✓ 
GABBROS OF EAST SOOKE AND ROCKY POINT/ 3 
Oligocene , 1 and the gabbro is, therefore, pre-Miocene, and pos- 
sibly pre-middle Oligocene. A period of erosion at least moder- 
ately long must have ensued, after the intrusion of the gabbro 
and before the deposition of the Sooke formation, so that the 
age of the gabbro is probably lower Oligocene. 
LITHOLOGICAL CHARACTERS AND MODE OF 
OCCURRENCE. 
GENERAL DESCRIPTION. 
Clapp 2 has described the principal rocks found in the East 
Sooke and Rocky Point masses. He distinguished hornblende, 
augite, olivine, and feldspathic gabbros, anorthosite and olivine 
anorthosite, pegmatite, aplite, and homblendite. In addition he 
described a granite facies which he found in other bodies in the 
Sooke map-area, although not in those under discussion. Closer 
examination has revealed the presence of a small amount of this 
granite facies on Possession point, in the East Sooke peninsula, 
and on some of the islands near Rocky point, in the form of 
dykes. 
The writer has grouped the rocks into four principal types : 
olivine 1 gabbro, augite gabbro, anorthosite, and granite. The four 
principal types are, however, further differentiated into numer- 
ous sub-varieties, characterized by differences in texture, grain, 
and composition. Detailed study has shown that the various 
types and sub-varieties grade into one another, in some places 
gradually, and in other places rapidly. Olivine gabbro . passes 
into augite gabbro by the decrease of the olivine content to 
zero, and either olivine or augite gabbro may pass into felds- 
pathic gabbro or anorthosite by the decrease of both olivine and 
augite. Suites of specimens can be obtained to show all stages 
of these gradations, with' the differences between the various 
1 Clapp, C. H., Geol. Surv., Can., Mem. 96, p. 335. 
2 Geol. Surv,, Can., Mem. 13, 1912, pp. 113*119. 
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