176 Proceedings of the JFernerian Society, 



Mr Robert Bald, mining engineer, then read a paper regarding 

 the edge coals, near Edinburgh. In particular, he noticed the 

 position and great aggregate thickness of these coals in the lands 

 of Duddingstone and Brunstain, the property of the Marquis of 

 Abercorn. The coals in this property, bounded by the sea on the 

 east, lie at an angle of about 65° with the horizon, dipping to the 

 south. They consist of two distinct groups, viz., the Dudding- 

 stone group on the north, and the Brunstain group on the south. 

 The North Green coal, which reaches within a few hundred yards 

 of the town of Portobello, is the most northerly, and lies within 

 a few fathoms of the mountain limestone. It yields the chief 

 supply of parrot or pitch coal for the gas-works. The limestone 

 encircles the whole of the great coal basin of the district, and is 

 held as a sure index for the finding of the coals in the basin. The 

 most southerly coal of the two groups is that named Greymechan, 

 which reaches within a few yards of the flat coals in the valley 

 of the Esk. The edge coals pass under the flat coals, and again 

 rise along the elevated ground in the Dalkeith district, dipping 

 to the north at an angle of from 13° to 18°. These are termed 

 half-edge coals. The Duddingstone coal seams are twenty in 

 number, and their aggregate thickness is sixty-eight feet. Those 

 of Brunstain are six in number, and their aggregate thickness 

 fifty-two feet. Hence these two groups of coal constitute together 

 120 feet thick of coal. Mr Bald mentioned, that the most strik- 

 ing geological feature of this coal-field, including the two groups, 

 is this : — That the distance from the seven-feet coal in Brunstain, 

 to the south parrot-coal in Duddingstone, is no less than 622 yards ; 

 that in this vast space there are only two thin beds of coal found, 

 the one being merely two feet, and the other two feet seven inches 

 thick. The author then shewed, that in each square yard of surface, 

 measured parallel with the dip of the coals, and taking into ac- 

 count the aggregate thickness of the coals, there exist no less than 

 thirty-six tons of coals ; and that, therefore, less than two impe- 

 rial acres would yield above 300,000 tons, equal to the whole an- 

 nual consumption of Edinburgh, Leith, and the surrounding towns 

 and villages. Upon these rich coals, collieries had been established 

 centuries ago. About forty years ago, they were drained by power- 

 ful atmosphere steam-engines ; but these being overpowered with 

 water, were abandoned, and no coal has been wrought there for 

 many years past. Now, however, the coal-fields have been let to 

 a capitalist in London, who is much engaged in mines ; and there 

 is no doubt that the workings will forthwith be revived with vigour 

 ^r\^ efficiency^ 



