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Some Blue Hill Shale Photos


Ramo

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Took a little walk through some shale, and found what I usually find there: lots of concretions and no fossils. Many of the concretions have what look like ammonite shell parts in them, but I've never found much in the shale. I like to look at field photos of different places, and thought some of you might want to see these.

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For one species to mourn the death of another is a new thing under the sun.
-Aldo Leopold
 

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Took a little walk through some shale, and found what I usually find there: lots of concretions and no fossils. Many of the concretions have what look like ammonite shell parts in them, but I've never found much in the shale. I like to look at field photos of different places, and thought some of you might want to see these.

you obviously found a sea turtle laying her eggs on the beach!

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Sorry about the big pictures, but I took the wrong camera, and I'm not smart enough to resize photos.

post-40-1234393538_thumb.jpg

For one species to mourn the death of another is a new thing under the sun.
-Aldo Leopold
 

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Last photo. This appears to be ammonite shell material to me. What do you think?

post-40-1234393634_thumb.jpg

For one species to mourn the death of another is a new thing under the sun.
-Aldo Leopold
 

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Guest N.AL.hunter

I once found similar stuff that turned out to be shell remains of a large type of oyster called something like Inoceramus. That's the best my memory allows.

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Bowkill,

I found this definition of a concretion;

A concretion is a compact mass of mineral matter, usually spherical or disk-shaped, embedded in a host rock of a different composition. This hard, round mass of sedimentary rock cement is carried into place by ground water. Concretions, the most varied-shaped rocks of the sedimentary world, occur when a considerable amount of cementing material precipitates locally around a nucleus, often organic, such as a leaf, tooth, piece of shell or fossil.

(Credit www.desertusa.com with the definition.)

A lot of time what happens is that the animal/plant/tooth/etc., that is the center of a concretion, in decomposition releases phosphorous which alters the sedimentary rock chemistry creating the "different composition" of rock in the host rock. Think calcium phosphate in a calcium carbonate world.

Umm, this all made a lot more sense to me before I wrote it.

JKFoam

The Eocene is my favorite

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I once found similar stuff that turned out to be shell remains of a large type of oyster called something like Inoceramus. That's the best my memory allows.

I don't know why, but for some reason, I was thinking Inoceramus when I looked at that picture. I found one in a concretion. It still has some shell material.

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