 the Wisconsin glaciation caused the crust to sink by in the vicinity of Rimouski.When the end of the glaciation started in 18,000 BP, it opened a sound in the Saint-Laurent valley, isolating the glacier covering Bas-Saint-Laurent from the one covering Côte-Nord.The isostatic rebound created an inland sea, the Sea of Goldthwait, which flooded the region under at most 200m of water in the area around Rimouski.