echolocation— A system bats use to locate flying prey by monitoring the patterns of high-frequency sound waves emitted by the bat.
ecofacts— Natural materials (e.g., stones, bones, seeds) used or transported but not physically modified by humans.
ecosystem— The system of ecological relationships on which a particular organism or group of organisms depends for existence. It may include such factors as weather, water, food, and predators.
edaphic— Pertaining to ecologic formations or effects resulting from or influenced by local conditions of the soil or substrate.
ejecta (volcanic tuff)— Material thrown out from a volcano.
elytra— Hardened forewings of a beetle, covering the membranous hindwings.
emplacement— A term used to refer to the process of intrusion (e.g., emplacement of granitic rocks).
en echelon— In apparent formation or in rows oriented in about the same direction.
endangered— As defined in the Endangered Species Act of 1973, refers to any species or subspecies in danger of extinction throughout all or a significant portion of its range.
endemic— Restricted to a locality or region.
epidote— A green mineral, Ca2 (Al, Fe+3 )3 Si3 O12 (OH). Occurs in low-grade metamorphic rocks.
epiphenomena— A superficial or secondary phenomenon accompanying another and caused by it.
equitant— Two-ranked leaves, flattened, with edges toward and away from the axis; astride, as the leaves of an Iris ; overlapping or "horseback" leaves.
erratic— A rock fragment transported by a glacier and deposited at some distance from where it was derived; generally, resting on bedrock of different lithology.
escarpment— A long, more or less continuous cliff or relatively steep slope produced by erosion or faulting.
ethnographic— Pertaining to aboriginal lifeways observed firsthand rather than reconstructed through archaeology.
exserted— Protruding, as stamens projecting beyond the corolla; not included, i.e., not protruded. (See Fig. 6.1.)