in the Neighbourhood of Edinburgh. 249 
Immediately above this limestone is another seam of coal, 
named “ The North Coal,” which, like the North-green seam, is 
4}. feet thick. With this seam all marine remains disappear, and 
we arrive at the coal strata of Loanhead, which, as the section 
shews, rise still higher in the system. 
The coal strata of Loanhead consist of alternating beds of 
sandstone, argillaceous and bituminous shale, containing iron- 
stone bands, coal, and some little limestone. The workable beds 
of coal are to the number of twenty-five. They are from 2 to 10 
feet in thickness. 
In these beds, the angle of inclination is still upon the increase. 
I found, upon descending into the mine of Loanhead, that the 
seam named the Stair-head coal, had a dip of 56° to the south- 
east. But it is affirmed, that, among some of the strata, the 
inclination is still greater. From these circumstances, the beds 
have acquired the name of Edge seams, in contradistinction to the 
more horizontal strata lying to the east of them, belonging to the 
Hawthornden system, which bear the name of the Flat seams. 
Where the edge and the flat seams appear in contact, which I 
found to be in the channel of Bilston burn, south of Loanhead, 
some confusion of the strata ensues, indicative of a great fault, 
yet unaccompanied with marks of violence. 
Among these coal-measures there are at least four slips or 
dislocations, by which the coal is variously thrown up and down 
from thirty to sixty fathoms. 
A section of the seams of coal, “ as they stand in the mines of 
Brughlee and Mavisbank,” was made some years ago. It is not 
every thing which the geologist could desire, as it does not 
include the character of the strata intervening between the coal- 
seams. But this deficiency I have supplied, as well as I was 
able, from the information which has been given me at the mine, 
particularly by Mr Ross. 
I have also submitted the section to some alteration in its 
arrangement, in order to shew at one view the overlying charac- 
ter of the strata. 
VOL, XIII. PART I, 1i 
