Microscopical Character of the Ore. — Adams. 89 
others show the peculiar mottled extinction produced by iiressure, 
while others again are distinctly seen to be in the act of breaking up 
into a mans of small grains. I'oth feldsi)ars also, althongli having 
more or less perfect crystalline forms, are almost invariably broken 
into little grains around their edges which gives them a somewhat 
rounded contour, the edges being often highly serrated. In addition 
to these feldspars the rock contains quartz, hornblende, epidote, 
ilmenite, sphene ( ?), apatite, hematite, calcite, chlorite and pyrite. 
The ijuartz is present in rather small amount and lies chiefly in 
corners or between the large feldspar individuals. It is uniaxial and 
positive and shows an uneven extinction. Judging from its moile of 
occurrence it is in great part at least a primary constituent of the njck. 
The hornblende occurs only in very small amount and is not seen in all 
sections. It is pleochroic in light green and light yellowish green tints 
and is without good crystalline form, being somewhat fibrous in char- 
acter, the extinction making an angle with the cleavage, for which the 
highest value observed was 17°. The epidote is present in small quan- 
tity, in irregularly shaped grains, or aggregates of grains, often asso- 
ciated with the hornblende. It shows the characteristic pleochroism 
and is probably secondary in every case. Primary epidote does how- 
ever occur in a similar, but unaltered mass of biotite granite, which is 
erupted through rocks of the same series as those cut by this granite 
on Wrangell island, Alaska. (See appendix 5 B, Annual Report of 
the Geological Survey of Canada, 1887). A small amount of ilmenite 
or titaniferous iron ore is also found in the sections. It is opaque and 
black, sometimes having a slight reddish tinge by reflected light. In 
one case a few small grains were seen imbedded in broken feldspar. 
Each grain had been broken into several pieces which lay close to one 
another and were cemented together by a greyish material resembling 
leucoxene, which is frequently observed associated with the iron ore 
in this rock. A few little flecks of hematite are seen as inclusions in 
the feldspar. The sphene and apatite are present in small amount, 
the latter being in rather short and stout crystals. 
In addition to these minerals the rock contains remains of some 
mineral now replaced by aggregates of decomposition products which 
fretjuently present rather perfect oblong outlines as if the original 
mineral had possessed a pretty good crystalline form. The principal 
constituent in these aggregates is calcite, which occurs in grains having 
the peculiar silvery white color usually exhibited by this mineral 
between crossed Nicols. Associated with it is chlorite, epi<lote, and 
often very small amounts of quartz, pyrite, and ilmenite or magnetite. 
In one of these masses a grain of light green somewhat fibrous horn- 
blende was found filled with calcite grains and associated with epidote, 
chlorite and hematite. The mass appears originally to have been all 
hornblende, of which these other minerals are decomposition product*, 
in fact all these aggregates probably rej^resent original hornblende 
grains, chlorite, quartz, calcite and epidote being the minerals into 
which the hornblende of granites usually splits up in decomposing. 
