ith the melting of ice
masses and the slow emergence of the coastal shelf, rising water
levels gradually flooded ancient shorelines. By about 6,000 years
ago, Northumbria was breached, forming what is now Northumberland
Strait, and cutting off Prince Edward Island from the mainland.
This process continues today, and parts of the southern Maritimes
are receding into the sea at a rate of about ten centimetres per
century. This is not true for all of Atlantic Canada, however.
Along the south shore of Labrador and parts of Newfoundland, the
land is still rebounding and a new shoreline is emerging.