The Carboniferous Succession heloiv the Coal-Measures. 451 



cherts, which at this locality are about 25 feet thick and dip 

 eastwards at 20°. Tlie cherts in turn rest on the uppermost beds of 

 limestone, so that the succession here is uninterrupted, and presents 

 no complications. In the Pendloside limestones, which are rarely 

 more than 2 inches in thickness, the following fossils were found : — 



Fosidonomya memlranacea, M'Coy. (Abundant.) 

 Acrolepis HopJcinsi (M'Coy). (Not rare.) 



A small portion of the same horizon, consisting of black shales 

 and thin black limestones, has escaped denudation, and may be 

 observed resting conformably on about 70 feet of black cherts (the 

 full section of which was not exposed) near the foot of the hill at 

 Pentre, near Gronant (see supra, p. 393) (lat. 53° 20' 20" N., long. 

 3° 21' 30" W.). At the east side of the entrance to this quarry we 

 have the following section : — 



3. Thin, plat.y black limestones. 



2. Soft, laminated black shales, 1 ft. 6 in. 



1. Black cherts in beds from 1 in. to 3 in. in thickness. 



The black limestones at the top of the section have the characteristic 

 'sawn edges' referred to later (p. 452). The black shales yielded 

 the following list : — 



Posidonomya Bechcri, Bronn. (Eare.) Plant-remains. (Indeterminable.) 

 Cladodus. (Teeth.) Acrolepis HopJcinsi. 



Beds identical with these are exposed on the west side of the 

 road at and below the well near Gronant Mine (lat. 53° 20' 1" N., 

 long. 3° 21' W.), where they are found to dip north at 13°. 



Succeeding these beds in order of deposition is the following 

 section of a large quarry in the wood facing to the south the Nant Hall 

 Hotel, near Prestatyn (lat. 53° 19' 50" N., long. 3° 23' 10" W.) :— 



Lady McLaren's Quarry. 



ft. in. 



16. Shales and limestone 12 



15. Shale ... 1 Fterinopecten papyraceus (Sow.). 



(Abundant.) 



14. Fissile limestone 2 Flerinopecten papyraceus (So-vf .) . 



13. Paper shales 



12. Platy black limestones and shales 1 Frodncius hemisphericus, J. Sow. 



Crinoids. 



11. Shale 



1 . Black limestone . . . 

 9. Shell bed (limestone) 

 8. Limestone and shales 



7. Shales 



6. Limestone 



5. Shales 



4. Thin platy limestones 1 G Fterinopecten papyraceus, OrbicU' 



loidea nitida. 



3. Fissile black shales 1 2 Glyphioccras sp., Amusium sp., 



plant-remains. 

 2. Black limestone ... ... ... 1 10 FhiUipsia Follmi, Cyathaxonia. 



1. Shale ... ... ... ... 2 0-f Atnplexi-zaphrcntis, Acrolepis, 



Wihonia, Elonichthys (scale), 

 large plates. 



