48 Stanley's Memoir on a Cave at Cefri in Denbigshire. 



may look for the introduction of the small portion of twigs, &c.; 

 for had the river descended in a slow and gliding stream, there 

 is no reason why branches of a larger size or other light sub- 

 stances might not have floated gently in. But admitting the 

 powerful irruption of a sudden flood, we can at once account 

 for things as we find them ; mountain torrents of this descrip- 

 tion, in their progress tear up trees, shrubs, and every minor 

 vestige of vegetation, root and branch ; they are the first victims 

 of such catastrophes, and are borne on the first headings of the 

 waters towards their final destination, leaving not a relic of their 

 existence near the scenes of their growth. Added to this, 

 knowing that the velocity of a descending stream is greatest at 

 the surface, and that the aqueous particles in the middle move 

 with greater rapidity than those at its sides, we see at once that 

 if the stream which deposited the lower stratum rushed by with 

 a velocity sufficient to force small pebbles on its influx into the 

 interior of the cave, the lighter floating extraneous masses, if 

 not carried away by the first rush before the flood had risen to 

 a level with the cavern, would have been confined to the centre 

 of the current, and nothing but here and there a trifling particle 

 of brushwood, probably torn from the very mouth of the cavern, 

 according to the rules which regulate the motion of fluids, would 

 have floated near the sides, or gained an entrance within. To 

 this cause we may again refer for the non-existence of fish 

 bone^i, for in such a tumult of waters, fish, like the uprooted 

 branches, must, if dead and floating, have been carried off in 

 the centre of the stream. From the peculiar pebbly character 

 o^ this lower stratum, we may then reasonably conclude, that 

 this first deposit was the result of a flood, so violent in operation 

 and so rapid in its motion, as to convey off the descending wa- 

 ters, without giving time for accumulations of earthy matter to 

 any considerable depth, and that after this, for an unknown 

 period, there was no recurrence of any similar disaster ; during 

 which time, the cave might again have become the resort of wild 

 animals, gradually strewing this new floor with similar fragments 

 of half consumed bones ; but that at the close of this period 

 another flood occurred, far more powerful in its agency and tre- 

 mendous in its operations. Without going back to former ages, 

 or trusting to traditionary reports, we have within the memory 



