TRANSACTIONS OF THE SECTIONS. 91 
many stems seen in the stone, with their roots ramified through it, and 
the stems quite vertical ; circumstances which clearly indicate that they 
grew in their present position. Mr. Craig then described the different 
carboniferous black band ironstones found in the upper coal formation. 
These he classed as the upper, which is about fourteen inches thick, 
and lies 24 fathoms above the first, or ell coal. It is only wrought in 
the parish of Old Monkland, at a place called Carnbroe. The middle 
or Airdrie black band lies about sixteen fathoms below the splint coal, 
and measures from fourteen to twenty-two inches thick; the lowest lies 
much lower in the stratification, and is of about the same quality and 
thickness as the Airdrie black band. 
3rd. Below the coals and ironstones already noticed, we arrive at a 
marine series, containing three or four limestones, which, with their as- 
sociated shales, contain—Encrinites, Bellerophons, Nucula, Euomphali, 
Orthoceratites, and other remains decidedly marine. This portion of- 
the strata contains only two or three very thin seams of coal; it is 
about 200 yards thick. This group is denominated the upper lime- 
stone series. 
4th. We now arrive at the lower coal series, which contains no lime- 
stones, but a number of coals, the lowest of which is the cannel coal, 
measuring from two to three feet thick. The main coal lies fifteen 
fathoms above the cannel coal. These and some other thin seams are 
associated in some localities with valuable black band ironstones. 
These are wrought at Keppoch, near Glasgow. The upper ironstone 
measures from fifteen to sixteen inches. The under band varies from 
four to ten inches in thickness. 
The black band ironstones of the Glasgow coal-field contain very 
little clay, and about as much carbonaceous matter as serves to calcine 
it ; on which account it is considered more valuable than the clay iron- 
stones hereafter to be noticed. 
Below the lower coal series there occur several small groups of clay 
ironstones imbedded in shale, each separated from the other by beds 
of sandstone and an occasional stratum of limestone. Mr. Craig showed 
a vertical section wherein all these beds were exhibited, the ironstones, 
amounting tosixty-six in number, twenty feet of which might be wrought 
in different winnings in the same pit. 
5th and 6th. Underneath these ironstones, shales, &c. lies the main 
limestone, measuring from four to six feet thick, beneath which isa 
layer of aluminous shale, from which alum is manufactured. This bed 
is followed by a seam of coal from four to five feet thick, of a sulphur- 
eous nature, and containing nodules of iron pyrites. These beds are 
succeeded by limestones, shales, and sandstones, and finally by an ex- 
tensive formation of thin compact limestones imbedded in shale, and 
finally by old red sandstone. Such is the general description of the 
strata developed on the Clyde and its tributaries, from Lanark to the 
Vale of Leven. 
Mr. Craig then entered upon a description of the different coal-fields 
in Ayrshire. The coal there appears in several basins, among which 
are those of Irvine, Kilmarnock, Ayr and Dalry. These contain from 
