At Gilmerton, near Edinburgh, and at Loanhead, about two miles 
south-west of Gilmerton, they have a continual change of strata, 
on account of their great declivity, which is about the angle of 45". 
The number and variety actually cut through in this field is so im- 
mense, that it would fill a large book to enumerate and describe 
them all. They are all, says Mr. Williams*, whose work is replete 
with the most interesting and useful information, what are commonly 
called coal metals, that is, such strata as are generally found to 
accompany beds of pit coal; and there are above sixty strata, or 
beds of coal, thick and thin, cut through at Gilmerton, in this noble 
section : among which, about twenty of them have been worked at 
Gilmerton, and the neighbouring coal fields. The rest are thin, 
though regular strata of coal, generally from about two feet, to three 
or four inches thick ; and some of them, though regular strata, not 
above one or two mches. In short, the strata cut through in this 
great section contain such an amazing number and variety, that they 
may be considered as a very complete assemblage, and example, of 
all the strata which accompany coal, excepting regularly figured 
basaltes, of w’hich there are none at Gilmerton, though they have cut 
through several beds of whin, of various colours, which approach the 
quality of that stone. 
The substances which in general accompany coals demand also 
some attention. Among these may be first noticed metallic sub- 
stances : thus Valerius Cordus f relates, that, with the bituminous 
coals which are dug near Cunharden, there also exists a bituminous 
vein of copper and of silver ; but iron is the substance most fre- 
quently found. Sulphur is also found to abound almost universally 
in pits of coal. Neither of these substances are, however, thus 
found in a state of purity, but are generally combined together in 
* Williams’s Mineral Kingdom, vol. i. p. 41. 
f Valerii Cordi Observationes, &c. p. 211 . 
