Jump to content

Central Texas Echinoids


sharko69

Recommended Posts

Hit a couple of spots yesterday and today trying to find some echinoids. Last night I spent an hour back at a road cut in Salado, TX. I had found a couple of fist sized samples the last time I was there and thought I would give it another shot. Walked for 45 minutes and found nothing. It was starting to get dark so I headed back to the car and found this one 15 feet from the front door as I was about to leave. Also found a partial ammonite?

post-15063-0-76021700-1410488731_thumb.jpg

post-15063-0-27312800-1410488756_thumb.jpg

Link to comment
Share on other sites

Hit a couple of spots yesterday and today trying to find some echinoids. Last night I spent an hour back at a road cut in Salado, TX. I had found a couple of fist sized samples the last time I was there and thought I would give it another shot. Walked for 45 minutes and found nothing. It was starting to get dark so I headed back to the car and found this one 15 feet from the front door as I was about to leave. Also found a partial ammonite?

The large 'fat' urchin is a Macraster species...most likely M. obesus. The "ammonite" is the internal cast of a nautiloid, as evidenced by the long "s" like sutures. The general area of that location is the Georgetown Formation.

The human mind has the ability to believe anything is true.  -  JJ

Link to comment
Share on other sites

This evening I went under the I-35 bridge in Georgetown where the SanGabriel river runs under and found these two.

The first photo is an internal cast of a regular echinoid...maybe a Coenholectypus. The irregular "heart" urchin is probably a Heteraster species. Both are common in the Walnut and Comanche Peak formation in the area.

The human mind has the ability to believe anything is true.  -  JJ

Link to comment
Share on other sites

Thank you so much for the information. So Georgetown formation in Salado? How common is M. Obesus? What are the barnacle looking concretions on the outside? Thanks again.

Link to comment
Share on other sites

Thank you so much for the information. So Georgetown formation in Salado? How common is M. Obesus? What are the barnacle looking concretions on the outside? Thanks again.

Georgetown Formation is part of the Washita Group - mapped as Kgt on the geologic map. The M. obesus can be locally common, but always impressive. Apparently, their tests were solid enough for many oysters and tube worms to use as "home base".

The human mind has the ability to believe anything is true.  -  JJ

Link to comment
Share on other sites

I really appreciate the information. Echinoids are new to me. I happened upon them by chance since I travel to Austin every couple of weeks and now I am on the hunt. Thank you for the information and the link to the map.

Link to comment
Share on other sites

JohnJ knows his echie stuff. Bingo, on the nose on all counts!!

Hard to find the obesus without the extra attached ostrea.

Congrats on that Obesus......great find!

Jess B.

Link to comment
Share on other sites

Thanks. He sure does and I always appreciate everyone's knowledge on this forum. It is amazing. That is the third obesus I have found in this location. Funny thing is I have walked the entire area and both times found all of them within 10 feet of where I parked.

Link to comment
Share on other sites

It will be a nice road when they finish it. Doubt I will be around to see it. Until then, thanks Txdot for exposing some fun stuff.

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
  • Recently Browsing   0 members

    • No registered users viewing this page.
×
×
  • Create New...