About an hour outside Chicago, between I-55 and Hwy. 53 exists a small township called Mazonia. I was there last before the snow had completely melted. The landscape, desolately flat, was dotted with these very thin, tall hills that look as if they were growing from the dirt like trees.
I had come there to dig.
See, in the late part of the 1800's, many people came to this area to work in coal mines. The carbon rich soil was ideal for this strip mining which continued in most towns until the 1930's, during which mines became depleted and other forms of energy were increasing in popularity. The coal companies eventually moved on, leaving in their wake, ghost towns such as Coal City, Carbon Hill, Braceville, and Braidwood. They also left hills of shale . . . the spoil piles.
Before this area became industrialized -- long, long before -- it was a shallow, salty sea.
Around 500 million years ago, during the Precambrian/Cambrian period of history, the majority of Illinois was part of a small, fertile sea. The sea, which consisted mainly of coral reefs, teemed with life such as squid, worms, polyps, clams, and shrimp-like animals. Over time the climate changed, the continents moved, and the sea covering this area was gone forever. It left a memory, however.
In the mud in the bottom of this sea dead organisms sank and became forever preserved. The mud turned into shale, containing an abundant fossil record of the once tropical Midwest. Today, the most detailed of these fossils -- which contain a record of soft parts of organisms, a rare occurrence -- can be found inside the spoil piles or shale beds in the form of iron nodules. These soft, round, brownish-red spheres of rock, when cracked open can reveal the secrets of this past environment. The Mazon Creek area is especially known for these fossils due to the Mazon River which unearths many of these treasures.
The fossils found in this part of the country are some of the best in the world, and are not difficult for the amateur hunter to locate.
During my last trip, digging in the cold at the frozen earth, we came upon about 10 nodules at the surface of the hill. I've meant to go back, but the fields that once were a reef will have to wait. . .
It's been a long time.