Diluvium. Those accumulations of gravel and loose materials, which, by some geologists, are said to have been produced by the action of a diluvian wave or deluge sweeping over the surface of the earth. Etym., diluvium, deluge.
Dip. When a stratum does not lie horizontally, but is inclined, it is said to dip towards some point of the compass, and the angle it makes with the horizon is called the angle of dip or inclination.
Diptera. An order of insects, comprising those which have only two wings. Etym., δις, dis, double, and πτερον, pteron, wing.
Dolerite. One of the varieties of the Trap-rocks, composed of augite and felspar.
Dolomite. A crystalline limestone, containing magnesia as a constituent part. Named after the French geologist Dolomieu.
Dunes. Low hills of blown sand that skirt the shores of Holland, England, Spain, and other countries.
Earth's Crust. Such superficial parts of our planet as are accessible to human observation.
Eopyrosis. A Greek term for a destruction by fire.
Elytra. The wing-sheaths, or upper crustaceous membranes, which form the superior wings in the tribe of beetles. They cover the body, and protect the true membranous wing. Etym., ελυτρον, elytron, a sheath.
Endogens. A class of flowering plants, whose stems present no distinction of wood, pith, and bark. The wood is disposed in bundles, placed nearer the axis than those of the previous year, as in palm trunks. This class answers to the Monocotyledones of Jussieu. Etym., ενδον, endon, within, and γενεσις, genesis, increase.