Beach Fossils

[collector]

Hi to all you fossil beach combers. Long, long ago when I was a child in a new tract house I found a shell in the woodsy area behind my house. I am attaching pictures of it. It had some kind of concretion on it but I loved shells and anything to do with the ocean so I kept it all of these years. I was born, grew up and still live in western NY. We don't have shells like this so someone had to bring it inland at some point. I recently have been reviving another childhood past time of collecting fossils and I noticed that some of the more recent coastal fossil shells look a lot like the modern ones. So my questions are how do you tell modern shells from fossil shells when you are beach combing and since I have a daughter and two sisters who live in coastal regions that I visit on occasion, how do you go about fossil collecting on the coast. Lastly I was wondering if my shell is older than I ever knew and is a fossil. It is about 5 1/2" in length.

Thanks for any input,

Patti

[MarleysGh0st]

I'm not sure if I can answer your general question about telling modern shells from fossil ones. I'd say those you find on the beach, instead of buried in sediment, are most likely modern.

This particular shell, though, is a gastropod. It looks like a channeled whelk to me, Busycotypus canaliculatus. While doing a little Googling to check my ID, I noticed some interesting information. You say you found this in the woods in western NY? You're right that these shells come from the Atlantic coast. This particular species was one that was used by the Iroquois to make beads for their wampum belts. I'm only speculating here, but perhaps they carried this shell as trade goods from the coast?

[collector]

That is an interesting idea Marleysgh0st. I have often wondered what the history of the shell was that brought it to such an unlikely spot. I have no idea how it got coated like it is.

[aqua]

Aren't shells just lovely? no factory, no human hands involved.

Cool that you kept it thru adulthood.

Shells are just precious.

[collector]

They are aqua. I am always in awe and to just find one naturally made work of art just sitting on a beach is so amazing.

[Auspex]

The encrustation may be biological; bryozoan or sponge, for example.

[collector]

There are parts of the inside that said bryozoan to me Auspex.

So to find shell fossils on the coast does one dig to find them?

[MarleysGh0st]

So to find shell fossils on the coast does one dig to find them?

Well, I was probably wrong to suggest that you dig for them. More accurately, people look for them on the beach after they've been washed out of cliffs and other fossil-bearing formations by storms, etc. Calvert Cliffs in Maryland is one such place.

I'm hoping that some of our forum members from the coast will add comments about their experiences. Seems like the goal for many of them is fossil shark teeth, though, and shells are only a poor consolation prize!

[collector]

So Marleysgh0st I should stop order on the new foldable shovel that fits in a suitcase? Just kidding. It will be fun to just poke around a bit the next time I visit my daughter. She is on the west coast south of San Francisco.

[Aurelius]

I've often wondered how on earth people tell modern shells from fossil ones. We once found a large, shiny white gastropod shell with lots of ornamentation. It looked brand new, except that it was still embedded in a small lump of rock - we'd never have known, had it come free.

Of course, the best shells of all are ammonite shells...

[collector]

It's funny how some things just resonate with people and ammonites are sure one of them. They are so neat.

Some of those crab fossils that have been on this forum are so great looking as well.

[Wrangellian]

There are definitely favorite fossil groups, and spectacular fossils from every group, but I can gain pleasure from finding even a simple bivalve imprint if it's an unusual one.

[collector]

I know what you mean Wrangellian. I'm not the kind of person that can become an expert in one area because I find them all so interesting.

[Wrangellian]

Yep... And if you're interested in the scientific as well as the aesthetic, etc. aspects then you learn to find every possible scientific 'clue' interesting. That's why I pick up everything I think has a small chance of being useful to someone doing a study, even if the chances are most of them won't be... you just never know!

[collector]

I know what you mean. I am already telling myself that I don't need to take some home because I already have enough of them and it isn't easy.

My husband is going to visit my daughter in California next week and I am trying to convince them to do some fossil hunting. My daughter said, " Oh yah I see fossils in the cliffs at so & so beach." Now they just have to get a few for me! We will see.

