COAL AND ITS CLASSIFICATION 263 
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material recorded as brown coal; and the quantity in the 
State is estimated as 30,000,000,000 tons ; it is being worked 
there for use as briquettes, and the generation of electricity. 
Brown coals are generally of Kainozoic age. The best- 
known English deposit, at Bovey Tracey in Devonshire, is 
Oligocene. The vast deposits in Germany and Russia are 
Lower Kainozoic. The lignite of Alberta, which is estimated 
at over 100,000,000,000 tons associated with twice as much 
black coal, is Cretaceous. Some Paleozoic deposits have been 
preserved as brown coal, such as that of Malovka, and the 
Papier Kohle of Toula in Russia. 
Brack Coat (exclusive of Cannel Coal)—Black coal ranges 
from a variety of lignite to anthracite, and includes three 
chief varieties, sub-bituminous, bituminous, and anthracite. 
The chief member of the series is bituminous coal. That 
term is a misnomer, as it was based on the view that coal 
contains bitumen which had been injected into a bed of earth. 
The insolubility of coal shows that it contains no bitumen, 
which can be made from it by destructive distillation. 
Sub-bituminous coal or black lignite differs from brown 
coal by being black, harder, and having less moisture; it 
differs from bituminous coal by splitting into slabs instead 
of breaking into rectangular fragments. It contains up to 
about 40 per cent. of moisture. The ash is often low, but 
varies indefinitely; if it exceed 50 per cent. the material 
becomes valueless. The fuel varies in heat value from 6000 
to 16,000 B.T.U. Its age is generally Lower Kainozoic or 
Upper Mesozoic. 
Bituminous coal or ordinary house coal is black, usually 
laminated, and breaks along vertical joints known as cleat 
into rectangular or columnar pieces. The lustre varies from 
dull to brilliant. The coal is friable so that it soils the hands. 
It ignites readily and burns with a bright yellow flame. Its 
average specific gravity is about 1-3. The moisture is from 
2 to 10 per cent. The ash in the varieties used commercially 
ranges from about 5 to 12 per cent. though it rises to 50 
per cent., and passes into coaly clay or sandstone. The 
percentage of fixed carbon varies from 40 to 80 per cent; 
the sulphur is usually, in the varieties worked, from % to 2 
per cent.; some seams contain 10 per cent. or more. Its 
calorific value varies from 10,000 to 16,000 B.T.U.