[Red Badger]

This means the these places once had WATER right up next to them.
IOW, the ocean’s level was much higher then...................

[SunkenCiv]

Yup, kaka happens. By contrast, places more seismically active have become submerged in the same interval -- gosh, it's almost as if there's not really much of a fluctuation in the actual sealevel over time. :^)