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MeargleSchmeargl

Modern shells and fossil shells: How to tell the difference?

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MeargleSchmeargl

I look at many a shell that I walk upon on a beach or creek, even at established fossil sites, and I wonder if some of these shells are fossil or not. This is particularly an issue at a place like the Calvert cliffs, where modern shells could wash from the Potomac just as easily as any fossil shells, and what makes it worse is that fossil and modern shells many times even have very similar color in places like river locations. As I am not a huge expert in fossil shells (or in particular, Bivalves as this would be the most common occurrence of confusion, being the most common modern shells on the banks of rivers), what are the big distinguishing features between modern and fossil shells?

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ynot

For Me it is whether it is set in rock or not, for others it is more an age thing.

Can be very hard to identify a fossil of an extant species that has a long history.

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Al Dente

Sometimes you can’t tell if a shell is old or not. When you go to the beach some shells are modern and many are hundreds to thousands of years old and they all look alike. 

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*THEO*

Some fossil bivalve shells can preserve their original color markings for millions of years and this makes the differentiation between fossil and non-fossil shells even harder:(.

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Spinosaurus

@Max-fossils knows a lot about fossil shells. maybe he can tell you.

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Tidgy's Dad

I guess it's just practice, experience and getting to know the localities. You get a 'feeling' for what's right and wrong. 

But in some cases I don't think there's any way you can tell. 

Unless you've got access to dating equipment! 

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Max-fossils
8 minutes ago, Tidgy's Dad said:

I guess it's just practice, experience and getting to know the localities. You get a 'feeling' for what's right and wrong. 

 

 

Very true. For me on the Zandmotor, there are both modern and Eemian shells, many of the same species. It can be incredibly hard to tell the difference between modern and fossil. Well, there are some tricks, but they don't work perfectly well. But now I can often recognize or feel whether a shell is fossil or not. Most of the time... 

The real struggle for me still are the oysters, the fossil ones and the modern ones are IDENTICAL :doh!:

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WhodamanHD
15 hours ago, MeargleSchmeargl said:

This is particularly an issue at a place like the Calvert cliffs,

Very much an issue. Only way to be sure is taking into account what is found in chunks of matrix. The cool thing with some is the original shell material is preserved, especially on some Chesapectans. Awe inspiring to hold the original shell of a 5 million year old creature. Sometimes you’ll get this with the Devonian too (need to be very lucky for this, @Rocky Stoner found one).

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Max-fossils

@WhodamanHD @MeargleSchmeargl just out of curiosity, what other fossil shell species (apart from Chesapecten nefrens and Ecphora gardnerea) do you find at Calvert?

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MeargleSchmeargl
1 minute ago, Max-fossils said:

@WhodamanHD @MeargleSchmeargl just out of curiosity, what other fossil shell species (apart from Chesapecten nefrens and Ecphora gardnerea) do you find at Calvert?

Found a historical president (*cough cough* Jeffersonius *cough cough*)

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Max-fossils
1 minute ago, MeargleSchmeargl said:

Found a historical president (*cough cough* Jeffersonius *cough cough*)

Like this one? (Chesapecten jeffersonius)1200px-Chesapecten_Jeffersonius_Outside.jpg.3ec13ad959d55fcfdb68c9bc08b861d8.jpg

 

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WhodamanHD
3 hours ago, Max-fossils said:

@WhodamanHD @MeargleSchmeargl just out of curiosity, what other fossil shell species (apart from Chesapecten nefrens and Ecphora gardnerea) do you find at Calvert?

Ecphora Gardenerae ;)

ecphora quadricostrata, panopea Americana, ostrea sp., Isognomon sp., chesacardium, glycemeris, Venus clams, turritella, the list goes on (and on and on). A pretty diverse fauna in the Shelly beds (Choptank FM beds below):

9E9064EC-721E-492D-AFB0-8768282E35C0.jpeg

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Max-fossils
20 hours ago, WhodamanHD said:

Ecphora Gardenerae ;)

ecphora quadricostrata, panopea Americana, ostrea sp., Isognomon sp., chesacardium, glycemeris, Venus clams, turritella, the list goes on (and on and on). A pretty diverse fauna in the Shelly beds (Choptank FM beds below):

 

7

Cool! Thanks

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MeargleSchmeargl
On 2/13/2018 at 11:56 AM, Max-fossils said:

Like this one? (Chesapecten jeffersonius)1200px-Chesapecten_Jeffersonius_Outside.jpg.3ec13ad959d55fcfdb68c9bc08b861d8.jpg

 

Right on the money. 

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Max-fossils
31 minutes ago, MeargleSchmeargl said:

Right on the money. 

Whoa, very cool! Would love to see a picture of yours :)

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MeargleSchmeargl
13 minutes ago, Max-fossils said:

Whoa, very cool! Would love to see a picture of yours :)

Don't have images, but it ain't the most complete specimen nonetheless...

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Max-fossils
Just now, MeargleSchmeargl said:

Don't have images, but it ain't the most complete specimen nonetheless...

Ah, ok.

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