striation (stri-a'-tion). (a) stria. (b) One of multiple scratches or minute lines, generally parallel, inscribed on a rock surface by a geologic agent, e.g., glaciers ( glacial striation ), streams (cf: drag mark ), or faulting (cf: slickenside ). Syn: scratch. (c) The condition of being striated; the disposition of striations. Adj: striated; striate.

linkage [geomorph] (link'-age). The joining at a sharp angle of two branches of a mountain range, as shown in plan view. Cf: deflection [geomorph].

acute bisectrix (a-cute'). In optically biaxial minerals, the direction bisecting the acute angle between optic axes. Cf: obtuse bisectrix.

confining bed (con-fin'-ing). A body of relatively impermeable or distinctly less permeable material stratigraphically adjacent to one or more aquifers. Cf: aquitard; aquifuge; aquiclude. Syn: confining unit .

tracheophyte (tra'-che-o-phyte''). A vascular plant; includes all plants that have a vascular system, i.e. xylem and phloem (Swartz, 1971, p.477).