390 Dr. Wheelton Hind Sf John T. Stohhs^ 



3. Description of the most important Sections. 



For the sake of clearness, the exposures of the Carbonifei'ous 

 Limestone have been described according to their topographical 

 arrangement rather than in their geological sequence. In this way, 

 where several fossil horizons occur at any one locality, they have all 

 been taken together as making up one section ; the correlation of 

 the individual horizons is dealt with in a later portion of this paper. 

 It has, however, been found possible to treat the exposures in the 

 Pendleside Series in their geological sequence, because of the acci- 

 dental fact of each section being limited to one zone, which has 

 enabled us to do this without involving any repetition or complicating 

 the description as between horizon and locality. 



Owing to the difficulty, in this sparsely populated district, in 

 indicating localities with sufficient precision by reference to topo- 

 graphical names (which, by the way, are often subject to alteration), 

 we have frequently resorted to their definition in terms of latitude 

 and longitude, as marked off on the " 1 inch Ordnance Maps," 

 believing that this is the only way (unless personally conducted) 

 in which other field geologists can in many instances locate the 

 collecting-ground with tolerable certainty. 



(a) Carboniferous Limestone. 



(i) The romantic coast scenery in the neighbourhood of Llandulas 

 is due to the irregular weathering of the Carboniferous Limestone 

 forming the hills. The dip of the beds northwards to the sea may 

 be beautifully seen in the series of long, parallel scars on both sides of 

 the valley of the Kiver Dulas, which has cut its way through the thick 

 limestones. Ffernant Dingle was visited by us, but we have nothing 

 to add to its description by Mr. A. Strahan, F.R.S., in the Geological 

 Memoir of that district. At Llandulas, in a quarry by the roadside 

 at the foot of Cefn hill (lat. 53° 19' 5" N., long. 3° 37' 50" W.), one 

 of the limestones is characterised by the abundance of Dnviesiella 

 Zlangollensis (Dav.). A little higher in the sei'ies another limestone 

 bed contained great numbers of Seminula aff. jficoj'dea, Vaughan. On 

 the south side of the hill, and south of the scattered village of 

 Llysvaen (lat. 53° 16' 20" N., long. 3° 38' 40" W.), almost level with 

 the road, a Productus Limestone may be seen, containing — 



Productiis afp. Cora (mut. D,), Vaughan. 



P. aff. Cora (mut. S,), Vaughan. 



P. fiemisphericus, approaching in some characters P. Cora. 



P. hemiaphericHS, Pliill. 



Following the same road further to the west, towards Bwlch-y- 

 gwynt, a rather sandy limestone, with quartz-nodules, occurs 

 somewhat higher in the series, with — 



Cyathophyllum Murehisoni, E. & H. (Very common.) 

 Koumckophyllid — Cyathophyllum. 

 Lithostrotion aff. Martini^ E. & H. 

 Syringopora cf. distans, p'ischer. 

 Chonetes papilionacea, Phill. (Common.) 



