Eames Shell (Evans, Zenith, Herman Miller??)  

How about some photos?

Photos added thanks

Are there any other markings on the underside of the chair?

The larger rubber shock mounts on the underside lead me to believe that your chair is 2nd generation, post-Zenith, production (around 1953-1957, if I recall correctly). I do not believe that 2nd gens were stamped with a maker's mark and I don't see any embossed mark in your photos.

There's plenty of archived info on here if you want to do more research. Nice chair! Cheers.