Mr. F. Forster's Observations on the South Welsh Coal Basin. 105 



by means of the Genwen Engine Pit, 800 yards to the westward. The 

 inclination of these two seams near the crop is upwards of 18|°, or 24 

 inches per fathom : they are underlaid at a considerable depth (proba- 

 bly from 90 to 100 fathoms) by the " Carnarvon or Boccas seams," 7 fath- 

 oms apart, the upper of which is 4 feet, and the lower 3 feet in thick- 

 ness. The pits by which these four seams were explored, have ceased 

 to work many years ago, and I could not therefore obtain any specimens 

 of the Coal for examination, but they bear the reputation of being ex- 

 cellent binding-Coal, and there can be no doubt that their proportion 

 of bitumen considerably exceeded that of the Gelle Gille seam. About 

 one mile to the eastward of the Carnarvon pits, and as nearly as can be 

 ascertained, in the water-level direction of the strata, is situated the 

 Llwchor Colliery. There appears every reason to suppose that the 

 upper seams of Coal there found, are the same as the Carnarvon seams, 

 and if so, the lowest seam at Llwchor Colliery must also be found under 

 the 3-feet seam at Carnarvon. The Engine pit at Llwchor intersects, 

 at the depth of 15 fathoms, a seam of 2| feet in thickness, at 25 fa- 

 thoms, another seam of 2^^ feet, and at 45 fathoms, a seam of 5| feet in 

 thickness ; the latter, which is of very good quality and texture {see 

 the table) is not known at Carnarvon CoUiery, but this may in all 

 probability be owing to the circumstance that the crop or outbreak be- 

 tween the two points traverses a part of the sandy bed of the river, and 

 for the remainder of the distance, across a thick alluvial deposit, form- 

 ing part of an extensive marsh, bounding its northern bank. The line 

 of section now crosses the river, at an angle of about 50° to the east- 

 ward of the full dip of the strata, a deviation which was necessary for the 

 purpose of reaching the opposite bank, at a station behind the outbreak 

 of the six seams of coal next in succession. The strata in this interval 

 are concealed by tlie sands forming the bed of the river, but an idea of 

 their position may be obtained by observing the course of the strata to 

 the south of the Llwchor Colliery, which, as has been before stated, is 

 about one mile to the eastward ; the seams of coal found in this col- 

 liery, rise to the southward at the rate of about 10 inches per fathom, 

 for upwards of half a mile, when they reach the summit of the hill on 



VOL. I. p 



