﻿80 BE. WOOLACOTT ON THE SUPERFICIAL DEPOSITS, ETC. [Eeb. I905, 



between Chester-le-Street and Kibblesworth along which the borings 

 do not conclusively prove this. At the former locality the rock- 

 surface lies at 93 feet, and near Kibblesworth at 111 feet, below 

 sea-level. Between these there is at Brown's Buildings a boring, 

 which was stopped in clay when a depth of 55 feet below sea-level 

 had been reached. The greatest thickness of superficial deposits 

 occurring in the ' Wash,' as ascertained by the borings, is 233 feet 

 at Newton Hall, Framwellgate (about 2 miles north of Durham), 

 but the depth may reach as much as 300 feet near that city. In 

 the paper just referred to, the course of the ' Wash ' appears to be 

 a straight line, this being due to the manner in which it is drawn, 

 as all the area, over which the depth of the deposits lying in it 

 exceeds 40 feet, has been coloured ; but the actual path of the 

 deepest part of the valley, or line along A^hich the pre-Glacial stream 

 flowed, may be a sinuous one. The number of borings is, however, 

 not sufficient to enable the course of the ancient river to be worked 

 out with any great exactness. 



The depth of the rock-surface and the field-evidence prove that at 

 its upper end the 'Wash' debouches into the valley of the pre-Glacial 

 Wear, and that it was the route taken by the drainage-waters of 

 the west of Durham County immediately before the Glacial Period. 

 It received a tributary stream from the east by Harraton, as it is 

 most probable that the watershed between the 'Wash' and 'Cleadon' 

 Valley (a tributary valley of the Tyne) had been lowered along the 

 line taken by the present river Wear, by two streams, one flowing 

 into the ' Wash,' and the other down the ' Cleadon ' Valley into the 

 Tyne. 



The deposits filling the ' Wash ' are, perhaps, the most varied of 

 all such deposits as have been studied in the district. Associated 

 with the blue stony Boulder-Clay are beds of sand and gravel lying 

 below, in, or upon it ; and leafy clay occurs at many parts near the 

 surface. The origin of these various formations has been already 

 fully discussed. 



The Wear flows along the southern end of this valley, often, 

 however, leaving the trend of it and cutting, down through the 

 superficial deposits into the rock; while the Team flows in a 

 northerly direction over the top of them, high above the level of the 

 rock-surface. The watershed between these two rivers is a very 

 low and indistinct one. 



The course of this valley and its connections with the pre-Glacial 

 Wear and Tyne can be clearly followed on the map (PL IX). 



(c) The Upper Wear and its Tributary Valleys. 



As in the case of the Tyne, the higher parts of the pre- and post- 

 Glacial Wear valleys and their tributaries correspond. Those 

 existing before the Glacial Period were partly filled with superficial 

 deposits, which reach a thickness of 110 feet at Escomb and 

 81 near Bishop Auckland ; but they were seldom entirely obliterated, 



