In the Laurentian Channel offshore eastern Canada, numerous tunnel valleys have been identified originating from the submerged valley of the St. Lawrence River, which is also of glacial origin. Seismic reflection profiles of the fill of tunnel valleys suggest that they are of various ages, with the youngest dating from shortly after the Late Glacial Maximum. They result from erosion by sub-glacial water crossing the eastern Scotian Shelf off Nova Scotia. They originate from the Laurentian Channel south of the Cabot Strait. Additionally, seismic profiles show deeply buried post-Miocene channels, some of which lie below modern sea level, cutting across the eastern part of the outer Laurentian Channel which have also tentatively been determined to be tunnel valleys. Seismic profiles have also mapped large tunnel valleys on Banquereau Bank and Sable Island Bank.