For the Shell of It

Went back to the desert wash near Jean,  Nevada where I had found my first geode. Was looking for more. Didn’t find any but I may have found my second and third brachiopod or fossilized shell.

The first example is pretty convincing but the second is a mite odd. I see by a Google image search that brachiopods are often distorted.

Too many times a publication or a web page presents perfect specimens instead of what is usually found in the field. I’ve posted the images to the Fossil Forum on FB, I’ll see what they say.


Phivos Martin Broedsgaard-Raptis from the FB Fossil Page responded to the second specimen. “We call it a ‘mussel fracture’, it comes as a resulted of a concentrated force and radiates outwards from the point of contact.” I am assuming that something injured this poor mussel and the resulting damage was captured in stone.

Or, perhaps not. There is a geological process called plumose fracture. See the Wikipedia Common photo below. Okay, what do we have? A biological phenomenon or a geological one? I’m leaning to biologic because the rock is round and not a square or chip fragment.



OR

Fig. 3.20f: Plumose structure and rib marks on an opening fracture in PMMA. Laboratory experiment (Rummel, 1987) on hydraulic fracturing induced fracture from pressurized cylindrical hole at left. - David D. Pollard

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