THE HILLSBOROUGH, NEW-BRUNSWICK, MASTODON AND COMMENTS ON OTHER PLEISTOCENE MASTODON FOSSILS FROM NOVA-SCOTIA

This is the first detailed description of the remains of a young adult American mastodon (Mammut americanum) found in 1936 in peaty silt and clay underlying till in gypsum karst near Hillsborough, New Brunswick . It documents 312 fossils comprising a partial skull with molar teeth and tusks, a neck vertebra, and much of the right postcranial skeleto n. An individual age of 15-18 years and a weight of 8.3 t are estimate d for this mastodon. Associated spheroids, containing cut wood fragmen ts and an unusually high clay content, are interpreted to be mastodon coprolites. Radiocarbon ages are 13600 +/- 200 (bone), 37200 +/- 1310 (coprolite wood), 51500 +/- 1270 (coprolite carbonate cement), and > 4 3000 BP (peat). Pollen in the coprolites and associated sediment indic ates a coniferous forest. Nine other mastodon fossils from Nova Scotia include a femur from Middle River, which dates 31 300 +/- 500 BP and contains pollen representing boreal forest - tundra, and three molars from offshore Georges Bank. All ages are judged minimal: the older fou r are at or near the limit of the method; the younger is likely incorr ect because of preservative contamination. Associated pollen assemblag es correlate with late last interglacial age deposits in the region an d differ from possible Middle Wisconsinan age deposits. The fossils ar e regarded as a single group and are assigned to a cool phase of the S angamonian interglaciation, probably oxygen-isotope substage 5a, prior to Wisconsinan glaciation.