Crassostrea Gigantissima, the giant oyster

[MeargleSchmeargl]

On Wednesday, relatives have invited me to accompany them to Shell Bluff along the Savannah River, home to the Dry Branch formation which is late Eocene (approx. 38 MYA) in age. This formation is home of an oyster bed, but not just any old oysters:

 

 

Enter Crassostrea Gigantissima, a YUGE prehistoric Oyster that can grow a whopping 20 inches long. That's almost as long as my forearm! 

 

So how much do you guys know about these behemoths? 

[Ludwigia]

That sure is a big one. Too bad the photo's so small I know nussing.

[Al Dente]

Good luck, they should be easy to spot. We have them here in North Carolina but are younger. Ours are Oligocene. They occasionally wash up on the beaches on the northern part of Topsail Island in NC.

[Kane]

Best of luck - I'm sure you'll bag a bunch. These oysters are quite interesting as they do provide insights into the slight cooling event on the southeast coast during the late Eocene. 

 

Perhaps a bit heavy reading, but this Masters thesis by M.B. Jarrett is interesting. He was able to section a number of these from Griffin Landing, GA along the same river you'll be at, subject them to an oxygen isotope analysis that has implications on the temperature of those shallow marine environments where these big ones thrived. https://getd.libs.uga.edu/pdfs/jarrett_matt_b_200908_ms.pdf

[RJB]

Thats one dang big oyster!!! 

 

RB

[FossilDAWG]

Some of the oysters at Griffin Landing have species of barnacles that are found only in the McBean Formation; keep an eye out as they should occur at Shell Bluff as well.  I have only collected at Griffin Landing, but there vertebrate material is very very scarce.  Also look around some at Shell Bluff as I recall there is another layer (don't remember if it is above or below the oyster bed) with a more diverse shell fauna.

 

Don

[Tidgy's Dad]

Good luck! 

Splendid oysters.

Even with my eyesight I may be able to spot one of those. 

[Max-fossils]

[MeargleSchmeargl]

Update: Went to Shell Bluff, and found out the place is private property, a gated community. So Uncle Frank and I decided the best option was postponement until we could figure out who on Earth the landowners are, and ask permission to hunt the bluff. We did, however visit Georgia Southern University's natural history museum, and saw the fabled Crassostrea Gigantissima oysters, a cluster of 5 in one piece (no images, as phone was DED at this point). All of them were almost as big as my arm. Giant is an understatement!

[Beau65]

Found on N. Topsail Beach 2/19.  Ruler pictured is 30cm, so this fossil is slightly longer.  Assume it is CG but would like comments including approx. epoch: Eocene?

[Philip T.]

On 4/2/2018 at 6:18 AM, Al Dente said:

Good luck, they should be easy to spot. We have them here in North Carolina but are younger. Ours are Oligocene. They occasionally wash up on the beaches on the northern part of Topsail Island in NC.

Do I assume correctly that the Topsail Island ones are the same species (Crassostrea gigantissima)?

Thanks!

Aloha,

-pt

[Al Dente]

1 hour ago, Philip T. said:

Do I assume correctly that the Topsail Island ones are the same species (Crassostrea gigantissima)?

Thanks!

Aloha,

-pt

Yes. You can find them in Oligocene quarries too. I think they are now called Striostrea gigantissima. Here's one from a quarry.