EOCENE (cos, dawn, and kainos, recent), a term introduced by Lyell to characterize the lower tertiary strata, from the idea that the fossil shells of that period contain an extremely small proportion (3+ per cent.) of living species. He accordingly looks upon these beds as indicating the dawn of the existing state of the testaceous fauna—no recent species having been detected in the older rocks. The gradual approximation of the living inhabitants of the globe to the present forms is the chief characteristic of the E. and newer deposits. The E. beds rest on the chalk. Like the other tertiary strata, these deposits occupy small and detached areas when compared with the older meas ures. It is not difficult to determine the relative position of primary or secondary strata, because of the great extent of particular beds, being frequently continuous over extensive districts. But tertiary deposits are more isolated, and occur in smaller and more detached patches; hence it is difficult to determine the contemporaneity of the sections of the various periods, occurring as they do in different isolated localities. Their relations must be determined from the petralogical structure of the beds, which, however, is very inconstant, or from the more satisfactory evidence derived from their fossiliferous contents.
In the following table are given the generally received divisions of this period, with the maximum thickness (in English ft.) of the English strata, and the French and Bel
gian equivalent beds: 0, 175 I Calcaire lacustre sup6rieur, and Grts de Fontaine- {. Hampstead series bleau.—Rupelien. 2 Gypseous series of Montmartre, Calcaire lacustre W • Bembridge series 115 i moyenne, and Calcaire siliceux.—Tongrien .
g4 3. Osborne series { 701 i des a 4. Headon series 182i( J Sables moyennes, Calcaire grossier, and Zits co 5. Bagshot series i i !e]ire and Bruxellien.
6. London clay series 480 Wanting in France .—Ypresien .
7. Plastic clay series 160 argile plastique et lignite.—Landenlen sulfirieur.
8. Thanet sands series 90 Wanting In France.—Landenien inferieur.
Total thickness 2542 feet.
EON, or EUDO DE STELLA, a religious fanatic of Bretagne in the 12th c., who claimed to be the final judge of mankind. He opposed the hierarchy of the church, and taught that the only true baptism was the baptism of the Holy Ghost given by the laying on of hands. He was believed to have miraculous power, and gained many followers. He was opposed publicly by the cardinal-legate Albericus, and in a book by archbishop Hugo of Rouen. Some of his disciples were burned to death for their heresy. In 1148 he was captured, with some of his leading adherents, and tried before the synod at Rheims, but escaped execution because thought insane. After his death his sect soon died out.