Cores from small basins in southwestern New Brunswick, above present sea level but below the former marine limit, were examined for microfaunal changes indicating a transition from marine to freshwater conditions. Carbon 14 dates of those transition points add to and strengthen a previous sea-level curve from the area. The oldest date places sea level at about 75 m above present at 16 000 years BP. Dates from the lower lakes (+ 10 m) appear to be anomalously old, and it is suggested that after 12 000 years BP erosion became a factor in marine areas. This erosion may be related to the overall breakup of ice in the North Atlantic and may explain why few dates younger than 12 000 years BP are found in raised marine deposits of New Brunswick and Maine.