682 MR. A. K. COOMARASWAMY ON THE [Nov. 1902, 
the minerals interlock, and chilled edges are not found, showing the 
contemporaneous character of these ‘ dykes,’ which are similar both 
to normal charnockites 
a and to the acid varieties 
of the Galle Group. 
More characteristic are 
the coarse pegmatite - 
patches and _ intrusive 
veins crossing the folia- 
tion (type 7). In these 
the component elements 
attain a large size and are 
frequently idiomorphic, 
with the exception of 
the wollastonite, which 
occurs in large masses 
moulding the other mine- 
rals (except pyrite, which 
however is rare in these 
veins). In such segrega- 
tion-veins the minerals 
wollastonite, orthoclase, 
and quartz predominate, 
pyroxene being present 
in less quantity. Calcite 
and apophyllite occur 
occasionally, but may be 
secondary. The largest 
wollastonite - individual 
measured 36 x 15 inches; 
quartz 11 x 53 inches; 
orthoclase 24 inches in 
greatest diameter; a hex- 
agonal prism of quartz, 
embedded in wollastonite, 
had a 3-inch prism side. 
The pyroxenes do not 
exceed a few inches in 
diameter, and are not 
always present. Scapolite 
was not found in the 
veins. Some veins consist 
almost entirely of wol- 
lastonite; one such, 2 to 4 
inches wide, was noted 
on the shore between the 
EKolus and north-western 
bastions. Occasionally in these pegmatite-veins druses are found, 
partly filled with calcite. When weathered out, these sometimes 
yield idiomorphic orthoclase or apophyllite. 
p. 688.] 
alternation of lime-silicate-pyroxene and 
—— ae 
DEERE asa. 
233 
eS 
TIES 
SSS = 
ee 
ORES 
a ai a 
is 
aes 
ofelspathic types of rock. 
< Swerrs2 
Se 
~ 
~ 
— 
Soa 
<= 
quart 
~oe 
figured in the present paper, fig. 7, 
Seer STN a Fer 
[At X x the specimen, figured in Quart. Journ. Geol. Soc. vol. lvi (1900) p. 603, was obtained ; and at x the rock 
Fig. 1.—Foliation in the Point-de-Galle Group, Galle Fort : 
