296 Edward Merrick— The River Tyne Drainage Area. 



TABLE II. 



j?®? I feet lower than the hills 

 <m I on *^ e "S^t bank. 

 582J 



Tynemouth 

 Byker Hill 

 Westerhope 

 Heddon Laws 

 Kip Hill . 



The second table clearly brings out the steady increase of difference 

 in surface levels on walking westwards, which is quite evident, as 

 both watersheds are near together. However, on nearing and passing 

 Hexham, it is not so easy to make a table as above, because the chief 

 eminences of the watersheds are widely separated. The southern 

 watershed of the River South Tyne is very much higher than the 

 watershed between the North and South Tyne, by about 1,000 feet ; 

 a still greater difference in levels than at Kip Hill. Between these 

 two watersheds lies a wide synclinal hollow, the main valley of the 

 Tyne. Bearing this difference of levels in mind, the thought arises 

 that it may have been caused by a fault running from east to west, 

 with its downthrow on the north, the magnitude of the downthrow also 

 increasing from east to west. 



Consider now what the effects of such faulting of the junction- 

 plane would be besides producing this difference in levels. (See 

 Fig. 1.) 



\ 

 N. 



a b c 



Fig. 1. — Alteration produced in the course of parallel contour-lines by faulting 

 at right angles to them, a, Original state, b, Position of Fault [Stublick 

 Dyke], c, Position of watershed to the induced tributaries [i.e. position 

 of the Corbridge Fold and the North Tyne]. 



1 . Far to the north of this fault the contour-lines would still run 

 in their original direction, parallel with the coastline of that period, 

 but on coming southwards they would sweep round towards the west, 

 ultimately becoming parallel with the fault. (Fig. lc.) 



2. The alteration in the direction of the contour-lines and slope of 

 the country would be accompanied by a change in the river drainage 

 on the north of the fault, for tributaries would come from the north 

 and north-west, increasing in length where the throw of the fault was 

 greater. 



3. A watershed running in a general north-westerly direction from 

 the fault would be produced to the north-east of these induced 

 tributaries. (Fig. lc.) 



4. Faulting to such an extent as this could not take place without 

 affecting the lie of the solid rocks. 



