A few ammonites I need an ID for

[Perfect Castaway]

 I went on a field trip with the Dallas Paleo Society about three years ago and haven't got around to IDing some finds. After searching through the back issues of The Fossil Record I think it was the Duck Creek formation which is upper and lower Cretaceous. Any help on these would greatly appreciated. 

 

Also, I'm on mobile and trying to resize my images so let me know if these are too small. 

[Tidgy's Dad]

I don't know about the ammonites, but the bottom photo is Inoceramus. 

[Heteromorph]

The first one is of the genus Mortoniceras and the second is of the genus Eopachydiscus.    

 

@BobWill

 

Ammonites - Spring Creek, Cooke Co., TX

[Perfect Castaway]

38 minutes ago, Tidgy's Dad said:

I don't know about the ammonites, but the bottom photo is Inoceramus. 

 

11 minutes ago, Heteromorph said:

The first one is of the genus Mortoniceras and the second is of the genus Eopachydiscus.

 

@BobWill

 

Ammonites - Spring Creek, Cooke Co., TX

 

 

Thank you guys! I admit, I try to do my own detective work on fossils as much as I can but... ammonites just all look the same to me 

[BobWill]

After all the years and all those fossils I still haven't gotten past the genus for this Mortoniceras ammonite. There are eleven different species that can be found in just the Duck Creek Formation where this came from and many more in the Cretaceous sites in Texas. I do know the species of the other one though. It's Eopachydiscus marcianus.

 

I used to think there were two species of Eos at this site because some smaller specimens have a venter that is narrower and comes to a sharper "V" shape while most larger ones are more rounded and much thicker at the venter. I was told they were the same and I later found evidence of this when I found one broken in such a way that I could see the difference in the earlier whorls compared to the outer more rounded whorls.

 

The first time I laid eyes on this site they were like stepping stones in the bedrock with many more eroding out of the banks. Almost 400 collectors and several years later we now have to wait for the kind of rain event that blows big boulders down the creek but those will come and there will be more hunts to follow.

[DPS Ammonite]

The clam is Inoceramus comancheanus.