\ 
468 COAL. 
round by a turn-frame, and drawn back to the pits 
by a single horse along another road. 
The principal mines in France are those of 
Lyonois, Forez, and Saint-Etienne. The two for- 
mer are situated in a valley wdiich was formerly 
covered by . the sea, and which extends from the 
Rhone to the Loire between two chains of primi- 
tive mountains. They occupy a space of six or 
seven leagues in length, and the coal rests upon the 
usual layers of stone and slate. The beds of coal 
near St. Etienne are placed in the earth almost in a 
horizontal direction, and are generally from three to 
six feet thick. The layers of slate which form the 
upper surface of the coal in these mines are full of 
vegetable impressions, and the frequent occurrence 
of this phenomenon has been a strong reason with 
many for supposing that coal owes its origin to de- 
cayed vegetable matter. 
There are several hills in the neighbourhood of 
St. Etienne where the mines have been on fire, and 
there are some, according to Patrin, where the fire 
yet subsists. It has been so violent, says this mi- 
neralogist, that we meet with enormous masses of 
slate which have been almost entirely converted into 
scoria. 
The coal-mine in the neighbourhood of Liege is 
the most productive of any in Germany . It oc- 
cupies a space of two miles, and consists of more 
than forty beds of coal, placed one above another, 
and separated by strata of stone from thirty to a 
