Texas Cretaceous clam

[Tony G.]

Collected this in Plano, Texas when I was a kid back in the early 1980s.  Construction equipment had dug up some limestone and piled it next to the road.  There were a lot of broken Inoceramus shells, this was the only intact fossil that I found.  Looks different than Inoceramus.  Does anyone know what species this would be.  I have never found another like it.  Measures 2 3/8 inches across.  

[DPS Ammonite]

It most likely is a Inocemamid clam. There are many types in the Austin Chalk. Does it have any shell remaining that has the characteristic fibrous calcite prisms that are normal to the shell? 

 

See this paper showing some of the Inoceramids from the Austin south of Dallas.

 

"An integrated study (inoceramid bivalves, ammonites, calcareous nannofossils, planktonic foraminifera, stable carbon isotopes) of the Ten Mile Creek section, Lancaster, Dallas County, north Texas, a candidate Global boundary Stratotype Section and Point for the base of the Santonian Stage" by Gale

 

https://geojournals.pgi.gov.pl/agp/article/view/9781/8317

[Tony G.]

3 hours ago, DPS Ammonite said:

It most likely is a Inocemamid clam. There are many types in the Austin Chalk. Does it have any shell remaining that has the characteristic fibrous calcite prisms that are normal to the shell? 

 

See this paper showing some of the Inoceramids from the Austin south of Dallas.

 

"An integrated study (inoceramid bivalves, ammonites, calcareous nannofossils, planktonic foraminifera, stable carbon isotopes) of the Ten Mile Creek section, Lancaster, Dallas County, north Texas, a candidate Global boundary Stratotype Section and Point for the base of the Santonian Stage" by Gale

 

 

 

https://geojournals.pgi.gov.pl/agp/article/view/9781/8317

This one seems to be only an imprint.  No original shell remains.