Geology of Coalbrook Dale. 423 



within a quarter of a mile of the new red sandstone, and passes gradually 

 into the next division. 



The middle division or the Aymestry limestone^ is formed of very thin 

 and roug;h beds of light gray and bluish, lumpy limestone, with a few seams 

 of clay ; and is characterized by a great abundance of Terebratula IVilsoni, 

 many of which are detached between tiie layers of limestone; and by a few 

 corals. It is well exposed along the New Cut near Broseley, between Dean 

 and The Dean, where it is brought up by a S.W. and N.E. slightly-developed 

 anticlinal line, the prolongation of which may be seen at several places, along 

 the slope of the hill, and particularly at Willey Church. I have traced this 

 deposit from the New Cut to Willey, also in the bed of Darley Brook ; and 

 the junction strata between it and the upper divisions, again appear on the 

 side of the lane leading from Barrow to Posenal ; it may be traced thence 

 by Ash Coppice, dipping 10° E.S.E. along the summit of the hills, to the east 

 of Much Wenlock, where it forms a range parallel to the limestone escarp- 

 ment of Wenlock Edge. Prom The Dean, it passes below the coal-measures 

 to nearly opposite Swinney Mill, on the side of the Severn, and close adjoin- 

 ing the out-crop of the new red sandstone, where it has been found at a depth 

 of 40 yards, underlying the lower coal-measures. At Aymestry, the lime- 

 stone passes upwards into thin beds of a yellow, deeply ferruginous, very soft, 

 and fissile sandstone, full of the Orlhis lunata, Leptcena {Producta) lata, Cy- 

 pricardia undata, and Terebratula lacunosa. 



The upper division. The beds above mentioned rapidly give way to the 

 sandstones of this division ; the lower beds of which are light-coloured, thin- 

 bedded, frequently very micaceous and fissile; and sometimes very much re- 

 semble the lower sandstones of the coal-measures*. The upper beds are 

 occasionally highly micaceous and of a deeper colour. 



The junction of this formation and the old red sandstone is well exposed 

 near Callaughton, where the former is exhibited in several quarries. Thence 

 it ranges to Wenlock Walton and Barrow Hill, dipping at an angle of about 

 8° under the old red sandstone. It is again brought to day on the summit of 

 Breakneck and Willey hills, by the Swinney fault throwing it into juxtaposi- 

 tion with the coal-measures, which at the Dean's Corner, appear at the base 

 of the last-mentioned hill. (See PI. XXXVI., Section 13.) It then ranges 

 under the thin capping of coal-measures at Linley Green Hill, and reappears 

 at Linley Hall. In the brook below the Hall, good sections of it are exposed, 

 overlaid by the old red sandstone, the beds being nearly horizontal or dipping 



* An experienced collier informed me, that the fissile sandstone capping Willey Hill, and ex- 

 hibited on the side of the lane leading from the Dean's Corner to Willey, was that which overlaid 

 the best coal, and it was only after a long search, that the discovery of the Lingula proved the 

 sandstone to belong to the upper Ludlow series. 



