THE UNIVERSITY OF CHICAGO PRESS

CHICAGO, ILLINOIS

Agents

THE CAMBRIDGE UNIVERSITY PRESS LONDON AND EDINBURGH

THE MARUZEN-KABUSHIKI-KAISHA

TOKYO, OSAKA, KYOTO

KARL W. HIERSEMANN

LEIPZIG

THE BAKER & TAYLOR COMPANY

NEW YORK

THE

JOURNAL OF GEOLOGY

A Semi-Quarterly Magazine of Geology and
Related Sciences

EDITORS

THOMAS C. CHAMBERLIN, in General Charge; ROLLIN D. SALISBURY, Geographic Geology;
SAMUEL W. WILLISTON, Vertebrate Paleontology; STUART WELLER, Invertebrate Paleontology;
ALBERT JOHANNSEN, Petrology; WALLACE W. ATWOOD, Physiography; WILLIAM H. EMMONS,
Economic Geology; ROLLIN T. CHAMBERLIN, Dynamic Geology.

ASSOCIATE EDITORS

SIR ARCHIBALD GEIKIE, Great Britain; HEINRICH ROSENBUSCH, Germany; THEOdor N.
TSCHERNYSCHEW, Russia; CHARLES BARROIS, France; ALBRECHT PENCK, Germany; HANS
REUSCH, Norway; GERARD De Geer, Sweden; ORVIlle A. Derby, Brazil; T. W. EDGEWORTH
DAVID, Australia; BAILEY WILLIS, Argentine Republic; Grove K. GilbeRT, Washington, D.C.;
CHARLES D. WALCOTT, Smithsonian Institution; HENRY S. WILLIAMS, Cornell University; JOSEPH
P. IDDINGS, Washington, D.C.; JOHN C. BRANNER, Leland Stanford Junior University;
RICHARD A. F. Penrose, Jr., Philadelphia, Pa.; WILLIAM B. CLARK, Johns Hopkins University;
WILLIAM H. HOBBS, University of Michigan; FRANK D. ADAMS, McGill University; CHARLES
K. LEITH, University of Wisconsin.

VOLUME XXI

JANUARY-DECEMBER, 1913

THE UNIVERSITY OF CHICAGO PRESS
CHICAGO, ILLINOIS