Mr. N. Wood on the Geology of Northumberland, S^c. 315 



which form the great deposit of those rocks in Berwickshire and the 

 vale of the Tweed ; and which, as before stated, have been mistaken 

 for the New Red Sandstone. 



This Red Sandstone, with occasional beds of Limestone, stretches 

 north and west into Scotland, where it joins and reposes against the 

 Grauwacke hills. — See Witham. Trans. Nat. Hist. Society, vol. i., p. 

 179. 



We see, therefore, that by extending the Section of the coast to the 

 Grauwacke hills of Scotland, we find exposed the whole series of the 

 medial order of Conybeare and Phillips, with these two peculiarities : 

 — 1. That several beds of workable Coal exist in, and below, the great 

 central deposit of Limestone ; and 2. That thick beds of Red Ferru- 

 ginous Sandstone, distinct in mineralogical character from the Old 

 Red Sandstone, occur below these great central beds of Limestone, 

 and underlying the Coal beds. 



Deferring for the present any further remarks on the position of these 

 rocks, I shall now endeavour to trace the basset of the various beds from 

 east to west, commencing at the same point as in Section, Plate XX VL, 

 or at the mouth of the Tyne, and stretching west to the New Red 

 Sandstone district of Carlisle. 



In all the Geological Maps which I have seen, the north-western 

 limits of tlie Coal Measures are laid down as follows ; viz. — From the 

 mouth of the Coquet to the north-west of Belsay, Stamfordham, Har- 

 low Hill, Newton, and Bywell ; the extreme western limit being Hed- 

 ley Fell. The regular Coal Measures do not, however, in the one case, 

 reach so far to the north-west as these localities ; the first Limestone 

 beds, near the bottom of the " Millstone Grit," cropping out to the 

 south of these places, whilst, on the contrary, I shall endeavour to 

 shew that to the west the lower beds of the Coal Measures stretch for 

 several miles beyond Hedley Fell. 



From the mouth of the Tyne, we find the Coal Measures dipping west 

 to Percy Main and Wallsend ; they then take a rise westward, until 

 the High Main Coal, which, at Wallsend, is above 100 fathoms from 

 the surface, crops out upon Newcastle Town Moor. Following the 



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