524 Reports and Proceedings — 



' Pennant Kocks.' The lower series is sometimes termed the ' iron-bearing 

 measures,' as it contains the bulk of the ironstone as well as coal, which 

 is bituminous on the east and gradually less and less bituminous westward, 

 until after passing the great dyke or fault in the Vale of Neath it becomes 

 anthracite. The upper series contains few iron-ores, and the coal is 

 bituminous, even when anthracite exists below it, as in the Swansea 

 district and elsewhere. 



In his communication to the British Association in 1837,' Sir W. E. 

 Logan stated that "the non-bituminous coal, or stone-coal, is found on 

 the north side and at the west end ; the bituminous coal on the south side 

 and east end ; and that there is an intermediate region occupied by an 

 intermediate quality." These conditions of the coal-seams indicated to 

 Logan " the possibility of a rule in the change of quality — namely, that 

 it occurs in parallel planes, cutting the seams of coal without regard to 

 their strike or inclination, and dipping to the south or east of south." 



These coals begin to became anthracitic at Rhymney ; and the change 

 becomes gradually more and more marked as we pass by Dowlais, Cyfartha, 

 Hirwain, Onlwyn, and Neath Valley, to the Swansea Valley,- according to 

 analysis given by Mr. David Mushet in the Appendix to his " Papers on 

 Iron and Steel," 8vo. London, 1840. At page 68 of this book Mr. Mushet 

 notes that " in South Wales as the coals approach the anthracite district 

 they are found to contain 90 per cent, (of carbon), with no more flame 

 than is necessary to convert the coal into coke." 



Mr. Etheridge (1885) accepts (p. 238) Professor Phillips's foregoing table ; 

 but he also arranges the coal-bearing portions as divisible into — 1. Upper 

 Pennant series ; 2. Lower Pennant series ; 3. White-ash series ; and gives 

 the following plan in addition : — 



1. Upper or PenUergare series, more than 3400 feet, 



2. Pennant-grit (Swansea) 3246 ,, 



3. Lower Coal-measures 450 to 850 ,, 



At p. 219 he reviews the whole of the series as — 



Coal-measures 11,000 feet. 



Millstone-grit ('Farewell Rock') 300 ,, 



Yoredale Rocks (' Gower Shale ') 1,600?,, 



Scar Limestone 1,9U0 „ 



Lower Limestone Shales 400 ,, 



15,200 



making the Coal-measures more than 1| mile thick, and the whole series 

 more than 2| miles. 



{To be continued in our next Number.) 



11. — Eeport of the Committee, consisting of Dr. John Evans 

 (Chairman), Mr. B. Harrison (Secretary), and Professors J. 

 Prestwich and H. Gr. Seeley, appointed to carry on excavations 

 at Oldbury Hill, near Ightham, in order to ascertain the existence 

 or otherwise of Eock-shelters at this spot. Drawn up by Mr. 

 B. Harrison. 



OWING to hindrances, the work could not be begun until August, 

 1890. The first excavation, immediately below the exposed 

 rocks, was unproductive in a great measure. This was owing to 

 huge trees being close by, the roots of which, forming a perfect 

 network, offered serious obstacles, as, though permission had been 



1 " Report," 1838, Trans. Sec. p. 85. 



» Bevau, " Geologist," vol. ii. 1859, pp. 78, 79. 



