DR THOMSON ON TUB STRATA OF BERWICKSHIRE. 89 



castle mines. The workmen at the period of my visit appeared healthy. 

 The wages of men were 20s. 6d. per week, and of boys of sixteen years, 

 10s. 



In order that the following table may be understood, I consider it ne- 

 cessary to explain the terms which are used by the miners, as they differ 

 from those employed in other places ; and I can do this with confidence, 

 because I have examined the rocks to which the names were applied, 

 along with the overseer of the mine : 



Tiles Shale, filled with shells and fossil vegetables. 



Dent Soft slate-clay or shale, with few organic remains. 



Metal Slate-clay. 



Freestone Sandstone. 



Whin Bazalt. (The term Whin is applied in Berwickshire to all 

 rocks except freestone and quartz.) 



Seam A coal bed. 



Section of Greenlaw Welb! Shaft, North Durham. 



Path. Feet. Inch. 



1 Red gravelly clay, . . .100 



2 Blue Metal, . . .050 



3 Coal, . ; " . .012 



4 Limestone, * . 10 



5 Coal, . . . . .006 



6 Grey tiles, . . .013 



7 Coal, . . . .011 



8 Blue tiles, . .007 



9 Freestone bed, . . .0010 



10 Coal, , . . .011 



1 1 White metal, . .036 



12 Grey freestone, . . .013 



13 Blue metal, . . 4 



14 Coal, . . ., . 4$ 



15 White metal, . . .043 



16 Grey freestone beds, . 12 2 



1 7 Coal, called Main coal not workable, .013 



18 Hard brown metal, slaty, . .025 



19 Good coal, rather splinty, . ,010 



20 White metal, with limestone scalp, .013 



21 Coal mixed with black dent, . ..010 



22 Grey freestone mixed with charcoal, .003 



23 Black metal, . . .003 



24 Coal, . . . '.003 



25 Dark brown metal, . . '? 1 3 



26 Coal, . >. v f . .003 



27 Limestone, very dun, . . I 4 



28 Good coal, . . .0 3 



29 Blue metal, 2 <i 



30 Limestone with freestone scalp, 007 



Carry forward, 



