333 A Geognostical Sketch of [Nor. 



whether they He over or under the lowest Northumberland forma- 

 tion with which I am acquainted. I am likewise uncertain about 

 the north side of the Tees, near the sea, which I did not visit, and 

 therefore leave the formations about that place unfilled up in the 

 map, though I think it not unlikely that the magnesian lime-stone 

 extends as far as the Tees, and even crosses into Yorkshire. 



The counties of Durham and Northumberland form the northern- 

 most part of England, and constitute a kind of triangle, baring its 

 apex at Berwick-upon-Tweed, and its base upon the river Tees, 

 which separates Durham from Yorkshire. On the east it is bounded 

 by the sea ; on the north, by the river Tweed ; on the west, by 

 Scotland and the county of Cumberland ; and on the south, by 

 Yorkshire. Its greatest length, from north to south, is about 88 

 miles ; while its greatest breadth, from east to west, reckoning 

 from Crossfell (which, though in Cumberland, is a part of the 

 Northumberland and Durham formations,) to Hartlepool, is about 

 52 miles. The whole east side of these counties is low, and 

 tolerably level ; though here and there we meet with hills, espe- 

 cially in the neighbourhood of Sunderland, and towards the north. 

 But the height above the sea increases as we proceed westward till 

 we come to the top of Crossfell, which is one of the highest 

 mountains in England, being elevated about 2901 feet* above the 

 level of the sea : yet so gentle and gradual is the elevation on the 

 east side, that one may ride on horseback to its very summit. On 

 the west side it is much more precipitous, rising abruptly from the 

 vale of the Eden in Westmorland and Cumberland. 



The whole of this space, as far as my observations extend, is 

 occupied by three distinct formations ; one of which is very widely 

 distributed ; but the other two, as far as we know at present, are 

 peculiar to Northumberland and Durham. These three are the 

 Independent Coal Formation, the Newcastle Coal Formation, and 

 the Magnesian Lime-stone Formation. The first of these constitutes 

 the basis of the two counties. It terminates westward with Cross- 

 fell, in Cumberland ; seems to occupy the whole of Durham ; and 

 constitutes, I presume, the whole of that part of Northumberland 

 which lies on the east side of the Cheviots. I observed it in the 

 vale of Wooler, at Tweedmouth, and at Belford ; and I believe 

 that coals are found almost all the way between Belford and 

 Morpeth. It extends a little way to the north of the Tweed, but 

 disappears almost immediately, being covered in the neighbourhood 

 of Berwick, and on the north side of it, by the newest floetz trap 

 xocks ; nor does the same formation make its appearance again till 

 we approach the town of Tranent, in East Lothian. 



I. This Independent Coal Formation is composed of beds that lie 

 one above another, and extend over the whole counties. They dip 

 to the east, and crop out towards the west, till at last the lowest of 

 them makes its appearance at Crossfell, lying immediately over the 



* Tliis is the height given by Co!. Mudge. Preceding observers had made this 

 mountain as high as 3390 fVet. 





