﻿Vol. 6l.] OF THE NORTHUMBERLAND AND DU EH AM COALFIELD. 79 



The borings are : — 







Super- 



| 





Super- 





Altitude. 



ficial 

 deposits. 



j 



Altitude. 



ficial 

 deposits. 





Feet. 



Feet. 





Feet. 



Feet. 



(a) Moorhouses ... 



230 



6 



(h) Low Chirton . . . 



102 



191 



(b) Billy Mill 



215 



15 



(i) Chirton (3) ... 



60 



111 



(c) Cbirton Hill ... 



201 



5 



(j) Chirton (4) ... 



62 



119 



(d) Chirton (1) ... 



160 



42 



(k) Burdon Main... 



50 



191 



(e) Chirton (2) ... 



153 



64 



1 (I) St. Hilda's 



30 



53 



(/) Chance Pit ... 



130 



60 



\(m) St. Hilda's, 







(q) Hopewell Pit... 



100 



60 



South Shields. 



40 



35 



Although throughout the greater part of its course the post- 

 Glacial Tyne flows at a higher level above the rock than the 

 pre-Glacial river, there being a considerable thickness of superficial 

 deposits between the present river and the rock-surface, yet the 

 general trend of the two valleys is the same, the one being super- 

 imposed on the other. Especially is this so in the higher reaches, 

 where the courses of the two waterways are almost identical ; but 

 in its lower parts, east of Newcastle, the rock is cut into at 

 many places, as, for instance, at Felling Shore, Bill Quay, and 

 St. Anthony's, and therefore the agreement between the old and the 

 new valleys is not so pronounced, the course of the present river 

 differing considerably from that of the former river in this region. 



Tributary streams entered the pre-Glacial Tyne on the south side 

 from the Allen, Devil's Water, Stanley Burn, Derwent and Cleadon 

 valleys, and the Wear flowed into it down the ' Wash' ; while from 

 the north it received the North Tyne, and a smaller stream through 

 Newcastle, a little to the west of the Ouseburn. 



(b) The < Wash.' 



The course, depth, and characteristics of this valley were thoroughly 

 worked out by Nicholas Wood & E. E. Boyd in 1864 (1), and, 

 although the genesis of such a valley was not clearly understood at 

 that time, yet the description of it is so excellent as to require 

 little further addition in this paper. Those writers showed that 

 the ' Wash ' extends from near Durham to the Tyne, and is filled 

 throughout with a great thickness of Boulder-Clay and beds of 

 sand and gravel. It is entirely carved out of the Coal-Measures, 

 through the Hutton and other seams, and the workings in the 

 various collieries along its sides have often been stopped by the coal 

 abutting against the superficial deposits along this valley. At 

 Durham the rock-surface, as proved by colliery-workings at Elvet 

 a little to the south, lies a few feet beneath sea-level, and the 

 maximum depth of 140 feet is found at Norwood New Pit, near the 

 junction of the ' Wash ' and the Tyne. As shown by Wood & Boyd, 

 its slope may be uniformly northward, but there is one part lying 



