Ammos of Texas Part 2 (Cracking out a new to me species!)

[JamieLynn]

I suceeded in busting out an ammonite from a chunk of limestone!  A first for me! Not 100% sure on the species, so if you have a thought on ID, I'd appreciate it. I thought it was Mortoniceras, but it doesn't have the "keel" on the outside (venter?) that they usually do.  I THINK it's a Sharpeiceras mexicanum. which are from the Buda formation which I think this might be. It also might be a Acomposocereas inconstans, because Eagle Ford is right near this area too. It was in Onion Creek in Central Texas, a new spot I'd not been to.

 

I knew ammonites had been found there so was hoping to find a few chunks (or a whole one!) but didn't really think I would, since others have hunted there recently. Found lots of Ostrea carinatums and a nice little very worn Leptomaria. But the find was this big hunk of limestone slightly less than a quarter of a smallish ammonite but with what looked like a weathering crack line that I thought maybe I could break it out!.  I decided to leave it if I found a good quality specimen and take it if I didn't. And I didn't. SO I hauled an aprox 25 lb rock up out of the creek into my car. FORTUNATELY at this low water crossing, there was a cement staircase! So no scrambling up an embankment, at least! 

 

Got it home and decided to try my hand at chiseling it out. I've not done this before, preferring to find things loose but hey, you got to try sometime. This one looked to be an easy bust out because of the existing crack lines. Well, it was and it wasn't. It took me a good while of chiseling to get it to crack along the line, but it did and I was rewarded!  Here is the rock with the ammo (right after I cracked it off) so you can see what it looked like pre hammering: 

 

 

Chiseled off a little more and got a nice little ammonite! 

 

then I tried a little more....and broke it.  Ah well. I was hoping for a nice full ammonite, but got a good 3/4 one instead. I am still happy with it! 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

[Mark Kmiecik]

That's a nice one. Congrats.

[facehugger]

Hey, that's pretty good!

[JamieLynn]

thanks!! I was too scared I was going to break it into little bits if I worked on it anymore, so there it is....still somewhat in situ.

[Fossildude19]

I like the natural look.  

Nice ammonite!

[Uncle Siphuncle]

Are you sure this isn't Austin Chalk?

[JamieLynn]

30 minutes ago, Uncle Siphuncle said:

Are you sure this isn't Austin Chalk?

 

No I am not. In fact, when I look at the geology map of where I was, it does have an Austin Chalk section righ near there which could have washed down. What are you thinking it might be?

 

[Monica]

Beautiful ammonite - congrats on wielding the hammer/chisel successfully!!! 

[Uncle Siphuncle]

Not sure off top of the head, Akers not in front of me.  But you might compare with Behavites and Submortoniceras for fun, looking for a match with those prominent ventral tubercles.  Have a look at Menabites too.  Ribs and tubercles should get you in the ballpark, but ultimately a close look at sutures proves most diagnostic, if preserved.

[JamieLynn]

When I look at pics in the HGMS books, it does not give many pics of the venter and when I look online to try to find pics, all of those seem to have a strong keel, so Hmmmmmmmm......