Giant Inoceramus clam?

[KimTexan]

I am a bit excited and probably rash in my thinking on this. I’m sitting in a creek and I believe I’m sitting on the remains of the largest clam I have ever seen. I’m having a hard time processing it and don’t know how to confirm my suspicions of how large this beast is.

Would anyone even be interested in checking this out?

Here are some pics.

If I am correct this clam goes at least from a foot to the right of the black thing to at least 3 feet to the left of my hammer.

 

This is is a layer of shell across the top of it.

More shell

Sounds like I may have an overactive imaginations, but I’m not sure how to explain it otherwise.

What do you guys think?

[Rockwood]

Not seeing the crystalline structure I would expect in a cross section. Can you ?

[Plantguy]

That ribbing looks very likely so you got my interest. I've seen pictures of huge ones (seems like people sized at I recall) but all I have is a very small one. ...How much time are you willing to invest in picking at it to expose more ....Have fun if you go down that path...Be interested in hearing what the local collectors say...

 

Regards, Chris 

[Rockwood]

23 minutes ago, KimTexan said:

3 feet to the left of my hammer.

The shell of a clam that size would be fairly thick. 

[KimTexan]

15 minutes ago, Rockwood said:

The shell of a clam that size would be fairly thick. 

Yes it would, but that doesn’t mean all of it would be preserved. This is the Austin Chalk where most everything is a steinkern in Chalk. You do find shell fragments in the Chalk though. I’ll post more pics later.

[Nimravis]

I say pitch a tent and work on it all night, and then report back in the morning. 

 

That really does look like a hard job Kim, but it would be nice to see some more of exposed, just for the seeing.

[BobWill]

I've seen some very large ones in the Duck Creek Formation and the ribbing is certainly oversized enough for a big one.  Sometimes layers of the shell get preserved as calcite and can be very thin so it's a possibility. I would try to knock off some of the overlaying matrix along the edge to have a look at the very least. Even if all you get to take home is a photo it would be worth a little effort if you're right.

[KimTexan]

How large have you seen them?

Preserved as calcite. That is helpful. Because two sides of the mass look a bit like calcite, but not quite and there is calcite in spots. I brought home 2 fragments that look a tad like calcite.

This mass of Chalk is sitting in the creek crossing the creek like a road bump that never eroded. The rest of the creek is eroded away flat for the most part. That in itself is a bit strange. I’ve hiked a lot of creeks in North Texas and that is something you just don’t see because of the makeup of the rocks. 

There are multiple clams at this location. One I found was at least 2 feet from hinge to edge of shell, but I couldn’t see the hinge or edge of shell.

I’ll post some more pics in a bit.

[DPS Ammonite]

Here's a post with a photo of several "medium" sized Inoceramus  clams from White Rock Creek in Plano, Texas. Note hammer for scale:

http://www.thefossilforum.com/index.php?/topic/67131-texas-inoceramus-clam/&tab=comments#comment-704698

 

 

[Ramo]

I've seen tons of huge clams in the niobrara.  Some species are almost paper thin, others over an inch thick.  All broken into numerous pieces.  I'm not too familiar with your fossils down there,  but I bet it is a big clam.

[KimTexan]

Ok. I’m not sure these pics will convince anyone. It is eroded away so it is hard to tell what you’re looking at.

I think it helps to have been hiking the creeks and getting to know how these clams look when really worn down. The best ones I have are from the North Sulfur River, but those don’t have shells either.

 

This is standing on the south edge of the beast. The areas circled in red are exposed shell that is very thin. They are in the same plane or layer/level. There is more shell to my right about 2 feet.

 

I forgot to rotate this one. More shell showing ribs. My finger is in the trough of one. You can see the layer of rock above it conforms to the same pattern of waves.

 

This is on the north side of it. The small circled area is an area that is better preserved with the crystalline structure. It has probably been more recently exposed than the area above it to the left, which kind of has that crystalline look to it. This is going up the side of the clam or may be a cross section of the clam. Not sure. The clam looks longer than wide so I assume the edges broke away.

 

Closer up of the part on the left.

 

This is looking from the top down closer to where I assume the hinge would be on the SE edge. You can see calcite looking veins that also look like clam or oyster shell that appear to have many layers.

 

Same area, but a little further west. The small circled area is the typical characteristic edge of an Inoceramus clam. This area in the pic is about 2 feet long.

 

This is a shot of the same area only from the side looking towards the north. Top center you can see the thin shell layers in the previous 2 pics. To the right where it turns brownish to grey you can see what looks like shell layers. This whole edge looks a bit calcite like in structure, but is a softer material due to weathering I believe.

 

 

This is another clam nearby. I can’t see the edge or the hinge, but what I can see looks to be about 2 feet. So it’s over 2 feet.

 

 

[KimTexan]

1 hour ago, Ramo said:

I've seen tons of huge clams in the niobrara.  Some species are almost paper thin, others over an inch thick.  All broken into numerous pieces.  I'm not too familiar with your fossils down there,  but I bet it is a big clam.

So how big have you seen them?

I read that the largest Inoceramus clam was over 3 meters, just about 10 feet wide.

I tried exposing more of the shell, but it is very fragile and comes off on chunks of why I’m removing at times.

The issue is that they are mostly steinkerns with only the outer or inner most layer being preserved, not the whole shell. I think it is the outermost layer because I’ve seen some with something growing on them,

 

[DPS Ammonite]

The biggest Inoceramus clams from the Plano area that I have seen are between 36 and 45 inches across.

