323 
secondary product. In some cases the remains of biotite are 
now only represented by chlorite and epidote together. 
Ilmenite is sparingly present with its leucoxenic 
decomposition product. 
Phenocrysts of quartz and oligoclase-andesine or andesine 
are present, and the remaining mass consists of a,fine-grained 
assemblage of allotrimorphic quartz and microcline, mostly 
untwinned.(2 
more usual. There is a minor amount of graphic intergrowth 
of quartz and felspar (microcline). 
e specific gravity of one of these ovoid segregations 
Was determined as 2655 (16? C). The specific gravity of 
the main granite is 2:668 (16° C). Die) = 27668. 
The segregations show a variable amount of biotite, the 
one in question being, if anything, freer from this mineral 
than the average. In some cases their slightly darker colour, 
(6) THE MINOR INTRUSIONS. 
For the purpose of later discussion these minor intrusions 
can be separated into three distinct groups:—(a) The grey 
aplite; (5) the pink aplite; (c) the white pegmatite. 
will be treated seriatim. 
. (a) The Grey Aplite.—This occurs as an intrusive mass, 
elliptica] in plan, behind Barn Bluff (vide map). 
Specimens it is a fine-grained light-grey rock with development 
The absence of microcline twinning in some sections of 
the potassic felspar is not considered sufficient evidence to 
rp oc si i i 
