NEW SOUTH WALES COALS. 203 
“same seam. ‘The composition of the ashes as well as of the coals 
may help us to correlate the coal seams of the different districts 
one with the other, 7.¢e., assist in determining their positions in a 
geological section of the whole of the coal measures as developed 
in different parts of the Colony. Judging from the composition 
of the ashes, one would be inclined to say, that not only do certain. 
of the coals in ‘each district come from the same seam, but that 
the western coals from Vale of Clwydd and Lithgow Valley belong 
to the same horizon as the southern coal from Berrima ; but much 
importance cannot be attached to this matter, certainly it would 
different parts of the working face. It would be well to take some 
tons weight of the coal, which should be broken up into pieces of 
moderate size and well mixed. From this heap portions should 
thrown into a smaller heap of a few hundred-weights ; after this 
smaller heap has been well mixed portions should be again removed 
radially and a third time well mixed ; this last could then doubt- 
less be regarded as a true sample and not a mere specimen, as 
a single lump of coal must necessarily be. Too much care cannot 
Possibly be taken over the collection and preparation of samples. 
