1850.] 



DAVIS ON THE NASH LIMESTONE. 



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tliis, as of every other similar 

 position and structure may be 



out towards the west. Its former 

 course towards Gorton may be traced 

 by the old workings on the south side 

 of * Folly Bank.' The shale also thins 

 out towards the west, but in this di- 

 rection the order of succession is dis- 

 turbed by a fault which has let down 

 an outlier of old red sandstone ex- 

 tending from *The Slough' over the 

 ' Deepmoors' to 'Radnor Wood.' Pro- 

 ceeding, however, from the Sandbanks 

 in a north-easterly direction across the 

 valley of the Lug to Stapleton Hill, 

 a section may be obtained free from 

 this fault, the line of which appears to 

 be from above Brook House at Staple- 

 ton, south-west, to Presteign, Slough, 

 and Radnor Wood, cutting oif the 

 Upper Ludlow and outliers of old red 

 sandstone on its north-west, from the 

 shale and Lower Ludlow on its south- 

 east side. As from the intervention 

 of the Knill valley on the south, so 

 from that of Presteign drained by the 

 Lug on the north, the precise thick- 

 ness of shale and Lower Ludlow can- 

 not be accurately determined. The 

 shale has been washed away to within 

 about fifty or sixty feet of the grit by 

 the denudation of the Presteign valley. 

 All that can be stated with certainty 

 is, that leaving the shale at the ' Sand- 

 banks ' on the south side of that val- 

 ley, at the distance of a little more 

 than a mile to the north-east, the 

 Lower Ludlow rock emerges at Sta- 

 pleton Hill from the gravel, and dip- 

 ping gently to the N.N.W. passes 

 under Upper Ludlow beds in Hill 

 Peak. 



An ascending section on each side 

 of the anticlinal line is thus obtained, 

 which will be more clearly under- 

 stood by reference to the annexed 

 sketch. 



Before proceeding to an examina- 

 tion of the fossil remains of Nash 

 limestone, the eccperimeMtum crucis of 

 geological problem, the evidence from 

 considered. 



