504 Dr. Wheelton Hind 8f John T. Stobbs— 



Teilia Beds with P. Becheri, the Black Limestones (Aberdo) of 

 Holloway and Trelogan with Cijathaxouia, and the Black Lime- 

 stones of Prestatyn with Zaphrentis alf. EnnishUleni. Probably the 

 latter two are nearly on the same horizon, and both must be 

 included in the Upper Dibimopkyllum zone. This Zaphrentoid coral 

 has occurred in the same zone at Bradbourne, Derbyshire, and 

 Eush, CO. Dublin. There is no doubt that the cherts overlie the 

 lower set of Black Limestones, but it is their relation to the 

 Posidonomya Becheri limestones which has been questioned. The 

 idea that the cherts are the homotaxial equivalents of the Millstone 

 Grit is obviously untenable on paleeontological grounds, the more so 

 if P. Becheri beds occur above them. 



The third solution of the question is that the chert beds occur at 

 different horizons in the series at different localities, that they are 

 higher at Pentre and near Gronant than they are near Holywell, 

 Trelogan, and Waenbrodlas. We know that cherts occur at many 

 horizons in the Upper Dibunophyllum beds of Derbyshire, both in 

 and below the Cyathaxonia zone. It is of the utmost importance 

 that the junction of the Cyathaxonia beds and the Posidonomya beds 

 should be recognised and mapped, because the junction is the 

 division between the Upper and Lower Carboniferous Series in the 

 Midlands. At this point the great faunal change takes place, at 

 this point the new fauna comes in, and moreover the faunal change 

 corresponds with well-marked change in lithological characters, 

 provided that the mere colour (black) is not allowed to cause 

 confusion of limestones on two distinct horizons.] 

 6. The Pendleside Series. 



In the neighbourhood of Prestatyn and Holywell the Pendleside 

 Series is well represented, typical fossils, flora and fauna, being 

 common. Immediately above the cherts are peculiar black lime- 

 stones of definite character (vide ante, pp. 450, 454), which are exactly 

 similar to those found in the lower part of the Pendleside Series 

 anywhere in the Pennine area. 



We have not yet found the lowest zonal fossil of this series, 

 Prolecanites compressus, in North Wales, except possibly at Teilia. 

 Posidonomya memhranacea, l\ Becheri, and Pterinopecten papyraceus 

 are abundant iti many localities. The first two species may be 

 considered as absolutely characteristic of this horizon, having never 

 yet been found in higher beds. 



At Teilia Quarry the following plants have been obtained, and 

 Mr. Kidston gives the following list, op. supra cit. A fine collection 

 is in the Grosvenor Museum, Chester, and we owe our thanks to 

 Mr. A. Newstead, the Curator, for an examination of the specimens. 

 *Adiantites antiquns. S. affinis. 



Sphenopteris Teiliana. Rhacopteris glabellata. 



*S. subgeiiiculata. R. ineqiiilatera. 



S. striata, ? Archeoptcris sp. 



*S. pachyrachis. *Asterocalamites scrobiculatics. 



* j, var. stenophylla. LepidopJtloios sp. 



^ S. Schlebani, 



Those species marked by an * have been obtained from beds containing the same 

 fauna at Poolvash, Isle of Man, Pendle Hill, and North Staffordshire. 



