Entomostraca. Cuvier's second section of Crustacea; so called from their relationship to insects. Etym., εντομα, entoma, insects.
Eocene. A name given to the lowest division of the tertiary strata, containing an extremely small percentage of living species amongst its fossil shells, which indicate the first commencement or dawn of the existing state of the animate creation. Etym., ηως, eos, aurora or the dawn, and καινος, kainos, recent.
Escarpment. The abrupt face of a ridge of high land. Etym., escarper, French, to cut steep.
Estuaries. Inlets of the land, which are entered both by rivers and the tides of the sea. Thus we have the estuaries of the Thames, Severn, Tay, &c. Etym., æstus, the tide.
Exogens. A class of flowering plants whose stems have bark, wood, and pith. The bark is increased by layers deposited within the previously formed layers and the wood of layers or rings placed outside of those of the previous year. This class answers to the Dicotyledones of Jussieu, and includes all common English trees except pines, &c. (See Gymnogens.) Etym., εξο, exo, outside, γενεσις, genesis, increase.
Experimentum Crucis. A decisive experiment, so called, because, like a cross or direction-post, it directs men to true knowledge; or, as some explain it, because it is a kind of torture whereby the nature of the thing is extorted, as it were, by violence.
Exuviæ. Properly speaking, the transient parts of certain animals which they put off or lay down to assume new ones, as serpents and caterpillars shift their skins; but in geology it refers not only to the cast-off coverings of animals, but to fossil shells and other remains which animals have left in the strata of the earth. Etym., exuere, to put off or divest.
Faluns. A French provincial name for some tertiary strata abounding in shells in Touraine, which resemble in lithological characters the "Crag" of Norfolk and Suffolk.
Fault, in the language of miners, is the sudden interruption of the continuity of strata in the same plane, accompanied Fig. 99.
