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rudaceous

British  
/ ruːˈdeɪʃəs /

adjective

  1. (of conglomerate, breccia, and similar rocks) composed of coarse-grained material Compare arenaceous argillaceous

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Etymology

Origin of rudaceous

C20: from Latin rudis coarse, rough + -aceous