Have I Just Found My First Clipped Penny

I think you figured it out. But on Photoshop I placed the original image, then used the canvas feature to make a 4000 Pixel square around the image. Then I make a huge circle around the curve of the edge of the coin. (Took several times to get the right size. I changed the lower canvas color to red, the moved the circle evenly the same amount just beyond the circle line. Then slid the circle over enough make the arc that you see on my image. Then cropped the image and saw, that the area in question was not in line the edge of the coin. That is how I created the curved ark. (Something new to me)

coop, you usually do get to the bottom of things
The answer was in the Fifth and Sixth pictures.