356 Megalonyx Jeffersomi. 



lar, the only one known when Cuvier wrote his notice of this 

 animal, will require revision. 



Locality, — As yet only three localities for the remains of this 

 interesting fossil are known — all in North America, viz. — 

 Greenbriar county, state of Virginia, Big-bone-lick, and White 

 Cave, Kentucky. 



Place in the Geological series. — The first notice we have of 

 the existence of this fossil genus is due to the late Mr Thomas 

 Jefferson, former President of the United States of North 

 America, who made them the subject of a memoir published in 

 the Transactions of the Am. Philos. Soc. of Philad. vol. iv. 

 p. 246. 



Mr Jefferson compared these fossils with similar parts of the 

 lion, to which he considered his animal congeneric. Plaster 

 casts of these bones were sent* to Baron Cuvier, who was thus 

 enabled to estimate them at their true value, and to arrange 

 them as pertaining to an animal of the tardigrade family, and 

 as allied to the Megatherium. 



The bones forwarded by Mr Jefferson to the American Phi- 

 losophical Society, consist of " a small fragment of the femur, 

 or humerus, a complete radius, a cubitus complete, broken in 

 two, three claws, and a half dozen other bones, belonging to 

 the foot or hand." A tooth and some other small fragments 

 were subsequently obtained by Palisot de Beauvois, from the 

 same cave. 



Similar caverns to that in which these bones were found, 

 exist in great numbers throughout the western part of Virginia, 

 Kentucky, Tennessee, and other portions of the great valley of 

 the Mississippi river, in the cavernous limestone, which here 

 constitutes the surface rock for hundreds of miles. Some of 

 these caverns,, such as the mammoth cave of Kentucky, are 

 several leagues in extent, and appear to have once been the 

 channels of subterranean rivers, a circumstance which may pos- 

 sibly explain the comparative rare occurrence of organic re- 

 mains within them. 



Nitre, or saltpetre, is not unfrequently found adhering to the 

 surfaces, and in the soil of clay, nmd, or stalagmite formed at 

 the bottom. The cave in Greenbriar county, Virginia, in which 

 the Megalonyx bones of Jefferson were found, is thus situated. 



