4 ms·
Interestingly enough the whole great lakes area was a sea, 400 million years ago. There are massive salt mines deep underground from those times.
by bluedino 5y ago
Interestingly enough the whole great lakes area was a sea, 400 million years ago. There are massive salt mines deep underground from those times.
- sidewndr46 5y agoWhy would there be deep underground salt mines from 400 million years ago?
- bluedino 5y agohttps://project.geo.msu.edu/geogmich/mibasin.html https://project.geo.msu.edu/geogmich/mibasin.html