This is what a Silurian coral reef looks like, 425 million years later.
I parked in the back/side lot at my local grocery store this morning while shopping for Thanksgiving. (The main lot gets very crowded on the day before holidays.) In warmer seasons, tree leaves and other vegetation block the view of the actual rock that marks the remains of an ancient ocean floor, and in colder months it’s usually dark when I shop. But with this morning’s sunlight hitting the leafless hillside, there it was, and I could see it as I pushed my cart out to the back forty (which hadn’t gotten parked up with the overflow yet).
So I paused a moment to get a picture to share 😀
Here are a couple links with more info on the reef.
First, the Wikipedia article on the reef: https://en.m.wikipedia.org/wiki/Schoonmaker_Reef
Then also some old (circa 1997 and vaguely GeoCities-looking) web pages from the Milwaukee Public Museum: https://www.mpm.edu/content/collections/learn/reef/wauwatosa-front.html
And finally a nice, detailed article on the reef’s history from WUWM (the NPR-affiliated radio station of the University of Wisconsin-Milwaukee): https://www.wuwm.com/environment/2016-05-27/did-you-know-theres-an-ancient-coral-reef-in-wauwatosa