The Theory of Copper Deposition — Lane. 303 
ANALYSKS OF STONK l-KOM LIGHTHOUSE POINT MAROUKTTK. 
Jniif :50, 1903. 
SiOo 4G.9S 47.67 57.25 47.10 
Alo O3 17. S5 17.55 18.10 17.47 
Fe2 O3 3.13 2.51 2.21 2.66 
FeO 10.30 12.69 12.42 12.93 
MgO 7.10 5. Go 6.35 6.88 
CaO 8.47 10.75 11.45 10.27 
Sodium O.xide 2.04. 2.21 1.98 1.91 
Potassium Oxidt- 60 .65 .66 .59 
Ho Oat about 800° C 1.97 .35 
Ho Oat 110° C 1.55 '40 
CO2 20 .18 
P0O5 143 .169 .158 .161 
S 097 .183 .086 .111 
CI 07 .05 .02 .09 
MnO 26 .19 .18 .15 
101.880 102.422 100.744 109.522 
Center 
Distance from margin Margin 616m 4115m 7600m 
E. E. Wark under direction of E. D. Campbell. 
levels and arc (page 40) rare in depth; "in other words they 
are abundant in that zone of the veins which lies between 
walls of those portions of the beds of the melaphyrc in 
which we should look for the most advanced stages of altera- 
tion in the components of melaphyre supposing' sucli alteration 
to be due to the action of descending- solution." By alkaline 
silicates he means analcite, apophyllite, orthoclase (and datolite 
is of the same age). Copper occurs of similar age in some of 
these deposits. In studying the alteration of the' lava flows 
which form so large a proportion of the Kewcenawan series, 
I find that the olivine is first to alter, then the augite, and 
lastly the feldspar. 
There are other arguments which may be used to support 
Pumpelly's theory with regard to the origin of copper. As 
has been said, down to say 500 or 600 feet the water of the 
mine is quite fresh. In the deeper mines while there is very 
little water it is an extremely strong solution of chlorides. The 
line between the two classes of water is reported to be very 
sharp, and there is a chance for a very interesting investiga- 
tion right here. It would seem quite difficult to suppose a 
circulation of this heavy water up into a light fresh w-ater, 
especially under high ground, and to imagine that there could 
