The Ivory Pond Mastodon (Mammut americanum) was found in South Egremont, Massachusetts, in 1982. A recent AMS radiocarbon assay on bone collagen yielded an age of 11,885 \textpm 30 rcbp (UCIAMS 193953), which currently calibrates to 13,580–13,770 cal BP. This date is
statistically similar to a much more imprecise date (GX9024-G; 11,440 \textpm 655 rcbp; 11,500–15,290 cal BP) previously obtained from the specimen. This age is similar to those of other American Mastodon specimens; collectively, these dates imply prior expansion of boreal forest (mastodon habitat) into the region ca. 14,600 cal BP. The location of this specimen east of the Hudson River implies that Late Glacial proglacial lakes that occupied the Hudson River Valley in the past were not a hindrance to megafaunal colonization of New England. The chronology and depositional contexts of this and other mastodon specimens in the region necessitate that human predation be considered as a possible cause of the extinction of this and other megafaunal species in the northeast US.