Teeth or scales?

[aek]

I came across about a dozen o f these. They measure <1mm. Middle Devonian, Cedar valley group Iowa. Any help appreciated. 

 

 

Edited August 16, 2022 by aek

[Al Dente]

The squared base makes me think of Acanthodian scales.

 

 

[aek]

@Al Dente thanks

[connorp]

Very neat, glad to see you found some cool stuff.

[aek]

@connorp thanks,  fun trip. Some interesting micros in these rocks. I have a ton more to process from different layers.

[connorp]

1 minute ago, aek said:

@connorp thanks,  fun trip. Some interesting micros in these rocks. I have a ton more to process from different layers.

Looking forward to seeing what you find. Were these scales from the fish layer on the top bench?

[aek]

58 minutes ago, connorp said:

Looking forward to seeing what you find. Were these scales from the fish layer on the top bench?

These came from a blue-ish gray layer deeper in the quarry. Not sure which layer unfortunately,,mid-lower. 

[aek]

@connorp after skimming through guidebook 87 these may have come from the bellula beds of the lower Rapid member. I'm judging this by looking at what I think might be a badly dissolved bellula brachiopod from the sample.

[connorp]

@aek How are you breaking down these samples?

[aek]

56 minutes ago, connorp said:

@aek How are you breaking down these samples?

The rocks are broken down into pieces less than inch diameter then dissolved in dilute formic acid. The residues are sieved, rinsed and then examined under microscope.

[connorp]

9 minutes ago, aek said:

The rocks are broken down into pieces less than inch diameter then dissolved in dilute formic acid. The residues are sieved, rinsed and then examined under microscope.

Are these from shales or limestones?

[aek]

4 hours ago, connorp said:

Are these from shales or 

Limestone