Basalt. 
283 
in ordinary types of our Tertiary basalts, neither is it 
so abundant. Perfect lath-shaped crystals are not 
common. There is no difficulty, however, in identify- 
ing them, as they are the first to catch the eye and 
give character to the rock in making a thin slice. 
Fig. 79. — Minerals seen in a slice of Basalt from Bondi, magnified 
60 diameters. 
1. — Olivine Crystal, bent while yet in a plastic condition. 2. — 
Olivine Crystal, with included grains of magnetite. 3. — 
Augite, partly attacked by the liquid magma. 4. — Augite 
Crystal, with a line of magnetite inclusions, showing a stage 
in the growth of the crystal. 5. — Augite, showing cleavage 
plates. 
The magnetite can be seen on every slide. It is a 
common inclusion in the olivine and augite, and may 
be seen forming a fringe or line around the faces of 
these minerals. A reddish colouration is sometimes 
