GEOLOGY. 277 



discovery of bone caves in this country is of a very recent date. 

 They have been found for many years in Europe; and in France in 

 great numbers. In this continent there are on record but two cases 

 of this kind ; one of them in Canada, the other in Virginia. Within 

 the last two years, caves containing considerable quantities of bones 

 have been discovered in various parts of Pennsylvania, particularly near 

 Carlisle and on the Susquehanna. The principal cave occurs on the 

 bank of the Susquehanna, in the limestone rock, nearly on a level 

 with the water, the entrance being ten feet high. The floor of the 

 cave is nearly on a level with the extremity, and the cave itself is 

 about 300 feet in length. On the bottom is a stratum of mud, in 

 whjch numerous bones are imbedded, about ten inches in depth. 

 This lies above several other strata of deposits, of stalagmite, &c. 

 There is a series of galleries near the roof of this cave, which can 

 only be reached by ladders, being sometimes eight or ten feet above 

 the floor of the cave. These are filled with mud, and in this mud the 

 bones are distributed. The remains have evidently come in from above, 

 as there is no other possible means by which they could be filled to 

 this height. The character of these remains is quite interesting, in 

 some respects. The number of species of mammalia found there is 

 nearly twice that of the species at present existing in Pennsylvania. 

 Nearly 5 per cent, consist of extinct species ; the remaining 95 per 

 cent, are recent. The recent bones are of various species of wolves, 

 foxes, rabbits, bears, muskrats, otters, lynxes, panthers, beavers, &c. 

 Besides the remains of mammalia, there are numerous remains of other 

 vertebrata, birds in great quantities, particularly wild turkeys, and 

 some of these of an enormous size, probably weighing thirty or forty 

 pounds. There are numerous bones of the swan, several ducks, and 

 some large waterbirds. Prof. Baird has also found the humeri of 

 birds quite as large as the pelican, and the lower jaw of a salamander, 

 quite different from the existing species. Of tortoises there are the 

 remains of eight or ten different ones in great abundance ; and the 

 bones of serpents are quite common. Some remains of fishes, vertebrae, 

 and scales, occur mixed with the mud. In that portion of the mud 

 which forms the upper two or three inches of the floor, some 

 Indian remains, such as arrow-heads and fragments of pottery, are 

 very perfectly preserved. In relation to the origin of these bones, 

 Prof. Baird remarks, " Whence came this vast accumulation of 

 remains ? I say ' vast,' because I possess of single species of deers, 

 remains that must have belonged to more than one hundred indi- 

 viduals, and I am very far from having cleared out the cave. Various 

 theories are proposed for the production of the bones. Some geologists 

 have supposed that they have washed in from without ; others that 

 they have been dragged in by wild beasts ; and this latter theory is 

 strengthened by the fact, that a great majority of the bones are of the 

 weaker animals such as would naturally fall the prey of any carnivorous 

 animal. 



" It has appeared to me, from the examination of the peculiar cir- 

 cumstances of the cave, that several causes have combined to furnish 

 this accumulation. I can hardly assent to the theory, that water has 



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