DIEIVION'ELIX (Neo-Lat., from Gk. &atticer, daimon, demon -f- 04, helix, spiral). A prob lematic fossil found in great numbers in the sandstones of the Loup Fork Tertiary of north western Nebraska and adjacent portions of Wyo ming. and known to the ranch men of the vicinity by the name of 'Devil's cork-screws: The fossil ranges through a thickness of about 250 feet of sandstones and varies in form from delicate fibrous structures in the lowermost beds, through cylindrical, spherical, cake-like, and irregularly twisted forms in successively higher horizons, till in the uppermost beds it assumes the form of a vertical left- or right-handed spiral spring, 2 to 10 feet high, with or without a central axis, and usually with a more or less curved fusiform or cylindrical 'trunk,' 3 to 20 feet long, that rises obliquely from the base of the spiral. The fibrous forms penetrate the sandstone and are also found traversing the surfaces of skulls and bones of fossil mammals entombed in the same beds. The spiral screws are wonderfully
regular in their proportions, both as to the angle of pitch of the spiral and a-s to the increase in diameter of the same from bottom to top. The whole mass of the fossil consists of an aggrega tion of twisted plant-fibres, which on examina tion with a microscope prove to have a simple cellular structure like that of parenchyma tissue. This cellular struct-u•e has been found in all parts' of the fossil, and clearly indicates its vegetable nature. The beds' in which the Memo nelix is found are of lacustrine origin, and it is possible that the fossil is of algal affinity. Prof. E. H. Barbour, the discoverer of Dnmonelix, has described it fully in a paper on the "Nature, Structure, and Phylogeny of armonelix," in the Bulletin of the Geological Society of America, vol. viii. (Rochester, l S97).