Mammal fossils have been found in a large number of Quaternary sediments all across Kentucky. The most famous site for mammal fossils is Big Bone Lick in northern Kentucky. Fossils of Cenozoic-age mammals are occasionally uncovered in alluvial depoists of the Mississippi and Ohio rivers. Fossil peccaries (a type of pig) were found and described in Fulton County. Mammal fossils have also been found in Kentucky caves.
(from Finch, W.I., 1972, Stratigraphy, morphology, and paleoecology of a fossil peccary herd from western Kentucky. U.S. Geological Survey Professional Paper 790, 25 p. [available at the Kentucky Geological Survey book store])
The bones pictured above are bones of mastodons on display at the museum in Big Bone Lick State Park. Mastodon americanus was originally named from bones found at Big Bone Lick.
Similar bones of large mammoths and mastodons have been found at other licks in northern Kentucky, in gravel depoisits of the Ohio river, and in sink holes deposits. Other animals that have been unearthed at Big Bone Lick include possible wolf, possible black bear, modern bison, ancient bison, two types of musk ox, American moose, wapiti elk, common Virginia deer, extinct stag moose, caribou, flat-headed peccary, extinct North American horse, possible tapir, and two types of giant ground sloth.
Bones of some of these animals that have been found in southern Ohio, can be seen at the Cincinnati Natural History Museum. Although mammoths and mastodons capture the spotlight, the most common fossil found at Big Bone Lick (and probably the most common mammal fossil found in Kentucky) was the modern bison. A skull of a bison on display at the Big Bone Lick State Park museum is shown above.