218 
FIG. 
Fig. 
FIG. 
FIG. 
Fic. 
Fia. 
FIG. 
FIG. 
WS) 
() 
ww 
TRANSACTIONS OF THE [APR. 15, 
sents secondary quartz and feldspar. The perlitic cracks are in 
fact preserved in a brightly polarizing substance, but this was not 
easy to represent in the drawing. >< 67 diam. 
. Skeleton erystals of magnetite in black felsite porphyry (petrosilex) 
from Hanford Brook. Spec. 570. > 67 diam. 
PLATE XIV. 
. Diorite-porphyrite, coarse grained. The hornblende is represented by 
heavy shading; the feldspar is lightly shaded. An attempt is also 
made to represent the zonal structure and decayed cores of the 
phenocrysts. The quartz is unshaded and the magnetite is dead 
black. Spec. 608. > 37 diam. 
. Diorite-porphyrite, fine-grained. The shading is the same as in Fig. 1; 
it shows in addition a well marked flow-structure, and quartz as 
phenocryst; the quartz in the groundmass is not represented, nor 
are the feldspar individuals distinguished. >< 30 diam. 
PLATE XY. 
. Fine-grained Norite. A phase of the olivine-gabbro at Dolin’s Lake. 
Biotite is represented by heavy parallel lines, plagioclase by light 
ones ; augite and hypersthene by irregular cracks, the hypers- 
thene sometimes showing schillerization with innumerable mi- 
nute parallel rods of magnetite. Spec. 473. > 77 diam. 
. Quartz-bearing diabase from west of the Coldbrook Marsh. The feld- 
spar is shaded with parallel lines, the augite by irregular ones, the 
magnetite being black and the quartz unshaded. The abundant 
apatite needles are too small to be shown in the figure. Spec. 
304. X< 20 diam. 
PLATE XVI. 
Soda-granite, from Titus’ Mill. The feldspar is stippled, the fine 
twinning of the anorthoclase, being represented where visible by 
parallel lines. Some attempt is made to show the comparative 
alteration of the feldspar by the heaviness of the stippling. Horn- 
‘ blende is represented by diagonally crossing parallel lines. Quartz 
is unshaded and magnetite is dead black. Spec. 661. > 18 diam. 
Soda-granite fine grained and porphyritic. From the Hammond 
River below Upham. Shading as in the last figure, but augite 
is represented by irregular lines. Spec. 666. > 37 diam. 
PLATE XVII. 
Granophyric structure in soda-granite from near Hardingville. The 
feldspar is represented by parallel horizontal lines; the quartz is 
unshaded; the hornblende is represented by diagonally crossing 
lines, zircon by irregular heavy cracks, and chlorite by arrow 
points. In the upper left hand quadrant the quartz is mostly in 
minute trigonal prisms variously shown by different sections. In 
the upper right hand quadrant the quartz is regular and minute 
at the centre, but becomes coarse and irregular outside. In the 
lower half the quartz is seen radiating out from a crystal of feld- 
spar, becoming coarser and more irregular as it continues its 
growth. The feldspar between these quartz growths is in part 
optically continuous with the central crystal. From Spec. 656. 
< 80 diam. 
