21 



The first workable bed, or Ell coal, is 45 to 50 fathoms below the 

 upper red sandstone of the first division ; the fifth bed is a splint 

 coal, and below it the remaining seams are less continuous, and of 

 inferior thickness. There are, besides, numerous beds of common 

 clay ironstone and blackband, a variety which contains enough car- 

 bonaceous matter to effect its calcination ; and this is usually done 

 at the mouth of the pits. The blackbands vary in thickness from 

 4 to 22 inches. There are three principal bands ; the upper, 14 

 inches thick, is 24 fathoms above the Ell coal, and is worked in Old 

 Monkland parish. Another, the mussel band, the second in descend- 

 ing order, is very remarkable as being almost entirely made up of 

 fresh-water shells, which are seldom found in the clays above and 

 below this ferrugineous band. It is 14 to 22 inches thick, and is 

 worked near Airdrie. This blackband is 16 fathoms below the splint 

 coal. The lowest bed is of the same quality, but lies much lower in 

 the series. With the other beds similar shells are associated ; and 

 in Ayrshire the same fresh-water coal series appears, with rich black- 

 band ironstones. The area occupied in Lanarkshire by this upper 

 coal series is about 20 miles long, and from 6 to 15 broad. 



18. Immediately north of the Necropolis hill, Glasgow, and 

 along the line of the Monklands canal, this fresh- water series reposes 

 upon limestones, shales, and- sandstones abounding in marine remains, 

 orthoceras, encrinites, bellerophon, euomphalus, nucula, productus, 

 spirifer, &c., and constituting the upper marine group. It contains 

 two seams of coal 12 and 14 inches thick, and irregular beds of iron- 

 stone ; total thickness, about 600 feet. North of Glasgow, across 

 the high ground between Bishopbriggs and Cumbernauld, the sand- 

 stones are of great thickness, and the " measures " are without coal. 

 Below these beds succeeds the lower coal group without lime- 

 stone, but with several blackbands, and beds of coal, of which the 

 lowest is a cannel coal, 2 to 3 feet thick. These coals and iron- 

 stones are worked north-west of the Kelvin, at North Woodside, 

 Jordanhill, &c. At the bottom of the whole group are nodular clay 

 ironstones, and thin limestones. The lowest group yet established 

 reaches from this horizon to the Ballagan beds, and contains marine 

 limestones (main limestone 4J feet thick), alum shale, and sulphureous 

 coal, 4 to 6 feet thick ; below which are other limestones and coal 

 beds, alternating and intermixed with tufaceous trap, to the bottom 

 of the series. At Hurlet, Duntocher, Campsie, &c., these limestones 

 and shales are well seen. The alum works at Campsie, on the south 

 side of the valley of denudation already alluded to, have been long 

 established in connection with the shale bed. These works embrace 



