a 
/ 
si THE NH 
\CROLOGIGAL MAGAZINE 
Monthly Fournal of Geology. 
WITH WHICH IS INCORPORATED 
MIB ~~ (GrlONL OG lGs ik 
FOUNDED IN 1864 BY THE LATE Dr. HENRY WOODWARD, F.R.S. 
EDITED BY 
R. H. RASTALL, Sc.D., M.Ins?.M.M., 
UNIVERSITY LECTURER IN ECONOMIC GEOLOGY, CAMBRIDGE, 
ASSISTED BY 
PROFESSOR J. W. GREGORY, D.Sc., F.R.S. 
F. H. HATCH, PH.D., M.Inst.M.M. 
PROFESSOR J. E. MARR, Sc.D., F.R.S. 
Sir JHTHRO J. H. THALL, Sc.D., LL.D., F.R.S. 
PROFESSOR W. W. WATTS, Sc.D., LL.D., M.Sc., F.R.S. 
HENRY WOODS, M.A., F.R.S. 
ARTHUR SMITH WOODWARD, LL.D., F.R.S. 
VOL. LVIII OF WHOLE SERIES. 
ee 
JANUARY—DECEMBER, 1921. eter 
ig Oya OGM hay ~ 
, fic > 
CH2 G7 723 015 
I a cow 
LONDON: SE Ghel Must 
DULAU & CO., LTD., 34-86 MARGARET STREET, 
CAVENDISH SQUARE, W.1. 
1921. 
