Category:Graywacke

Gray"wacke`, n. Etym: [G. grauwacke; grau gray + wacke wacke. See Gray, and Wacke, and cf. Grauwacke.] (Geol.)

Defn: A conglomerate or grit rock, consisting of rounded pebbles sand firmly united together.

Note: This term, derved from the grauwacke of German miners, was formerly applied in geology to different grits and slates of the Silurian series; but it is now seldom used.