142 



PROCEEDINGS OP THE GEOLOGICAL SOCIETY. 



[June 1, 



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Dumb Hall Well 

 (47 yards deep). 



Thorpe Salvin. 



Harthill Well (23 

 yards deep). 



Balborough Park Pit 

 (50 yards). — 



Comberwood Colliery 

 (50 yards). 



Killamarsh I.'/ 



^ (30 yards). — - 



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oak, so little gas is 

 given off from the coal 

 that we experience no 

 difficulty at present in 

 working with naked 

 lights. 



The following are 

 the points of greatest 

 interest proved by this 

 sinking : — 



1. The existence of 

 a soft sand-rock at the 

 bottom of the Permian 

 beds in this district, 

 which seems to be 

 the equivalent of the 

 "Quicksand" of the 

 north. 



2. The absence of 

 any workable seam of 

 coal in this district, at 

 least in the 300 yards 

 of coal-measures above 

 the " Wathwood " or 

 "ShireoakThickCoal." 

 Thirty-seven feet of 

 coal were passed 

 through in the sink- 

 ing, butonlyfour seams 

 are of a workable 

 thickness. 



3. The existence of 

 a Eed Ironstone in the 

 upper measures, which 

 promises to be of great 

 commercial value. 



4. The " Top Hard 

 Coal" seems to thin 

 out towards the east 

 under the Magnesian 

 Limestone ; for at Kil- 

 lamarsh and near its 

 outcrop, six miles west 

 of Shireoak, it is 6 

 feet thick, while with 

 us it is only 3 feet 9 

 inches. 



The " Wathwood 

 coal " being found 

 within one yard of the 



