What is the cool clam from the Cretaceous Mural Limestone from southern Arizona? Trigonia? http://skywalker.cochise.edu/wellerr/fossil/pelecypod/bumpy2.htm
See if anyone can confirm that it is one of these: Quadratotrigonia mearnsi?
https://www.researchgate.net/figure/Trigoniid-bivalves-Mural-Formation-in-Sonora-and-Arizona-Figure-A-B-Buchotrigonia_fig4_249897573
Thanks,
John
,