A mastodon is a member of the genus Mammut, which strictly defined, was endemic to North America and lived from the late Miocene to the early Holocene. Mastodons belong to the order Proboscidea, the same order as elephants and mammoths. Mammut is the type genus of the extinct family Mammutidae, which diverged from the ancestors of modern elephants at least 27-25 million years ago, during the Oligocene.
Mastodon
Mammut americanum molar tooth, Rotunda Museum
The 1806–1808 painting The Exhumation of the Mastodon by Charles Willson Peale
Colored lithograph of the "Missourium" (= Mammut) skeleton, ca. 1845
The Holocene is the current geological epoch, beginning approximately 11,700 years ago. It follows the Last Glacial Period, which concluded with the Holocene glacial retreat. The Holocene and the preceding Pleistocene together form the Quaternary period. The Holocene is an interglacial period within the ongoing glacial cycles of the Quaternary, and is equivalent to Marine Isotope Stage 1.
Holocene cinder cone volcano on Utah State Route 18 near Veyo
Bronze bead necklace, Muséum de Toulouse