iat 
MOLUMEAXX: acs , NUMBER 4 
THE 
JOURNAL or GEOLOGY 
A SEMI- QUARTERLY 
EDITED BY 
THOMAS C. CHAMBERLIN AND ROLLIN D. SALISBURY 
With the Active Collaboration of 
SAMUEL W. WILLISTON ALBERT JOHANNSEN WILLIAM H. EMMONS . 
Vertebrate Paleontology Petrology Economic Geology 
STUART WELLER WALLACE W. ATWOOD ~- ROLLIN, T. CHAMBERLIN 
Invertebrate Paleontology Physiography Dynamic Geology 
ASSOCIATE EDITORS 
SIR ARCHIBALD GEIKIE, Great Britain GROVE K. GILBERT, Washington, D.C. 
HEINRICH ROSENBUSCH, Germany CHARLES D. WALCOTT, Smithsonian Institution 
‘THEODOR N. TSCHERNYSCHEW, Russia HENRY S. WILLIAMS, Cornell University 
CHARLES BARROIS, France JOSEPH P.IDDINGS, Washington, D.C. 
ALBRECHT PENCK, Germany JOHN C, BRANNER, Leland Stanford Junior University 
HANS REUSCH, Norway RICHARD A. F. PENROSE, Jr., Philadelphia, Pa. 
GERARD DEGEER, Sweden WILLIAM B. CLARK, Johns Hopkins University 
ORVILLE A. DERBY, Brazil : WILLIAM H. HOBBS, University of Michigan © 
T. W. EDGEWORTH DAVID, Australia FRANK D. ADAMS, McGill University. 
BAILEY WILLIS, Argentine Republic CHARLES K. LEITH, University of Wisconsin 
MAY-JUNE 1912 
CONTENTS 
DYNAMIC RELATIONS AND TERMINOLOGY OF STRATIGRAPHIC CONFORMITY 
AND UNCONFORMITY. - Be Bae oe eters pedals Shae es W. QO: CrosBy 289 
THE VALUE OF CERTAIN CRITERIA FOR THE DETERMINATION OF THE ORIGIN 
OF FOLIATED CRYSTALLINE ROCKS. II dale - - J. D. TRUEMAN 300 
AN OCCURRENCE OF COAL WHICH BEARS EVIDENCE OF UNUSUAL CONDITIONS 
ACCOMPANYING TRS DE POSIEDION) oye - - - JEssE E. HypDE 316 
_ THE GEOLOGY OF SOUTH MOUNTAIN AT THE JUNCTION OF BERKS, LEBANON, 
AND LANCASTER COUNTIES, PENNSYLVANIA - - = wer dln NGM ATON «23m 
_ MURAENOSAURUS? REEDII, SP. NOV. AND TRICLEIDUS? LARAMIENSIS KNIGHT, 
AMERICAN JURASSIC PLESIOSAURS Sy ie ey - Maurice G. MEHL 344 
METAMORPHIC STUDIES - - - - - - C. K. Leira anp W. J. MEAD 353 
PETROLOGICAL ABSTRACTS AND REVIEWS - hi tivur = Avsinectauah tia cele iredia, = -. 362 
ee a ee a ee ee 
RECENT + Cosel dive - - - - = = = : ui 2 2 2 - 380 
Che Anib ersity of Chicago yo 
CHICAGO, ILLINOIS 
AGENTS: 
THE CAMBRIDGE UNIVERSITY PRESS, Lonpon anp EpINBuRGH 
WILLIAM WESLEY & SON, Lonpon 
TH. STAUFFER, LeEtrzic 
THE MARUZEN-KABUSHIKI-KAISHA, Toxyo, Osaka, Kyoro 
