![Scallop fossil](https://samnoblemuseum.ou.edu/wp-content/uploads/2017/02/Neithea-texana-OU-28307-1.jpg)
![Scallop fossil](https://samnoblemuseum.ou.edu/wp-content/uploads/2017/02/Neithea-texana-OU-28307-1-848x1024.jpg)
Neithea texanaOU 28307; Scallop bivalve; Lower Cretaceous; Fort Worth member, Caddo Formation; Marshall County, Oklahoma; CC BY-NC-ND 4.0
Neithea texana
![Bivalve fossil](https://samnoblemuseum.ou.edu/wp-content/uploads/2017/02/Lima-sp..jpg)
![Bivalve fossil](https://samnoblemuseum.ou.edu/wp-content/uploads/2017/02/Lima-sp.-1024x723.jpg)
Lima mexicanaBivalve; Lower Cretaceous; Fort Worth member, Caddo Formation; Marshall County, Oklahoma; CC BY-NC-ND 4.0
Lima mexicana
![Bivalve fossil](https://samnoblemuseum.ou.edu/wp-content/uploads/2017/02/Tapes-aldamensis-OU39415.jpg)
![Bivalve fossil](https://samnoblemuseum.ou.edu/wp-content/uploads/2017/02/Tapes-aldamensis-OU39415-1024x1000.jpg)
Tapes aldamensisOU 39415; Bivalve; Lower Cretaceous; Goodland Formation; Bryan County, Oklahoma; CC BY-NC-ND 4.0
Tapes aldamensis
![Bivalve fossil](https://samnoblemuseum.ou.edu/wp-content/uploads/2017/02/Cyprimeria-texana.jpg)
![Bivalve fossil](https://samnoblemuseum.ou.edu/wp-content/uploads/2017/02/Cyprimeria-texana-1024x909.jpg)
Cyprimeria texanaBivalve; Lower Cretaceous; Goodland Formation; Marshall County, Oklahoma; CC BY-NC-ND 4.0
Cyprimeria texana
![Bivalve fossil](https://samnoblemuseum.ou.edu/wp-content/uploads/2017/02/Homomya-sp-OU-28306.jpg)
![Bivalve fossil](https://samnoblemuseum.ou.edu/wp-content/uploads/2017/02/Homomya-sp-OU-28306-1024x891.jpg)
Pholadomya sp.Bivalve; Lower Cretaceous; Fort Worth, Caddo Formation; Marshall County, Oklahoma CC BY-NC-ND 4.0
Pholadomya sp.
![Bivalve fossil](https://samnoblemuseum.ou.edu/wp-content/uploads/2017/02/Protocardia-texana-OU-14040.jpg)
![Bivalve fossil](https://samnoblemuseum.ou.edu/wp-content/uploads/2017/02/Protocardia-texana-OU-14040-1024x928.jpg)
Protocardia texanaOU 14040; Bivalve; Lower Cretaceous; Fort Worth member, Caddo Formation; Marshall County, Oklahoma; CC BY-NC-ND 4.0
Protocardia texana
![Bivalve fossil](https://samnoblemuseum.ou.edu/wp-content/uploads/2017/02/Pholadomya-sabae-OU-39405.jpg)
![Bivalve fossil](https://samnoblemuseum.ou.edu/wp-content/uploads/2017/02/Pholadomya-sabae-OU-39405-1024x817.jpg)
Pholadomya sabaeOU 39405; Bivalve; Lower Cretaceous; Kiamichi Formation; Marshall County, Oklahoma; CC BY-NC-ND 4.0
Pholadomya sabae
![Bivalve fossil](https://samnoblemuseum.ou.edu/wp-content/uploads/2017/02/Inocerannas-comanchianus-OU-28291-.jpg)
![Bivalve fossil](https://samnoblemuseum.ou.edu/wp-content/uploads/2017/02/Inocerannas-comanchianus-OU-28291--1024x836.jpg)
Inocerannas comanchianusOU 28291; Bivalve; Lower Cretaceous; Fort Worth, Caddo Formation; Marshall County, Oklahoma; CC BY-NC-ND 4.0
Inocerannas comanchianus
![Bivalve fossil](https://samnoblemuseum.ou.edu/wp-content/uploads/2017/02/Trigonia-emoryi-OU42341.jpg)
![Bivalve fossil](https://samnoblemuseum.ou.edu/wp-content/uploads/2017/02/Trigonia-emoryi-OU42341-1024x898.jpg)
