﻿Vol. 6 1.] OF THE NORTHUMBERLAND AND DURHAM COALFIELD. 77 



eastward. Thus, at Norwood New Pit, about a mile above Newcastle, 

 and at the confluence of the 'Wash' and the Tyne, solid rock is met 

 with at a depth of 140 feet below sea-level, and at Burdon Main, 

 8 miles lower down, it is 141 feet below ; while, in between, all 

 the borings prove it at a less depth, the maximum being 98 feet. 

 This may be accounted for by supposing that none of the sinkings 

 are in the deepest part of the pre-Glacial valley ; if, however, they 

 convey an accurate idea of the present real slope of the rock- 

 surface, we have here (if the conception of the pre-Glacial valleys 

 contained in this paper be correct) a definite proof of considerable 

 differential east-and-west movements during or since Glacial times. 

 The only way in which such an interesting point in the superficial 

 geology of the Northern Coalfield could be settled, would be by 

 making a line of borings across the Tyne Valley at some place 

 between Norwood New Pit and Burdon Main, and thus obtaining 

 the greatest depth of the rock-surface at some definite part. Until 

 such a series has been completed, the explanation of one of the 

 most interesting questions connected with the pre-Glacial valleys of 

 the great Northern Coalfield, and with the geological history of the 

 rivers of the North-East of England, must remain conjectural. 



It has been already stated that the raised beach cannot be traced 

 very far inland, and that therefore the elevation that took place 

 when it was produced may have been a differential one, being 

 accentuated along the coast (p. 72). If this be so, we may have here 

 the explanation of the non-deepening of the rock-surface of the Tyne 

 Valley as the sea is approached. 



The following are the principal borings down the Tyne, from 

 Ryton to its mouth : — 



Locality. 



Altitude. 



Depth op 



superficial 



deposits. 



Height of rock- 

 surface above, 

 or depth below 

 sea-level. 



Ryton 



Feet. 



32 



20 



20(?) 



16 

 

 



75 



60 



71 



50 

 100 



50 



Feet. 

 67 



Feet. 

 - 35 



Stella 



40 - 20 



Blaydon 



145 -125 2 



Norwood New Pit 



156 -140 



Elswick 



68 — 68 3 



Newcastle High Level 



Felling 



70 - 70 

 132 - 57 



Low Walker 



133 - 73 



Wallsend 1 



170 - 99 



Howdon Old Pit 



133 - 83 



Percy Main 



193 - 93 



Burdon Main 



191 







! 



1 The altitude of the G Pit at Wallsend is given as 172 feet in the ' Borings & 

 Sinkings,' but from the maps I suspected this to be wrong, and the manager, 

 Mr. Phillips, kindly took the level for me. It proves to be 71'02 feet. 



2 Two others give similar evidence, one of —109 and aonther —77. 



3 Many borings along the Tyne at Elswick afford corroborative evidence. 



