Editing Bas-Saint-Laurent (section)

=== Topography ===
[[File:Amphithéâtre-St-André.jpg|thumb|right|Inselbergs in [[Saint-André-de-Kamouraska]]]]
The topography of Bas-Saint-Laurent has two main elements : the plateaus of the [[Appalachian Mountains]], called [[Notre Dame Mountains]], and the lowlands in the fine stripe of land along the [[Saint Lawrence river]]. These are separated by an intermediate area of [[ridge]]s and [[foothills]] which meld with the plateaus. The Notre Dame Mountains, are a group of small mountains with summits reaching between {{convert|600|and|700|m|abbr=on}} high.{{sfn|Fortin|Lechasseur|1993|p=36}} the landscape is sometimes interrupted by valleys, like the [[Témiscouata valley]] or [[Matapedia Valley]].{{sfn|Portrait régional|2010|p=5}} These two parallel valleys allow access to [[The Maritimes]], [[Maine]] and [[Chaleur Bay]].{{sfn|Portrait régional|2010|p=7}}

The littoral, spanning across {{convert|320|km|abbr=on}}{{sfn|Portrait régional|2010|p=4}} is composed of riverside land of altitudes ranging from {{convert|0|to|250|m|abbr=on}} above sea level. This area has a depth of {{convert|5|km|abbr=on}} before reaching the mountains in the west of the region, but reaches {{convert|25|km|abbr=on}} in the vicinity of Rimouski, only to shrink again in the eastern limits of the region.{{sfn|Portrait régional|2010|p=5}} This riverside land disappears entirely between the municipalities of [[Sainte-Félicité, Bas-Saint-Laurent, Quebec|Sainte-Félicité]] and [[Grosses-Roches]].{{sfn|Fortin|Lechasseur|1993|p=36}} In the western part of the territory, this littoral plain is interrupted by [[inselberg]]s, ridges reaching that can reach 200m in height, typical of the riverside land of Bas-Saint-Laurent{{sfn|Portrait régional|2010|p=5}}

In the [[Quaternary]], the region was marked by glaciation. the [[Wisconsin glaciation]] caused the crust to sink by {{convert|200|m|abbr=on}} 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.{{sfn|Fortin|Lechasseur|1993|pp=39–40}}

The withdrawal of the Sea of Goldthwait was gradual, 2,000 years ago the isostatic rebound stabilised at around {{convert|1|mm|abbr=on}} per year, the withdrawal of the water formed a number of narrow streaks of emerged land near the riverside between [[Rivière-du-Loup]] and [[Rimouski]], known today as [[Île aux Lièvres (Saint Lawrence River)|Île aux Lièvres]], [[Île Verte, Quebec|Île Verte]], [[île aux Basques]], [[île du Bic]] and [[île Saint-Barnabé]].{{sfn|Fortin|Lechasseur|1993|p=41}}