Notice on the Gravel Bed of St. Lawrence Colliery. 285 



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 some- 

 times on the Coal head, and sometimes in the roof above it. As this Gra- 

 vel gave out a considerable quantity of water, and as the workings were 

 approaching the River Tyne, they were, from a measure of prudence, dis- 

 continued. 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 Sand- 

 bed ; an attempt had been made to drift through it when I got the manage- 

 ment 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 



VOL. II. 3 L 



