inadunate (in-ad'-u-nate). Any crinoid belonging to the subclass Inadunata, characterized by firmly jointed calyx plates, a mouth concealed by the tegmen, and arms that are free above the radials. Range, Ordovician to Triassic.
GeoWord of the Day
The GeoWord of the Day is a free service of the American Geosciences Institute. All of the terms and definitions are from the Glossary of Geology, 5th Edition Revised.
range finder . A tachymeter designed for finding the distance from a single point of observation to other points at which no instruments are placed. It uses the parallax principle, and is usually constructed to give a rapid mechanical solution of a triangle having the target at its apex and the range finder at one corner of its base. See also: telemeter.
pyrometry (py-rom'-e-try). The measurement of high temperatures by electrical or optical means, using a pyrometer. Its geologic application is to incandescent lavas.
leeward (lee'-ward). adj. Said of the side or slope (as of a hill or prominent rock) sheltered or located away from the wind; downwind. n. The lee side, or the lee direction. Ant: windward.
sheeted dikes . A swarm of parallel or subparallel igneous dikes so closely spaced that little or no intervening wall rock is preserved.
pygidium (py-gid'-i-um). A caudal structure or terminal body region of various invertebrates; esp. the posterior part or tail piece of an exoskeleton of a trilobite, consisting of several fused segments. Pl: pygidia. Adj: pygidial. Cf: abdomen.
Zemorrian (Ze-mor'-ian). Pacific Coast marine stage: lowermost Miocene (below Saucesian).
bolson plain . A broad, intermontane plain in the central part of a bolson or semibolson, composed of deep alluvial accumulations washed into the basin from the surrounding mountains.
hydrodolomite (hy-dro-do'-lo-mite). A mixture of hydromagnesite and calcite.
dynamic denudation . A concept of landscape and regolith evolution combining elements of several basic geomorphic and pedologic theories. A key element is the idea that denudation occurs along three surfaces: the land surface itself, the bedrock weathering front, and an intermediate surface associated with textural contrasts which promote subsurface lateral mass fluxes (Johnson, 1993).
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