pendennis wrote:
Beneath Detroit is one of the largest salt mines in the U.S.,
1200 feet below street level, and covering 1500 acres. However availability
from other sources made the mines unprofitable. Estimates are that the inland
sea which covered this area 400 million years ago, evaporated, leaving the
huge salt layer. Over time, and a number of ice ages, the salt was covered.
Amazing at the diversity of North America's geology!
HERE'S THEIR STORY..
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