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 1 

 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. i i 



