GABBROS OF EAST SOOKE AND ROCKY POINT. 
9 
banding, in which gabbros of widely differing grain and composi- 
tion are arranged in long parallel ribbons or bands. These bands 
vary from 1 to 6 feet in thickness; the contacts between them 
are always gradational, but the gradation always very rapid, 
usually not over an inch or two in width. The gabbros compos- 
ing these bands are fresh and unsheared; they occasionally are 
characterized by flow textures arranged parallel to the long axis 
of the band. The grain of the different bands may vary from 
rather fine (average 1 mm. or less) to quite coarse (average 4 or 
5 mm.) ; the composition, from a rather basic olivine gabbro with 
perhaps 60 per cent of ferromagnesian mineral to a highly feld- 
spathic gabbro almost anorthosite. The composition of the feld- 
spar, however, rarely varies from one band to another. 
Flow textures are also frequently found in these rocks. 
They occur at times, as mentioned, in the bands of primary 
gneiss just described; they may be observed occasionally in one 
variety of rock at its contact with another; although in some 
places near the periphery of the intrusive they affect the whole 
rock mass. They are always of the same type. The pyroxene 
forms narrow laths or needles which have been arranged with 
their long axes parallel to one another and at the same time a 
certain amount of parallelism of the feldspars has also been 
induced. 
Anorthosites. 
The anorthosites consist usually of bytownite, Ab 20 An 80 , 
with less than 5 per cent of ferromagnesian constituents. They 
are equigranular and medium to coarse-grained, with an average 
grain of 2-3 mm. They are chiefly remarkable on account of 
their manner of occurrence in small isolated masses. A few 
large masses are found in the East Sooke body, one, several 
hundred feet long, on the top of mount Maguire, a smaller one 
on the east shore of the peninsula, near Beechey head, a third on 
the west coast; but large masses are uncommon and are apt to 
contain in places considerable quantities of pyroxene and olivine. 
The remainder of the anorthosite is scattered throughout the 
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