Northumberland and Durham. 15 



ago, on the Town-moor and Fenham estates, which continued to 

 burn for 30 years. It began at Benwell about a quarter of a mile 

 north of the Tyne, and at last extended itself northward into the 

 grounds of Fenham, nearly a mile from where it first appeared. 

 There were eruptions at Fenham in nearly 20 places ; sulphur and 

 sal-ammoniac being sublimed from the apertures ; but no stones of 

 magnitude ejected.* Red ashes and burnt clay, the relics of this 

 pseudo-volcano, are still to be seen on the western declivity of 

 Benwell hill, and it is credibly reported that the soil in some parts of 

 the Fenham estate, has been rendered unproductive by the action of 

 the fire. 



At Byker St. Anthony's, and at an adjoining dolliery, the Low 

 Main coal is found at 59 fathoms below the High Main ; but 

 though the seam proved to be 6j feet thick, the workings of it were 

 abandoned as unprofitable ; the coal being extremely fragile, and the 

 mines very subject to the fire damp. On the south side of the 

 Tyne, at Felling, Tyne Main, and Gateshead Fell, the quality of 

 this coal is very much improved, and under the name of the Hutton 

 Main, it forms one of the most valuable seams on the Wear. 



I must refer to the series of sections for a more complete view of 

 the other coal seams. 



I now proceed to give a more particular account of the sub- 

 stances that form the coal measures. 



Of the coal itself three varieties are found ; the common or Slate 

 coal, Cannel coal, here called Splint, or Parrot coal, and Coarse 

 coal, also called Splint. 



The texture of fine splint is compact, the cross fracture con- 

 choidal, and the fragments are cubical. Coarse coal is slaty in its 



* See a paper by Dr. Lucas Hodgson, on the Salt sublimed, in the Phil. Trans. No. 130. 



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