C. edule or C. glaucum?

[paul monfils]

The first one is certainly C. edule.  I would say the second one, based on external appearance (less flattened ribs with wider spaces between), is most likely C. glaucum.  However there is one typical characteristic of C. glaucum that I don't see on your specimen.  Because the shell is usually quite a bit thinner than that of C. edule, you can usually see the lines of the ribs on the interior of the shell, from the lip all the way to the umbones, while in C. edule you can only see them in a narrow band near the lip.  But in spite of that variation, I would go with C. glaucum.