Seashells: fossil or not?

[Max-fossils]

Hello everyone,

 

Hereby three shells. I would like to know whether they are fossil or not, because I can't tell...

Pics 1 & 2: a gastropod from an unknown location (8cm long). Also, does anyone know the species?

 

Pics 3 & 4: two rough piddocks (Zirfaea pilsbryi) (each about 7 cm). The white one is from an unknown location; the blue/grey one was found on the Zandmotor (Pleistocene fossils and modern material).

 

Thanks in advance for your help,

 

Max

[Max-fossils]

[Fossildude19]

Where were they found, Max?

[ynot]

The divider lines between fossil and non fossil is not always very clear. It is easy to say it is a fossil if it has been set in stone. But when it is old but has not been lithified, then the only way to tell is by where it came from. Many sites that are very old have not had the shells lithified, but they are still considered fossils.

Tony

[Max-fossils]

25 minutes ago, Fossildude19 said:

Where were they found, Max?

It says already: the gastropod is unknown, the white piddock also unknown, and the blue/grey piddock is from the Zandmotor (NL)

[Max-fossils]

24 minutes ago, ynot said:

The divider lines between fossil and non fossil is not always very clear. It is easy to say it is a fossil if it has been set in stone. But when it is old but has not been lithified, then the only way to tell is by where it came from. Many sites that are very old have not had the shells lithified, but they are still considered fossils.

Tony

Thanks for the great explanation! The Zandmotor is a rather recent site (Pleistocene) and the location only exists since a few years. You can read a lot about the Zandmotor by doing a quick Google search. Also, the fossils from the ZM (short for Zandmotor) are ready to be picked up, they're not set in stone.

The criterias for the ZM to see whether a seashell is fossil or not are:

1) it kind of feels like stone

2) the colors are dull, and from white to dark grey

3) (this only works for a few bivalves) see if light passes through it (if yes, you're sure it's not fossilized; if no, it could be fossil, but it's not sure)

 

But those criterias don't always work. For example, oysters, even fossil, are still a bit shiny; and they never let light pass through (modern and fossil). In fact,any seashells from the ZM have their own criteria to know whether they are fossil or not; and I have no clue what the criterias are for piddocks, though I think that they're the same as those listed above.

 

But all the things I just said are only for the ZM and the other beaches from Holland. While the gastropod and the white piddock probably come from somewhere else. 

 

Thanks for the help, 

 

Max

[Fossildude19]

32 minutes ago, Max-fossils said:

It says already: the gastropod is unknown, the white piddock also unknown, and the blue/grey piddock is from the Zandmotor (NL)

 

 

Oops. Missed that somehow.  

[Ramon]

Probably not a fossil.

[Max-fossils]

11 hours ago, Ramon said:

Probably not a fossil.

Thanks, but can you tell me why you think that?

[Rockwood]

I wonder if, in theory even, a person could show a shell to be modern by studying the growth lines and comparing them to climatalogical data in a way similar to what dendrochronologists use to date wood ? 

[Max-fossils]

5 minutes ago, Rockwood said:

I wonder if, in theory even, a person could show a shell to be modern by studying the growth lines and comparing them to climatalogical data in a way similar to what dendrochronologists use to date wood ? 

That is a good idea! Yet I have no clue on how to do that

[Rockwood]

2 hours ago, Max-fossils said:

That is a good idea! Yet I have no clue on how to do that

Just sort of planting a seed. If you ever end up using the concept you can give me a credit in your Nobel acceptance speech  

[Max-fossils]

1 hour ago, Rockwood said:

Just sort of planting a seed. If you ever end up using the concept you can give me a credit in your Nobel acceptance speech  

Haha, I surely will!