In his memoir of 1853 on “Extinct Species of American Ox” (Smithson. Contrib. Knowl., vol. V, art. III, p. 10), Doctor Leidy included _Mylodon_ among the genera found at Natchez. In his memoir of 1855 on the “Extinct Sloth Tribe of North America” (Smithson. Contrib. Knowl., vol. VII, art. V, p. 48) he gave a list of the bones and brief descriptions of them. They all belonged to one individual, which was about half-grown. In a list furnished to B. C. L. Wailles by Doctor Leidy (Wailles, Agric. Geol., Mississippi, 1854, p. 286), 4 species of _Xenarthra_ are included among the mammals found fossil in the Pleistocene of Mississippi. These are _Megalonyx jeffersonii_, _M. dissimilis_, _Mylodon harlani_, and _Ereptodon priscus_. Cope regarded _M. dissimilis_ as the same as _M. jeffersonii_, and Leidy was disposed to consider his _Ereptodon priscus_ as identical with one of the species of _Megalonyx_. A list of the fossil vertebrates found in the vicinity of Natchez will be given on page 392. TENNESSEE. (Map 3.) 1. _Elroy, Van Buren County._—In 1831 (Jour. Acad. Nat. Sci., Phila., ser. I, vol. VI, pp. 269–286, plates XII to XIV; 1835, Med. Phys. Res., pp. 319–331, plates XII to XV), Richard Harlan described a number of bones of _Megalonyx jeffersonii_ which had been purchased for the Academy of Natural Sciences, Philadelphia, and which he reported had been found in “White Cave,” Kentucky. This was supposed to be situated near Mammoth Cave. It was ascertained later that the bones had been found in Bigbone Cave, Van Buren County, Tennessee.