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Geology/Rock? With fossilized bones- many bones


Hello, I found what looks like to me possibly a fossilized dinosaure dropping. After a heavy rain fall at the camp grounds we found it peaking out of the sand. It is in the shape of an egg but it's loaded with fossil bones. It is 9 1/2 in long. I am hoping to attach a picture. Thank you

Hi Kim,
Very interesting specimen you have there.

Technically it's a bioturbated mudstone.  "Bioturbated" means that the sediment was disturbed by living things; animals, plant roots or, in this case, worms.

The structures you are seeing are not fossil bones, but they are fossils.  They are the remains of the burrows left by worms or other invertebrates.  As the critters moved through the mud they created the tunnels which later filled with mud and minerals.   

Here are a couple of sites that show how complex worm burrows can get:

Hope this helps.


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C. Robert Reszka, Jr.


I can answer any general geology question (rocks, minerals, stratigraphy, geomorphology etc.). My expertise is in the geology of the Michigan Basin, PreCambrian, Paleozoic and Recent. I can answer questions concerning mining and petroleum exploration and production and the laws concerning those activities. I can also answer questions concerning stratigraphy of the Michigan Basin. I will also answer questions about mineral and rock collecting in the Basin. I won`t be able to answer many specific questions on hydrology, geophysics or geochemistry. I may be able to answer very general questions in those venues.


I have been working for the State of Michigan for 36 years as a Geologist and a Resource Analyst. I have experience with Subsurface Geology and Petroleum Geology, mining in Michigan, and Sand Dune Mining and Protection issues.

Michigan Basin Geological Society

Decade of North American Geology.
Bedrock Geology of Michigan

BS Wayne State University

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