276 Mr. Farey on the Pontefract Sandstone Rock. [April, 



east course is resumed by its basset, passing south of Hedingly 

 village, and north of Woodhouse village, where there are large 

 flagstone quarries in it ; and about half a mile north-west from 

 these, on Hedingly Common, fire-clay and ganister are dug in 

 the third coal shale, and coarse third grit, north of this, near 

 Mean Wood (see Phil. Mag. vol. xxxix. p. 102). 



From the Woodhouse quarries, this fourth rock passes on the 

 south of Potter Newton and Chapel Allerton, north of Allerton 

 Gledhow, past Rounday flagstone quarries, north of Redhall 

 Houses, by Berkby Farm, past Thorner flagstone quarries ; and 

 soon after, this rock, with an easy dip about south-east, disap- 

 pears* under the edge of the unconformable Pontefract rock, 

 on the south of Thorner village. 



The northern edge of the third grit rock, from the excellent 

 and well-known quarries at Bramley Fall, by the Leeds and 

 Liverpool Canal, declines obliquely, and crosses the Air River, 

 about a mile above Kirkstal Bridge : thence its course is up 

 Hascar Wood, and proceeds thence mostly with a very bold and 

 decided northern edge, until, on the south side of Bardsey vil- 

 lage, this rock also disappears under the Pontefract rock, in the 

 same place and manner, as Mr. Smith has mistakenly shown, 

 with regard to the lower or northern edge of the rock (i), which 

 he calls the " Bradgate rock ; " but why it is so named I do not 

 know. 



The existence of ganister (galliard, or crowstone), and the 

 prevalence of clays adapted to the uses of the potter (like those 

 of Newton, anciently), and the makers of furnace bricks, lying 

 as floors to their coal seams, has been ascertained at short dis- 

 tances, throughout the course between the third and fourth grit 

 rocks, indicated above, as regularly here as in Derbyshire (almost 

 to the neighbourhood of its county town), wherein, these import- 

 ant features of the coal series were first ascertained, and such 

 details published in its county report, as can leave no kind of 

 doubt on the subject. 



In the manner above described, the strata northward, continue 

 to have a south-eastern dip (which would have been a south- 

 south-west dip, but for the deepening of the trough line in each 

 stratum, to the east-south-east, or nearly) into the great trough 

 of coal-measures herein described; in consequence of which, 

 my second grit rock approaches and passes under the Pontefract 



* There can be little reason for doubt, that after the basset edge of this fourth rock 

 has passed some distance under the yellow limestone, it turns northward, and has an 

 uninterrupted course under its unconformable cover, into Durham, a;;d that there, some- 

 where near to Morton, liolam, or Brusselton, this important rock emerges again from 

 under the Pontefract rock, and has doubtless a long course across that county and Nor- 

 thumberland, which course I could ascertain and depict as certainly, I think, as several 

 years ago I did, as to 94 miles of its course across Derbyshire and Yorkshire (see Phil. 

 Mag. vol. lxxxix. p. 102), and as to a great many miles of its course in Flintshire (see 

 Phil. Mag. vol. xlv. p. 1 66). Why has this matter slept, and no one attempted to map 

 the gritstone rocks of the Wear and the Tyne coal-field ? 



