560 Reports and Proceedings — 



Address to the Geological Section op the British Associa- 

 tion, BY Professor T. Eupert Jones, F.E.S., F.G.S., President 

 of the Section, Cardiff, August 19th, 1891. 



[Concluded from the November Number, p. 524.) 



Looking at these Coal-measures alone, and considering that slow de- 

 pression accompanied their formation, the mind is strained in estimating 

 the time required for the gradual subsidence to 10,000 feet, with shallow 

 water always in place, and jungle growing steadily after jungle, inundation 

 following inundation at intervals, — -and is somewhat confused in reasoning 

 on the possible causes and the exact processes by which not only the 

 sinking of this region of the earth's crust was brought about, but how, in 

 turn, the 10,000 feet of new accumulations and deposits were raised into 

 the great undulations, which Professor Ramsay has described and depicted 

 in his Memoir before mentioned, and how and when they were slowly worn 

 down day by day into the present beautifully varied surface of South 

 "Wales and adjacent country. 



I may here remark that the analogous coal-field of Nova Scotia, investi- 

 gated by Sir W. E. Logan, Sir J. W. Dawson, and others has a thickness 

 of 14,570 feet, including seventy-six seams of coal and ninety distinct 

 Stigmarian underclays. 



Mr. W. Galloway communicated, in 1885, to the Cardiff Naturalists' 

 Society ^ some valuable observations on both the vertical and the horizontal 

 occurrence of different coals in South Wales; and showed by a map (pi. iii.) 

 where the ' seam-coal ' mainly exists in the large eastern third ; the 

 ' intermediate coal ' in the narrow middle third ; and ' anthracite ' in the 

 loestern third of the Glamorgan-Monmouthshire area. He refers to the 

 gradual transition from bituminous to anthracitic coal along a hypothetical 

 plane passing through the coal-field, with its major axis lying E.N.E. — 

 W.S.W., and its minor axis dipping at a very low angle towards S.S.E. He 

 accepts Professor Geikie's tabular scheme of the strata at p. 21. Mr. W. 

 Galloway has favoured me with the following remarks on the vertical place 

 of the several kinds of coal in the series : — " The long-flaming bituminous 

 seams are about 700 yards higher in the ground than the semi-bituminous 

 seams ; the semi-bituminous, or good steam-coal seams are 200 or 300 

 yards above the dry steam-coal seams ; the last are perhaps 300 yards 

 above the bastard anthracites ; and these inferior anthracites may be 400 

 yards or more above the perfect anthracites. You have thus somewhere 

 about, say, 1500 or 1600 yards from the long-flaming coals to the 

 anthracites. It may be a good deal more in some parts of the coal-field ; 

 but, as the deepest shaft is only about 800 yards, we cannot get a direct 

 measurement." 



Of these three sorts of coal — the long-flaming dry coals above have some 

 seams suitable for gas-making ; the middle are caking coal, good for making 

 coke ; the others produce dry steam-coal and anthracites. 



6. Output of Coal in South Wales. — The following is the official account 

 of the quantity of coal raised in South Wales last year as compared with 

 that got ten years ago :— 



^ Trans, vol. xvii. 1886, pp. 20-34. 



