gsminmag Mineralogical Magazine Mineralogical Magazine 0026-461X Mineralogical Society 10.1180/minmag.1933.023.143.02 On a New Barium Plagioclase Felspar Nockolds S. R.B.Sc., Ph.D. Geology Department, Manchester University, Zies E. G. Geophysical Laboratory, Carnegie Institution, Washington, U.S.A. 12 1933 23 143 448 457 Copyright © 1933, The Mineralogical Society 1933