Volume XVII : Number 6 
THE 
Journal of Geology 
A Semi-Quarterly Magazine of Geology and 
Related Sciences 
SEPTEMBER-OCTOBER, 17909 
EDITORS 
T. C. CHAMBERLIN, zz General Charge 
Re Dy SALISBURY R. A. F. PENROSE 
Geogruphtc Geology Economic Geology 
J. P. IDDINGS C. R. VAN HISE 
Petrology - Structural Geology 
STUART WELLER W. H. HOLMES 
Paleontologic Geology Anthropic Geology 
S. W. WILLISTON, Vertebrate Paleontology 
ASSOCIATE EDITORS 
a SIR ARCHIBALD GEIKIE O. A. DERBY 
ie Great Britain , Brazil 
as a ROSENBUSCH ,__ ; G. K. GILBERT 
eo Ey Washington, D. C. 
teres BARROIS He S. WILLIAMS 
France Cornell University 
"ALBRECHT PENCK a °C. D. WALEOTT 
: Germany e Smithsonian Institution 
_ HANS REUSCH J.-C. BRANNER 
Norway Stanford University 
GERARD DE GEER W. B. CLARK 
Sweden ; Johns Hopkins University 
Tr, We Ee DA VLD as, WILLIAM H. HOBBS : 
Australia University of Michigan 
DES iS C PRINS CLUE W), Wccessze 
The Aniversity of Chicago Press 
CHICAGO AND NEW YORE 
Wittiam Westry & Son, Lonpon 
