278 



THE GEOLOGIST. 



roads against the '^dip," or ''in the land." From these ''land- 

 headings" or " stall-roads," stalls are turned, i.e., excavations are made 

 at certain intervals along the land-headings, and parallel with the dip- 

 headings, from which the ore is extracted. The annexed cut represents 

 the method of " pillar and stall " working, as this mode of mining is 

 termed. 



Lign. 5.— Example of " Pillar and Stall " working. 



The dark shading shows the buttresses allowed to stand for the sup- 

 port of the roof and maintenance of the ways. The lightly-shaded 

 parts show the ore-ground which is being gradually worked away by 

 the enlargement of the " stalls " represented by the blank spaces. 



But the majority of the workings in the Dean Forest mines exhibit 

 little of this regularity ; since, after the dip-headings are driven, the 

 churns are followed in all their irregularities of form, as seen in the 

 sketch of the Devil's Chapel (PL YIII.) in which the darkly-shaded por- 

 tions show the " churns " from which the ore has been removed. The dark 

 line A is a " lead." At C, C, are seen small masses of ore in situ. The 

 " crease " is displayed in the separating buttresses. B, in the fore- 

 ground, is a " drift" driven across the " measures." D represents an 

 opening made on a " lead." The number of mines at present in work 

 in the Forest amounts to about twenty, commanding some 3,500 acres 

 of ironstone, and, if continually exploited, at an average yield of 1,000 

 tons per day, would make the quantity raised equal to a rate of 300,000 

 tons per annum ; the "get," however, is much less than this. 



The length to which this paper has already extended warns me now 

 to conclude, otherwise, I had intended to have introduced some account 

 of the regulations attending the granting of " gales " or mining-awards 

 in the Forest of Dean by the Crown. I will, however, return to this 

 subject when describing the coal-measures of the district. 