[Rockwood]

2 hours ago, KimTexan said:

I think it is the outermost layer because I’ve seen some with something growing on them,

Sounds quite possible periostracal foils (with bacterial assist) are sometimes all that remains as a fossil.

[fifbrindacier]

5 hours ago, KimTexan said:

This is another clam nearby. I can’t see the edge or the hinge, but what I can see looks to be about 2 feet. So it’s over 2 feet.

It seems to me you have a huge inoceram clam with bits of shell preserved.

For comparison, look at that Inoceramus Steenstrup (i'm not meaning you have that species) from the Greenland Institute of Natural Resources (the other valve of it is in the Geological Museum of Copenhague), Denmark. It is 70 inches long.

This species lived between 83 and 63 million years ago.

[caldigger]

A couple of those would make one heck of a clam bake!

[dalmayshun]

wow

[RJB]

Ive seen some really big clams in my time and those look like big clams.  The thing is, what do you do with them? 

 

RB

[caldigger]

30 minutes ago, RJB said:

Ive seen some really big clams in my time and those look like big clams.  The thing is, what do you do with them? 

 

RB

Clam chowder for the entire county.

[GeschWhat]

Even if it breaks apart, I would try to expose as much as I could just to see how big it is. So cool, Kim! 

 

[Rockwood]

1 hour ago, RJB said:

Ive seen some really big clams in my time and those look like big clams.  The thing is, what do you do with them? 

 

RB

The most practical thing I found was just collect the largest piece that you can reasonably expect to make it home with.

Of course I did forget my camera, and second trip proved impractical. 

But photos are good too. 

[KimTexan]

My question is would anyone who studies clam fossils or a museum be interested in it? I have zero interest in the thing other than it confirms my suspicions that they get enormous. My belief was that they got to be over 5 feet from fragments I’d seen in other creeks.

 

I don’t know for sure, but from the looks of what I can see, I know it sounds preposterous, but it looks to be about 8 feet from where I can see what I believe would be the front edge of the clam to the bank, where I think the hinge would be. I believe the hinge may still be under 8-10 feet of the soil in the creek bank. I didn’t have a measuring tape with me. I can’t tell how wide it was or how much of the width remains. It looks like quite a bit may have eroded away or it was broken before being fossilized.

There are a few other quite large clams near it, but nothing the size of it.

[KimTexan]

19 minutes ago, Rockwood said:

The most practical thing I found was just collect the largest piece that you can reasonably expect to make it home with.

Of course I did forget my camera, and second trip proved impractical. 

But photos are good too. 

I have no interest in the clam. 

Taking pics of it is like taking pics of a dinosaur skeleton with only the end of the femur exposed here, the ischium there and a phalange elsewhere. You can’t really capture the value of it for others in pics until it is excavated.

I tried uncovering more shell, but often the shell fragments would stick to the rock fragment I was removing rather than staying with the whole.

 

Here are a few pics of the mass. The water in this area of the creek is largely backed up by construction debris and a few trees that got pushed into the creek with the construction and clearing of land.

I don’t know if these clams had wavy edges or not. There is a wave in the rock face on the front edge. Makes me wonder what made that happen. It is within the area where I’d expect the clam to extend to. My bag and hammer are sitting where I found the exposed shell.

 

This is it from the south looking to the north. My rock hammer is there for perspective. From what I can tell from clam shell pieces it extends into the bank on the right and over to near were you can see water on the left.

 

This is the piece that made me stop and look around. I wasn’t sure if it was just stone or clam. The edges of it had that almost crystalline look to them, but very worn. Also, I’ve found some clams with the layers like this that were flaking and crumbling away. This is maybe 3 x 2.5 feet.

At first I thought it was the clam, but as I looked I realized it extended far beyond this piece. I think it’s part of the clam, but could be wrong.

 

There is clam shell exposed in spots all along this edge. I’m not sure which are from the big clam though. One I’m sure is from another clam, because the ridges are much smaller, but it is still a large clam.

 

If it is indeed clam this is the exposed cross section of sorts of the edge of the clam. It appears it goes further down than is exposed. This edge has that kind of crystalline look typical of Inoceramus cross sections, but it does also look almost calcite like, but if either it is weathered significantly from long exposure and is not definitively either.

From all of this it would seem the bottom side of the clam is still likely present and not weathered. Whether it was preserved to the degree that it is identifiable or not is a different matter. You’d never know unless you excavated it.

If it were preserved it would make a spectacular museum piece. 

 

Maybe I’ll email Tom Dill and Roger Farish to get their thoughts. Tom is the Dallas Paleontological Society president and Roger is a retired paleontologist who is a long time DPS member and more I’m sure.

 

It seems like it may be worthy of study or examination for scientific purposes just because of the size. I wish the preservation were better. It appears to have been exposed a long time.

[KimTexan]

5 hours ago, fifbrindacier said:

 

For comparison, look at that Inoceramus Steenstrup (i'm not meaning you have that species) from the Greenland Institute of Natural Resources (the other valve of it is in the Geological Museum of Copenhague), Denmark. It is 70 inches long.

This species lived between 83 and 63 million years ago.

I have seen this pic before. I became curious as to how large the Inoceramus got a while back and went looking for info after I’d found some large fragments in the Duck Creek Formation.

I’m sure it is a different species, but if you compare the width of the ridges of the one pictured above to the width of ridges on what I found yesterday I believe the width on the one I found may be greater. Where the ridges were exposed was about 3 feet from where I believe the front edge of the clam would be, so the width would only get bigger.

[Rockwood]

30 minutes ago, KimTexan said:

It seems like it may be worthy of study or examination for scientific purposes just because of the size.

In your situation I think you nailed it.