COAL-FIELD OF CLACKMANNANSHIRE. 129 



the valley of the Devon, at the foot of the Ochill 

 Mountains, where they form a Trough, as it is term- 

 ed by the miners, and rise very quickly, nearly in a 

 vertical direction. There the coals, with the whole 

 of their accompanying strata, are found in a con- 

 forming situation, and parallel with the strata whieh 

 compose the Ochill Mountains ; which strata lie at 

 the elevated angle of 73 degrees with the horizon. 

 The coal strata next the mountains, are denominat- 

 ed in the miners language Edge Metals ; that is, 

 strata nearly vertical. 



In this coal-field, which has been accurately as^ 

 certained by pitting and boring to the depth of 703 

 feet, there are no fewer than 142! beds or distinct stra- 

 ta, variously alternating, as represented Plate V. 

 Fig. 1., and minutely described in the first volume 

 of the Society's Transactions. Of these, there are 24 

 beds of coal ; which in thickness, amount to 59 feet 4 

 inches ; the thinnest bed of coal being only 2 inches, 

 and the thickest 9 feet. The strata in this sec- 

 tion contain numerous varieties of sandstone, slate- 

 clay, bituminous shale, indurated clay or fire-clay, 

 and clay ironstone. There are neither greenstone, 

 limestone, nor any of the trap-rocks to be found con- 

 nected with the workable coals ; but an immense 

 bed of greenstone, named Abbey Craig, is found on 

 the western boundary of the county next Stirling- 

 shire, under which are regular strata of slate-clay, 

 sandstone, thin beds of limestone, and large sphe- 



vol. in. r 



