No. XIII.—Notice on the Gravel Bed of St. Lawrence Colliery. By Mr. Matthias Dunn.
Read November 30, 1834.
Whilst Geology is making such rapid strides, and is met by so laudable a readiness to communicate facts, whereby to elucidate theory and to enable human reason to dive into the hidden mysteries of past ages, it has occurred to me to submit to the examination of the Society, a short description of a peculiar formation of Sand and Gravel, which spreads over a part of the collieries of Saint Lawrence and Gateshead Park, in this neighbourhood.
In prosecuting the workings of the latter colliery in the High Main Coal about the year 1790, the roof of the workings suddenly altered from a firm and united Sandstone to a mixture of Gravel, which floated sometimes on the Coal head, and sometimes in the roof above it. As this Gravel gave out a considerable quantity of water, and as the workings were approaching the River Tyne, they were, from a measure of prudence, discontinued. The accompanying Plan, Plate XIV., shews the extent of the Gravel in that direction, but it does not at all seem to have infringed upon the thickness of the coal.
In the year 1831, the Saint Lawrence Colliery, on the north side of the River Tyne, was re-opened; and in pursuing the old workings, at the depth of about 28 fathoms from the surface, it was discovered that they had also been originally stopped by the intervention of the same Gravel and Sandbed; an attempt had been made to drift through it when I got the management of the Colliery in May, 1832, but had failed, owing to the weakness of the timber.
As we considered this an important point to perforate, we re-commenced the drift by repairing all the timber and strengthening it, as described by the
