single crystal diffractometer . An instrument, often automated and computerized, that facilitates the orientation of a single crystal for diffraction of X-rays (or neutrons) by any set of lattice planes, and subsequent measurement of the intensity of the diffracted beam.
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ventral valve . The pedicle valve of a brachiopod.
basement fold . An obsolete term for a compressional structure (fold or thrust) that formed within a continent and affected the entire thickness of the continental crust. This obsolete term is the English translation of Argand's plis de fond.
mictite (mic'-tite). Coarsely composite rock formed as the result of contamination of a magma, by the incorporation and partial or complete assimilation of country-rock fragments, under conditions of relatively low temperature and probably at relatively high levels in the crust (Dietrich and Mehnert, 1961). Rarely used.
median lamina . In many stenolaemate bryozoans, the erect median colony wall from which zooids grow in two back-to-back layers to form bifoliate colonies. Syn: mesotheca.
frost creep . Soil creep resulting from frost action (Kerr, 1881).
saltierra (sal-ti-er'-ra). A deposit of salt left by evaporation of a shallow, inland lake. Archaic. Etymol: Spanish, "salt earth".
hydrogenesis (hy-dro-gen'-e-sis). The natural condensation of moisture in the air spaces of surficial soil or rock material.
chute [hydraul] . An inclined water course, either natural or artificial.
filter feeder . An animal that obtains its food by removing particulate organic matter from water that passes through a part of its body used as a filter; e.g., bryozoans, barnacles, bivalves. Cf: suspension feeder.