﻿Vol. 6l.j OF THE NOETHTTMBERLAND AND DURHAM COALFIELD. 



81 



and hence the new streams that formed after that epoch agreed in 

 direction with the old. The chief difference is that, while the pre- 

 Glacial streams ran over the rock-surface, the present watercourses 

 flow in the same valleys over thick deposits of Boulder-C]ay and the 

 associated formations. Thus, the upper Wear and its tributaries 

 (the Beechburn, Bedburn, and Linburn) all flow over Boulder-Clay 

 in well-marked valleys of pre-Glacial development, and another 

 tributary waterway of the same age is now occupied by the 

 Gaunless. Below Bishop Auckland the trend of the old and new 

 valleys still continues to be very much the same as far as Durham. 

 At Page-Bank Colliery, near which the pre-Glacial course probably 

 passes, there is a thickness of 108 feet of superficial deposits, with 

 the rock-surface lying at an elevation of 150 feet. The old valley 

 then runs a little to the east of Sunderland Bridge, and afterwards 

 by Butterby Mill, where there is a thickness of 155 feet of surface- 

 deposits ; then, stretching through by Shincliffe and Old Durham, it 

 keeps on the east side of the city of Durham, and joins the valley 

 of the ' Wash ' already described. 



The following are the principal borings down the Wear, from 

 Bishop Auckland to Durham, and thence along the valley of the 

 ' Wash ' to Norwood New Pit : — 



1 



Locality. 



Altitude. 



Depth op 



superficial 



deposits. 



Height of rock- 

 surface ABOVE, 

 OR depth below, 

 sea-level. 



(1) Bishop Auckland 



(2) Page-Bank Colliery 



(3) Butterby Mill 



(4) Elvet Colliery 



(5) Newton Hall, Fram well gate... 



(6) Ford Cottage, west of Cocken 



Hall 



Feet. 

 300 

 258 

 270 



230 



40 

 41 

 110 

 50 

 50 

 25 



16 



Feet. 

 81 

 108 

 155 

 120 

 233 



90 

 134 



(?) 

 161 

 166 



158 

 156 



Feet. 

 4-219 

 + 150 

 4-115 

 O 1 



- 3 



- 50 



- 93 ^ 



- 55 " or more 

 -111 



-116 

 -133 

 -140 



I 



(7) Chester-le-Street 



(8) Brown's Buildings 



(9) Near Kibblesworih 



(10) Lamesley 



(11) Near High Team 



(12) Norwood New Pit 





1 The rock-surface lies slightly below sea-level at this point, as proved by 

 workings in Elvet Colliery. 



" J This boring was discontinued in the superficial deposits, after passing 

 through 165 feet of them. 



■ Between Bishop Auckland and Durham the pre-Glacial Wear 

 received several conduent streams, the principal of which came 

 U. J. G. IS. No. 241. a 



