532 OSSIFEROUS CAVES OF GOWEE. 



the existing beach, and they contain groups of individuals 

 of species of Litorina, associated upon the cavern floors 

 apparently, as they were when alive. It is in the highest 

 degree improbable that these mollusca could have lived in 

 distant recesses of the caves, accessible to the waves, but far 

 removed from light. They must have been in close proximity 

 to the mouths of the caverns then, as they are now, showing 

 that in this case also sufficient time has not yet lapsed to 

 admit of any considerable recession of the cliffs by the wast- 

 ing action of the sea. Denudation is visible in the indenta- 

 tions of Swansea Bay and Oxwich Bay upon the softer strata 

 of the coal measures; but of a date long anterior to the 

 Cave period. 



The next point which suggests itself for inquiry is : are 

 there any indications of a general subsidence of the coast 

 line, or of local depression in the vicinity of the caves ? Mr. 

 Starling Benson cites, in support of this idea, as an estab- 

 lished fact, 'the well-known remains of large trees, now 

 several feet under high-water mark, in Swansea Bay.' * 

 Colonel Wood informs me that there are evidences along the 

 whole line of coast, from Swansea to the eastern point of 

 Oxwich Bay, of submerged forests; stumps and trunks of 

 trees being occasionally exposed by the action of the tidal 

 currents. I have stated above, that the marine deposits in 

 the caves are not at a uniform level, either in relation to 

 each other or to the Mewslade raised beach. The floor of 

 ' Bacon Hole' is fully 30 feet above high water, and above the 

 reach of the waves in the heaviest gales. The marine 

 deposits in ' Bosco's Den ' have been washed out to a depth of 

 31 feet back from the mouth, the waves having free access to 

 the interior during high tides. In ' Bowen's Parlour ' both 

 the chambers, upper and lower, have been completely swept 

 out, the solid dividing floor of cemented breccia alone re- 

 maining of all the former deposits. If the sea has not 

 encroached much, and the cliffs receded, these appearances 

 are only explicable on the supposition that there has been a 

 depression affecting at least the cited caves. 



That the newest of the cave strata have been subjected to 

 at least one violent shock is clearly proved by the rent and 

 shivered condition of the stalagmitic boss of ' Bosco's Den' ; 

 and it is equally clear, from the uncemented state of the 

 fragments, that this shock is of a very modern date, and 

 subsequent to the commencement of the date of deposition 

 of the superficial layer of sandy peat, which covers the floor. 

 The late Mr. Stutchbury observed in ' Durdham Down ' a 

 dislocation in a vein of spar, which led him to the belief that 



1 Op. cited, p. 16. 



