I've cropped your scan, enlarged it, removed the "S" and rotated the image.

I see an owl. The owl is facing to the right, and the extension on the "U" is actually the owl's feet. Mostly hidden by the "S" is the outline of the owl's right wing.

The owl's head is facing right, towards us and I can see the "vee" shape of an owl's beak and the two slits for eyes.

Am I alone on this? The fish suggestion is more obscure, but the owl stands out.

Jim