Adopted 6 October 1936 on Geological Survey sheet 407A, Ashcroft, as labelled on Geological Survey sheet 557, Kamloops, 1895.
Source: BC place name cards, or correspondence to/from BC's Chief Geographer or BC Geographical Names Office
"Trachyte: a usually light-colored volcanic rock consisting chiefly of potash feldspar; from the Greek word trachys, meaning rough."
"Trachytic: of or relating to a texture of igneous rocks in which lath-shaped feldspar crystals are in almost parallel lines."
Source: Merriam-Webster OnLine (www.m-w.com), or Webster's New International Dictionary, 2nd edition, unabridged, 1951