Identifying or Miss-identifying

With the end of summer and fire danger too high to do much work or any work with equipment, I have been able to do a few other things.  Fossil hunting is one of those activities that I can do on a spurs notice without any prior planning anytime I find a chance to sneak away.

Being very much a novice at this activity, I like to drag along those with much more knowledge than I have so a couple of us when a-huntin’.

I was excited to see this fossil embedded in the rock edge of a creek bed.

My companions tested my abilities by my making me recite what I knew about this object. I had a few off the top of my head, this is what I though I knew;

1. Had not been excavated by humans, the rock surrounding the piece was washed away by the creek over the years. So the fossil is harder than the rock that is formed around it.
2. It is a fairly large piece from other examples we had seen during this outing, approximately 12 inches long, 1 inch in diameter. Other fossils found in the area suggest the age being around 33 million years old.
3. It is straight like what I would imagine a bone being, but does not have ends that look like bone and the length and diameter would suggest that it is a stem or trunk of a plant.

While #1 and #2 are not wrong, #3 was only half the answer. My friends did what they could to give me a little more information. By examining one of the fragments we could see no growth rings, that threw out the plant idea completely. Through the middle of the fossil a center-filled ring was seen.

Recent publications suggest that this fossil was made my a shrimp-type animal burrowing through sandy soil. As it burrows, it creates a void in the soil like an earthworm hole. As the shrimp moves through the hole, it leaves a thin layer of substance similar to slime or a slug trail so the pathway stays open.

During the fossilization process the sandy soil turns to rock and the slime allows calcite to form inside the burrow. A hard shell covering forms over the fossilized burrow hole. Even this is conjecture on the parts of paleontologists because a fossil of the shrimp in question has never been found.

We left the fossil remains embedded in the rock as we were mainly out to observe and learn rather than collect this eons-old artifact site.