1823.] M)\ Farei/ on the Pontefract Sandstone Rock. 273 



in Yorkshire, that near to the edge of the yellow limestone, 

 about south-east from Wakefield, the highest visible rock or 

 stratum of all the great coal-field of Yorkshire, Derbyshire, and 

 Nottinghamshire, might be found, and ought to be carefully 

 sought for and ascertained; but which interesting service to 

 science has not yet been performed I believe. 



The late Mr. Edward Martin, whose excellent brief account 

 of the. South Wales coal-field is printed in the Philosophical 

 Transactions for 1806, has described its highest valuable seam 

 of coal to be found, only in a local patch or hummock, between 

 Neath and Llanelly, but has not mentioned the place ; nor has 

 he traced the bottom line of the trough, which he merely says, 

 " may be drawn in an east and west direction through the middle 

 of the basin." In May, 1806, Mr. Martin favoured me, by trac- 

 ing the trough-line on my large map of England and Wales, by 

 Gary, from which I beg here to record its range. Commencing 

 westward, it enters the southern part of Kidwelly Marsh, passes 

 Penbre, Llanelly, Courty Carney, north of Pentalassa, by Cadox- 

 ton, Glyn-Carwg, Llandevodwy, Tonna-yodwr, Eglwysilan, 

 Energh, Bedwas, Mynyddyslwyn, and thence curves up the 

 Ebwith Valley to near Lanhiddel, and there ends, according to 

 Mr. M. the dips of the measures from the north-west, north, 

 north-east, and east, centering there, as the end of the deep 

 line of Trough. 



On comparing Mr. Smith's planning of the Pontefract rock 

 with the interrupted and detached observations which I have had 

 opportunities of making in Yorkshire, I beg to point out (truth 

 being my object on all occasions) th° following errors, which 

 have been committed in the Yorkshire map, beginning south. 

 The north part of the village of Todwick, which probably stands 

 on the Pontefract rock, has been represented as standing on a 

 hummock of the limestone, but whose edge does not proceed so 

 far westward by near a mile, 1 believe ; and the limestone is 

 here mistakenly represented as detached by the Pontefract rock 

 appearing round it on the east; but the large quarry of limestone 

 (for export by the Chesterfield Canal, see Derb. Rep. i. 411 and 

 434, and iii. 318), called Pecks Mill, or Dog-kennel; and 

 another quarry in South Anston town, east of the church (i. 411), 

 clearly prove this to be an error. 



My unfortunate ignorance of the unconformable character of 

 the Pontefract rock, when surveying this border of Derbyshire 

 in 1809, prevented my considering, as now I think probably 

 may be the fact, that from near South Anston town to the town 

 of Rotherham (see Derb. Rep. i. 169), this same rock uncon- 

 formably stretches out upon the coal-measures, having its west- 

 ern edge in Todwick, Conduit Hill, Aston, Aughton, Treton, 

 Catline, Brinkworth, and Eccleshall, and extends near a mile 

 north-west from Rotherham, along the Doncaster road ; and I 

 consider my friend Smith as wrong, in representing the Rother- 



New Series, vol. v. T 