[Wrangellian]

You never stop looking just because you have 'enough' at home.. given the possibility that you will find something new, or a better specimen than the ones you have at home, in which case you can turf some of the lesser ones.

[BobWill]

Keep in mind that the following comes from an amateur who often gets things wrong but I thought I'd see if I can add to the confusion.

Outside of being evidence of something once alive the usual standard for "fossil" is that it be older than 10,000 years. That always seemed very arbitrary to me and not everyone agrees but it's a starting place. The cool thing about fossil shells it that they can also be found far inland in solid rock that formed from sediments laid down when seawater covered areas that are now high and dry.

I suppose a modern shell could be filled with material washed in that has particles fine enough to compact into dense clay which might be little different from some much older filler that never solidified more. So I suppose the context of where it's found, if known, would help with dating. Also knowledge of index species which had a relatively short fossil record could help.

To further complicate things, fossilization, when it involves mineralization, happens at very different rates...and the different kinds of mineralization only include a few of the many ways things can be fossilized...so....wait, what was the question?

[collector]

Thanks BobWill for all of the information. There is such a great range in age of fossils. 10,000 to what, 600,000,000 years or so ago! I have a hard time with getting my head around so many years. What got me going was seeing pictures of shell fossils that are obviously from the young end of the spectrum. They looked so much like modern shells that I would have not recognized them as fossils if I found them on a beach. That led to how do you tell the difference, is it structural differences or where they are found i.e. in rocks etc. I then remembered my funky out of place shell that is almost a fossil based on how long I've had it and thus to my dual questions.

I hope it isn't too long until I can check out some coastal cliff areas for fossils.

Patti

[Wrangellian]

The oldest fossils come from 3 500 000 000 (3.5 billion years) ago or so, but most of the obvious non-stromatolite ones are up to about 570 million. The 10 000 year cutoff at the young end is arbitrary but apparently it's as good as anything anyone has proposed so far as a workable definition! There are shells from the Eocene that you'd swear were recent, because they have managed to remain unaltered for that length of time (while other, younger ones might have been altered). There are even rare occurrences as far back as the Ordovician period of snails and the like with color patterns preserved! though they are not typically loose, white shells that you would think came from the nearest beach. Long story short, I guess the only way to tell whether a shell is a fossil or not is where it came from - if its source sediments can be determined to be 10 000+ yrs then it's a fossil. If it is found out of its stratigraphic context then probably the only chance the average collector has of determining whether it is a fossil is if you can figure out that it as an extinct species from more than 10 000 years ago.

I'm sure it's only a matter of time before you start showing us new finds!

[collector]

Thanks Wrangellian. That was a lot of good information for me. Now how am I supposed to deal with the idea of 3.5 billion year old fossils when 600,000,000 was too much! As for my funky shell it will have to remain the shell I found in the woods when I was a kid.

[Scylla]

you could always just have it radiocarbon dated:

http://www.radiocarbon.com/carbon-14-dating.htm?gclid=CImqtcKszroCFZMDOgodBkQAJA

[collector]

That was a great idea Scylla but in looking at the site I think it would ruin the shell to test it. They have to remove surface of the shell to remove contamination.

[Scylla]

Well, it all depends on how accurate you want them to be, if you are willing to live with more uncertainty, you could get away with less destructive cleaning. This isn't for a scientific publication, after all. It probably isn't worth the price, but at least now you know that someday you might be able to solve the puzzle

[Wrangellian]

Thanks Wrangellian. That was a lot of good information for me. Now how am I supposed to deal with the idea of 3.5 billion year old fossils when 600,000,000 was too much! As for my funky shell it will have to remain the shell I found in the woods when I was a kid.

Most collectors don't deal with fossils more than 525 million, I guess mainly because they're not as interesting to most people (interesting to me!) - less diverse and harder to find.

Your shell might not remain unid'd, hang onto it.

[collector]

Thank you Scylla. It is good to know there is an option.

I will be keeping my shell Wrangellian. When I was young it spoke to me of the ocean. Now it speaks to me of my childhood.

Have you posted pictures of your oh so very old fossils?

Patti