As I understand the feature was connected to the general weirdness of the area - ie. being a huge glacial meltwater lake dammed in the south by the Weald-Artois anticline and by the remaining glacier mass in the north - around the end of the last glacial maximum.
Trying to remember a story of an OL falling for a girl who works at a convenience store but doesn’t say anything because she thinks she’s still in high school. One night there she passes out and wakes up on a couch in the backroom. Then she finds out the worker is actually older than her, she just happens to look young for her age