Found with Gryphaea ID Help

[pendrak]

Hi- I found this today at Lake Benbrook, Tarrant County Texas. I was looking for newly exposed large ammonoids. I believe that it is possibly from the Woodbine formation because I also found some nice Gryphaea- looks like maybe Parasmilia but it also looks like has a shell- 3.5 inches x 1 inch.  Your expert help appreciated- Thanks-

 

[DPS Ammonite]

Your bivalve on the right is a Texigryphea. 

The cone shaped fossil probably is a rudist bivalve, a rare find for the area.

 

Maybe a local can ID the rudist.

@erose @JohnJ @Uncle Siphuncle @FranzBernhard

 

The Goodland Formation at Benbrook has Texigryphea and ammonites. 

[abyssunder]

Hard to say if it's a solitary scleractinian coral or a rudist.

[JohnJ]

I think that's a solitary coral.  Erich @erose would know better which one.

 

[DPS Ammonite]

Here are a couple of rudists that look like horn corals that died out in the paleozoic. They both have the distinctive "Coolie Hat" shaped top shell. Note that the Benbrook fossil, also has a slanted "Coolie Hat" top.

 

First photo is from: http://www.sedgwickmuseum.org/index.php?page=coastal-plains

 

The second one is from the Smithsonian Museum.

 

 

[erose]

3 hours ago, JohnJ said:

I think that's a solitary coral.  Erich @erose would know better which one.

 

Think DPS Ammo is on to this with rudist. There are some solitary corals in the Cretaceous, but never seen anything that big. Certainly not Parasmilia. 

 

Being a rudist there should have been many of them. If you can find others that are broken and show a cross section that could help. Coral would show septa filling the cup and a rudist would have a central hollow chamber surrounded by smaller vessicles.

 

PS If it is a rudist it is a very nice specimen.

[pendrak]

Thank You for the help.

 

[abyssunder]

Can you take a picture straight from the top?
As it was said, a cross section (1-1.5 cm below the supposed comissure) would be on help.

[pendrak]

Here are two more pictures. It was on top of the ground and not in the limestone so it washed down from a higher elevation.

[Uncle Siphuncle]

I agree that if rudist, you’d likely find more.  Keep in mind that at super well known sites like Benbrook, collectors often dump or inadvertently drop finds from other sites, and Penn sites an hour +/- west give up lots of horn corals. Site “cross pollination” is most likely at high use sites.