Account of the Mineral-Fields of Airdrie and Bathgate. 177 
cease in Stirlingshire, where the Bannockburn coal, which is un- 
doubtedly an open burning coal, towards the Carron Works, 
is there converted into one of the most valuable caking coals 
in Scotland ; and this change to all appearance is caused by 
the immense bed of trap rock which passes under this coal- 
field. Thin beds of coal which lie nearer this trap rock are 
converted into anthracite, or glance coal. The same change, 
apparently from the same cause, is to be seen in the Dollar 
coal-field in Clackmannanshire. 
These instances, and many others in Scotland, leave no 
doubt of the effects produced in coals by this class of rocks, 
and hence I am led to infer, that the slip does throw up the 
coals and their accompanying strata, to the west; but this 
view is only hypothetical. 
Mountain- Limestone. 
This mass of limestone passes under all the workable 
beds of coal which have been ascertained in the Bathgate 
coal-field. It is no less than forty feet thick, and of very 
superior quality, suitable for all the purposes to which lime is 
applied, more particularly when used as a flux in the blast- 
furnaces, where four tons of this limestone produces the same 
effect as six tons of the limestone at present generally used 
in the Airdrie blast-furnaces. The expense of carriage of 
this limestone to the furnaces prevents it being used ; but 
the railway now making will open upa very great sale for it, 
and be very advantageous to the agricultural interests of 
_ the country, as well as for the iron-works and buildings. 
Tronstones. 
lronstones abound in this mineral-field, but the distance 
from blast-furnaces renders them of no value ; and no account 
was taken of them when sinking the pits. 
The ironstones which have been found are of three kinds, 
Viz :-— 
1s/, The Mushet ironstone band, found in the roof of a 
coal at the town of Bathgate. It is from six to eight inches 
VOL. XLVIII. NO. XCV.— JAN. 1850. M 
