the mineralogical character of the altered vein 
material as compared with the unaltered, and a considerable enrichment in 
silver values towards the bottom or actually beneath the altered zone. 
12. Dr. L. J. Spencer, F.R.S.—International Agreement in 
Mineralogical and Crystallographical Nomenclature. 
Afternoon Excursion to study the Glacial Phenomena in the Toronto 
Region. 
