NO. 2014. ON A PLEISTOCENE CAVE DEPOSIT— GIDLEY. 95 



present roadbed. This opening so nearly overhead probably at one 

 time served as a trap through which were introduced the animals 

 whose remains are now in the deposits of the bone cavern. There 

 are other openings along the line of outcrop of the ledge, one of them 

 at about the same level with the bone-bearing deposits, appearing at 

 the north end of the ridge where it slopes abruptly down into the 

 Wills Creek Valley. These openings may or may not have communi- 

 cated at one time with the caverns intersected by the railroad cut, 

 but probably had nothing to do with the accumulation of material 

 in the latter. 



From Brown's * account of the Conard Fissure, it would seem that 

 the conditions governing the accumulation of material in the Cumber- 

 land Cave were quite similar. The bones for the most part are much 

 broken, yet show no signs of being water worn. They are found 

 scattered fairly uniformly throughout the entire mass of unstratified 

 accumulations which consist entirely of cave clays and breccias, 

 unevenly hardened and more or less cemented together by stalactitic 

 materials. There is an almost entire absence of admixture of sand 

 or gravel, or in fact anything that would suggest the possible aid of 

 stream currents in sorting or placing the material during the process 

 of accumulation. It seems probable therefore that this little fossil- 

 bearing pocket represents the accumulation of a great number of 

 years in which the conditions were such that animals, both large and 

 small, sometimes by accident, sometimes by being dragged there 

 by carnivores, occasionally became entrapped in the upper cham- 

 bers of the cave. Thus carcasses of the larger animals were proba- 

 bly caught and held in crevices not far beneath the surface of the 

 ground and remained there until the bones were sufficiently macerated 

 to allow them to fall apart by their own weight, when the separated 

 bones would work their way by gravity to lower and lower levels until 

 they finally came to rest at the bottom of the cavern then a hundred 

 feet or more below the surface of the ground. The broken and scat- 

 tered condition of the bones found in the deposits would be accounted 

 for in this way. 



The mammals represented in the collection are undoubtedly 

 Pleistocene and probably pre-Wisconsin in age; a more exact geo- 

 logical horizon of the deposits, however, can not at present be 

 determined. From this preliminary study they appear to be about 

 the equivalent of the Port Kennedy cave deposits, the fauna of 

 which was described by Cope ' and is now regarded as early Pleisto- 

 cene. The Cumberland Cave fauna may represent a somewhat later 

 phase. But this supposition can be verified or disproven only by a 

 careful comparison of the material with that from Port Kennedy 

 and other localities. 



» Memoirs Amer. Mas. Nat. Hist., vol. 9, pt. 4, 1907, pp. 163. 

 » Joum. Acad. Nat. Sci. PhUa., vol. 11, 1899, pp. 194-267. 



