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Memoir on a Cave at Cefh in Denhigshire visited by the Rev. 

 Edward Stanley, F. G. S., F. L, S., Src. With a Plate. 

 Read before the Geological Society of London, ^Oth May 

 1832. And communicated by the Author, with the permis- 

 sion of the Council. 



On inspecting a map of North Wales, it will be seen that se- 

 veral minor streams, rising, some of them, a little to the east- 

 ward of Llanvcost, and others still farther eastward in the heart 

 of Denbigshire, particularly from the small lake of Llyn Aled, 

 and the mountains adjacent, effect a junction, and form the river 

 Elwy ; which, after proceeding in its course through a beau- 

 tiful valley, between two ranges of limestone hills, more or less 

 precipitous on the left, though inclining to undulation on the 

 right, takes a sharp turn at Cefn, where the cliff terminates 

 abruptly, and then shapes its course towards the sea, uniting 

 itself with the Clwyd, a little to the southward of Rhyddlan, 

 near St Asaph. At this point of curvature at Cefn, it must 

 either have forced a passage by breaking down a barrier, con- 

 necting the present headlands of Cefn and Galltfaenan, or, as 

 long as it was checked by this interruption, have formed a vast 

 Jake, not inferior in size to that of Bala, or some of the still 

 more extensive lakes of Cumberland, receiving at this point 

 another tributary stream, the brook Meirchion, which rushes 

 through a lengthened gorge from the S. W., and occasionally 

 discharges a powerful body of water. 



Having thus briefly described the localities and prominent 

 features of the country, I shall proceed to the more particular 

 objects of this paper. 



In the month of February last, being in the neighbourhood, 

 I was induced by some friends who had spoken highly of the 

 natural beauties of the vale of Cyffredan *, to visit a perforated 

 rock named Cefn cave, through which the road passes at a little 

 distance above the bed of the river Elwy. This perforated 

 rock is clearly a natural production, though, possibly, art may 



• This name is I believe only strictly ai)plicable to that portion occupied 

 by the brook Meirchion, but I have been informed that it also applies to the 

 whole valley. 



