30 
proportion of the iron was also removed, and it is noticeable that there 
was no oxidation from ferrous to ferric iron as in the other instance des- 
cribed. Potash and soda are absent in these rocks, but it will be noted 
that magnesia, CO 2 , and lime also display the same peculiarity of behaviour, 
noted previously, of increasing relatively after the large initial loss. 
Both sets of analyses concur, therefore, in indicating large absolute 
losses of material during shear. Apparently, any constituent may be 
driven out if present in excess of the amount needed to form the schist- 
making minerals. Lime is the constituent most severely affected in both 
sets of analyses, presumably because very little of it entered into any of 
these minerals. The analyses suggest that the conversion of magnesia, 
potash, and water into sericite, chlorite, and talc took place at a very early 
stage in the shearing process, and that the excess amounts of these con- 
stituents was at once eliminated, so that thereafter they increased in rela- 
tive amount. The behaviour of C0 2 is very puzzling, suggesting that it 
entered in some form into one or more of the schist-making minerals. 
CONCLUSION 
This paper describes the analysis of samples taken from the Associated 
Goldfields mine, McVittie township, Ontario. The samples consist of 
rocks varying from unsheared materials outside of a strong fault to highly 
sheared materials within the fault. The results confirm those announced 
by C. K. Leith and W. J. Mead in “Met amorphic Geology.” The shear- 
ing in each case tended to eliminate constituents in excess of those required 
for formation of the schist-making minerals. 
The writer realizes to the full the weaknesses inherent in the data. 
It is clear that a fault zone in an area where juvenile solutions have been 
active is not an ideal spot for securing entirely reliable samples, as some of 
them might be altered by such solutions; and in fact one analysis, No. 5, 
had to be discarded because such vitiation seemed evident. It is also 
evident that the two samples of unaltered rock, 1 and 2, show that it is 
not as uniform in composition as might be desired. In spite of these 
defects, however, the results appear so clean-cut and definite as to be 
worth presentation. 
It will also be observed that the writer has carefully avoided discus- 
sion of the processes by which elimination of material took place. Such 
-discussion would be pure guess-work. Presumably liquefaction must 
have taken place, possibly by combination with water or some other 
volatile constituent; but at present there are no data at hand to furnish 
a basis for theory. It is interesting and suggestive to note, however, the 
uniform presence in the sheared zone of very thin veinlets, mainly of car- 
bonates, the presence of which does not cause unexpected variations in 
composition except in a single instance. It is difficult to explain them 
except under the supposition that they represent a part of the original 
rock constituents arrested during departure. Were they composed of 
materials introduced by juvenile or other solutions, there would surely 
be pronounced irregularities in all the analyses. 
