The name Vlie refers to a strait between sea islands, Vlieland and Terschelling. It seems that the firmly below-sea-level excoriations in the far north (the Groote Vliet) by Medemblik and the IJ (near Amsterdam) were all deep parts of the same body of water in the height of the Roman Warm Period and Medieval Dark Age sea rises (transgressions). Most of the surrounding basin of the vast harbour-like body of water of the Netherlands is reclaimed from it (nationally called polderisation; in England called the making of a fen).
The name Vlie refers to a strait between sea islands, Vlieland and Terschelling. It seems that the firmly below-sea-level excoriations in the far north (the Groote Vliet) by Medemblik and the IJ (near Amsterdam) were all deep parts of the same body of water in the height of the Roman Warm Period and Medieval Dark Age sea rises (transgressions). Most of the surrounding basin of the vast harbour-like body of water of the Netherlands is reclaimed from it (nationally called polderisation; in England called the making of a fen).