454 PROFESSOR HEDDLE ON 
4. In tetrahedral crystals with octahedral modifi- 
cations; in graphic granite, at Rispond, in Sutherland. 
(fig. 4). 
5. In the combination of the octahedron with dodeca- 
hedron ; in coarse oligoclase-granite, in the cliffs near 
Caligaig (fig. 5). 
6. In twin éetra-octahedrons, in a syenite boulder 
near Tongue (fig. 6). With amazon stone, ilmenite, &c. 
Octahedral crystals also occur here. 
7. In flattened octahedra, in the great granite veins 
of Roneval, in Harris. 
The form is as figured—o. Figure 70 is the 
simplest form of ilmenite ; these are drawn in natural 
position (figs. 7 and 8). 
The similarity of these, when the ilmenite crystal 
is placed in vertical position, quite excuses JAMESON 
setting this magnetite down as being ilmenite. But o 
on 7=122°30’, and 7 on 7’=86°10' (fig. 8); 
while 0 on 0o’=109°28’, and o’ on o”= 
109°28’, (fig. 7). 
8. In granite, with dolomite and pale- 
green fibrous hornblende, in the Sally- 
villy Quarry, near Alford, Aberdeenshire, in twin tetra-octahedra, somewhat 
like fig. 6. 
9. In chlorite slate, at several spots on the shores of Loch Fyne, in minute 
octahedra. 
1. Is found imbedded in minutely foliated chlorite at Pundygeo, Fethaland, 
Shetland. It occurs in simple and also in hemistrope crystals, up to one inch: 
in size. 
Its colour is jet black, its lustre brilliant ; the powder is blue-black. It is 
very difficult to reduce it to powder, even under water. 
