There are coal-mines at and near Eregli (anc. Heracleia) which yield steam coal nearly as good in quality as the English, but they are badly worked.
There are extensive beds of good coal, including thick seams of steam coal near the Rand and other goldfields.
In some instances the coal seams may be changed as a whole, as for instance in South Wales, where the coking coals of the eastern side of the basin pass through the state of dry steam coal in the centre, and become anthracite in the western side.
In the Northumberland steam coal district, where it is carried out in the most perfect manner, the bords are 5 to 6 yds.
The gases from the bituminous house coals of South Wales are comparatively free from marsh gas, as compared with those from the steam coal and anthracite pits.
