BONE-CAYES 12^ NORTH WALES. O 



immediately surrounding limestone rocks ; but there are also fel- 

 stones and other igneous rocks from other Welsh areas, and granitic 

 and gneissic rocks from northern sources. "\Yhether the deposits in 

 this exposure belong to the so-called Middle Glacial sands and 

 gravels, or whether they are of the age of the intercalations fre- 

 quently found in the Upper Boulder- clay of the district, I am not 

 prepared to say. Sands and gravels occur in this area, as is well 

 known from the researches of Mr. D. Mackintosh, and others, at 

 much greater elevations. I noticed a considerable deposit in the 

 gorge east of the Oratory in the grounds of St. Beuno's College, at 

 a height of over 500 feet ; and Mr. Mackintosh has described such 

 deposits at heights of over 1200 feet on the mountains to the south- 

 east *. 



The ravine in which the caverns are situated was doubtless ex- 

 cavated either before or during glacial times, and was filled up with 

 glacial deposits which have since been gradually removed by sub- 

 aerial denudation. Evidence of this fact is furnished by the portions 

 still remaining at various horizons in cliff hollows and at other 

 points, and the sediments in the caverns tend also, in my opinion, 

 to point to the same conclusion. 



Feyi^noit Befno Caveen. 



This cavern (fig. 2) is so named from its proximity to the well- 

 known St. Beuno's Well, which is situated in the ravine. A trial 

 examination was made just within the entrance by Mr. Luxmoore and 



Fig. 2. — Ground-plan of Ffynnon Beuno Cave. 

 I (Scale, 35 feet to 1 inch.) 



A. Entrance. B. Opening into west tunnel. 



C. Chamber extending from main tunnel, D, to fissure cavern, E. 

 F. A rapidly descending mining-shaft, 

 -f . Points where flint implements were found in undisturbed earth. 



Quart. Journ. Geol. Soc. vol. xxxvii. p. 360. 



