Unused Mike Roberts card C28580, whose caption we could hardly paraphrase, so we will just let you read it:  “Daimonelix, Devil’s Corkscrews … These two weathered stone corkscrews are actually the fossilized contents (casts) of burrows made by the rodent PALEOCASTOR.”  Digging deeper (sorry!), Wikipedia tells us:  “Palaeocastor is an extinct genus of beavers that lived in the North American Badlands during the late Oligocene period to early Miocene. Palaeocastor was much smaller than modern beavers.”  That’s enough.  Grade: 1