Copper in the Aniniikie Rocks. Vll 
Character of the rock. — The rock in which the copper occurs 
is a fine-textured purplish-brown trap strongly amygdaloidal 
in some portions and only feebly so in others. The least amy- 
gdaloidal portions when examined in thin section prove to be 
typical diabase. Slender idiomorphic plagioclase crystals 
lie embedded in allotriomorphic masses of purplish to yellow- 
ish gray augite and in yellowish green masses of chlorite which 
is doubtless the result of the alteration of the augite. Yellow- 
ish brown iron oxide partly opaque and partly translucent oc- 
curs in profusely scattered grains. 
The more amygdaloidal portions show in thin sections a 
finer texture but an equally strongly pronounced ophitic struc- 
ture. Augite is not so abundant and plagioclase is the domi- 
nant mineral. A portion of the base appears to be glass, be- 
ing colorless and isotrophic ; and the augite is probably repre- 
sented in part by the glass and in part by certain decomposi- 
tion products interstitial between the feldspars. Magnetite 
and brown iron oxide are generally distributed. The crystals of 
plagioclase are arranged tangentially to the periphery of the 
amygdaloidal cavities. The latter are filled with calcite or 
dolomite and a brightly polarizing fibrous or lamellar mineral 
doubtless a zeolite. In the thin sections examined no cop- 
per was detected, but macroscopically it may be seen scattered 
through the rock in small grains which do not appear to fill 
up the round vesicles, but to be more irregular in shape. 
The brown red sandstone above referred to is very fine tex- 
tured and could not be identified as a sandstone with certain- 
ty in the field. In this section it is seen to consist of an aggre- 
gate of rounded, pear-shaped and angular grains of feldspar^ 
pyroxene, chlorite and quartz, all the grains having a coating 
of iron oxide. A good deal of the secondary matrix appears 
to be feldspar, probably albite and orthoclase, audit is full of 
slender colorless needle-like microlites. Twinning lamella3 of 
the secondary feldspar are in some cases distinct, but for the 
most part are not apparent. Some of the rounded clastic 
grains of feldspar show feeble traces of secondary growth. 
Proportion of Copper. — A few specimens of the rock were 
collected with the view of ascertaining its average value as a 
copper ore. Four of these have been submitted to Mr. F. L. 
Sperry, chemist to the Canadian Copper Co., at Sudl)ury,who 
has very kindly analyzed them. These specimens taken from 
