1896.] Petrography. 577 
alteration of the bronzite into olivine. -+ By complete fusion one concre- 
tion, which is thought. by the author to have been a bronzite-augite 
aggregate, has been changed to a mass of rounded augite and olivine 
grains imbedded in a glass which locally is replaced by nepheline. The 
alteration of the bronzite, as indicated by the study of a number of 
sections, is into olivine, augite, magnetite and glass. Among the rare 
constituents of the olivine concretions are chrome diopside and pico- 
tite. The augite concretions or inclusions, consist almost exclusively 
of a monoclinic augite with which is usually associated a little olivine. 
In the interiors of the concretions the augite contains fluid enclosures, 
but toward their peripheries the enclosures are all of glass. Often bé- 
tween the augite grains are little nests of calcite. One of the inclusions 
observed. by the author is abnormal in that it is composed of a small 
nucleus of augite surrounded by a zone of brown biotite. 
Of the foreign inclusions, the author describes two kinds—the calea- 
reous and the granitic. The basalt in the neighborhood of limestone 
inclusions loses its biotite and magnetite. Nearer the inclusions the 
augite microlites become light colored and magnetite grains are again 
developed. At the boundary of the limestone fragment is a rim of 
large augites, whose ends are directed toward the center of the inclu- 
sion. . This latter itself is composed of the remnants of calcite grains 
imbedded in a brown glass, in which are also well formed crystals of a 
scapolite. The sandstone inclusions have been changed to a mass of 
quartz grains lying in a brown glass, the whole being surrounded by 
the usual zone of augite microlites. The granite inclusions first lose 
their mica. The old feldspar has given rise to newly developed feld- 
spar. 
The dolerite seem to occur as a number of small flows that have run 
together. It presentsno special peculiarities.: The dyke basalt cutting 
the tuffs and dolerites. sometimes contains well defined crystals of 
olivine, which occasionally occur as interpenetration twins. 
Igneous Rocks of British, Columbia.—The petrographiecal 
characters of the principal rocks occurring within the area of the 
Kamloops. Map-sheet of British Columbia are described by Ferrier,’ 
These rocks embrace feldspathic actinolite schists, diabase porphyrites, 
harzburgite, amphibolites, diabase tuffs, cherts, gabbros, orthophyres, 
augite-porphyrites, porphyrites, basalts, pecrite-porphyrites, andesites, 
trachytes, dacites, diorites, granites, syenites, quartz-porphyries, alnoite 
and a series of much altered rocks. The descriptions are all brief. 
2 Annual Rep. Geol. Surv. of Canada, Vol. VU, Pt. B,, p 349, 
40 
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