• Sam Ocon posted a new activity comment 10 months, 4 weeks ago

    10 months, 4 weeks ago
    10 months, 4 weeks ago

    Hi, @Angela-Baxter. Where in Michigan did you find this? We can use Macrostrat: https://macrostrat.org/map/#/z=1.5/x=16/y=23/bedrock/lines/ to figure out how old it is.

  • Jennifer Bauer posted a new activity comment 11 months ago

    11 months ago
    11 months ago

    Hi @angela-baxter & @i-edwards – it’s certainly possible it’s banded chert! It’s hard to make a confident ID without more images. Chert would be pretty hard so if you tried to scratch it with the penny it shouldn’t make a mark. If it was calcite it may make a mark! Could be a next step test.

  • Isaac E. Pope posted a new activity comment 11 months ago

    11 months ago
    11 months ago

    Greetings, @angela-baxter and @jbauer! Banded chert was my first thought as well; observe the conchoidal fracturing along the edge on the lower right. At the very least, the mineralogy is cryptocrystalline silicate (which is often involved in permineralization) but banded chert is logical to me.

  • Sam Ocon posted a new activity comment 11 months ago

    11 months ago
    11 months ago

    Hi @Angela-Baxter! I agree with everyone’s ID of horn coral. Would you be willing to update the taxonomy to reflect this ID? It would be Kingdom -> Animalia; Phylum -> Cnidaria; Class -> Anthozoa. We can also work together to figure out what age this is and what rock unit this came from.

  • Jennifer Bauer posted a new activity comment 11 months ago

    11 months ago
    11 months ago

    Interesting specimen @angela-baxter. This certainly looks like a fossil. Are there any other features on the other side? And to confirm you found it in Michigan?

    It’s possible it is a stromatoporoid, sort of a mat forming sponge that forms in interesting layers with bumps on the top. https://en.wikipedia.org/wiki/Stromatoporoidea