22 
MUSEUM BULLETIN NO. 30 . . 
and also those between the different types. The varieties of oli- 
vine gabbro described on page 9, are usually found to possess 
gradational relationships with one another so that although the 
zone in which gabbro of one texture passes into gabbro of another 
is usually only a few inches in width, sometimes as narrow as 
one inch, still there is no sharp line of demarcation between 
them. Faintly intrusive relations are found in several places, 
however, and when these occur it is nearly always the com- 
mon type of olivine gabbro which is intruded by the special- 
texfUred types. The relations which establish the fact of 
intrusion are : ( 1 ) in places, long narrow stringers of the intru- 
sive penetrate the intruded rock; (2) very slight decrease in the 
size of the grain of the component minerals of the intrusive 
occurs near some of the contacts ; (3) flow textures in the intru- 
sive rocks are developed along many of the contacts. 
The relations between the olivine and augite gabbros are of 
much the same character. At several places, as on Bentinck 
island and the western end of Sooke peninsula, the augite gabbro 
is clearly equivalent in age to the olivine gabbro, as it merges into 
the olivine gabbro by gradual increase of olivine. Furthermore, 
it is interbanded with the olivine gabbro to form a primary 
gneiss. At several other points, notably at the southwestern 
corner of the peninsula and on Race rocks, the augite gabbro is 
distinctly later than the olivine gabbro, since it has intruded it in 
the manner described, and has broken off fragments which are 
now included in the augite gabbro. At two points, however, in 
the olivine gabbro area around Beechey head, these relations are 
exactly reversed, and similar phenomena show the augite gabbro 
to be intruded by the olivine gabbro. 
The anorthosites possess similar relations to both olivine 
and augite gabbros. The gradational relations may best be 
seen on mount Maguire, where the fairly pure anorthosite 
merges in places into true gabbro by increase in the olivine- 
augite content. The same gradational relation is found along 
the edges of the large anorthosite masses on the south and west 
coasts, as well as along those of the small masses scattered 
through the augite gabbro. In the latter places the gradation is 
