Volume XVII oo Number 3 
THE 
Journal of Geology 
A Semi-Quarterly Magazine of Geology and 
Related Sciences 
APRIL-MAY, 19009 
EDITORS 
T. C. CHAMBERLIN, zz General Charge 
R. D. SALISBURY R. A. F. PENROSE 
Geographic Geology Economic Geology 
J. P. IDDINGS Gon VANGEISE 
Petrology Structural Geology 
STUART WELLER W. H. HOLMES 
Paleontologic Geology Anthropic Geology 
S. W. WILLISTON, Vertebrate. Paleontology 
a ASSOCIATE EDITORS 
SIR ARCHIBALD GEIKIE Ga ks ene BR 
Great Britain s Washington, D. C. 
H. ROSENBUSCH H. S. WILLIAMS 
. Germany Cornell University 
CHARLES. BARROIS GD. WALGOim 
France : Smithsonian Institution 
ALBRECHT PENCK J...C. BRANNER 
Germany _ Stanford University 
HANS REUSCH We ober GUAR 
Norway Johns Hopkins University 
GERARD DE GEER O. A. DERBY 
Sweden Brazil 
The Wenz DAWA) WILLIAM H. HOBBS 
Australia University of Michigan 
The Aniversity of Chicago Press 
CHICAGO AND NEW YORE 
Witiraw Westey & Son, LONDON 
