The Carboniferous Succession below the Coal-Measures. 391 



Above the preceding horizon is a very ptire white limestone, 

 containing — 



Chonetes papilionacea, Phill. (Very common.) 

 Huomphalus pentangulattis, Sow. (Comraon.) 



(ii) On the east side of the Vale of Clwydd, near the western 

 biise of Moel Hiraddug, at a quarry between Pentre-cwm and 

 Pentre-bach, the so-called 'basement beds' (of the Geological 

 Survey) are exposed, which here consist of alternating limestones 

 and soft calcareous sandstones. The following list was obtained : — 



Zaphrentis-Yike Coral. 



Athyris expatisa, Phill. 



Chonetes papilionacea, Phill. (Convex form.) 



Gliothyris glabristria (Phill.). 



Productus sp. 



Seminula &E. Jicoidea, Vaughau. (Very common in one bed.) 



Spirifer sp. 



Archceosigillaria Vanuxemi (Gopp.). 



Other plant-remains with Spirorbis attached. 



The importance of this section lies in the abundance of Seminula 

 Jicoidea, which fixes the horizon in the series. The discovery of 

 ArchcBOsigillaria Vanuxemi, which was fairly common in the plant- 

 bed, is of more than ordinary interest, since it has only been 

 recorded hitherto " from the lower beds of the Mountain Limestone 

 in the neighbourhood of Shap Toil-Bar, Westmoreland," ' and in 

 that instance the horizon and locality are both somewhat vague ; 

 we are now able to give these particulars for the new find with 

 precision. 



(iii) In the next quarry, nearer to Dyserth, and 10 feet above the 

 very thick bed of white limestone seen in its southern end, we 

 collected — 



Dibnnophylltmi sp. 



Athyris expansa, Phill. 



Chonetes papilionacea, Phill. 



Spirifer. (With few thick and deep angular ribs.) 



Buomphalus sp. 



Fucoid (?). 



(iv) Beds, higher in the series than the preceding, are exposed in 

 a large quarry at Dyserth, bordering the south side of the New- 

 market road, and in those constituting the floor of the quarry we 

 obtained — 



Cyathophyllum Murchisoni, E. & H. 



Dibunophyllum sp. 



Chonetes papilionacea, Phill. 



C. papilionacea, Phill. (Convex variety.) 



Productus hemisphericus, J. Sow. 



Martinia glabra (Mart.) . 



(v) A smaller quarry is being worked near Meliden (lat. 

 53° 18' 50" N., long. 3° 24' 30'' W.), where the beds may be observed 

 dipping north at 50°. On account of the high dip comparatively 

 few beds are exposed, but these are very fossiliferous, as may be 

 supposed from an inspection of the following list : — 



1 R. Kidston: Trans. Nat. Hist. See. Glagow (1899), p. 40. 



