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The Upper Ordovician Nautiloid Beds of Graf, Iowa


Nimravis

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1 hour ago, Nimravis said:

It is like the Conasauga   :)

Ooh now I'm really interested! :D

Every single fossil you see is a miracle set in stone, and should be treated as such.

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2 hours ago, Nimravis said:

It is like the Conasauga   :)

Like the Conasauga? To the bucket list! :D

Every single fossil you see is a miracle set in stone, and should be treated as such.

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1 hour ago, MeargleSchmeargl said:

Like the Conasauga? To the bucket list! :D

No, to the amount of trilobites that are found at the Conasauga site.

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5 minutes ago, Nimravis said:

No, to the amount of trilobites that are found at the Conasauga site.

I know. Still interested! :D

Every single fossil you see is a miracle set in stone, and should be treated as such.

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@KimTexan  Please note I did not write that Nautili mated and died. I noted the theory for the survival of the Chambered Nautilus was due to their reproductive strategy of mating multiple times. Only know what I read about modern squid, belemnites and ammonites mating and dying.

 

@Nimravis I was able to access Witzke and Glenister 1987 "Upper Marquoketa Formation in the Graf area, eastern Iowa through Google Scholar PP103-108 Note especially "Marquoketa Deposition" pp106-107  if I understand it correctly "episodic mass mortalities occurred in surface waters that were oxygen and nutrient rich" this attracted large numbers of nautiloids. Mass extinctions occurred when there was an influx of oxygen poor, phosphatic rich water that killed off the fauna.

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On ‎4‎/‎8‎/‎2018 at 12:04 AM, KimTexan said:

I’m with @MeargleSchmeargl. If I am ever up that way I must take a detour. I’d love to go there.

That is an awesome place!!! Wow! I’ve never seen anything like it for cephalopods. Very cool. Thank you for sharing your trip. Love the pics.

 

@fossilnut I’m not sure about the mating one time and then dying. Some of them can get huge. My dad lives near Fayettevile, Arkansas and there have been a couple very large orthoceras found there which were in the 5-6 feet range. Also, someone posted a fragment of one on here a month or so ago from SE Kansas that was quite large. I suppose there could have been some physiological or anatomical problem that prevented those individual specimens from mating, but that seems like it would be a very rare occurrence.

Regarding ammonites on the same topic. I’m rather skeptical they only mated once when they come of age and then died, because some of the ones we find in Texas are enormous, over 40 inches.

Someone from the Dallas Paleontological Society told me that one of the members had found a 6 foot one in Texas once. Then there is one 8 foot 6 inch one found in Munster, Germany. I’m not sure how such great size can be explained if they can only mate once and die. There must be more to the story. I do know some species mate and die. I don’t question that. But how would we get the monstrous sizes if it were so? If they lived now we would have ammonite tales like we have shark, alligator and crocodile stores. They’d be big enough to devour a human.

 

 

6ft monster was at the bottom of the creek we were crossing . (Central Texas)

Could not cross at spot where we saw it. Crystal clear water 4-5ft deep.

 

I personally have only found two of what I would consider enmasse die offs of cephalopods.

Both were isolated stones, one contained ~300 ammonites the other stone contained ~200.

The strange thing about both stones found miles apart most of the specimens, contained in the stones,

were within a quarter of an inch in size of being the same size.

Cephalopod mass die offs did occur but as to when and why is debatable. 

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@Nimravis@KimTexan@bone2stoneWanted to pass on 2 interesting cephalopod sites you may not know about. www.tonmo.com/pages/nautiloids Nautiloids the first cephalopods.  There is a section on giants and speculation on pathological giants. Also www.the cephalopodpage.org/ammonite.php  Ammonite maturity and old age. The Chambered Nautilus (extant) lives for 15 years but only becomes sexually mature at 10 years of age. Reproduces for the last five according to the literature. Whether this translates back to fossil nautilus forms is uncertain. Hope you find these sites useful

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