222 REPORT — 1886. 



was taken at a distance of about sixteen feet from the entrance at the 

 shaft, and fig. 2 just within that entrance. The order in that por- 

 tion of the cavern examined this year accorded in the main with that 

 found during the previous researches, but within the entrance there was 

 a greater thickness of sand, less of the laminated clay, and more bone- 

 earth than in the other parts of the cavern. The bone-earth seems to 

 diminish in thickness rather rapidly outwards under the glacial deposits, 

 but it was found as far out as the excavations have been made. Here 

 the bone-earth rests directly on the limestone floor, with no local gravel 

 between, as in the cavern. 



It would be interesting to know how far the cave earth extends under 

 the glacial deposits, but this could only be ascertained by making a deep 

 cutting through the terrace of glacial deposits, which extends for a con- 

 siderable distance in a westerly direction. The glacial deposits here are 

 undoubtedly in an entirely undisturbed condition, and are full of smooth 

 and well-scratched boulders, many of them being of considerable size. 

 Among the boulders found are granites, gneiss, quartzites, flint, felsites, 

 diorites, volcanic ash, Silurian rocks, and limestone. Silurian rocks are 

 most abundant. It is clear that we have liere rocks from northern sources, 

 along with those from the Welsh hills, and the manner in which the lime- 

 stone at the entrance to the cavern in the shaft is smoothed from the 

 north would indicate that to be the main direction of the flow. The 

 marine sands and gravels which rest immediately on the bone-earth are 

 probably of the age of the Moel Tryfaen and other high-level sands, and 

 the overlying clay with large boulders and intercalated sands maybe con- 

 sidered of the age of the so-called upper-boulder clay of the area. The 

 latter must evidently have been deposited by coast-ice. Whether the 

 caverns were occupied in pre- or only in inter-glacial times it is difficult 

 to decide, but it is certain that they were frequented by pleistocene 

 .animals and by man before the characteristic glacial deposits of this area 

 were accumulated. The local gravel found in the caverns, underlying the 

 bone-earth, must have been washed in by streams at an earlier period, 

 probably before the excavation of the rocky floor of the valley to its 

 present depth. From the glacial period up to the present time excavation 

 has taken place only in the glacial deposits, which must have filled the 

 valley up to a level considerably above the entrances to the caverns. The 

 characteristic red boulder clay with erratic blocks from northern sources is 

 found in this area to a height of about 500 feet, and sands and gravels in 

 the mountains to the S.E. to an elevation of about 1,400 feet. The natural 

 conclusion therefore is that the caverns were occupied by an early pleisto- 

 cene fauna and by man anterior to the great submergence indicated by the 

 high-level marine sands, and therefore also before the deposition of the 

 so-called great upper-boulder clay of this area. As there is no evidence 

 against such a view it may even be legitimately assumed that the ossi- 

 ferous remains and the flint implements are of an earlier date than any 

 glacial deposits found in this area. 



Ffynnon Beuno Cave. 



This cavern, which yielded the greatest number of bones in the 

 previous researches, has now been cleared out in all those parts where 

 the deposits appeared to have been undisturbed by man. A considerable 

 addition to the number of bones and teeth has been made this year, but 

 DO new forms have to be added to those already mentioned. 



