Nanjemoy MD fossil ID #1

[MGooden]

Good evening, brand newbie here. We recently went shark tooth hunting on the beach at Purse State Park in Maryland and along with sand Tiger/goblin/mackerel shark teeth, Gastropod internal molds, stingray dental plates, I collected a few other items that seemed unique. I looked online at some fossil sites for the Paleocene era but man I have to admit I was ready to toss these. Figured it was worth an ask here. 
 

I used the centimeter side of my ruler to take photos of each of the items and will post each in a separate post. 
 

 

Edited December 14, 2022 by MGooden

[val horn]

Skolith

[Rockwood]

Horizontal of  Skolithos or Planolite I think is more in order, based on how I read the bedding. Such a small piece is hard to be certain of though.

[val horn]

How do they differ?

[Rockwood]

21 minutes ago, val horn said:

How do they differ?

In orientation to the sediment surface. Skolithos are perpendicular,  Planolites are nearly parallel with or on the surface (bedding plane).

[MarcoSr]

This is not a Paleocene trace fossil.  It is much older, Cambrian Period.  It washed downriver from much older deposits. 

 

Marco Sr.

[MGooden]

4 hours ago, MarcoSr said:

This is not a Paleocene trace fossil.  It is much older, Cambrian Period.  It washed downriver from much older deposits. 

 

Marco Sr.

Oh wow, that is so interesting! Thank you so much for sharing.

Edited December 14, 2022 by MGooden

[MGooden]

16 hours ago, Rockwood said:

Horizontal of  Skolithos or Planolite I think is more in order, based on how I read the bedding. Such a small piece is hard to be certain of though.

Thank you for this information. And this would be from the Cambrian Period, as Marco Sr. mentioned?

[MarcoSr]

9 hours ago, MGooden said:

Thank you for this information. And this would be from the Cambrian Period, as Marco Sr. mentioned?

 

I should have been clearer.  You can find Paleocene Skolithos but the geologic age of the rock  is Cambrian according to my good friend Dr. Weems, a USGS emeritus.

 

Marco Sr.

[MGooden]

On 12/15/2022 at 7:52 AM, MarcoSr said:

 

I should have been clearer.  You can find Paleocene Skolithos but the geologic age of the rock  is Cambrian according to my good friend Dr. Weems, a USGS emeritus.

 

Marco Sr.

I appreciate your response! this language is all new to me, so sometimes I'm confused as to how to ask a question. So to clarify does this mean the rock itself is from the Cambrian period but the fossil of the Skolithos was created during the Paleocene period?

Edited December 17, 2022 by MGooden

[Rockwood]

57 minutes ago, MGooden said:

So to clarify does this mean the rock itself is from the Cambrian period but the fossil of the Skolithos was created during the Paleocene period?

The trace fossil was  most likely created during the Cambrian Period at the time the rock was deposited. The name of the trace may be what is thrown in doubt by this information. Trace fossils are named for their morphology and not a specific maker. When the complete shape is not seen clearly identifying traces can be tricky.

[MGooden]

1 hour ago, Rockwood said:

The trace fossil was  most likely created during the Cambrian Period at the time the rock was deposited. The name of the trace may be what is thrown in doubt by this information. Trace fossils are named for their morphology and not a specific maker. When the complete shape is not seen clearly identifying traces can be tricky.

That makes sense. Thanks so much!

[MarcoSr]

7 hours ago, MGooden said:

I appreciate your response! this language is all new to me, so sometimes I'm confused as to how to ask a question. So to clarify does this mean the rock itself is from the Cambrian period but the fossil of the Skolithos was created during the Paleocene period?

 

Let’s try to explain it this way.  Back in the Cambrian you had a sandy sea floor.  A marine creature then borrowed into that sand or fed in that sand causing the raised line (the raised line is the trace fossil.  It is not the remains of the marine creature itself but evidence of the marine creature burrowing or feeding in the sand) that you see in your piece.  That sandy line and surrounding sand turned to stone over the millions of years.  Natural forces then broke up the stone layer and your piece was carried away by the Potomac River to where you found it.

 

Marco Sr.

Edited December 17, 2022 by MarcoSr
totally rewrote and added to the reply

[MGooden]

13 hours ago, MarcoSr said:

 

Let’s try to explain it this way.  Back in the Cambrian you had a sandy sea floor.  A marine creature then borrowed into that sand or fed in that sand causing the raised line (the raised line is the trace fossil.  It is not the remains of the marine creature itself but evidence of the marine creature burrowing or feeding in the sand) that you see in your piece.  That sandy line and surrounding sand turned to stone over the millions of years.  Natural forces then broke up the stone layer and your piece was carried away by the Potomac River to where you found it.

 

Marco Sr.

That is excellent, thank you so much for the very thorough explanation. Clearly I'm super new to fossils and overwhelmed with Google research, so this is super appreciated - all of yall!