This is quite a large snail: about 2-1/2″ at its widest and 2-1/8″ at its narrowest. As such, it fits comfortably in my hand and, for many years, I carried it in my coat pocket (hence the darkening of the surface by the oil of my hand).
The back tells us less about the animal, but is no less interesting:
I think about the “carapace” of my current home that I crawl into for refuge, and wonder if some future paleontologist will discover it fossilized, complete with furniture (and even me?) in it!