64 
J. R. H. McWhae. 
of about 60° which may be replacements along the .amphibole cleavages. 
Epidote forms irregular aggregates (average diameter 0.5 mm.) whic'h may 
in ]*art replace felspars. Some ei)idote was introduced at a later stage along 
cracks. The felspar is untwinned oligoclase which is difficult to distinguish 
from (juartz. Accessory minci'als are apalitCj titanite, iron ore, and zircon. 
The approximate mineralogical com[)osition is quartz 32 ])er cent., 
chlorite 30 per cent., epidote 25 per cent., plagioclase 10 per cent., and 
titanite and other accessories three per cent. Another specimen of this group 
(22488) is almost black in colour and contains SO per cent, chlorite. 
Table 2. 
Si02 
AI2O3 
Fe 203 
FeO 
MsO 
CaO 
ICO 
NagO 
H2OJ- 
H20~ 
TiO, 
MnO 
P2O5 
BaO 
ZrOg 
S 
Norms. 
Q 
Or 
Ab 
... 
di 
hy 
mg 
ii 
ap ... 
py ! 
C.I.P.W. olasaifioation II, 4, 
I. 
0/ 
/o 
59-23 
16-18 
1-48 
5-63 
4-24 
9-58 
0-10 
0- 65 
1- 71 
0-20 
0-61 
0-13 
0-19 
Nil 
Nil 
003 
99-96 
25-86 
0- 56 
5-76 
40-87 
4-86 
11-50 
2-09 
1 - 22 
0-34 
0-10 
II. 
0/ 
/o 
50-20 
15-00 
3-83 
8-93 
6-04 
10-65 
0- 07 
1- 90 
1-62 
0- 07 
1- 06 
0-16 
0-12 
99-65 
6-18 
0-56 
16-24 
31-97 
16-41 
19-18 
5-57 
2-13 
0-34 
I. Quiirtz-plao'ioelase-epidote-ehlorite roek (22487), xenolith in upper 
granitic gneiss, l,a\vns\vootl, W.A. {Anal. J. R. H. McWliae). 
II. Schistose plagioclase amphibolite (1241) xenolith in upper 
granitic gneiss, Toodyay, W.A, (23, p. 105). 
(m) Silliiiuuiite-iiiica .schist (19103) is a slightly contorted, lustrous, 
grey schist, composed largdy of platy mica, two to four mni. long, some 
of which is black biotitc. Xenoliths of this type are of rare occurrence. 
rile iiiaiii eoiislituciit is muscovite "which has 2V approximately 40°. 
It contains poikiloblastic inclusions of sericite and chloritised biotite. 
