Trip Report: Starved Rock Clay Pit, August 17, 2019
By Dave Carlson
Email: [email protected]
“You gotta go in the mud sometimes to figure who you are” – Andy Irons.
“Madness….madness.” – Major Clipton, “Bridge on the River Kwai”.
Who goes into a clay pit during a rain storm? Rock and fossil collectors, of course! Technically, we waited until the rain stopped to go in and collect. No vehicles got stuck because the road is good, but the same can’t be said for the people. More than one shoe is entombed in the Pennsylvanian mud, to be found by future generations.
This trip produced the expected pyrite balls in large numbers, pyritized wood and pyritized Stigmaria “bark”.
Pyrite ball approx. 1 inch diameter (above), and a cylinder of pyrite (below).
Pyritized wood (above), and Stigmaria “bark” (below).
The black (Mecca Quarry) shale was productive. It is quite hard at this location, but when left out in the weather tends to split along planes of weakness that sometimes hold fossils. Some of the finds are shown below.
Dunbarella, and an unidentified nautiloid (above), and Aviculopectin (below).
Acanthodian (“Spiny Sharks”) spines (above), and stomach ejecta (shark vomit) (below).
A group of 4 Listracanthus “spines” (above), and a Tyrannophontes theridion shrimp (below), which is about 1 inch in length.
There were a few other finds in the category of rocks and minerals. One was banded chert, which I’ve found in much greater quantity in previous visits. I also picked up a fist-sized rock from the road because it contained calcite crystals (an assumption) in a hard gray matrix. When exposed to 365 nM UV the gray matrix (not the crystals) fluoresces peach/pink. I have cleaned the rock thoroughly, and examined it with magnification, and I see no evidence of paint or other substances. It has no streak on a white streak plate. It can be scratched by a nail, and it does not scratch glass. Please contact me if you have experience with fluorescent minerals and know what this might be.
Fluorescent specimen in normal light (above), and in 365 nM UV light (below).
The clay pit can be a challenging place to collect. With perseverance and an understanding of what is there, interesting specimens can be found, even on a day when it is raining. Major Clipton was wrong.
Thanks to all those who sent me pictures for this report:
Brian Borcherding
Andrew Ek
Rich Kerrill
Roger Klocek
Charles Nicchia
Connor Puritz
Ben Riegler
Ed Wagner
