Coenholectypus Echie and a Sponge, perhaps? Central Texas

[JamieLynn]

Pretty sure this is coenholectypus but am stumped on the species. It's bigger than the planatus I have found previously and from the underside you can definitely see the more pentagonal shape like a transpecosensis (can you tell I've been looking in my Field Guide to Texas Fossils?). I found it in Salado Creek in Bell County, do not know what formation. Obviously very water worn, and it is weirdly wonky, (why would it be so dismorphic?) but it sure is a big one! I was rather excited to find this one! 

 

Also found this- it looks like a sponge? (Pictures in comments) But I can't really find any fossil sponge from Cretaceous era that look similar. Could just be limestone. I hope it's a sponge. Any help is appreciated! 

[JamieLynn]

Sponge?

[JamieLynn]

Any one have any ideas? Nobody? Bueller?

[ynot]

@Uncle Siphuncle

[Uncle Siphuncle]

1 hour ago, ynot said:

@Uncle Siphuncle

Too worn for me to help.

[JamieLynn]

thanks you anyways. 

[abyssunder]

The second specimen might be a sponge, now having a silica content.

[JohnJ]

As Dan mentioned, the echinoid is extremely eroded.  Still, the pentagonal opening in the first photo and it's relatively large size both suggest a Phymosoma or Tetragramma species.  

[JamieLynn]

that's what I was hoping!!  I didn't know because all the raised bumps were worn off, since you can only see the indentions made me think it was Holectypus. 

[ricardo]

36 minutes ago, JamieLynn said:

made me think it was Holectypus

Where is the periproct? I can't see it like in Holectypus or Coenholectypus periproct locus and shape.

[JamieLynn]

I was just going by lack of ornamentation. I just learned what the periproct is.  But I am going with JohnJ's post that it is rather Phymosoma or Tetragramma