384 
THE GEOLOGIST. 
A Wash oe Drift theough the Coalfields of Dueham. By 
Messrs. N. Wood and E. F. Boyd. — Tlie course of an ancient river, to 
wliicli tlie paper related, differed from the courses of the Tyne and of the 
Wear. It passed almost in a direct line from Durham to the river Tyne 
at Newcastle. It was 93 feet below the present level of the* Wear, and 
140 feet below the level of the foundations of the High Level Bridge, 
which were 30 feet below the bottom of the river. Having, in the prose- 
cution of their professional duties, had many opportunities of collecting 
information of the particulars of the thicknesses of the covering of gravel, 
sand, and clay spread over the surface of the coalfield of Durham more parti- 
cularly, in various situations and under different circumstances, and having 
had frequent opportunities of observing the effect of the abrasion of the 
mineral strata of the districts, and especially of a particular wash or drift 
in the coalfield of Durham which has denuded a considerable portion of 
the coal-measures, the authors laid before the Association the results of 
their experience. Premising that such a wash or drift can be traced 
through the coalfield from the vicinity of the city of Durham to the 
river Tyne at Newcastle, traversing a portion of the valley of the Wear, 
passing Chester-le-Street, and following the valley of the river Team, and 
terminating at the river Tyne, their communication consisted of a plan 
of the district in question, and a series of sections showing the line of the 
wash and the depth to which it extends, with various other particulars. 
An examination of the different cross sections, particularly those nearest 
to the river Tyne, will encourage the idea that the deepest portion of the 
denudation was by the eastern side, and that the edges of the strata 
nearest to that side are more upright and abrupt. JN'o trace of shells 
whatever has been found in any part of its course, nor of bones or animal 
remains. The pieces of shale which were observed entire and resting on 
edge against the eastern side, as if recently broken from their stratified 
bed, contained on examination the usual ferns and plants of the Carboni- 
ferous series ; all the stones and pebbles in having their edges entirely re- 
moved and rendered smooth, particularly those of harder character, bore 
evidence of long exposure to the abrading infiuence of water in motion, 
and whenever the bottom on which the diluvium rests was exposed, there 
are unmistakable evidences that the water which carried the debris was in 
motion and of great j)ower. At the sinking of the Ouston pit, the first solid 
strata met with after sinking through the 23| fathoms of cla}^ and sand 
was a strong freestone, the upper surface of which was furrowed with rough 
and scored outlines and polished, as may be noticed in the exposed bed of 
a mountain-torrent passing over a strong rock. The edges of the coal- 
seams adjoining the denudation, as the Hutton seam by Harbour House 
and Frankland, and the main coal-seam at Urpeth, were worn and rounded 
off in some instances where the upper portion of the seam having been 
tender had given way to the abrading action, whilst portions of that 
nearer the floor remained,* the intervening parts being filled up with clay 
and boulders and broken pieces of coal. The contemplation of this re- 
markable deposit suggests to the authors considerations of the following 
character: — 1. The extent and cause of opposition which the dislodged 
waters of the ocean met with in their progress to their ultimate sea-level. 
If the magnesian limestone hills of Boldon, Pensher, Houghton, Pitting- 
ton, and Quarrington (superimposed over the coal-measures), formed as 
decided a barrier as they now present. 2. The quantity of debris with 
which they were charged, and the opportunity thus afibrded them of de- 
positing these by the action of gravitation, exercised during the above op- 
position met with, until the silting process was completed up to the level 
