On KESa CAVES, CO. SLIGO. 25 1 



gt-aphy, lies considerably below the mouths of the caves, with a steep 

 talus slope now separating them, and it is highly improbable that there 

 has ever been a plateau of drift material so high as the mouths of the 

 caves at any time since the disappearance of the ice. There seems, there- 

 fore, to be no other explanatioji possible for the gravel deposit than that it 

 has been washed into the mouth of the cave at a time when the ice was at 

 least as high as the escarpment into which the caves are cut, and that the 

 mouth of the Plunkett Cave was already an open passage at that period. 



Hence it becomes a point of much importance to determine whether 

 the caves contain any deposits of older date than the glacial period, and 

 this point deserves especial prominence in any future exploration. The 

 yellow clay with chei't, the lowest deposit discovered, is not a true 

 * boulder clay.' It seems to be such material as might be derived 

 from the solution of the limestone mixed with sand and mud from the 

 waters entering the cave from without. We were not satisfied that this 

 clay was older than the gravel deposit. No fossils having as yet been 

 found in the yellow clay, the question as to its relation to the glacial 

 period is at present of geological interest only, and no palaeontological 

 point is involved. 



If a fossiliferous deposit were discovered below the yellow clay it 

 would be of much scientific interest. That pre-glacially filled fissures 

 may occur in the Carboniferous limestones in this country is shown by the 

 presence of an earth-filled fissure overlain by boulder clay in a limestone 

 quarry at Howth, which one of us examined recently, but without noticing 

 any fossils in it. 



A block and cone of crystalline stalagmite were found in the clay in the 

 Water Gallery, but these were the only examples noticed of this ancient 

 • form of stalagmite which had evidently been broken up in this cave. 



The lower portion of the clay seemed to be devoid of bones as well aa 

 of any relics of man, but in the upper portion of this deposit we found 

 animal remains, including a human tooth ; and a little charcoal was met 

 with in four different spots. This strongly contrasted with the abundance 

 of the latter material, which was everywhere present in the upper stratum 5 

 and even these few traces of it must be mentioned with caution, as 

 burrowing animals may have penetrated into the clay, and thus might 

 have transmitted into it some bits of charcoal from the upper stratum. 

 Remains of domestic animals, so abundant in the latter, were virtually 

 absent from the clay, a bone or two of ox and of goat being all the relics 

 in it assignable to those mammals. The pig was, however, represented in 

 four places. 



The characteristic animal throughout this stratum was the brown bear, 

 whose bones and separated teeth numbered sixty at least, and occurred in 

 all parts of the cave, becoming more frequent in the inner galleries. Fox 

 was found in fourteen places, hare in seven, red deer in four, rabbit in three, 

 wolf in at least one instance, and lemming once (at the entrance), while 

 frog and field-mouse occurred repeatedly. 



We sank deep sections in several parts of the cave, with the result 

 that it was found to narrow downwards and was filled in that direction 

 with barren clay, which became yellow and tenaceous as the rock was 

 approached in our excavations. Near the cave's mouth large quantities 

 of yellow clay were found, and it may be proper to treat it as a separate 

 deposit distinct from the brown sandy clay. No drift stones have been 

 noticed in the yellow clay. 



