94 
Tlie American Geologist. 
August, 1898 
stant factor and serving as the basis of calculation. A slight 
gain is noted in the potash. This may in all probability be due 
to error in analysis, since the amount of this constituent found 
in the rock is scarcely more than appreciable and renders 
the results, therefore, somewhat unreliable. 
Apparently, the change noted in the above table, in pass- 
ing from the fresh to the partially altered rock, has been prin- 
cipally one of hydration. A slight oxidation, however, has 
taken place in the olivines, revealed under the microscope in 
the slight iron stains, and restricted entirely to this mineral 
wherever noticed in the slide. The only appreciable loss for 
any of the constituents is in the magnesia, which has been 
wholly derived from the breaking down of the olivines, and 
is, presumably, the result of the leaching action of percolating 
waters. 
"B." 
Calculated Loss of Material in the Partially and Wholly 
Decomposed Rock. 
Partially alter- 
ed Olivine diii- 
baee. 
Decompo.sed 
Olivine diabase 
Calculated to 
total of 100. 
Calculated amounts 
saved and lost 
I 
II 
III 
IV 
V 
VI 
VII 
VIII 
IX 
Z 
p 
O 
o 
< 
9-^ 
" 
cc 3 
^1 
' '€■ 
c 
-1; 
.2o 
— Q 
.Sz 
^•J3 CS 
C8 3 
^1 
p 
2 
01 
OS 
"ffl 
t 
Oj 
m 

ft 
E 
h 
12 
"o 
Eh 
|| 
3-S 
•313 
.11 
°3 
§,§ 
3 
S 
So 
"o-g 
S 
tea 
II 
SiOo 
Al.Og.-- 
*Fe,03.. 
CaO 
MgO .... 
NagO.... 
KoO 
h;o 
47-87 
14-43 
11.55 
10.45 
10.58 
3-47 
G.61 
1.82 
Not net, 
10.93 
5-83 
4.49 
4.28 
G.91 
0.45 
1.82 
37-09 
13-19 
35-69 
0.41 
G.57 
1-75 
0-33 
11.83 
12.72 
8.22 
28.25 
0.02 
0.20 
I .GO 
0.20 
11.83 
47-49 36 77 
14.32 13.08 
11.46 35-39 
10.37 0.41 
10.50 0.56 
3-44 1-73 
0.61 0.33 
I. 81 11.73 
35-57 
10. 07 
0.00 
10.23 
10.30 
2.87 
0.49 
0.00 
25.08 
29.58 
100.00 
1.25 
1.72 
16.30 
17.29 
loo.oot 
74-93 
70.42 
0.00 
98-75 
98.28 
83-70 
82.71 
0.00 
Total . . . 
100.78 
28.71 
I GO. 86 
62.44 
lOG.GO 
100.00 
169-53 
49-72 
*Iron is taken as the constant factor in the above calculations. 
fGain. 
JPercent. 
