GEOLOGY 



No. 6. The Eallarat or Upper Busty Seam. 



No. 7. The Hand Seam. A thin coal, not industrially valuable, 

 but very constant and useful as a datum horizon in attempting corre- 

 lations. 



No. 8. The Stone Coat, or Tilley Seam. 



No. 9. The Hodge, or Splint Seam. The term ' splint ' is applied 

 to a hard stony coal breaking up in flat slabs, and to some extent inter- 

 mediate between common coal and cannel. It is by no means restricted 

 to this horizon, many of the other coal seams containing bands of ' splint,' 

 some of which are persistent over considerable areas. 



No. 10. The TCard^ Three Quarter, Harvey, Constantine, Beaumont, 

 Barlow Fell, or Towne ley Main Coal, or (in the Consett district) 'No. i ' 

 Seam. This set of names is a good example of the troublesome no- 

 menclature of the Durham seams. 



No. 1 1 . The Ruler Coal. 



No. 12. The Hutton, Main, or Five Quarter Seam. This is prob- 

 ably the most famous of north country coal seams. It yields in different 

 districts the best household, the best coking, and the best gas coal. In 

 Northumberland it is known as the Loiv Main, and it is in its shaly 

 roof that the finest series of fish and amphibian remains have been 

 collected. 



No. 13. The Brass Thill. Not the same as No. 16. 'Thill' in 

 the local dialect means the underclay, and * brass ' is marcasite or rhom- 

 bic iron pyrites. A coal with much sulphide of iron in it (pyrite or 

 marcasite) is said to be * brassy.' 



No. 14. The Low Main Seam. This is not the Northumbrian 

 seam of that name. It is however, in part, the Hutton Seam of the Con- 

 sett district, a complicated bit of correlation due to the splitting up of 

 seams already referred to. 



No. 15. The Maudlin Seam. In the Wallsend district, only sepa- 

 rated from Durham by the river Tyne, this is known as the Bensbam 

 Seam, and that name is sometimes also used for it in the neighbour- 

 hood of Gateshead, where, indeed, the village of Bensham is situated. 



No. 1 6. The Main Coal (in the Pelton district near Chester-le- 

 Street) or Brass Thill (in the Consett district). 



No. 17. The Hard Coal (of Pelton). This seam on the eastern 

 side of the coalfield and in the Consett district is known as the Five 

 Quarter Seam. 



No. 1 8. The Shield Row Seam, or (in the Wearmouth district) 

 the Three Quarter Seam. This is the celebrated High Main Seam of 

 the Northumbrian side of the Tyne, from which the original ' Walls- 

 end ' coal was obtained close to the easterly termination of the Roman 

 wall. 



No. 19. The Splint or Craw Coal. Not, of course, the same as 

 the much lower No. 9. The Coal Measures above this seam are de- 

 nuded away to what extent must always remain unknown to us. 



It will be understood that the intervals between these nineteen 



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