COAL. 463 
in the former of these run the beds of coal of two 
or three feet thick ; but it is remarked that none of 
the layers of clay contain any of this mineral. 
Among the mines of coal which are remarkable 
for their local elevation, may be mentioned that of 
Saint-Oulx, a town of Piedmont. According to 
the barometrical measurement of Dr. Guerin, it is 
180 fathoms above the surface of the sea. Although 
this mine may be rich, it has been worked only two 
years, on account of its almost inaccessible elevation. 
This height, however, is comparatively nothing to 
that in which Leblond observed layers of coal in 
Peru. He tells us that he found beds of this sub- 
stance in the Andes, near Santa-Fe-de-Bogota, which 
were situated two thousand two hundred fathoms 
above the ocean. 
In Scotland the mines of Carron, of Edinburgh, 
and of Glasgow, are chiefly distinguished for their 
produce. There are three beds of coal at Carron, 
the first of which is about 40 fathoms below the 
surface, the second 50 , and the third 55 . Only 
two beds are worked at Edinburgh, and one of 
them is remarkable for its situation, the opening of 
the mine being hardly forty fathoms from the sea, 
and only three fathoms above high-water mark. 
The mines of Glasgow stretch from the north-east 
to the south-west, and occupy a considerable space 
of ground. Here are several beds of coal, placed 
on each other, and continued nearly from the sur- 
face of the ground to the depth of three hundred 
