Weathering or Imprint?

[BLT]

Hi, I’m hoping someone will tell me whether or not this rock has a fossil imprint? Or are the grooved lines running through the surface just natural weathering? The rock was used as a stepping stone in my yard in middle Tennessee, which is Mississippian with St. Louis Limestone & Warsaw Limestone. 

[sTamprockcoin]

Ichnofossil - possibly worm burrow molds. Check the literature on your area and see if any formations are reported to have them. Could also be burrows that weathered off.

[BLT]

Just now, sTamprockcoin said:

Ichnofossil - possibly worm burrow molds. Check the literature on your area and see if any formations are reported to have them. Could also be burrows that weathered off.

I will look into that. Thank you!

[ynot]

The piece looks like there is a discrete layer that is a different type of rock from the base.

This could be a vein that has adhere to the bedrock when it was weathered out.

The ridgeing could be from burow traces or just the way the rock crumbles.

Burows could cause a weak zone within the bedrock making it more likely to separate under stress.

[BLT]

3 minutes ago, ynot said:

The piece looks like there is a discrete layer that is a different type of rock from the base.

This could be a vein that has adhere to the bedrock when it was weathered out.

The ridgeing could be from burow traces or just the way the rock crumbles.

Burows could cause a weak zone within the bedrock making it more likely to separate under stress.

Thanks!  I’ve noticed a lot of the rocks around here have distinctive layers, often with the fossils being in the middle layers. It’s odd that I hadn’t ever really noticed that until I started looking for fossils. 

[ynot]

12 minutes ago, BLT said:

Thanks!  I’ve noticed a lot of the rocks around here have distinctive layers, often with the fossils being in the middle layers. It’s odd that I hadn’t ever really noticed that until I started looking for fossils. 

Many sedimentary rocks will have variation in the layering. This is usually caused by seasonal cycles, but can also be indications of environmental changes.

Think of a long drought followed by an long flood cycle over decades or centuries. Or a region being uplifted (geologically) so it goes from deep sea to shallow lagoon to dry land. The environment will dictate the type of rock that will be deposited, or the rock will describe the type of environment it was laid down in.

Does that make sense?

[BLT]

1 minute ago, ynot said:

Many sedimentary rocks will have variation in the layering. This is usually caused by seasonal cycles, but can also be indications of environmental changes.

Think of a long drought followed by an long flood cycle over decades or centuries. Or a region being uplifted (geologically) so it goes from deep sea to shallow lagoon to dry land. The environment will dictate the type of rock that will be deposited, or the rock will describe the type of environment it was laid down in.

Does that make sense?

Yes, that does make sense. Thank you for explaining in terms I can actually understand. Lol. Some of the information on the forum is wayyy over my head. (I often enjoy reading it though.)  Here is one of the rocks with the layers. It mostly has the tiny (or crushed?) fossils in the middle layer, although the other layers appear to have a few in them, too. 

[FranzBernhard]

Looks like there are some crionoid columnal segments in the last rock. Is it possible to make a close-up photo of the "best" spot?
Thanks!
Franz Bernhard

[BLT]

19 minutes ago, FranzBernhard said:

Looks like there are some crionoid columnal segments in the last rock. Is it possible to make a close-up photo of the "best" spot?
Thanks!
Franz Bernhard

Absolutely! I just took a few pics of the areas that seem to have identifiable fragments.

[BLT]

[BLT]

[BLT]

[FranzBernhard]

Thanks! Some nice bryozoans there!
Franz Bernhard

[BLT]

1 minute ago, FranzBernhard said:

Thanks! Some nice bryozoans there!
Franz Bernhard

You are welcome! ~ Tracey

[FranzBernhard]

24 minutes ago, BLT said:

But I am not totally sure that this is also a bryo. Other oppinions required!
Franz Bernhard

 

[Bronzviking]

Tracey, I see a bryozoa bottom left. This cone-shaped critter resembles the orthocone. Is it raised or is it an impression in the rock? We still have to consider era like in your last post but cool critters for sure!

[BLT]

40 minutes ago, Bronzviking said:

Tracey, I see a bryozoa bottom left. This cone-shaped critter resembles the orthocone. Is it raised or is it an impression in the rock? We still have to consider era like in your last post but cool critters for sure!

Gotcha. Thanks! The white area is an impression. The attached dark area is raised and ridged. It is also very thin. I took more pictures.