ID Texas Nautilus Type Fossil

[diadigger]

My son found these 2 fossils while we were metal detecting an old home site. They were in the creek bed. I know they have a name, but can't remember what they are called. Anyone know? Thanks!!

(I posted them in Today's Finds, along with our coins)

 

Amazon Forum Fav 👍

Family Maps of Hinds County, Mississippi, Deluxe Edition - Grab it through Amazon!

[diadigger]

I received a reply in (Todays Finds section) telling me that they are "AMMONITES". 300 to 400 million years old.

 

[Charlie P. (NY)]

http://www.paleodirect.com/ammortho.htm

I think they "made it" for longer than 100 million years. 400 million to 65 million years ago, give or take.

 

[fossis]

My son found these 2 fossils while we were metal detecting an old home site. They were in the creek bed. I know they have a name, but can't remember what they are called. Anyone know? Thanks!!

(I posted them in Today's Finds, along with our coins)

Hello diadigger, nice finds your son made, we find these
along the OK & TX border.

Fossis.............

 

[diadigger]

Thanks! We are in north Texas. Being from Calif, we don't see this sort of stuff.....only gold nuggets!

 

[kraken]

It looks like Mortoniceras equidistans, Lower Cretaceous. By any chance do you live in Grayson Co., Texas?

 

[Nashoba]

Kinda curious as to their size here??

~Nash~

 

[irbaddadjoe]

Hey diadigger. I will trade you these for your gold nuggets.

 

[Dosamigos]

Nice.
I'm also in the North Texas area and ammonites are abundant where I live. Most dont seem to have near the definition as those pictured. Found one like that, that was flawless. I've placed it on the mantel of my fireplace.

 

[gallileo60]

Awesome finds...I have picked up a few in the Hill Country as well.....Did not find any on the last trip tho.......

 

[LanceHall]

Mortoniceras for sure, but not 100% about equidistans. Equidstans has three equal distant nodes (bumps) across the ribs and I can't really see those unless very weak. The other one with nodes (spikes) near the center maybe called "Drakeoceras". These dang things have went through so many name changes and reassignments it almost takes a degree to ID them properly.

They are just a little more than 100 myo.

I bet they came from the Duck Creek/Fort Worth formation. I have some geo maps digitised here: http://www.geocities.com/lancelhall/fossils/maps.htm

Ammonites and nautiluses diverged at least 400 mya. The obvious differences are the coiling of the shell and the position of the internal blood tube (siphuncle). With some of those Mortoniceras you can actually find the siphuncle preserved as a black tube running around the edge of the fossil.