Mr Menteath 07i the Geology of Nilltsdale. 315 



sides of the greywacke hills. Coal is worked in several places. 

 It occurs near the surface, in thick seams, from nine feet to. 

 twelve, but as yet no accurate borings have been made to ascer- 

 tain the number of beds of it which this basin contains. The 

 best sort is found at the great elevation of upwards of 1000 

 feet above the sea, at Mansfield, on the north side of Corson- 

 scon Hill. The coal of Mansfield is a cubical and splinty coal, 

 raised in very large square pieces. There are three principal 

 beds, of nine, eleven, and twelve feet in thickness. Not far from 

 the pits where the coal is now raised, there occurs a curious coal 

 deposit, which appears to be a small isolated basin. This bed, 

 which is believed to be the three above mentioned beds united 

 into one, is no less than thirty feet thick, and is immediately 

 under a peat-moss, which does not exceed twenty feet in thick- 

 ness, and is in a complete state of decomposition. 



Imbedded in the seam of coal of twelve feet in thickness, we 

 meet with a bed of cannel-coal sixteen inches thick ; and lately 

 another bed of the same coal, twenty-t^v^ inches in thickness, has 

 been found in an isolated situation. Both these are very free 

 of sulphur. To the westward, nearly between the sources of 

 the Afton and Nith, a bed of cannel coal, three feet thick, is 

 met with, but being sulphurous, is not adapted for the prepara- 

 tion of gas. On the estate of Mansfield, there is a bed of glance 

 coal or anthracite {blind coal) four feet thick. 



The coal is associated with slate-clay, bituminous shale, and 

 sandstone. The sandstone is of a yellow colour, but soft, and 

 therefore of inferior quality. 



The carboniferous or mountain limestone which underlies the 

 coal of the New Cumnock basin, is found in great quantities, 

 and may be s^d to fringe the coal of this basin. There are se- 

 veral liraeworks in it, where it is burned and prepared for mar- 

 ket. On the side of Consonscon Hill, which is greywacke, and 

 at a considerable elevation, the limestone, which is of an excel- 

 lent quality, crops out. It is burned, and supplies a great range 

 of country, not only in this basin, but that of Sanquhar. 



On the banks of the Afton, one of the tributaries of the Nith, 

 before it leaves the New Cumnock Basin, galena or lead glance 

 occurs in transition rocks, and has been wrought for a consider- 

 able time, but to no great extent. 



