This item is referred to colloquially as Cornucopia, and its identity has not been resolved. The horns vary in length and strength, and may occur in arrays arising from a sheet of material. The structured appear melanised and probably chitinised. Differential interference contrast. They are not uncommon. Material from Nymph Creek and Nymph Lake, thermal sites within Yellowstone Park, photograph by Kathy Sheehan and David Patterson.