We found the stone is from the Lower Cretaceous period, 100 to 140 million years ago (please see previous post "Old Wildlife"). The snail-like impressions are "turritella" which, amazingly enough, were snails! There are many types of turritella, so we don't know which these are.
Thank you so much, Jane. I appreciate your trouble. This close-up of the rock looks even better, I can make out several different things. Finding a name for that periwinkle-like shellfish is fantastic. So interesting, this. Cheers.
