( 419 ) 



XI. — On some Fossil Plants from Teilia Quarry, Gwaenysgor, near Prestatyn, Flint- 

 shire. By Kobert Kidston, F.K.S.E., F.G.S. (With Two Plates.) 



(Read 17th December 1888.) 



Teilia Quarry, from which the fossils described in this paper have been collected, is 

 situated about a quarter of a mile north-east of the village of Gwaenysgor, which is 

 distant about five miles from Ehyl and one from Prestatyn. 



The geology of the district has been fully described by Mr G. H. Morton, F.G.S., # 

 from whose paper the following notes are compiled : — 



A considerable part of North Flintshire is occupied by a great development of lime- 

 stone, which is generally referred to in writings on the subject as "Carboniferous Lime- 

 stone." It forms a tract of hilly ground, some of the higher points rising to a height of 

 over 800 feet. These limestones lie immediately beneath the Cefn-y-Fedw sandstones, 

 and occupy a hollow of considerable extent in Silurian strata. 



From distinctive lithological characters, the limestones can be divided into four groups, 

 all of which can be well studied in the steep escarpment near Prestatyn in the north- 

 west of the county. 



In the north of Flintshire, the following are the four subdivisions of the limestones 

 that occur: — 



Name. 



Thickness in 

 Feet. 



Locality where well exposed. 



I. Upper Black Limestone, 

 II. Upper Grey Limestone, 



III. Middle White Limestone, 



IV. Lower Brown Limestone, 



Red Basement Beds, .... 



200 

 500 

 600 

 400 



Prestatyn and Llanasa. 

 Coed-yr-Esgob and Gwaenysgor. 

 Graig-fawr and Dyserth. 

 Moel Hiraddug and Marian-cwm. 



Teilia Quarry is situated in beds which form the base of the Upper Black Limestones, 

 — the uppermost subdivision of the series, — and in the present paper it is only with this 

 subdivision we have to deal. 



This subdivision receives its name from the prevalence of black, fine-grained, thin- 

 bedded limestones, which in weathering assume a light brown colour. This limestone 

 was formerly worked for making hydraulic cement. 



According to Mr Morton, the original deposit was a calcareous mud, and rapid 

 decomposition may account for so few organic remains being found. 



All the fossil plants from Teilia Quarry have suffered more or less from decay before 



* " The Carboniferous Limestone of the North of Flintshire," Proceedings Liverpool Geol. Soc, Sessions 1885-86, 

 vol. v. pp. 175-197. See also Mem. Geol. Survey — " Geol. of Coasts adjoining Rhyl, Abergele, and Colwyn," (Explanation 

 to Quarter Sheet 79 N.W.), by A. Strahan (with Notes by R. H. Tiddeman), 1885. 



VOL. XXXV. PART II. (NO. 11). 4 A 



