From the three mastodon sites located in Hyde Park, Watkins Glen, and North Java, NY, the earliest wood macrofossils that contain sufficient ring counts for dendrochronological purposes include two boreal species: Picea spp. (spruce spp.) and Larix laricina (eastern larch). Their radiocarbon dates range from 12,548±38 to 11,970±80 ¹⁴C BP, within the Bølling period of 13,000-12,000 ¹⁴C BP and the beginning of the Older Dryas period of 12,000-11,800 ¹⁴C BP. Only one dendrochronological sample of the boreal species was found at each of the Hyde Park and Cornell's Gilbert Mastodon sites: the Hyde Park sample dates to 12,548±38 ¹⁴C BP, and the Gilbert sample dates to 12,269±66 ¹⁴C BP. The North Java Mastodon site’s wood includes 34 boreal species samples: sample G21 dates to 11,970±80 ¹⁴C BP. This sample and other North Java samples are contained in 5 chronologies. These floating chronologies offer a possible 643-year extension to the early end of the current terrestrial ¹⁴C data based on floating European tree-ring chronologies into the period that is now covered mainly by the Cariaco Basin marine data.