Thank you so much Diver Down
We have a area two miles in radius of hills that are made of these shells and petrified clams;etc.
I better get out and do some more walking.
It's Carcharodon megalodon . . . OR . . . it's Carcharocles megalodon, depending on which evolutionary path you believe this shark followed.
Some taxonomists still hold to a relationship between C. megalodon and the modern great white shark (Carcharodon carcharias); but, more shark taxonomists now believe that C. megalodon was not related to the great white. Most believe that C. megalodon was the end of an evolutionary line (Otodontidae), and that the modern great white evolved from a lamnid (makos) shark.