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Trace fossils? Coral? Anemone? Worms?!?


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Hey there!  This is my first post on The Fossil Forum.  I don't have a lot of knowledge about fossils, but I sure do know how to find them.  Hopefully these aren't too obvious and boring, but I'm incredibly curious anyway.  I found these near Sheep Bridge north of Phoenix, Arizona.  Here the Verde river has cut through deep layers of ancient lava, sandstone, mudstone, etc.  I was exploring for crystals up on a steep hill along the river's canyon walls when I came across a whole lot of these things.  They are very fragile and I didn't want to break apart some of the 2-3 foot wide boulders of them so as to preserve them for others to find.  Anyway, my understanding is that this area was once a sea floor, so I'm assuming they are some type of coral, anemone or something similar.  The fossils are composed mostly of the same sediment which encases them, so I suppose they must be trace fossils, but please correct me if I am wrong.  Other not-so-filled-in ones even had crystals and other minerals lining the cavity.  As well, I looked at a geological map of Arizona and the area I was exploring is composed of the following...  

Late to Middle Miocene Basaltic Rocks (8-16 Ma):  Mostly dark, mesa-forming basalt deposited as lava flows. 

Pliocene to Middle Miocene Deposits (2-16 Ma):  Moderately to strongly consolidated conglomerate and sandstone deposited in basins during and after late Tertiary faulting. Includes lesser amounts of mudstone, siltstone, limestone, and gypsum. 

There are a couple photos of some ball shaped objects which were very easy to knock apart from the surrounding stone.  I have no idea what those could be.  The rest of the photos are of the coral looking objects.  Some of them, if still intact, were nearly 24 inches long, but I left those behind and only took smaller samples.  Please note how the "head" of the corals appears to flare out and is larger than the rest of the stem.  Finally, some of them appear to have a little node sticking out of the "head," but I suspect that may be due to weathering as these are very fragile fossils.  Thank you all so much for your interest and help and I look forward to learning more!























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Tidgy's Dad

I think they are burrows. 

Something burrowed down into the seafloor sediment or maybe even rock and built a calcite tube for itself. 

The burrows later became infilled with sediment themselves and preserved as these molds. 


Hello, and a very warm welcome to TFF from Morocco. :)

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DPS Ammonite

Welcome to the Forum.

I second that they are burrows.

There are no marine rocks in the area with fossils. Mostly Tertiary rocks. Did you find any of the sagenitic purple agate?

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Thank you for the quick replies you two!  This is really exciting to me and I hope to learn more about what types of little critters could have made these burrows.  I think half the joy of finding these fossils comes from letting my imagination wander while visualising the processes which created them over time.  As for the purple agates, I found some small not so glorious pieces, but my eyes must have been more focused on crystals/chalcedony because I got a lot of them!  

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15 hours ago, Arizonadirtbag said:

There are a couple photos of some ball shaped objects which were very easy to knock apart from the surrounding stone.  I have no idea what those could be.  






if encased in alluvial/eluvial terrain (but no doubt they can be found also enclosed within lithified rocks)  ,

then they  resemble someway the so called armored sand/clay balls




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