Trigonia emoryiOU 42341; Bivalve; Lower Cretaceous; Duck Creek Member, Caddo Formation; Marshall County, Oklahoma; CC BY-NC-ND 4.0
Trigonia emoryi
![Oyster fossil](https://samnoblemuseum.ou.edu/wp-content/uploads/2017/02/Peilina-quadriplicata-1.jpg)
![Oyster fossil](https://samnoblemuseum.ou.edu/wp-content/uploads/2017/02/Peilina-quadriplicata-1-1024x950.jpg)
Peilina-quadriplicataOyster bivalve; Lower Cretaceous; Denton Formation; Marshall County, Oklahoma; CC BY-NC-ND 4.0
Peilina-quadriplicata
![Oyster fossil](https://samnoblemuseum.ou.edu/wp-content/uploads/2017/02/Texigryphaea-roemeri-OU-14027.jpg)
![Oyster fossil](https://samnoblemuseum.ou.edu/wp-content/uploads/2017/02/Texigryphaea-roemeri-OU-14027-977x1024.jpg)
Texigryphaea roemeriOU 14027; Oyster bivalve; Lower Cretaceous; Grayson Formation; Marshall County, Oklahoma; CC BY-NC-ND 4.0
Texigryphaea roemeri
![Oyster fossil](https://samnoblemuseum.ou.edu/wp-content/uploads/2017/02/Texigryphaea-navia-OU-14038-1.jpg)
![Oyster fossil](https://samnoblemuseum.ou.edu/wp-content/uploads/2017/02/Texigryphaea-navia-OU-14038-1-984x1024.jpg)
Texigryphaea naviaOU 14038; Oyster bivalve; Lower Cretaceous; Kiamichi Formation; Marshall County, Oklahoma; CC BY-NC-ND 4.0
Texigryphaea navia
![Oyster fossil](https://samnoblemuseum.ou.edu/wp-content/uploads/2017/02/Ilmatogyra-arietina-OU13998-1.jpg)
![Oyster fossil](https://samnoblemuseum.ou.edu/wp-content/uploads/2017/02/Ilmatogyra-arietina-OU13998-1-1024x772.jpg)
Ilmatogyra arietinaOU 13998; Oyster bivalve; Lower Cretaceous; Grayson Formation; Marshall County, Oklahoma; CC BY-NC-ND 4.0
Ilmatogyra arietina
![Oyster fossil](https://samnoblemuseum.ou.edu/wp-content/uploads/2017/02/Exogya-costata-OU-37496.jpg)
![Oyster fossil](https://samnoblemuseum.ou.edu/wp-content/uploads/2017/02/Exogya-costata-OU-37496-1024x1016.jpg)
Exogya costataOU 37488; Oyster bivalve; Lower Cretaceous; Grayson Formation; Marshall County, Oklahoma; CC BY-NC-ND 4.0
Exogya costata
![Oyster fossil](https://samnoblemuseum.ou.edu/wp-content/uploads/2017/02/Exogyra-texana-OU-37352.jpg)
![Oyster fossil](https://samnoblemuseum.ou.edu/wp-content/uploads/2017/02/Exogyra-texana-OU-37352-1024x803.jpg)
Exogyra texanaOyster bivalve; Lower Cretaceous; Goodland Formation; Choctaw County, Oklahoma; CC BY-NC-ND 4.0
Exogyra texana
![Oyster fossil](https://samnoblemuseum.ou.edu/wp-content/uploads/2017/02/Lopha-subovata-OU-28301-.jpg)
![Oyster fossil](https://samnoblemuseum.ou.edu/wp-content/uploads/2017/02/Lopha-subovata-OU-28301--1024x774.jpg)
Lopha subovataOU 28301; Oyster bivalve; Lower Cretaceous; Fort Worth, Caddo Formation; Bryan County, Oklahoma; CC BY-NC-ND 4.0
Lopha subovata
![](https://samnoblemuseum.ou.edu/wp-content/uploads/2017/02/Rastellum-Arctostrea-carinatum-OU-28621.jpg)
![](https://samnoblemuseum.ou.edu/wp-content/uploads/2017/02/Rastellum-Arctostrea-carinatum-OU-28621-1024x677.jpg)
Rastellum (Arctostrea) carinatumOU 28621; Bivalve, "Denture clam"; Lower Cretaceous; Denton Formation; Marshall County, Oklahoma; CC BY-NC-ND 4.0