I need some help identifying these two specimens. I have collected and cleaned at least 50 of each specimen. The majority of them were found in the upper Glen Rose formation of Edwards, Real and Uvalde County Texas. I've been told that they are both called "deer hearts," even though they look different. Given the different physical characteristics (deep lines on the right specimen and "ears" on the left specimen), I'm guessing that they are different species. My best guess is either Arctica roe