Rooks. 
03 
Hornblende is a constituent of many Australian 
granites. This is a blaokish -green mineral, whioh 
may be distinguished from the mioa in the same 
rock by its not splitting into thin loaves. 
G. When granite is examined in the field it is soon to 
have intruded dykes, veins, and tongues of its 
own material into the rocks above and around it. 
This proves a former liquid or plastic condition. 
There is abundant evidence to show that this 
former condition of granite was altogether due to 
heat. 
7. (Jetting results together, wo are able to say that 
Granite is a fire-formed rock made up of 
three distinct crystalline minerals, quartz, 
felspar and mica, with a fourth mineral, 
hornblende, often present. 
Tho student must not oonoludo that because granite was in ft molten condition 
water could not also bo present. Dry heat, such is wo see in furnace operations 
ban left proof of its effect upon rocks. Geologists, however, recognise beat of 
another kind that is, boat in tho presence of moisture or superheated steam 
under great pressure— as having playod a more important part in the n akimr of 
roc.kw. * * 
