Why was this Sea in North America on Old Maps?

Here is yet another giant body of water on old maps of North America that turned out not to exist. I’ve covered a few others and they are all associated with the wish to find a quick passage to Asia but each has its own unique backstory. RareMaps.com Sources ---------- Guillaume De L Isle / Jean-Claude Dezauche 1783 - https://www.raremaps.com/gallery/detail/81091/carte-du-canada-qui-comprend-la-partie-septentrionale-des-et-de-lisle-dezauche Philippe Buache 1780 - https://www.raremaps.com/gallery/detail/70578/planisphere-physique-ou-lon-voit-du-pole-septentrional-ce-buache Guillaume De L Isle / Philippe Buache 1763 - https://www.raremaps.com/gallery/detail/79737/carte-damerique-dresssee-pour-lusage-du-roy-en-1722-de-lisle-buache Louis Jolliet 1689 - https://www.raremaps.com/gallery/detail/73650pc/tabula-exhibens-regiones-quasdam-recens-detectas-in-america-jolliet Other Internet Sources -------------- https://www.oldworldauctions.com/info/article/2021-08-The-Last-Great-Cartographic-Myth http://antiqueprintsblog.blogspot.com/2017/04/the-french-seek-route-to-western-sea.html https://sea-of-the-west.info/title http://www.biographi.ca/en/bio/fonte_bartholomew_de_1E.html https://collections.britishart.yale.edu/catalog/orbis:12324099 Book Sources ----------- The Phantom Atlas by Edward Brooke-Hitching French Translations - Kevin Mallet Social Media ------------------------ Map Shop - http://thegeographygeek.com/ Instagram - http://instagram.com/thegeographygeek Patreon - https://www.patreon.com/geographygeek Email Newsletter - http://eepurl.com/hSeKpj