322 
colour is dark brown to greenish-yellow. The pleochroism 
is intense, showing practically complete absorption. 
biotite encloses such minerals of earlier formation as apatite, 
zircon, and ilmenite. 
Chlorite and epidote are developed as secondary pro- 
ducts. The small amount of muscovite occurs in association 
with thé biotite, and is of later crystallization. It remains 
clear and unaltered. 
patite occurs in slender needles and small hexagonal 
prisms. It is most abundant as inclusions in the biotite. 
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ircon, like apatite, is enclosed in biotite, and occurs 
in short prisms. It is usually surrounded by faint pleochroic 
haloes. ; 
Epidote is present, associated with biotite and plagio- 
clase; it probably results from the interaction of biotite 
and plagioclase, and is obviously of secondary origin. Calcite 
may be developed in addition. 
Kaolin occurs as a dust accompanying both felspars. 
The cores of some sections of the plagioclase show plen- 
tiful sericite, occurring in small flakes, sometimes to the 
complete exclusion of the felspar, from which it has developed. 
It is probably paragonitic in composition. : 
The order of crystallization of the constituent minerals 
may be subdivided as :— 
lopment is then referable to an early stage. The order o 
cessation of crystallization is more truly represented by the 
above arrangement. 
earing the completion of crystallization, the sodic 
character of the plagioclase had become marked, in pec 
sections oligoclase-albite being developed independently, an 
Adamellite group. - a 
eu Cognate Xenoliths.—These occur as ellipsoidal or ovoi 
jatches 1n the main granite. In hand specimens they appear 
