The river Dearness rises near Tow Law, some 10 miles west-southwest from the city of Durham, and flows for 10 miles in an easterly direction, to its junction with the river Browney near Langley Bridge. It has a total fall of about 700 feet, or from 900 feet to 200 feet above sea-level, and a mean width of about 12 feet. In its course it is fed by several small streams, which also form "washes" on a smaller scale, for a short distance up the side of the valley. After its confluence with the river Browney, at a further distance of 3½ miles, occurs the confluence of the river Browney with the river Wear near Croxdale. The "wash" described in these notes may therefore be regarded as a tributary of the larger or principal wash of the Team valley.

The Dearness valley is well-developed laterally, being enclosed by well rounded hills rising to a height of 400 feet above the present level of the river at its lower reaches, and having a width between the summits of about 2 miles.

Geologically, the valley is situated in the Upper Coal-measures, with the exception of the recent deposits of clay, sand, etc. The coal-seams, which are continuous throughout, have a total rise of 1,100 feet, which is in excess of the surface-rise by 400 feet. The proved workable coal seams in the strata at the termination of the valley, from the top of the series, are :— The Hutton, Harvey, Busty and Brockwell. The Hutton and Harvey seams outcrop naturally, apart from glacial action, in their order up the valley.

A deposit of Boulder Clay, near the surface, is present all along he valley. It rests on the Coal-measures, and is overlain by thin beds of sand and gravel. It is an irregular, unstratified and very compact deposit, having a maximum thickness in the lowest parts of the valley and thinning out towards the summits of the hills.

Proceeding in the direction of the valley, the base of this deposit. is seen to be of an undulating character, and consequently variable in thickness. It thus lies in depressions, the river flowing generally over the top of this deposit, but at some places where the deposit is absent in the bed of the valley, the river has cut its way down several feet into the solid rocks. Between the confluence of the Dearness and the Browney rivers and the junction of the Browney with the Wear near Croxdale, the bed of the original valley rises 80 feet.

Just before reaching the "wash-out," the coal-seams become softer and of a red colour in the cleavages. The burning qualities are also reduced, the deterioration becoming more pronounced as the wash-out is reached. Approaching the wash-out, the seam first thins out and afterwards detached streaks of coal occur at intervals; and the underclay or seggar is also softer. At the sides, the edge of the deposit lies against almost vertical cliffs near the bottom. The maximum thickness is about 100 feet.

The clay is of a dark blue colour, very stiff at the bottom and in the centre, and becoming softer at the sides near the top. In some places it is dry, and strong enough to stand for a considerable time without timber and in other places it is wet and apt to swell where sandy partings are present. The boulders are thoroughly embedded in every variety of position in the clay, and are more rounded, smaller and more striated near the bottom, the shales especially being smooth and finely striated. The direction of the striae is found generally to be in a line with the longitudinal direction of the stone, but no arrangement is observed with regard to the stones themselves and their position in the clay. The proportion of boulders to clay is about equal in the upper part of the clay, and less frequent in the lower parts.

Many of the boulders are found to be of material not belonging to the locality, such as calcspar, blue limestone, and ironstone ; the remainder being principally shale and sandstone. The writer has not found any fossiliferous remains in this deposit. Resting on the top of the clay is a bed of sand, gravel and large boulders, with pieces of decayed wood, and it is full of water. Beds of sand and boulders with water intercalated in the clay are present in some parts of this deposit.

The period during which the faulting occurred in the coal-seams appears to have been antecedent to this deposit, as no trace of them has been found in the clay. The effect of this Glacial Drift, primarily, in cutting out large areas of workable seams, and secondarily in subjecting the adjacent areas of coal to deteriorating atmospheric agencies is considerable. To what extent separately, the effect of glacial action and that arising from other natural agencies, is a matter of conjecture. A considerable thickness of strata with the enclosed coal-seams must have been scooped out of the valley by ice. An additional effect has been the subjection of the lower seams to the deteriorating action of atmospheric agencies by removing part of the natural cover.

The coal-seams under this deposit, which are situated less than 100 feet from the surface, are found generally to be deteriorated, though the same seam will resume its normal quality where the thickness of older rock-cover increases, found by following the contour-lines to the rise and by approximating — if the information is not at hand from the lower seams — the levels of the strata, and also by an examination of the surface to discover whether the Boulder Clay exists there or not. Thus, a coal-seam considered useless in the lower parts of the valley may exist in good condition in small areas higher ap. This reasoning is complicated somewhat by the fact that the Glacial deposit lies in hollows for where the Drift is developed, the bottom of the deposit (for all practical purposes) may be considered the surface, — such it would be during the Glacial period — and, consequently, the upper coal-seams would be deteriorated in quality.

The drainage-level also must be taken into consideration. The average inclination of the seams up the valley is 1 in 48, and being considerably in excess of the surface-rise, brings the top-seams successively above the drainage-level. Water would consequently percolate through the joints of the coal, reducing the quality by removing the enclosed gases, and leaving behind sand- and dirt-partings of a red colour. Thus in the same seam approaching this deposit the coal is deteriorated on each side of the wash-out to a greater width higher up the valley, where the coal has remained above the river-level, than lower down the valley, where the seam would be above the drainage-level during the Glacial period only. This process would he assisted by the gullety nature of the upper strata, which would form both water channels and outlets for gas from the coal. To some extent to the action of alternating extreme colds during the Glacial period may be attributable the broken-up character of the strata surrounding the deposit.

Mr. A. L. Steavenson (Durham) said that about 35 years ago they had a paper on the Team valley wash by the late Mr. E. F. Boyd and Mr. Nicholas Wood. This paper gave a very excellent account of the Team valley wash, and was illustrated with sections. A similar wash extended into Weardale, where they were cutting it with a steam navvy, when baring the limestone.

Mr. Philip Kirkup (Cornsay) said that he did not quite understand the statement as to the total rise of the strata being 1,100 feet. On a line between Stanley pit and Hedley Hill colliery, the Brockwell coal seam outcrops at about 50 feet above the bed of the stream, on the south side of the valley. The base of the "wash" at this point is approximately 100 feet below the bed of the river Dearness, so that the ancient river or glacier had really scooped out rocks below the Coal-measures, in fact 150 feet into the Ganister series. All the coal-seams deteriorated in quality as the "wash" approached them. The red colour in the cleavages was caused by oxide of iron. He would like Mr. Elwen to produce some of the striated stones which he believed must be more common in the lower portion of the valley than in the upper. He had found boulders of basalt, greenstone, sandstone and blue limestone in the clay.

Mr. T. L. Elwen said that he arrived at the rise of strata as 1,100 feet by taking the depth of the Brockwell seam, 600 feet in the lower reaches of the river, and adding to this the natural rise at the surface, 500 feet, obtained from the Ordnance survey-maps, he obtained a total rise of 1,100 feet. He would exhibit some of the striated stones at the next meeting.

The President moved a vote of thanks to Mr. Elwen for his paper.

Mr. P. Kirkup seconded the resolution, which was cordially approved.