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



ham " red rock" (g), and the " Ackworth rock " (c) as entering 

 Derbyshire, west of Pebley Lane ; believing that these rocks in 

 proceeding southward pass under the edge of the Pontefract 

 rock and disappear before they quit Yorkshire. 



The thirteenth grit rock of the Derbyshire series, on which 

 Killamarsh church stands, seemed proved, as well by its basset 

 edge as by the ironstone rakes worked on both sides of it, to 

 range northward by Belk Lane, east of Wales Wood, west of 

 Swallownest colliery, by Park Hill and Folken (and having 

 crossed the Rother), by Orgrave, east of Highhazles colliery, 

 through the western part of Tinsley village (and having crossed 

 the Don), east of Massborough, &c. 



On the west and south-west of the village of Kippax, Mr. 

 Smith has omitted to notice a point of the Pontefract rock, which 

 spreads out beyond the village of Great Preston, and has upon it 

 two detached hummocks of yellow limestone, which last he has 

 placed too far north. From Berwick in-elmet, the Pontefract 

 rock has been coloured 1-i mile too far down the Aberford Vale. 

 At the same time that this remarkable unconformable projection, 

 wants extending 1-i- mile further west, so as to surround and 

 underlie four detached hummocks of the yellow limestone, 

 which, most unfortunately, my friend has wholly omitted to 

 notice ; because, I think, the sandy rock supporting these four 

 hummocks, and resting upon the edges of five of the gritstone 

 rocks, and six of the coal shales of my Derbyshire series, pre- 

 sents, when taken in connection with the facts of the Garforth 

 colliery, and the " shell ironstone " rake (in my ninth coal 

 shale, Derb. Rep. i. 217 and 414), near at hand, the com- 

 pletest case of the unconformableness of the Pontefract rock, and 

 those above it in the new series, which can any where be found 

 in the same space. 



The largest and most western of these limestone hummocks 

 lies on the north of Seacroft village, and east of Rounday Farm, 

 which last gives name to the large old shallow quarries worked 

 in this hummock, which is a very flat one, containing apparently 

 only the lower yellow beds (below the " blue beds " mentioned 

 in Derb. Rep. i. 157 and 408, and ii. 409), covered in great part 

 by an alluvial clay patch, which stretches thence north-east for 

 1-]- mile. 



The second of these hummocks is around Barnbow houses ; 

 Berwick town stands on the next, which hummock is about a 

 mile long north-east and south-west, and half as wide ; and the 

 last and smallest of these hummocks lies north of the last, and 

 north and west of the Brooks, meeting on the north of Berwick: 

 it is in part covered by alluvial clay. 



The next projection of the Pontefract rock which has been 

 omitted, extends west-south-west from the continuous edge of 

 the limestone, and incloses the conspicuous limestone hummock 

 of Elstoft, where there are quarries ; and which limestone is 



