1S14.] Northumberland, Durham, &c. 415 



post ; for it is curious that the name of all the rocks in the coal and 

 lead mining districts are quite different from each other. The 

 colliers and lead miners have little communication with each other. 

 Their mode of working is quite different, so that they cannot supply- 

 each others' places. The colliers appear to my eye to be a stouter 

 and healthier race of men than the lead miners. There are about 

 25 beds of sand-stone in the Newcastle Coal Formation, some of 

 them of considerable thickness, but the greater number thin. The 

 stone is usually fine-grained. It is soft, and not very durable when 

 used as a building stone. Its colour is most commonly grey, with 

 a shade of yellow ; but its appearance must be familiar to every 

 person who has visited Newcastle, as many houses in that town are 

 built ot it. There is a free-stone bed in the hill to the south of 

 Newcastle, called Gateshead Fell, which makes excellent grind- 

 stones. Accordingly almost all the grind-stones used in Great 

 Britain, and indeed on the Continent also, are made here. 



:5. The slate-clay in this formation is called metal-stone, and is 

 usually distinguished by prefixing the name of its colour. Thus 

 some beds of it are called Hue metal-stove, others grey metal-stone. 

 When very much indurated it is called ir/iin ; for 1 did not find this 

 name applied to sand-stone by the Newcastle colliers ; probably 

 because their sand-stone is always soft. The number of slate-clay 

 beds is about 32 ; and they are usually thinner than the sand-stone 

 beds with which they alternate. Both the sand-stone and slate-clay 

 form the roof and floor of coal-beds, but the latter much more 

 frequently than the former. I have observed both in immediate 

 contact with the coal, without the smallest sensible alteration in the 

 properties of this combustible substance. 



4. The number of vein*, or dykes, as they are called, traversing 

 this formation is very considerable. They seem to run in all direc- 

 tions. The most celebrated of them all is called the Great Dvke, 

 not in consequence of its size, which is very inconsiderable, but 

 because the beds on the north side of it are thrown down 90 

 fathoms. Its direction is N. N. E. and S. S. W. It enters the 

 sea a little to the south of Hartley, or about three miles north of 

 Shields ; and, running westwards, crosses the Tyne at Lemingtnrt, 

 nearly opposite to Blavdon, about fuur miles west from Newcastle 

 Bridge. It continues in the same direction as far as it has been 

 traced. This vein is only a few inches thick, and it is filled with 

 soft clay and slate-clay. 



There is another very considerable dyke, which appears first at 

 the sea side at North Shields, and, running in nearly a due west 

 direction upon the north --ide of the Tyi < , passes through Chapel 

 Hill, a little to the north of Newburn-on-the-Tyne. It has been 

 traced still farther west in the same direction. Tins vein is filled 

 with sand-stone, which 1 consider as a very curious circumstance. 

 1 am not sure that any similar vein has ever before be n observed in 

 a coal-field. It occasions no shift in the position of the beds, and 



on that account has acquired but little celebrity among the colliers ■ 

 but mineralogists, I flatter myself, will do it more justice. 



