The Field Museum Science NewsFlash blog has a great post about a recent donation of Mazon Creek fossils. The Thomas V. Testa collection of Mazon Creek fossils was just received from Field Associate (and ESCONI member) Jack Wittry. It's probably one of the largest private and certainly one of the best collections. The donation, which consists of about 7000 Mazon Creek fossils, brings the Field Museum's total to over 50000 specimens.
Mazon Creek, an area about 50 miles southwest of Chicago, is one of the richest fossil sites in the world. It was once the swampy coastline of a warm sea that covered much of North America—the landscape was a little like Louisiana today. When animals died there, they sunk into the mud and were rapidly buried before they got a chance to rot, forming fossils inside hard nodules of rock. The fossils in this area were first discovered in the 1800s, but it wasn’t until the area was strip-mined for coal in the 20th century that large numbers of fossils were collected.
Mazon Creek fossils are some of the best in the world—they’re plentiful, they’re extremely well-preserved, and they represent lots of animals that don’t normally fossilize very well, including soft-bodied animals like worms.
“This is probably the largest private Mazon Creek collection, and certainly the best,” said Mayer. “We need collections large enough to study the diversity of the living things at Mazon Creek and the variation that occurs within individual species and the whole ecosystem.” But Testa’s collection, which he carefully amassed over decades, doesn’t just contain a large number of fossils—they’re also very high quality, because Testa was picky about which fossils he actually added to his collections.
The Testa fossils range from shrimp to fish to amphibians to worms. “Plus, there’s a lot of diversity among all these species represented. For example, with different kinds of worms, a roundworm is as different from a spoon worm as a jellyfish is from a wolf,” said Mayer.
